Aramid fibers composites to innovative sustainable materials for biomedical applications

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Aramid fibers composites to innovative sustainable materials for biomedical applications

6

Elaheh Kowsari1, Vahid Haddadi-Asl2, Farshad Boorboor Ajdari1 and Jafar Hemmat3 1

Department of Chemistry, Amirkabir University of Technology, Tehran, Iran 2Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, Tehran, Iran 3 Biotechnology Department, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran

6.1 POLYMERIZATION AND FABRICATION Generally, aromatic polyamides (APs), a prominent category of condensation polymers with two synthetic strategies, have been commonly defined dealing with polyamide (PA) production, including: 1. Direct polycondensation (DPC) reaction of a diamine and a dicarboxylic acid. 2. Polycondensation reaction via a diamine and an aromatic diacid chloride.

6.1.1 DIRECT POLYCONDENSATION Different suitable condensing materials such as arylsulfonyl chlorides and diphenyl chlorophosphate have been extensively employed in the last few decades for polycondensation (Higashi and Mashimo, 1986, 1985). Although these materials have great potential for use in direct reactions, there is limited research on aliphatic
aromatic and APs. Based on the DPC of hydroxybenzoic acids, diamines, and (aromatic) dicarboxylic acids, the Vilsmeier adduct was employed as a promising candidate for AP synthesis, constructed through the application of pyridine (Py), N, N-dimethylformamide (DMF), and arylsulfonyl chlorides. DPC has been used as a mild-condition strategy for the synthesis of PAs and attributed copolymers (Kowsari et al., 2015a,b; Mallakpour and Kowsari, 2005a,b,c,d,e,f,g,h,i,j, 2006a,b, c,d,e,f,g, 2004a,b). Due to their unique features green solvents of ionic liquids are friendlier environments than the commonly used organic ones for extensive applications in terms of catalysis, energy storage, and materials chemistry (Kowsari, 2011). The DPC Materials for Biomedical Engineering: Biopolymer Fibers. DOI: https://doi.org/10.1016/B978-0-12-816872-1.00006-6 © 2019 Elsevier Inc. All rights reserved.

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reaction was carried out for N, N0 -(4,40 -oxydiphthaloyl)-bis-L-phenylalanine diacid using different types of aromatic diamines (Mallakpour and Kowsari, 2005a,b,c,d, e,f,g,h,i,j) in the presence of ionic liquid. The DPC mechanism in triphenyl phosphite (C18H15O3P) as a condensing function with ionic liquids was performed in the absence of any further materials, for example, Py and LiCl, employed in similar procedures with commonly used solvents. Thus, as catalyst and solvent ionic liquids are high performing agents. Kowsari et al. (2014) worked on the preparation of optically active monomers with two rings of imide groups used for synthesizing of optically active polyionic liquid (OAPIL) and optically active poly(amide-imide)s (OAPAIs). The synthesized materials were used for DPC reaction with different loads of silica nanoparticles. According to in situ DPC, hybrid materials of OAPIL/SiO2 and OAPAI/ SiO2 including sulfonic acid -SO3H groups were obtained. Using the typical DPC method, Kowsari et al. (2015a,b) linked chain of polymers with bearing imidazole groups of a poly(amide-imide) (PAI) through preparation of 4,40 -(1,4-phenylenediisopropylidene) bisaniline and also synthesized diacid-diimide by condensation process of 3,30 ,4,40 -benzophenone tetracarboxylic dianhydride and (S)-(1)-histidine hydrochloride monohydrate materials.

6.1.2 POLYCONDENSATION REACTION VIA AN AROMATIC DIACID CHLORIDE AND A DIAMINE Interfacial or solution reaction between diamine and dicarboxylic acid chlorides (monomers) is the most common method for PA formation. Before the polymerization, monomer materials should be prepared. The DPC reaction was developed for several aromatic diamines and diacid chloride for introducing different type of PAs. There are some reported aromatic diamines for this purpose (Mallakpour and Kowsari, 2003) including 2,4-diaminotoluene, 4,40 -diaminodiphenylether, p-phenylenediamine, 4,40 -sulfonyldianiline, 1,5-diaminonaphthalene, 4,40 -diaminodiphenyl methane, and m-phenylenediamine. The mentioned diamines reacted with trimethylsilyl chloride (C3H9SiCl) with o-cresol (C7H8O) as a polar organic media. The DPC reactions were followed by reflux conditions and low-temperature solution DPC immersed in C3H9SiCl conditions. Based on the high-yield methods, several moderate viscose OAPAIs (0.21
0.42 dL/g) were prepared.

6.2 MONOMERS Concerning nylons, incorporation of diacids or their derivatives with diamines forms the applied monomer. Table 6.1 describes the monomers used for poly(arylamides) (PAAs). The acid groups are activated as they are redesigned into acid chlorides. Table 6.2 lists some examples of traditionally available PAAs.

6.3 Hyperbranched Polymers

Table 6.1 Monomers for Poly(Arylamide)s Diamines

Remarks

1,4-Phenylenediamine 1,3-Phenylenediamine 3,4-Diaminodiphenyl ether 4,4-Diaminodiphenyl ether Diacids Terephthaloyl chloride Isophthaloyl chloride 2-Chloroterephthaloyl chloride 1,4-Bis(4-carboxyphenoxy)naphthalene 2,6-Bis(4-carboxyphenoxy)naphthalene 5-Amino-2-(4-aminophenoxy)-pyridine AB2 types 2,3-Bis(4-aminophenyl)-quinoxaline-6-carboxylic acid 2,3-Bis(4-aminophenyloxyphenyl)-quinoxaline-6-carboxylic acid

Kevlar, Twaron Nomex Technora Films Kevlar, Twaron Films Organically soluble Organically soluble Organically soluble Hyperbranched polymers Hyperbranched polymers

Reproduced from Fink, J.K., 2014. High Performance Polymers, second ed., Elsevier, United Kingdom, pp. 301
320. Copyright (2014), with permission from Elsevier.

Table 6.2 Examples of Commercially Available Poly(Arylamide)s Tradename

Producer

Remarks

Aramica Armos Heracron Hydlar Ixef Kevlar Mictron Nomex Rusar Sulfron Technora Teijinconex Thermatex Twaron

Asahi Chimvolokno JSC Kolon Industries, Inc A. L. Hyde Co. Solvay Advanced Polymers Dupont Toray Industries DuPont Termotex Co., Mytishchi Teijin Chemicals Teijin Chemicals Teijin Chemicals Difco Performance Fabrics, Inc. Teijin Twaron B.V.

p-Aramid film

Reinforced aramid fiber p-Aramid fiber p-Aramid film m-Aramid fiber Sulfur modified aramid m-Aramid fiber Aramid and aramid blend fabrics

Reproduced from Fink, J.K., 2014. High Performance Polymers, second ed., Elsevier, United Kingdom, pp. 301
320. Copyright (2014), with permission from Elsevier.

6.3 HYPERBRANCHED POLYMERS Hyperbranched polymers (HBPs) are known as throughly branched macromolecules with a 3D dentritic framework. HBPs have rapidly grown in various

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application fields such as coating and drug delivery, due to favorable chemical and physical features (Kowsari, 2012). Monticelli et al. (2003) prepared the HBP of AP according to the DPC reaction of 5-(4-aminobenzoylamino)isophthalic acid (ABZAIA) and for incorporating various end groups. ABZAIA was then melted and mixed with polyamide 6 (PA6). To understand the effect of HBP loading on properties of blended composition, different wt.% of ABZAIA (from 5%
30%) were applied and both glass transition (Tg) and viscosity results described the full miscibility of the composition range. The results showed that the PA6 end group does not play an effective role in miscibility, but it may contribute to amide groups (H bonding) interacting with functional end groups of HBPs. Through the precipitation of diluted solutions, well-separated powder particles were obtained with blends and neat polymers. To support the idea of full miscibility for contents, by melt mixing of HBP, the factor of Tg increased linearly again. Melt rheology (strongly modified behavior), solubility tests, and blend characteristics showed that p(ABZAIA) creates reactive blends with PA6 through melt mixing. Based on the modified Higashi’s strategy, Monticelli et al. (2000) reported hyperbranched aromatic polyamides (HBAPs) with solubility in dimethyl sulfoxide (DMSO), DMF, N-Methyl-2-pyrrolidone (NMP), and dimethylacetamide (DMAc), using DPC mechanism of ABZAIA. The synthesized poly(ABZAIA) showed a viscosity of 0.2 and 0.3 dL/g (H2SO4, 25 C) and Tg measured at 150 C
275 C. Size-exclusion chromatography (SEC) apparatus equipped, used for the evaluation of distribution of molecular weight within three electrodes. Based on SEC, the values of Mw and Mw/Mn were 55,000 and 300,000 g/mol and 3
4, respectively, with a polydispersity index and low values of a constant. The comparison values of a and [η] show the hyperbranched, close-to-globular form of poly(ABZAIA), and 40 wt.% of synthesized polymer under polarized light, in NMP solution, indicating shear birefringence. Moreover, the nitrogen adsorption/ desorption isotherm results presented c.40 m2/g for a specific surface area. Yu et al. (2010) through (one-pot) melt polycondensation grafted nano-silica particles on HBAPs. For preparing amine groups as the growth points, particles in the first step were processed by silane coupling materials and then modified surface grafted by HBPs with high portion on 32.8%. To obtain the optimum parameters of grafting, temperature, feeding ratio, and time effective reaction conditions were carefully analyzed. It was understood that the steric impediment between the HBPs during the graft procedure plays a profound role in conducting molecular framework of the grafted polymers, while uptake of grafting monomer onto SiO2 particles prior to the reaction boosted the molecular weight of nongrafted polymers and improved the degree of branching. Shabbir et al. (2010a,b,c) reported on pyrimidine moieties-containing carboxylic acid terminated aromatic and semiaromatic hyperbranched polyamide-esters (HBPAEs) according the DPC reaction of diacid chlorides (A2) and 4-hydroxy2,6-diaminopyrimidine (CBB0 ) with molar ratio of 2:1 (A2: CBB0 ) (no catalyst) with solubility in organic solvents of N-methyl-2-pyrrolidone (C5H9NO) and DMF (C3H7NO). The obtained materials showed a Tg range of 180 C
244 C as

