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Tensile Properties of coconut Coir single fiber with alkali treatment and reinforcement effect on unsaturated polyester polymer
Available online at www.sciencedirect.com
ScienceDirect www.materialstoday.com/proceedings Materials Today: Proceedings 22 (2020) 300–305
2018 2nd International Conference on Nanomaterials and Biomaterials, ICNB 2018, 10–12December 2018, Barcelona, Spain
Tensile Properties of coconut Coir single fiber with alkali treatment and reinforcement effect on unsaturated polyester polymer Arya Widnyanaa, I Gde Riana, I Wayan Suratab, Tjokorda Gde Tirta Nindhiab,* a
Under graduate student at Study Program ofMechanical Engineering, Engineering Faculty, Udayana University, Jimbaran, Bali, 80361, Indonesia b
Study Program ofMechanical Engineering, Engineering Faculty, Udayana University, Jimbaran, Bali, 80361, Indonesia
Abstract Many reports related with alkali treatment on coir of coconut are available but the data related with the stress-strain curve is not provided. In this research stress-strain curve of tensile test data of the coconut single fiber obtained from alkali treatment with 5% NaOH is provided. Seven repetitions was conducted. The results indicate that the fiber is linier elastic with no indication as ductile material. The average of tensile strength is 130.9 MPa, failure (maximum) strain is 22.4 % and modulus of elasticity is 681.4 MPa. Randomly addition of 3 cm length of coconut fiber with fraction 15% in to the unsaturated polyester give maximum reinforcement that reach tensile strength of the composite about 24.5 MPa © 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the 2018 2nd International Conference on Nanomaterials and Biomaterials.
Keywords: Coconut, single, fiber, tensile, strength, reinforcement, unsaturated polyester
1. Introduction Composites material can be made in various way, one of that is by a polymer resin reinforced by fibers, merging physical enactment of polymer such as the appearance, bonding, physical properties of polymers and mechanical properties of the fiber. For these purpose the exchange of industrial fibers with natural fibers could be considered. Natural fibers traditionally employed in sacking, ropes and weaving that present various abilities to be used as
* Corresponding author. Tel.: +62-08179405539; fax: +62-0361-4746071. E-mail address:[email protected] 1876-6102© 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the 2018 2nd International Conference on Nanomaterials and Biomaterials.
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reinforcement elements in composites. The usage of synthetic fibers is confined due to high production cost whereas natural fibers apart from being cheap in cost, it is also amply available, less weight and strong [1]. Coconut coir is available in abundance in tropical countries as a waste product after consumption. Such abundance can fulfill the demand of filler based composites while reducing waste. Processing and procurement of coconut coir is cost effective than other artificial fillers [2]. Coconut coir belongs to the category fibers/fibrous materials, have high cellulose content and thus high lignin content, which it is strong, and highly durable and resilient. Coconut fiber is obtained from the Mesocarp of the fruit of Cocas nucifera, from the coconut palm tree, which belongs to the Palme. The lightness of the fibers is due to the cavities arising from the dried out sieve cells [3]. Coconut fiber having green properties of 36.52% lignin, 33.61% cellulose 33.61%, 29,27 % pentosan, ash 0.61%. Meanwhile the dry properties as 29.23% lignin, 26.00 %total water soluble, 23.81 cellulose, 8.50 % hemicelluloses [3]. The highest percentage in the coconut fiber which is lignocelluloses material is lignin which makes the fiber having very high and stiffer when compare to other natural fiber. The lignin provide the plant tissue and the individual cells with compressive strength and also stiffness the cell wall of the fiber. The lignin content influences the structure, hydrolysis rate, properties, flexibility. High lignin content appear to be more flexible and finer [3]. Coconut fiber is widely use for many application and still in progress for many other purpose. It is the only fruit fiber that usable in the textile industry [3]. Addition of coconut fiber in to the matrix polymer is found increasing damping ratio that make composite not only suitable for strength related properties but also for giving advantage to the structure in reducing the high resonant [4]. Coconut fiber is potential to be develop as filter for ultrafine particle emitted by motor vehicles [5]. Interestingly coconut coir have potential use for carbon paper of gas diffusion layer (GDL) in proton exchange membrane fuel cells (PEMFC) [6]. Recently coconut fiber is developed for leaf spring. The main objective of this project is to reduce the weight of an automobile by replacing its steel leaf spring with composite leaf spring that would produce same deflection when the load applied is constant [7]. Research also pay attention on coconut fiber composites that can become a substitute for plywood and medium density fiber boards used in packaging application [8]. Composite with coconut fiber as reinforcement was initiated also for military helmet [9]. For many application above mentioned, coconut coir need to be treated by using alkali treatment in order to obtain fine fiber of coconut. It is the purpose of this research to provided tensile properties data of coconut coir single fiber with alkali treatment and observe reinforcement effect on unsaturated polyester polymer. 2. Experimental The section coconut coir is soaked in alkali (5 % NaOH) for 2 hours and gently stirring until the fiber well separated. The reason of selection of this 5% concentration of NaOH solution was because previous research indicated that with concentration 5%NaOH resulting the highest surface roughness (4 mm) comparing to other higher concentration (10%, 15% and 20%) [10]. The fiber obtained was washed with distillated water. Clean fiber was dried in the oven at 90oC. The diameters of coconut fiber of each tested material were measured. Optical microscope is used to measure the diameter of the coconut single fiber. The diameter measurements were performed on coconut single fiber at three different equidistant points of the fiber. The average of the fiber diameter represented the mean diameter value for each single fiber that was investigated. The tensile strength test analysis has been carried out following standard test method for tensile strength and modulus of elasticity of fiber [11]. Tensile testing has been performed to evaluate the tensile strength, modulus elasticity, and strain (ϵ) of coconut single fiber. Seven times repetition of valid tensile tests were conducted. The average value of tensile test will be provided. A mounting tab (Fig. 1) is used for specimen mounting. Suitable adhesive is placed on the mounting tab with define gage length. The fiber is bond to the mounting tab. The gauge length in this research is 50 mm.