6.4 Aramid Fibers

well as a branching degree of .60% and inherent viscosity (ηinh) range of 0.21
0.28 dL/g. The products displayed an excellent thermal retention of 90% at 346 C
508 C. Shabbir et al. (2010a,b,c) synthesized and poly-condensed an aromatic triol using different diacid chlorides and produced a series of hydroxy-terminated HBPAEs without gelation. 13C NMR, 1H NMR, and Fourier transform infrared spectroscopy (FT-IR) characterized the branching degree and structures. Moreover, thermally stable HBPAEs showed high solubility in aprotic solvents with Tg and a viscosity range of 74 C
112 C and 0.15
0.21 dL/g, respectively. These thermally stable polymers were found to be soluble in aprotic solvents. Inherent viscosities and Tg values lie in the range of 0.15
0.21 dL/g and 74 C
112 C, respectively. Following their recent investigations Shabbir et al. (2010a,b,c) employed materials of 6-hydroxy-2,4-bis(40 -nitrobenzamide)pyrimidine (NAL) and AB2type monomer to synthesize the thermally stable pyrimidine moieties-contained HBPAEs rely on amidation process. NAL polymerization was performed homogeneously to obtain a gel-free polymer (HBPAE 1) containing active end groups, and then HBPAE 2 and 3 were prepared through derivation of nitro-terminated HBPAE 1. The complete modification and structure characteristics of prepared HBPAEs were studied using FT-IR. The inherent viscosity (ηinh) achieved was 0.23 dL/g and the dispersin B was 0.41. Although amorphous HBPAE 1 was solved in organic solvent of DMF partially, both modified HBPAE 2 and 3 showed great solubility in DMSO, DMAc, and NMP as organic solvents. In addition, pyrimidine rings and intrinsic end groups significantly affected the glass transition temperature (Tg) of HBPAEs. Fig. 6.1 shows the structural repeat units of HBPAE 2 and their notations for 1H and 13C NMR spectra.

6.4 ARAMID FIBERS Kevlar is a commercial brand of fibers made up of light weight strong para-aramids related to other aramids such as Nomex and Technora. It is usually utilized as cotton fibers, fabrics, and textiles or as a major part of composite materials. The yellow color of the Kevlar fiber (KF) is formed through a combination of strong and weak electron system bonds in both the linear and lateral directions of polymer chains. If the fibers are bended in a loop, they become twisted internally. Such particular properties of fibers are transferred into the composites. For example, multilayered Kevlar-epoxy single-direction fibers are linearly strong but show weaknesses laterally. Since the compressive resistance level is less than the stress/ tensile strength, the bend/flexure due to load is an issue. Nomex has robust molecular-resistant chains produced from poly meta-phenylenediamine, which is not melted or flowed under high temperatures. It is robust and sustainable both chemically and thermally until 3500 C. The Kevlar (poly-paraphenylene terephthalamide (PPTA)) manufacturing process is expensive. There are also issues with

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FIGURE 6.1 Structural repeat units of HBPAE 2 and their notations for 1H and

13

C NMR spectra.

Reproduced from Shabbir, S., Zulfiqar, S., Ahmad, Z., Sarwar, M.I., 2010a, Synthesis and properties of hyperbranched polyamide
esters derived from 1,3,5-tris(40 -droxyphenylcarbamoyl)benzene. Tetrahedron 66, 1389
1398. Copyright (2010), with permission from Elsevier.

application of concentrated sulfuric acid and maintenance of aqueous insoluble polymer during the twisting and combination process (Yang, 1992). KFs are made up of long molecular PPTA chains. Existing interchain bonds make the textile highly resistant. Molecular hydrogen bonds between carbonyl groups and protons of polymer chains add to the Kevlar resistance. In addition, some of the PI stacking is made through the benzo-aromatic reactions among the closed layers. As a fibrous polymer, Kevlar has shown resistant against high temperature levels. Its stress/tensile resistance is reduced 10%
20% at high temperature levels which is further lowered in a few hours. For example, it shows about 10% decrease in 160 C during

6.4 Aramid Fibers

a 500 hours of nonstop operation, and 50% of its resistance is lost in 70 hours at 260 C. When the Kevlar is spun, the resulting fibers have stress/tensile resistance of around 3620 MP and relative density of 1.44. Such intermolecular hydrogen bonds are formed between carbonyl groups and nitrogen-hydrogen (bond)s. Additional resistance is generated through stacking interactions among adjacent aromatics. The Kevlar structure consists of relatively rigid molecules that tend to form flat sheet-like structures. Aramid fibers exist in different forms that may be utilized to make composites such as glass and carbon fibers. Because of its low weight, good thermal stability, and excellent toughness, aramid fibers are under consideration. KFs are made up of long molecular PPTAs. Orientation and arrangement of the chains and the bonds creates specific properties including: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

High stress/tensile resistance and low weight Low elongation at rupture Good toughness High modulus Excellent dimensional stability Low electrical conductivity High tear/rupture resistance High chemical resistance Flame resistant and self-extinguishing Low thermal shrinkage Retention of properties at very high and very low temperatures Very low creep Excellent wear and friction resistance (Yang, 1992).

By the synthesis phase, aramid polymer is solved in the sulfuric acid solution and turn into fibers. The thickness of fibers is limited to a few microns, and the final morphology is achieved at 150 C
550 C. Based on the degree of molecular orientation and arrangement, Kevlar strength and resistance levels are different. Kevlar is a promising material in the aerospace industry. Kevlar 149 has been recently introduced as the most resistant one. Kevlar is also known for applications in projectiles and thermal protection, due to their potential to absorb energy. A dual-electron P system creates double bonds in most chemically structured polymer bonds, which brings about the aramid thermal stability. Thermal degradation of such polymers does not begin at temperature levels below 400 C and might not occur until 500 C if located in an inert atmosphere. The regularly arranged repetitive structure and elongated and smooth form of the chains enhances the crystalline properties up to 80%, which is too much for an organic polymer. Crystallographic studies have shown that the axis of polymer chains is the same as fiber axis. Heterogeneous polymer structure linearly and laterally brings about considerable stress/tensile resistance to the fibers. The external forces are tolerated through strong chemical bonds of polymer chains. Adjacent polymer chains are kept together in a crystalized area through the van der Waals interactions and

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hydrogen bonds, which are weaker than chemical bonds and separated easily. Thus, the fibers have poor mechanical properties laterally. Nomex has long-resistant molecular chains made up of PPTA. It does not melt and flow. Coaling and destruction last until 350 C. It is chemically and thermally stable. Nomex is also heat and flame resistant.

6.5 ARAMID COMPOSITES 6.5.1 COMPOSITE In general, composite can be described as follows: • • • •

A substance made up of a matrix and a reinforcing (5% minimum) Combination of matrix and fibers (or reinforcing materials) with 5% content is known as the composite Composites are made of a matrix and a reinforcement US Metallurgy Association; macroscopic combination of two or more substances with distinct interface is known as the composite

The composite is made up of two parts: matrix and reinforcement. Around the reinforcement, the matrix is relatively fixed. The reinforcement enhances the mechanical properties of the structure. In general, reinforcement could be sized as short fibers or as long continuous ones. Composites can be classified as either natural composites such as bone, muscle, or wood, or as artificial (engineering) composites. Artificial engineering composites in terms of their matrix phase; 1. Ceramic matrix composite 2. Polymer matrix composite (PMC) 3. Metal matrix composite Composites can also be classified in terms of the reinforcement type: 1. Fiber-reinforced composites (FRC) 2. Particle-reinforced composites The matrix and reinforcement of this type of composite are made of biodegradable materials. Biological synthetic polymer is used as the matrix and botanical fiber is utilized as the reinforcement in such composites. The main advantage of these composites is the potential for controlling the properties of the composites in accordance with the user requirements. Composites also have the following advantages: • • •

Considerable mechanical resistance compared to its weight Considerable resistance against corrosion Excellent fatigue properties compared to metals

6.5 Aramid Composites

• • • • •

Good thermal insulation properties Due to rigidity under a given load, less creep is observed compared to metals High stability Low volume-to-weight ratio Light weight and so much stronger and lighter than steel

6.5.2 POLYMER MATRIX COMPOSITES PMCs are comprised of a polymer resin (reinforced plastic with large molecules) as the matrix and some fibers as the reinforcement. These composites have wide applications, due to suitable properties in ambient temperature, ease of manufacturing, and low costs. Such composites are classified by the type of glass, carbon, and aramid fibers. PMCs with glass fibers include continuous and discontinuous glass fibers in the polymer matrix. However, the glass will be replaced by carbon as the reinforcement of PMCs in the near future because carbon fibers have shown considerable stability and modulus compared to other reinforcement fibers. It should be noted that aramid fibers are materials with high stability and modulus and were introduced in the early 1970s. In addition to the three types of reinforcing fibers (i.e., glassy, carbon, and aramid), Bohr, silica carbide, and alumina oxide are sometimes utilized in PMCs. Bohr fibers are applied in military aircraft components including helicopter blades and in some sports equipment. Silica carbide and alumina are utilized in tennis rackets, printing applications, and in the heads of missiles.

6.5.3 FIBER-REINFORCED COMPOSITES Technologically, the most important composites are the ones in which the dispersed phase is in string form. Reinforced string/fiber composites have shown considerable roughness/stability. Such characteristics are known as specific stability/modulus. This type of composite could be categorized in terms of string/fiber length. The mechanical properties of this composite depend on the string/fiber characteristics and the level of matrix force transferred to the fiber/string. Thus, fiber critical length is important in the stability and roughness of this type of composite. The mechanical properties of FRCs also depend on the fiber stress
strain characteristics, matrix phase, volumetric share of the phase, and force direction. Alignment of fibers induces counterproperties. In this case, the strain
stress behavior depends on the force direction (vertical, horizontal). A decrease in fiber thickness enhances stability and roughness of the fiber compared to the matrix. Materials used as reinforcing fibers show considerable strain strength. Fibers/ strings could be categorized in three classes based on their thickness and characteristics as whiskers, fibers, and strings. Whiskers are thin single crystals with a considerable length-to-thickness ratio. Whiskers are the most resistant and stable materials known thus far and include graphite, silica carbide, and silica nitride as well as alumina oxide (Mallick, 2007).

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6.5.4 ARAMIDS AS HIGH-PERFORMANCE POLYMERIC BUILDING BLOCKS FOR ADVANCED COMPOSITES Aramid composites are insulated and do not produce electricity when in contact with metals. Although the stress/tensile behavior is linear and failure (fatigue/rapture) takes place in higher stress/tensile levels, the compressive and stress/tensile properties of aramid composites are ductile and their final resistance is somehow less than the composite fibers of glass and carbon. The aramid fibers together with glass and carbon could be used to create hybrid composites so that the properties of both fibers could be utilized. By applying a combination of fibers in a composite, various desirable outcomes in terms of properties and economic issues can be achieved. This type of composite is known as a hybrid composite.

6.5.4.1 Aramid fiber composites Li et al. (2016a,b) prepared reinforced composites of aramid fiber silica aerogel (RAFSA) in a pressure drying environment. The inlaid microframework of aramid fibers in aerogel structure indicating a symbol of supporting skeletons to meet strong aerogel matrix and mechanical properties, with layered design of fiber dispersal. FT-IR characterizations of RAFSA showed that these materials combined together through a physical conjunction of aerogel and aramid fibers show no chemical linking and with different fiber components (1.5%
6.6%) showed ultralow thermal conductivity (0.0227 6 0.0007 W/m/K). Additionally, RAFSAs displayed efficient flexibility and elasticity due to layered frameworks of the fiber distribution accompanied by the mechanical strength, low density, and softness properties of the fibrous aramids. Pure silica aerogels play a vital role in common utilization conditions and showed a thermal stability of 290 C according to thermogravimetry-differential scanning calorimetry (techniques) (TG-DSC) analysis. There is a large number of application prospects for RAFSAs in the fields of piping insulation and other heat conservation applications. Aramid fiberreinforced silica aerogel developed by Li et al. (2016a,b) provides advantages of thermal insulation, significant flexibility, and low-density features. The developed flexibility including (5%) fiber was achieved through a three-point bending test except of thermal isolation characters. By increasing fiber contents, a monotonous plunging was observed close to 0.142 g/cm3 while thermal conductivity experienced a slight increase (0.0221
0.0235 W/(m K)). According to the hot plate test, both prepared composite and one-dimensional (1D) showed similar transient thermal transfer. This feature was further evaluated through Fourier’s law to understand heat transfer, and the TG-DSC characterization exhibited 285 C as thermal stability. The reported results proved that as-prepared RAFSA materials have high practical potential due to their superior thermal insulation. An efficient and facile mussel-like inspired modification procedure was studied by Wang et al. (2016a,b) to develop the interfacial union of the composites of rubber/aramid fibers. The predeposition of aramid fiber surfaces was conducted through poly(catechol/polyamine) (PCPA) layer, constructed according to the

6.5 Aramid Composites

oxidation polymerization of catechol/polyamine (CPA) in the presence of UV beams. Later, for introducing epoxy groups onto the surface of aramid fibers, the PCPA-coated materials were further grafted via ethylene glycol di-glycidyl ether (EGDE). The pull-out test is an effective technique for understanding the role of grafting time and EGDE concentration in the force of adhesion between rubber matrix and aramid fibers, and it was achieved by 85.6% as a maximum increase concerning of adhesion force, which is high compared to the dopamine in a previous report with an improvement of 67.5%. Compared with conventional dopamine chemistry methodologies, this method indicated several advantages such as shorter deposition periods ( . 3 h) and lower costs ( . 1% of dopamine price). This method proved to be highly reliable for functionalizing of fiber surfaces, and exhibited a remarkable efficiency in the rubber industry. The composites of selfreinforced polymer are one of the fastest growing fields in engineering polymers, and have been increasingly investigated in moderate performance of thermoplastic fibers. Zhang et al. (2010) worked on typical self-reinforced composites on the basis of high-performance aramid fibers by using surface dissolution to fuse PPTA fibers together to form an “all-aramid” composite. By immersing materials in H2SO4 (95%) during the selected time range, dissolved fiber surfaces were partially transfigured into a PPTA interphase or matrix phase. Then, by extraction of sulfuric acid and drying, a reinforced all-aramid composite was obtained. The morphology and thermal and mechanical properties of these single-polymer matrixes were then analyzed. The optimum processing method showed a unidirectional composite with good interfacial bonding and high consolidated content (B75 vol.%). Compared to typical aramid/epoxy films, the all-aramid composites indicated a Young’s modulus and tensile strength of B65 and 1.4 GPa, at room temperature, respectively. However, because of the same high-temperatureresistant PPTA polymer for matrix, interphase, and fiber, an excellent modulus by 50 GPa was retained over 250 C, showing the high potential of all-aramid composites for high-temperature investigations. Patterson and Sodano (2016) reported a simple nanoparticle-sized zinc oxide (ZnO) with aramid fibers that enjoy UV absorption and interfacial reinforcement simultaneously, for developing reinforced fiber composites. The modified aramid fiber through a one-step nanoparticle deposition procedure experienced enhanced (by 18.9%) interfacial shear strength in the presence of nanoparticles of ZnO during a single-fiber pull-out test. Then, according to a typical hydrolysis process, the fibers were treated to show the significance of oxygen functional groups at the interface as well as oxidizing at the surface, which showed further interface enhancing between nanoparticle and fiber surface by 33.3%. Moreover, the mechanical properties remaining for coated fibers, due to the absorption characteristics of ZnO, analyzed by light source of artificial UV exposure, for 24 hours. Compared to uncoated bare fibers, ZnO-coated fibers showed a modulus and retention tensile of 21% and 25%, respectively. The results show that the nanoparticles of ZnO are a simple and new multifunctional fiber that can provide more durable and stronger structural fiber composites due to improved interfacial consolidation and high resistance to UV

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exposure. Wang et al. (2016a,b) developed a modified mussel-inspired method to enhance interfacial adhesion of aramid fiber to a rubber matrix. Through a simple dip-coating procedure, catechol, and polyamine could initially codeposit as a PCPA coating on the surface of the aramid fiber. Then, the PCPA layer could be further grafted with a silane coupling agent γ-(glycidyloxypropyltrimethoxysilane) (GPTMS). The results indicated that GPTMS was successfully grafted onto the aramid fiber surface via the bridging of the PCPA layer. The interfacial adhesion between the aramid fibers and the rubber matrix was improved compared to that achieved by polydopamine in a previous study. In addition, this method is more applicable to the rubber industry than polydopamine coating because of its cost effectiveness and short reaction time. Due to their exceptional mechanical features and 1D cylindrical geometry (very high aspect ratio and nanosized diameter), carbon nanotubes (CNTs) are perfect filler materials for polymeric fiber reinforcement. Liu and Kumar (2014) summarized condition procedures and developed properties of carbon nanotube-reinforced polymeric fiber, since these materials exhibit polymer chains in during CNT polymer interaction, with the benefit of higher orientation, improved mechanical properties, and compact packing rather than bulky polymers. The structure characterization and interphase were analyzed. Additionally, more extensive polymer and fiber processing to construct much stronger and robust composites are currently in the early phases of exploration and development. Existing CNT materials in polymeric fibers, in addition to improved tensile features, provide other advantages including fiber thermal shrinkage, thermal stability, chemical resistance, thermal conductivity, thermal transition temperature, and electrical conductivity. Although composite reinforcement shows high strength and extraordinary modulus by employing small and strong CNTs, nanocomposites suffer from the disadvantages of the mechanical parameters of individual nanotubes. Moreover, the unavailability of strong polymers due to effective utilization in nanotube films as well as poor load transfer and defective dispersion affect the experimental results. Similar analogous morphological properties of aramid nanofibers (ANFs) and CNTs also provide high potential for completing the dispersible intrinsic with the advantages of mechanical efficiency of nanotubes, which qualifies solvent-based processing technique. Zhu et al. (2015) reported on multiwalled CNTs and ANFs films prepared through vacuum-assisted layer-by-layer (LBL) assembly and vacuumassisted flocculation with Young’s modulus (stiffness) and strength of up to 35 GPa and 383 MPa, respectively, showing the most significant measures among all randomly reported nanotube composites. The multiple interfacial interactions between ANFs and nanotubes consisting of hydrogen bonding and π
π stacking, which probably shows the main responsibility of the obtained mechanical performance, was characterized by various spectroscopic and imaging techniques. The thermomechanical features of CNT-containing nanocomposites was further investigated and resulted in ultralow thermal expansion coefficients (2
6 ppm/K) and excellent thermal stability ( . 520 C). According to the obtained results, it is obvious that ANFs known as favorable nanoscale building blocks (NBBs) for

6.5 Aramid Composites

functional stiff and ultra-consolidate composites are potentially extensible to nanoscale filler nanocomposites. The efficiencies of fiber-reinforced materials depend strongly on the interfacial phase between the matrix and fiber as well the intrinsic of each singular component comprising the composite. Park et al. (2015) used a typical LBL assembly to modify the surface of glass fiber for boosting the interfacial characteristics of epoxy materials/glass fiber. Solution-processable graphene oxide (GO) and ANF were appointed as active ingredients for above assembly to address the interfacial challenges of the glass fibers due to their providing outstanding mechanical features and rich functional groups. Compared to pure glass fiber, the interfacial shear strength and surface free energy of coated glass fiber achieved by 39.2% and 23.6%, respectively. Moreover, the epoxy matrix-glass fiber’s interfacial adhesion interactions were distinctly tunable directly by redesigning the framework and the setup of layers, taking advantage of the versatility of the assembly. Fig. 6.2 shows a schematic of the assembly of a negatively charged ANF (2) and positively charged GO (1) with multilayer coating on a glass fiber by nanoscale blending LBL fabrication. Elastomers such as polyurethanes (PUs) are known to suffer from stiffness, and fillers are commonly used improve this property. Moreover, ANFs as prominent NBBs have been used due to their outstanding nanocomposites. Using two forms of vacuum-assisted flocculation (VAF) and LBL assembly, Kuang et al. (2015) reinforced ANFs to produce waterborne polyurethanes (WBPUs). Among the PU-based matrixes, the highest values of ultimate strength and modulus achieved were 98.02 MPa and 5.275 GPa, respectively. The manifold interfacial

FIGURE 6.2 Schematic of the preparation of a positively charged graphene oxide (GO) and negatively charged aramid nanofiber (ANF) multilayer coating on a glass fiber via a nanoscale blending layer-by-layer (LBL) assembly. Reproduced from Park, B., Lee, W., Lee, E., Min, S.H., Kim, B.S., 2015. Highly tunable interfacial adhesion of glass fiber by hybrid multilayers of graphene oxide and aramid nanofiber. ACS Appl. Mater. Interfaces 7, 3329
3334. Copyright (2015), with permission from American Chemical Society.

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interactions resulted in highly efficient achievements for PUs and ANFs with similar frameworks. A computer simulation confirmed the multiple hydrogen bond formation with well-defined spacing of amidic groups. Furthermore, LBL assembly compared to the VAF technique, due to presenting more improved stiffness and definitive strength, provided higher load conduction. However, the VAF strategy has advantages in ultimate strength developing at low ANFs loadings. It is expected that this study extends fundamental connotation dealing with innovative nanofillers design for nanocomposites as well as practical composite materials incorporation.

6.5.4.2 Poly(amide-block-aramid) alternating block copolymers Rigid liquid crystal-containing block copolymers have been comprehensively used for preparing materials of blocks of flexible blocks of hexamethylene adipamide (PA 6,6) and poly(p-phenylene terephthalamide) (PPTA) prepared by Ruijter et al. (2006) in a one-pot system through reacting of an amine-terminated PPTA oligomer with PA 6,6 monomers based on a low-temperature DPC reaction in miscible organic solvent of NMP. By combination of mean-square, end-to-end distance for coil-rod block copolymer (CRBCP) with the homopolymers natural viscosity, through a semi-empirical model, the molecular weight (MW) was measured dealing with CRBCP materials. Seyler and Kilbinger (2010) prepared monodisperse “hairy rod oligomers” through oligo(p-benzamide) (O-PEG)-containing chains of alkyl and combined with chains of polydisperse poly(ethylene glycol) (PEG). According to a typical peptide constructor, 4-amino-2-hexyloxybenzoic acid employed to form the well-defined O-PEG oligomers. The PEG self-assembly blended hairy rod 2 coil block copolymers where both polar and nonpolar organic media was used and the self-functioning in solution considered via transmission electron microscopy and dynamic light scattering as a polarity of the substrate, solvent function and equilibration time. Each fibers and fiber-like bundles of conjugated materials could be detected. Due to presence of all intramolecularly saturated hydrogen (H) bond donors in these aramid oligomers, based on NMR studies, π-stacking is main responsible for the aggregation mechanism in this class of substituted oligo-aramids. Crystallography of copolyaramids (CPA) comprised of short amine aliphatic chains (5 2 10 CH2 groups) and rigid segments of poly(pphenylene terephthalamide comprised of 3 2 11 aromatic cycles was conducted by Manet et. al. (2006) by slow saturation with methanol vapors of sulfuric acid solutions at room temperatures. The monodisperse rigid block 3AR6DA, indicated a relatively sharp and weak diffraction spots within electron diffraction and typical single crystal diffraction, respectively. Other polydisperse rigid blocks wARnDAs, exhibited a similar low resolution (distinguishable) peak broadening diffraction graph, showing a challenging crystal phase disturbance. All obtained plots contributed to the hk0 level, with perpendicular status of chains to the lamellar plane. Atomic force microscopy confirmed the multilamellar of crystals, with regular enhancing thickness for each lamella, what was attributed to the number of existing aromatic groups in the rigid segment. Therefore, the rigid segment length

6.5 Aramid Composites

affects the average lamellar thickness value directly, which means the chain folding can be observed by adding a short aliphatic chain fragment.

6.5.4.3 Surface modification of aramid fibers Sa et al. (2014) worked on a new method of biomimetic surface modification to investigate another type of aramid called a meta-aramid (MPIA) fiber to improve the properties of rubber matrix and adhesion. Through the understood adhesive proteins in mussels composition, a surface-adherent and thin self-polymerized poly(dopamine) (PDA) film from dopamine (DOPA) onto a metaphenylene isophthamide (MPIA) surface was conducted at room temperature where MPIA fibers immersed in a solution of DOPA. Additionally, to modify the MPIA fiber surface with epoxy groups, according to a one(/two)-step approach, the surface of the PDA-coated MPIA, grafted via epoxy functionalized silane (KH560), and confirmed through characterization technique. The modified MPIA fibers (MMPIAF) adhesion measured based on analysis of single-fiber pull-out, and MMPIAF with rubber matrix, in comparison with untreated MPIA fibers, experienced an enhancement of 62.5%. Wang et al. (2013) based on a facile strategy developed aramid fibers with the beneficial of excellent electric conductivity. Through modification surface of poly(m-phenyleneisophthalamide) (PMIA) fibers via PDA molecules, silver nanoparticles assisted by electroless silver plating (ESP) immobilized on poly-MPIA fibers. Based on PMIA substrate immersing in alkaline solution of DOPA, the PMIA surface was deposited by PDA layers. The functional groups of indole and catechol in PDA can chemically linked to silver ions (Ag1/Ag21). To obtain a well-defined silver layer on the surface of PMIA, reducing agent of glucose was employed to convert silver ions into nanoparticles of silver, in which produced a compact and homogeneous silver deposition. Fig. 6.3 shows the schematic imagination of fabrication procedure of PMIA 2 PDA/Ag composite by PDA-assisted ESP. The electrical resistance for silver-containing PMIA fibers was achieved by 0.61 mΩcm, according to a four-point probe resistivity meter technique with an adequate stability throughout ultrasonic process as well as a controllable Ag component. Using hyperbranched polysiloxane synthesis including epoxy groups and double bonds on KFs. Zhang et al. (2014) reported new grafted Kevlar fibers (HSi-gKFs) with an adjusted molar ratio of 1.1
1.4 for water and silane, respectively. The unconnected dot morphology of HSi-g-KFs successfully converted to condensed dot morphology and then a compact coating of hyperbranched polysiloxane. Significantly improved surface wettability and UV resistance are remarkable properties of all HSi-g-KFs in comparison with KFs in addition to much higher thermal stability. Retention of the break extension and modulus during UV irradiation (168 hours) was obtained by 95%
97% for HSi-g-KFs. The employed method introduces a facile strategy for developing high-performance aramid fibers dealing with cutting-edge applications.

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FIGURE 6.3 Schematic illustration of procedure for fabrication of PMIA 2 poly(dopamine) (PDA)/Ag composite by PDA-assisted electroless silver plating. Reproduced from Wang, W., Li, R., Tian, M., Liu, L., Zou, H., Zhao, X., et al., 2013. Surface silverized metaaramid fibers prepared by bio-inspired poly(dopamine) functionalization. ACS Appl. Mater. Interfaces 5, 2062
2069. Copyright (2013), with permission from American Chemical Society.

6.6 BIOMEDICAL APPLICATIONS OF ARAMID COMPOSITES 6.6.1 ARAMID COMPOSITE SCAFFOLDS FOR BIOMATERIALS APPLICATIONS Due to the material processing options and chemical properties of biodegradable polyesters, their application in medicine have been studied. However, there is an important drawback of leaking of acidic degradation materials. During this process the released acidic products present some disadvantages in terms of providing inflammatory reactions and local pH drops compared to these materials; however, polyesteramides (PEA) during the degradation show lower pH drop. According to Hemmrich et al. (2008), reproducible synthetic strategy was developed for the poly(ester amide) type C. Hemmrich used adipic acid, 1,4-butanediol, and ε-caprolactam materials in a two-step (one-bath) reaction, and then manufactured tissue engineering products by employing the scaffolds of PEAderived 3D textiles. The conformation structure of PEA-type C in various batches evaluated by size exclusion chromatography and NMR as well as mechanical and features while polymer was designed into nonwovens via textile assembling. X-ray photoelectron spectroscopy and cytotoxicity evaluations were conducted before cell seeding to determine the scaffold extraction effect. The engineered carriers were seeded with human preadipocytes and considered for cellular differentiation and proliferation. PEA-type C was prepared based on simultaneous polycondensation with adipic acid and 1,4-butanediol and

6.6 Biomedical Applications of Aramid Composites

ε-caprolactam polymerization (ring-opening) under ultravacuum condition (250 C). Optimum nonwoven scaffold cleaning was performed by Soxhlet extraction. These extracted PEA-derived materials presented prominent differentiation, proliferation, and adherence of preadipocytes. The obtained results point to an ideal implementation of assembled nonwoven carrier for clinical utilization. Furthermore, because of their biodegradability and tunable mechanical characteristics polymeric elastomers such as poly(1,3-diamino-2-hydroxypropane-copolyolsebacate) (APS) have been remarkably employed in soft tissue engineering. However, due to low viscosity, poor solubility in conventional solvents, and the high temperature required for thermal curing these polymers have been restricted for the fabrication of nanofibrous scaffolds of extracellular matrix (ECM)mimetic applying APS. To overcome the drawbacks of these polymers, Mukundan et al. (2015) used polycaprolactone (PCL) for conjugated uncrosslinked APS prepolymer and then fabricated it in scaffolds of ECM-mimetic nanofibrous APS. The effect of total polymer concentration on ultimate tensile strength and elastic modulus is shown in Fig. 6.4. The developed structures of fibrous scaffolds were analyzed for their degradation, physicochemical, mechanical, and thermal characteristics. Moreover, the effect of total polymer accumulation (15%
30%, w/v) and different mass ratios of PCL:APS (0:1, 1:1, 2:1, and 4:1) on the tensile characters, fiber morphology, thermal, and chemical features of the PCL:APS scaffolds were evaluated. Results showed that fused fiber structure derived from a high ratio of APS in the polymer mixture improved the diameters of the fiber. The concentration of APS is in agreement with the scaffold degradation and degree of hydration as the selective loss of APS polymer from scaffolds within degradation indicated by DSC and FT-IR characterizations. Composites with the ratio 1:1 of PCL:APS, compared to other scaffold ratios (4:1, 2:1, and 0:1), demonstrated a high-elastic modulus of 30 6 2.5 MPa. On the other hand, the ratio of 2:1 of PCL:APS showed improved tensile strength and stiffness of the electrospun composites through enriching concentrations of polymer (15%
30%, w/v). In comparison to scaffolds comprising pure PCL, biocompatibility measurements applying dichloromethane (C2Cl2) mouse myoblast cells exhibited increased cell spreading on scaffolds containing APS (6 hours). Based on these results, a thermoset elastomeric nanofibrous scaffold containing APS polymers was developed through conjugating with PCL polymer (semicrystalline) as APS:PCL scaffold. Properties including mechanical, tunable physicochemical, and degradation were further studied for use in manufacturing of skeletal muscle tissue engineering. Fig. 6.5 shows the spreading and adhesion of C2Cl2 mouse myoblast cells.

6.6.2 ANTIMICROBIAL ARAMID COMPOSITES Kim and Lee (2013a,b) worked on preparation of m-aramid/antimicrobial polyacrylonitrile (m-aramid/(PAN)) hybrid composites. By dissolving the m-aramid and PAN in polar aprotic solvent of DMSO ((CH3)2SO), a thin layer was produced on

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FIGURE 6.4 Effect of total polymer concentration on (A) elastic modulus and ultimate tensile strength; (B) hydration; (C) degradation rate (mass loss) under accelerated condition (0.05 M NaOH); and (D) morphology of fibers before and after accelerated degradation. The white arrows indicate formation of pores after degradation (n 5 4
5; significant differences at P ,.05 ( ) compared to 15% (w/v) and ( ) compared to 30% (w/v); one-way ANOVA followed by posthoc Tukey test). Reproduced from Mukundan, S., Sant, V., Goenka, S., Franks, J., Rohan, L.C., Sant, S., 2015. Nanofibrous composite scaffolds of poly(ester amides) with tunable physicochemical and degradation properties. Eur. Polym. J. 68, 21
35. Copyright (2015), with permission from Elsevier.

a glass plate, then congealed in distilled water. And also, the interaction of m-aramid and PAN molecules were analyzed through dynamic mechanical tests, and then according to a swatch analysis including suspensions bacterial, the antimicrobial performance was evaluated. In the presence of Staphylococcus aureus and Escherichia coli, the m-aramid/PAN films exhibited a reduction by 7-log during 5 minutes. The efficiency of antimicrobial of m-aramid/PAN films is summarized in Table 6.3. Kim and Lee (2013a,b) synthesized nanosized webs and hybrid films of chitosan/m-aramid. Typically, for preparing the chitosan/m-aramid hybrids, the chitosan salt and m-aramid are dissolved in DMSO and then in a alkaline solution of NaOH. The nanosized web was produced based on the electro-spinning method,

6.6 Biomedical Applications of Aramid Composites

FIGURE 6.5 Adhesion and spreading of C2Cl2 mouse myoblast cells after (A) 6 h and (B) 24 h in culture. Cells were cultured on APS
PCL composite scaffolds for 6 and 24 h, respectively, and fixed and actin cytoskeleton was stained with phalloidin (green) and nuclei stained with Hoechst (blue). Hydrophobic PCL scaffolds show round cell morphology at an earlier time point of 6 h, whereas cells easily spread on composite APS
PCL scaffolds by 6 h. However, at a later time point of 24 h, no difference was observed in cell morphology on all the scaffolds including PCL. (C) Metabolic activity (Alamar blue) of C2Cl2 cells on 0:1 and 4:1 APS:PCL scaffolds showing increased cell proliferation over 7 days on both PCL as well as APS
PCL scaffolds. Reproduced from Mukundan, S., Sant, V., Goenka, S., Franks, J., Rohan, L.C., Sant, S., 2015. Nanofibrous composite scaffolds of poly(ester amides) with tunable physicochemical and degradation properties. Eur. Polym. J. 68, 21
35. Copyright (2015), with permission from Elsevier.

since these materials enhanced the surface area of assembled composites, showing good potential for antimicrobial application. Both X-ray diffraction and FTIR techniques were used for determining the chitosan/m-aramid miscibility as well as SEM scanning for determining the morphology of hybrid composite. Moreover, similar to the S. aureus and E. coli, chitosan/m-aramid showed improved surface area derived from the nanosized webs, achieving a reduction of 7-log. Table 6.4 describes the antimicrobial efficacy of the nanosized webs and prepared films.

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Table 6.3 Antimicrobial Efficacy of the Films Escherichia colia

Wt.%

Contact Time (min)

Bacterial No. (cfu/mL)c

Staphylococcus aureusb

Log Reduction

Bacterial No. (cfu/mL)c

Log Reduction

NDd NDd 0.08 NDd NDd 0.05 NDd NDd 0.06 NDd NDd 0.27

1.58 6 0.10 3 107 1.60 6 0.26 3 107 1.64 6 0.11 3 107 1.69 6 0.58 3 107 1.54 6 0.33 3 107 1.26 6 0.21 3 107 1.73 6 0.29 3 107 1.51 6 0.38 3 107 1.54 6 0.27 3 107 1.63 6 0.10 3 107 1.56 6 0.13 3 107 1.12 6 0.34 3 107

0.23 0.22 0.21 0.20 0.24 0.20 0.19 0.25 0.19 0.21 0.23 0.23

1.63 6 0.15 3 107 0 0 1.67 6 0.36 3 107 0 0 1.72 6 0.37 3 107 0 0 1.57 6 0.22 3 107 0 0

0.21 7.43 7.43 0.20 7.43 7.43 0.19 7.43 7.43 0.23 7.43 7.43

Unchlorinated PAN/m-Aramid 100/0 95/5 0/100 100/0 95/5 0/100 100/0 95/5 0/100 100/0 95/5

5

10

30

120

2.47 6 0.25 3 107 2.50 6 0.22 3 107 1.51 6 0.52 3 107 2.42 6 0.30 3 107 2.48 6 0.15 3 107 1.63 6 0.34 3 107 2.48 6 0.38 3 107 2.41 6 0.21 3 107 1.61 6 0.20 3 107 2.12 6 0.14 3 107 2.44 6 0.16 3 107 9.80 6 0.44 3 106

Dichlorinated OAN/m-Aramid 0/100 100/0 95/5e 0/100f 100/0 95/5e 0/100 95/5e 0/100f 100/0 95/5e 0/100

5

10 30

120

2.43 6 0.13 3 07 0 0 2.42 6 0.23 3 107 0 0 1.84 6 0.11 3 107 0 0 8.70 6 0.50 3 106 0 0

d

ND 7.26 7.26 NDd 7.26 7.26 0.0ld 7.26 7.26 0.33 7.26

Total bacteria: 1.84 3 107 cfu/sample. Total bacteria: 2.67 3 107 cfu/sample. Bacterial no. data are expressed as mean 6 standard deviation of a triplicate analysis. d No determination. e [Cl 1]%: 0.21. [Cl 1 ]%: 3.05. f [Cl1]%: 3.05. Reproduced Kim, S.S., Lee, J., 2013a. Antimicrobial polyacrylonitrile/m-aramid hybrid composite. Ind. Eng. Chem. Res. 52, 10297
10304. Copyright (2013), with permission from American Chemical Society. a

b c

6.6.3 THE USE OF ARAMID COMPOSITES IN MODERN ORTHOPEDIC MEDICINE The in situ polymerization with vacuum-solution impregnation (resin transfer molding-aided) methods was employed to form composites of Kevlar/3D-braided

6.6 Biomedical Applications of Aramid Composites

Table 6.4 Antimicrobial Efficacy of the Films and Nanosized Webs Escherichia colia Sample (m-Aramid/ Chitosan, wt.%) Film (100/0) Film (85/15) Nanoweb (100/0) Nanoweb (85/15) a

Contact Time (min) 60

Staphylococcus aureusb

Bacterial No. (cfu/mL)c

Log Reduction

Bacterial No. (cfu/mL)c

Log Reduction

7.36 6 0.65x107 2.20 6 0.27x107 6.90 6 0.39x107 0

0.07 0.59 0.09 7.93

4.30 6 0.83x107 2.82 6 0.36x107 4.63 6 0.33x107 0

0.16 0.34 0.13 7.79

Total bacteria: 8.60 3 107 cfu/mL. Total bacteria: 6.20 3 107 cfu/mL. Bacterial no. data are expressed as mean 6 standard deviation of a triplicate analysis.

b c

Reproduced Kim, S.S., Lee, J., 2013b. Miscibility and antimicrobial properties of m-aramid/chitosan hybrid composite. Ind. Eng. Chem. Res. 52, 12703
12709, Copyright (2016), with permission from American Chemical Society.

Table 6.5 Samples Used in This Study (Total Fiber Volume Fraction in the Composites: 30%) HF3D/MC Sample Definition

C3D/MC

A

B

C

D

K3D/MC

Kevlar fiber volume fraction (%) Carbon fiber volume fraction (%) Relative Kevlar fiber volume fraction (%)

0 30 0

6 24 20

12 18 40

18 12 60

24 6 80

30 0 100

MC, Monomer Casting; C3D, Three-dimensionally braided carbon; HF3D, Hybrid Fabric (three dimensional); K3D , Three dimensional kevlar (fiber composite) Reproduced from Wan, Y.Z., Chen, G.C., Huang, Y., Li, Q.Y., Zhou, F.G., Xin, J.Y., Wang, Y.L., 2005. Characterization of three-dimensional braided carbon/Kevlar hybrid composites for orthopedic usage. Mater. Sci. Eng. A 398, 227
232, Copyright (2005), with permission from Elsevier.

carbon (K-3DBC). Wan et al. (2005) investigated the flexural properties, shear strength, load
displacement, and impact property as a K-BC function proportion. They formed and characterized several fiber composites of K-BC (volume: 0%
100%). The fractal property of the prepared composites was analyzed using environmental scanning electron microscopy. Table 6.5 describes the different samples in this research (volume fraction of fiber: 30%). Synergistic effects for shear strength, strain, impact character, modulus and flexural strength of the 3DBC films were evaluated. The hybridization method is an effective strategy for tailoring the features of the 3DBCs for orthopedic utilizations. It was found that hybridization provided high flexural modulus and strength for the 3DBC films. Amon the disparate 3DBCs, sample A has high potential for use in human cortical bone and biomedical metals due to the close modulus to human bones and significant strength. However, with impact strength, the prevalent composites of 3DBCs-MC showed no significant hybrid effect. Fig. 6.6 shows the SEM diagrams of impact fractal surfaces.

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FIGURE 6.6 Scanning electron microscopy micrographs of impact fracture surfaces (A and B) C3D/MC; (C) Sample A; (D) Sample D (E
G) K3D/MC. Reproduced from Wan, Y.Z., Chen, G.C., Huang, Y., Li, Q.Y., Zhou, F.G., Xin, J.Y., Wang, Y.L., 2005. Characterization of three-dimensional braided carbon/Kevlar hybrid composites for orthopedic usage. Mater. Sci. Eng. A 398, 227
232, Copyright (2005), with permission from Elsevier.

6.6 Biomedical Applications of Aramid Composites

Table 6.6 Properties of Carbon Fibers, Kevlar Fibers, and Epoxy Resin Used in This Study Materials

Carbon Fibers

Kevlar Fibers

Matrix

Type Tensile strength(MPa) Tensile modulus (GPa) Elongation at break (%) Density (kg/m3) Filament diameter (μm)

PAN 2800 200 1.5 1760 7

Kevlar 49 3260 105 2.7 1440 12

Bisphenol60 3.2 1.8 1200


Reproduced from Wan, Y.Z., Wang, Y.L., Huang, Y., Luo, H.L., He, F., Chen, G.C., 2006. Moisture absorption in a three-dimensional braided carbon/Kevlar/epoxy hybrid composite for orthopedic usage and its influence on mechanical performance. Compos. Part A Appl. J. 37, 1480
1484. Copyright (2006), with Permission from Elsevier.

Hybrid composite of 3D-braided carbon/Kevlar/epoxy was considered in terms of behavior of moisture uptake, through submerging in Hank’s solution for .1700 hours (37 C). Then the sorption plots and different parameters such as sorption rate (k), maximized moisture content (Me), and diffusion coefficient (D) were analyzed. Compared to nonhybrid films, a Fickian procedure was observed for hybrid materials without any “hybrid effect,” improving relative to k, D, and Me factors. Moreover, shear and flexural features affected by moisture absorption were studied by Wan et al. (2006). Table 6.6 describes the material properties for the epoxy resin, Kevlar, and carbon fibers, use in this work.

6.6.4 ARAMID COMPOSITES FOR MEDICAL IMPLANTS AND DEVICES Different kinds of materials such as polymeric materials used as substrates and packaging of have been successfully employed in biomedical implantable devices as discussed by Teo et al. (2016). Both biostable and biocompatible polymers have been extensively employed in biomedical implantable devices due to their water and gas permeabilities that play a profound role in electronic circuit protection. Based on the reported advantages of biopolymers, various types of synthetic polymers have been efficiently applied for packaging such as parylene, polytetrafluoroethylene, poly(methyl methacrylate), polydimethylsiloxane, PU, polyvinylidene fluoride, polyamide, polyimide, polyethylene, and polypropylene as well as liquid crystalline polymers. These biopolymers can enhance functionalization of body systems and be used in a variety of medical products as devices and implants. Based on the US FDA’s Title 21 of the Code of Federal Regulations, biomedical devices and implants are classified into 15 categories. Table 6.7 shows 15 categories of a list of conventional medical implants. Synthetic polymers traditionally used in different implants with their advantages and disadvantages are listed in Table 6.8. Nylon is the most typical PA used

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Table 6.7 Common Medical Implants Under Code of Federal Regulations by the US Food and Drug Administration (FDA) (Teo et al., 2016) FDA Category

Common Devices

Anesthesiology

• Epidural catheters

Cardiovascular

• • • • • • • • • • • •

Dental Ear, nose, and throat

Pacemaker Implantable Cardioverter/defibrillator Left ventricular assist device Mechanical heart valves Artificial blood vessels Catheters Dentures Dental implants Cochlear implants Stapes implants Nasal implant for nose reconstruction

Gastroenterology and urology

• Penile implant • Neurostimulator in sacral nerve stimulation • Foley catheter • Artificial urinary sphincter implant • Hernia or vaginal mesh

General and plastic surgery

• • • • • • • •

Hematology and pathology Neurology

Synthetic blood vessels Breast implants Cheek, jaw, and chin implants Lip implants Titanium surgical implants Hip implants Central venous access device Peripherally inserted central catheter

• Implantable pulse generator for deep brain stimulation • Neuroprosthetics • Cognitive prostheses • Catheters

Synthetic Polymer Material Used • • • • • • • • • • •

Polyethylene Polytetrafluoroethylene Polyamide Polypropylene Polyethylene Polytetrafluoroethylene Polyamide Polyethyleneterephthalate Polydimethylsiloxane polyhydroxyalkanoates Polymethylmethacrylate

• • • • • • • • • • • • • • • •

Polydimethylsiloxane Liquid crystal polymer Silicone Parylene Polyethylene Polydimethylsiloxane Polyethylene Polytetrafluoroethylene Polyamide Polyhydroxyalkanoates Silicone Polypropylene Polyethyleneterephthalate Polytetrafluoroethylene Silicone Polydimethylsiloxane

• • • • • • • • • • • •

Polyethylene Polytetrafluoroethylene Polyamide Polyimides Polydimethylsiloxane Parylene Liquid crystal polymers Su-8 Polyethylene Polytetrafluoroethylene Polyamide Polyhydroxyalkanoates (Continued)

6.6 Biomedical Applications of Aramid Composites

Table 6.7 Common Medical Implants Under Code of Federal Regulations by the US Food and Drug Administration (FDA) (Teo et al., 2016) Continued FDA Category

Common Devices

Obstetric and gynecologic

• Intrauterine device (IUD) • Intravaginal rings • Etonogestrel-releasing contraceptive implant • Urogynecologic surgical mesh implants • Fetal micropacemaker • Dexamethasone intravitreal implant • Retinal prosthesis • Artificial intraocular lens • Glaucoma valve • Fluocinolone ophthalmic implant • Orbital implant • Catheters • Dexamethasone intravitreal implant • Retinal orothesis • Artificial intraocular lens • Glaucoma valve • Fluocinolone ophthalmic implant • Orbital implant • Catheters • Orthopedic implants

Ophthalmic

Ophthalmic

Orthopedic

Synthetic Polymer Material Used • Silicone • Polyurethane • Polypropylene

• • • • •

Polymethylmethacrylate Polyethylene Polyethylene Polytetrafluoroethylene Polyamide

• Polyethylene • Polyether ether ketone • Polyhydroxyalkanoates

Reproduced from Teo, A.J.T., Mishra, A., Park, I., Kim, Y.J., Park, W.T., Yoon, Y.J., 2016. Polymeric biomaterials for medical implants and devices. ACS Biomater. Sci. Eng. 2, 454
472, Copyright (2016), with permission from American Chemical Society.

Table 6.8 Advantages and Disadvantages of Materials PVDF

Advantages

Disadvantages

• Chemically inert • Good material stiffness and strength • Strong piezoelectric effect • Good biocompatibility • High resistance to hydrolysis

• Unable to form smooth films • Low thermal stability • Poor adhesion properties to other materials

(Continued)

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Table 6.8 Advantages and Disadvantages of Materials Continued Polyethylene

Polypropylene

Polymethylmethacrylate

Silicone

Advantages

Disadvantages

• Good chemical resistance • Material mechanical properties modifiable according to molecular weight • Low melting temperature • Light weight • Quick drying characteristics • Porous HDPE has good biocompatibility, good elasticity, and strong antiinfective properties • Nontoxic • Has two forms, copolymer and homopolymer, with different mechanical strengths • High melting point • Good dielectric properties • Mechanically strong • Light weight • Poor thermal and electrical conductivity • Acceptable biocompatibility • Radiolucency • Chemically inert • Low toxicity • Good biocompatibility • Good electrical insulation • Low thermal conductivity • Thermal stability • High gas permeability • Hydrophobic (context dependent) • PDMS • Clear • Nonflammable • Parylene • Good conformity • Able to provide thin layer of coatings (1
2 μm) with low friction coefficient

• Has, plastic, feel to skin • Low ability to be dyed • High friction coefficient

• Nondegradable • Semirigid material that can cause local discomfort in patients • Not confirmed if fully biocompatible • High curing temperature • Does not support osseointegration of the structure with other structures • Long-term effects not studied • High coefficient of friction • Soft (prone to damage during implantation) • Size and swelling • PDMS • Hydrophobic (context dependent) • Propensity for protein absorption • Possible contamination of cyclic silicone monomer • Parylene • Low mechanical strength • Weak adhesion • High moisture absorption rate • Low life-expectancy (Continued)

6.6 Biomedical Applications of Aramid Composites

Table 6.8 Advantages and Disadvantages of Materials Continued Polyimide

Advantages

Disadvantages

• Good chemical resistance • Good mechanical and electrical properties • Low creep • High tensile strength • Flexible, can be folded into compact module for restricted spaces • Constant dielectric constant over wide frequency range with low loss tangent • Stable over wide range of temperatures

• High moisture absorption

PVDF, Polyvinylidene fluoride; HDPE, High-density polyethylene; PDMS, Polydimethylsiloxane Reproduced from Teo, A.J.T., Mishra, A., Park, I., Kim, Y.J., Park, W.T., Yoon, Y.J., 2016. Polymeric biomaterials for medical implants and devices. ACS Biomater. Sci. Eng. 2, 454
472. Copyright (2016), with permission from American Chemical Society.

in implants and fibrous composites due to high mechanical strength, which plays a vital role in manufacturing of dentures and suture materials (Teo et al., 2016).

6.6.5 ARAMIDS AS POTENTIAL SUPPORTS FOR PROTEIN IMMOBILIZATION Cosulich et al. (2000) reported on the bioactivity performance of hyperbranched aramids (HBAs) and α-amylase-derived materials. Different derivatives of HBAPs prepared at different reaction conditions based on (1) reactant pairs (A2 1 B3 or A3 1 B3 or A2 1 B4) and (2) AB2-type monomers methods with as protein supports.Carboxylic functional groups were added to the aramid surface in order to facilitate its linkage to amino groups of α-amylase residues (amino acids). Aramids prepare high-efficient protein immobilization compared to conventional insoluble supports and have been used as support due to their high capacity for binding. The enzyme stability during different conditions and preserved bioactivity as durability function were studied as prepared immobilized enzymes. Measurements of catalytic efficiency (kcat) and enzyme affinity for the substrate (km) were analyzed to understand the enzymatic activities. The combination of polymeric support with enzymes, divided into three adducts classes due to presenting distinct enzymatic attributes. And also, it may be deduced that HBAs are promising supports concerning protein immobilization. In addition, simple synthesis methods through the structure approachability of polymers allows new approaches for developing derivatives of tuned enzyme-based supports, which

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Table 6.9 Residual Enzymatic Activity (%; Average of Two Determinations; Standard Deviation Does Not Exceed 15%) as a Function of Storage Time and pH (Measured 7 Days After the Cross-Linking Reaction) Sample Code

3 Months

6 Months

pH 4.7

pH 6.5

pH 9

AB2 Y1 Y8 AB6 V17 V14 V13 Y22 V15 Y34 Y33 AB50 Free amylase

100 100 70 90 100 85 50 100 100 100
100 100

100 100 54 81 100 78 37 100 100 100
74 100

28.8 54.5
48.5


30
40 86.7
50.6

100 100
100


100
100 100
100

13.2 409
34.3


15.6
336 633
100

Reproduced from Cosulich, M.E., Russo, S., Mariani, P.A., 2000. Performance evaluation of hyperbranched aramids as potential supports for protein immobilization. Polymer 41, 4951
4956. Copyright (2000), with permission from Elsevier.

provide advantages such as catalytic aptitude, structural stability, and predefined binding affinity. Table 6.9 describes the time storing, remaining percentage of enzymatic activity (%), and pH evaluated during a week of cross-linking reaction.

REFERENCES Cosulich, M.E., Russo, S., Mariani, P.A., 2000. Performance evaluation of hyperbranched aramids as potential supports for protein immobilization. Polymer 41, 4951
4956. Fink, J.K., 2014. High Performance Polymers, second ed. Elsevier, United Kingdom, pp. 301
320. Hemmrich, K., Salber, J., Meersch, M., Wiesemann, U., Gries, T., Pallua, N., et al., 2008. Three-dimensional nonwoven scaffolds from a novel biodegradable poly(ester amide) for tissue engineering applications. J. Mater. Sci. Mater. Med. 19, 257
267. Higashi, F., Mashimo, T., 1985. Direct polycondensation with tosyl chloride in pyridine by formamide catalyzed alcoholysis. J. Polym. Sci. Polym. Chem. Ed. 23, 2999
3005. Higashi, F., Mashimo, T., 1986. Direct polycondensation of hydroxybenzoic acids with thionyl chloride in pyridine. J. Polym. Sci. Part A: Polym. Chem. 24, 1697
1701. Kim, S.S., Lee, J., 2013a. Antimicrobial polyacrylonitrile/m-aramid hybrid composite. Ind. Eng. Chem. Res. 52, 10297
10304. Kim, S.S., Lee, J., 2013b. Miscibility and antimicrobial properties of m-aramid/chitosan hybrid composite. Ind. Eng. Chem. Res. 52, 12703
12709.

References

Kowsari, E., 2011. Advanced applications of ionic liquids in polymer science. In: Kokorin, A. (Ed.), Ionic Liquids: Applications and Perspectives. Intech Publisher, Australia. Kowsari, E., 2012. Synthesis and applications of hyperbranched polymers. In: Kowsari, E. (Ed.), Polymer Synthesis. Nova Science Publisher, New York. Kowsari, E., Hosseini, S.M., Bakhshandeh, M.B., Ghrehkhani, E., 2014. Synthesis and characterization of s-histidine-derived poly (ionic liquid)/silica nanocomposites and their application in the enantioselective hydrolysis of a chiral ester. J. Appl. Polym. Sci. 131, 39595. Kowsari, E., Ansari, V., Moradi, A., Zare, A.R., Mortezaei, M., 2015a. Poly(amide-imide) bearing imidazole groups/sulfonated polyimide blends for low humidity and medium temperature proton exchange membranes. J. Polym. Res. 22, 77. Kowsari, E., Zare, A.R., Ansari, V., 2015b. Phosphoric acid-doped ionic liquidfunctionalized graphene oxide/sulfonated polyimide composites as proton exchange membrane. Int. J. Hydrogen Energy 40, 13964
13978. Kuang, Q., Zhang, D., Yu, J.C., Chang, Y.W., Yue, M., Hou, Y., et al., 2015. Toward record-high stiffness in polyurethane nanocomposites using aramid nanofibers. J. Phys. Chem. C 119, 27467
27477. Li, Z., Cheng, X., He, S., Shi, X., Gong, L., Zhang, H., 2016a. Aramid fibers reinforced silica aerogel composites with low thermal conductivity and improved mechanical performance. Compos. Part A Appl. Sci. Manuf. 84, 316
325. Li, Z., Gong, L., Cheng, X., He, S., Li, C., Zhang, H., 2016b. Flexible silica aerogel composites strengthened with aramid fibers and their thermal behavior. Mater. Des. 99, 349
355. Liu, Y., Kumar, S., 2014. Polymer/carbon nanotube nano composite fibers
a review. ACS Appl. Mater. Interfaces 6, 6069
6087. Mallakpour, S., Kowsari, E., 2003. Synthesis and characterization of novel, optically active poly(amide-imide)s from N, N0 -(4,40 -sulfonediphthaloyl)-bis-L-phenylalanine diacid chloride and aromatic diamines under microwave irradiation. J. Polym. Sci. Part A: Polym. Chem. 41, 3974
3988. Mallakpour, S., Kowsari, E., 2004a. Application of microwave irradiation for synthesis of novel optically active poly(amide imides) derived from diacid chloride containing epiclon and L-isoleucine with aromatic diamines. J. Appl. Polym. Sci. 93, 2218
2229. Mallakpour, S., Kowsari, E., 2004b. Microwave-assisted and conventional polycondensation reaction of optically active N, N-(4,4-sulphonediphthaloyl)-bis-L-leucine diacid chloride with aromatic diamines. J. Appl. Polym. Sci. 93, 2992
3000. Mallakpour, S., Kowsari, E., 2005a. Preparation and characterization of optically active and organosoluble poly(amide-imide)s from polycondensation reaction of N, N0 -(4,4’sulphonediphthaloyl)-bis-L-isoleucine diacid with aromatic diamines. Polym. Adv. Technol. 16, 466
472. Mallakpour, S., Kowsari, E., 2005b. Soluble novel optically active poly(amide-imide)s derived from N, N0 -(4,40 -oxydiphthaloyl)-bis-L-leucine diacid chloride and various aromatic diamines: synthesis and characterization. J. Appl. Polym. Sci. 96, 435
442. Mallakpour, S., Kowsari, E., 2005c. Preparation and characterization of new optically active poly(amide imide)s derived from N, N0 -(4,40 -sulphonediphthaloyl)-bis-(s)(1)-valine diacid chloride and aromatic diamines under microwave irradiation. Polym. Bull. 53, 169
180. Mallakpour, S., Kowsari, E., 2005d. Direct polycondensations of N, N0 -(4,4-oxydiphthaloyl)-bis-L-leucine diacid by use of tosyl chloride in the presence of N, N0 -“dimethylformamide. Polym. Adv. Technol. 16, 795
799.

201

202

CHAPTER 6 Aramid fibers composites to innovative sustainable

Mallakpour, S., Kowsari, E., 2005e. Synthesis and characterization of new optically active poly(amide-imide)s containing epiclon and L-methionine moieties in the main chain. Polym. Adv. Technol. 16, 732
737. Mallakpour, S., Kowsari, E., 2005f. Synthesis and properties of novel soluble and thermally stable optically active poly(amide-imide)s from N, N0 -(4,40 -oxydiphthaloyl)-bisL-phenylalanine diacid chloride and aromatic diamines. Polym. Bull 54, 147
155. Mallakpour, S., Kowsari, E., 2005g. Synthesis of organosoluble and optically active poly (ester-imide)s by direct polycondensation with tosyl chloride in pyridine and dimethylformamide. Polym. Bull. 55, 51
59. Mallakpour, S., Kowsari, E., 2005h. Synthesis and properties of organosoluble and optically active poly(amide-imide)sbased on epiclon and (s)-(1)-valine undermicrowave irradiation. Iran Polym. J. 14, 81
90. Mallakpour, S., Kowsari, E., 2005i. Polycondensation reaction of N, N0 -(4,40 -oxydiphthaloyl)bis-L-isoleucine diacid chloride with aromatic diamines. Iran Polym. J. 14, 799
806. Mallakpour, S., Kowsari, E., 2005j. Ionic liquids as novel solvents and catalysts for the direct polycondensation of N, N0 -(4,40 -oxydiphthaloyl)-bis-L-phenylalanine diacid with various aromatic diamines. J. Polym. Sci. Part A: Polym. Chem. 43, 6545
6553. Mallakpour, S., Kowsari, E., 2006a. Polycondensation reaction of N, N0 -(4,40 -oxydiphthaloyl)-bis-L-methionine diacid chloride with aromatic diamines: synthesis and properties. J. Appl. Polym. Sci. 99, 1038
1044. Mallakpour, S., Kowsari, E., 2006b. Preparation and characterization of new thermally stable and optically active poly(ester-imide)s by direct polycondensation with thionyl chloride in pyridine. Polym. Adv. Technol. 17, 174
179. Mallakpour, S., Kowsari, E., 2006c. Thermally stable and optically active poly(amideimide)s derived from 4,40
(hexafluoroisopropylidene)-N, N0 -bis-(phthaloyl-L-methionine) diacid chloride and various aromatic diamines: synthesis and characterization. Polym. Bull. 57, 169
178. Mallakpour, S., Kowsari, E., 2006d. Preparation and characterization of new optically active poly(amide-imide)s derived from N, N-(4,4-oxydiphthaloyl)-bis-(s)-(1)-valine diacid chloride and aromatic diamines. Polym. Eng. Sci. 46, 558
565. Mallakpour, S., Kowsari, E., 2006e. Microwave heating in conjunction with ionic liquid as a novel method for the fast synthesis of optically active poly(amideimide) s derived from N, N0 -(4,40 -hexafluoroisopropylidenediphthaloyl)- bis-L-methionine and various aromatic diamines. Iran Polym. J. 15, 239
247. Mallakpour, S., Kowsari, E., 2006f. Thionyl chloride/pyridine system as a condensing agent for the polyesterification reaction of N, N0 -(4,40 -oxydiphthaloyl)-bis-L-leucine and aromatic diols. Iran Polym. J. 15, 457
465. Mallakpour, S., Kowsari, E., 2006g. Synthesis of novel optically active poly(ester imide)s by direct polycondensation reaction promoted by tosyl chloride in pyridine in the presence of N, N-dimethyformamide. J. Appl. Polym. Sci. 101, 455
460. Mallick, P.K., 2007. Fiber-Reinforced Composites: Materials, Manufacturing, and Design, third ed. CRC Press, Florida. Manet, S., Tibirna, C., Boivin, J., Delabroye, C., Brisson, J., 2006. Single crystals of chainfolded copolyterephthalamides. Macromolecules 39, 1093
1101. Monticelli, O., Mendichi, R., Bisbano, S., Mariani, A., Russo, S., 2000. Synthesis, characterization and properties of a hyperbranched aromatic polyamide: poly(ABZAIA). Macromol. Chem. Phys. 201, 2123
2127.

References

Monticelli, O., Oliva, D., Russo, S., Clausnitzer, C., tschke, P.P., Voit, B., 2003. On blends of polyamide 6 and a hyperbranched aramid. Macromol. Mater. Eng. 288, 318
325. Mukundan, S., Sant, V., Goenka, S., Franks, J., Rohan, L.C., Sant, S., 2015. Nanofibrous composite scaffolds of poly(ester amides) with tunable physicochemical and degradation properties. Eur. Polym. J. 68, 21
35. Park, B., Lee, W., Lee, E., Min, S.H., Kim, B.S., 2015. Highly tunable interfacial adhesion of glass fiber by hybrid multilayers of graphene oxide and aramid nanofiber. ACS Appl. Mater. Interfaces 7, 3329
3334. Patterson, B.A., Sodano, H.A., 2016. Enhanced interfacial strength and UV shielding of aramid fiber composites through ZnO nanoparticle sizing. ACS Appl. Mater. Interfaces 8, 33963
33971. Ruijter, C.D., Jager, W.F., Groenewold, J., Picken, S.J., 2006. Synthesis and characterization of rod 2 coil poly(amide-block-aramid) alternating block copolymers. Macromolecules 39, 3824
3829. Sa, R., Yan, Y., Wei, Z., Zhang, L., Wang, W., Tian, M., 2014. Surface modification of aramid fibers by bio-inspired poly(dopamine) and epoxy functionalized silane grafting. ACS Appl. Mater. Interfaces 6, 21730
21738. Seyler, H., Kilbinger, A.F.M., 2010. Hairy aramide rod 2 coil copolymers. Macromolecules 43, 5659
5664. Shabbir, S., Zulfiqar, S., Ahmad, Z., Sarwar, M.I., 2010a. Synthesis, characterization and functionalization of thermally stable hyperbranched polyamide-ethers based on 6hydroxy-2,4-bis(40 -nitrobenzamide)pyrimidine. Polym. Degrad. Stab. 95, 500
507. Shabbir, S., Zulfiqar, S., Ahmad, Z., Sarwar, M.I., 2010b. Synthesis and properties of hyperbranched polyamide
esters derived from 1,3,5-tris(40 -droxyphenylcarbamoyl) benzene. Tetrahedron 66, 1389
1398. Shabbir, S., Zulfiqar, S., Ahmad, Z., Muhammad Ilyas Sarwar, M.I., 2010c. Pyrimidine based carboxylic acid terminated aromatic and semiaromatic hyperbranched polyamide-esters: synthesis and characterization. Tetrahedron 66, 7204
7212. Teo, A.J.T., Mishra, A., Park, I., Kim, Y.J., Park, W.T., Yoon, Y.J., 2016. Polymeric biomaterials for medical implants and devices. ACS Biomater. Sci. Eng. 2, 454
472. Wan, Y.Z., Chen, G.C., Huang, Y., Li, Q.Y., Zhou, F.G., Xin, J.Y., et al., 2005. Characterization of three-dimensional braided carbon/Kevlar hybrid composites for orthopedic usage. Mater. Sci. Eng. A 398, 227
232. Wan, Y.Z., Wang, Y.L., Huang, Y., Luo, H.L., He, F., Chen, G.C., 2006. Moisture absorption in a three-dimensional braided carbon/Kevlar/epoxy hybrid composite for orthopaedic usage and its influence on mechanical performance. Compos. Part A Appl. J. 37, 1480
1484. Wang, W., Li, R., Tian, M., Liu, L., Zou, H., Zhao, X., et al., 2013. Surface silverized meta-aramid fibers prepared by bio-inspired poly(dopamine) functionalization. ACS Appl. Mater. Interfaces 5, 2062
2069. Wang, L., Shi, Y., Chen, S., Wang, W., Tian, M., Ning, N., et al., 2016a. Highly highly efficient mussel-like inspired modification of aramid fibers by UV-accelerated catechol/polyamine deposition followed chemical grafting for high-performance polymer composites. Chem. Eng. J. Available from: https://doi.org/10.1016/j.cej.2016.12.015. Wang, L., Shi, Y., Sa, R., Ning, N., Wang, W., Tian, M., et al., 2016b. Surface modification of aramid fibers by catechol/polyamine codeposition followed by silane grafting for enhanced interfacial adhesion to rubber matrix. Ind. Eng. Chem. Res. 55, 12547
12556.

203

204

CHAPTER 6 Aramid fibers composites to innovative sustainable

Yang, H.H., 1992. Kevlar Aramid Fiber. John Wiley & Sons, New York. Yu, Y., Rong, M.Z., Zhang, M.Q., 2010. Grafting of hyperbranched aromatic polyamide onto silica nanoparticles. Polymer 51, 492
499. Zhang, J.M., Mousavi, Z., Soykeabkaew, N., Smith, P., Nishino, T., Peijs, T., 2010. Allaramid composites by partial fiber dissolution. ACS Appl. Mater. Interfaces 2, 919
926. Zhang, H., Liang, G., Gu, A., Yuan, L., 2014. Facile preparation of hyperbranched polysiloxane-grafted aramid fibers with simultaneously improved UV resistance, surface activity, and thermal and mechanical properties. Ind. Eng. Chem. Res. 53, 2684
2696. Zhu, J., Cao, W., Yue, M., Hou, Y., Han, J., Yang, M., 2015. Strong and stiff aramid nanofiber/carbon nanotube nanocomposites. ACS Nano 9, 2489
2501.