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Fig. 1. Single fiber arrangement for tensile test.
The tensile strength test analysis has been carried out following standard test method for tensile strength and modulus of elasticity of fiber [11]. Tensile testing has been performed to evaluate the tensile strength, modulus elasticity, and strain (ϵ) of coconut single fiber. Seven times repetition of valid tensile tests were conducted. The average value of tensile test will be provided. A mounting tab (Fig. 1) is used for specimen mounting. Suitable adhesive is placed on the mounting tab with define gage length. The fiber is bond to the mounting tab. The gauge length in this research is 50 mm. The tensile strength (σ) was calculated by using Equation 1. Where F is force to failure (N), A is a cross sectional area fracture plane normal to fiber axis (m2). The tensile strain (ϵ) was measure by using Equation 2 [11].
σ =
F A
(1)
The tensile strain (ε) was measure by using Equation 2. Where Δl is elongation of the gage length(mm) and l0 is the gage length (mm) [11]
ε=
Δl l0
(2)
Young’s modulus (E) of the fiber was calculated by using Equation 3[11].
E=
σ ε
(3)
The research was continued to understand the reinforcement effect of addition coconut fiber obtained with alkali treatment to unsaturated polyester polymer. The coconut fiber is cut around 3 cm in length and mixed randomly in to unsaturated polyester polymer with metiletilketon peroxide as hardener. The tensile test sample for this purpose was followed ASTM D3090 standard [12]. It was prepared 4 variations (mass %) of sample for this purpose namely: 0%, 5%, 10%, and 15% . The curing temperature is 60oC for 2 hours. The graph of strain versus strain was presented to analyze the reinforcement mechanism. Fractography of fracture surface was observed by using optical microscope.
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3. Result and discussion The coconut fiber can be released from coconut coir by alkali treatment as introduced in this research. The release is caused by reaction of the alkali solution with lignin and hemicelluloses as reported in previous publication [10]. The result of tensile test for single fiber of coconut that is treated with alkali treatment (5% NaOH) is presented in Fig. 2 and the value can be found in Table 1. For all 7 samples that are tested, all reveal linier elastic properties with no indication as ductile fiber. The average tensile strength is found about 130.9 MPa with average failure strain 22.4 %. The Average of modulus elasticity (E) is 681.4 MPa. The tensile strength and failure strain that is obtained in this research were found lower than previous report [10]. This is could be due to in this research, the immersion time in alkali solution is for 2 hours. Immersion time in the alkali treatment in the previous report is 3 hours. Other reason is due to different source of coconut.
Fig. 2. Graph of stress-strain curves of 7 coconut single fibers with alkali treatment.
Table 1. The averages of tensile strength, maximum strain and Modulus Elasticity of coconut single fiber with alkali treatment (5% NaOH). Average Tensile strength (MPa)
Average max. strain %
130.9
22.4
Average modulus elasticity (MPa) 681.4
Addition of coconut fiber is found yield a positive effect for reinforcement of unsaturated polyester as can be seen in Fig. 3. In general, for all variation of coconut fiber fraction (5%, 10%, and 15% of coconut fiber) in to the matrix of unsaturated polyester, yield a higher tensile strength compared to one that without coconut fiber reinforcement (Table 2). The highest tensile strength is found at the sample with composition of 15% coconut fiber with average value reach 24.5 MPa. The values of failure strain are found decrease with the addition of coconut fiber until addition of 10% coconut fiber. If the addition coconut fiber is added until about 15 %, the value of average failure strain was found the same with the one without addition of coconut fiber which is reach 2.2%.
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Fig. 3. Graph of comparison stress-strain curve of unsaturated polyester reinforced coconutfiber with alkali treatment (5% NaOH) Table 2. The averages of tensile strength, maximum strain and modulus elasticity of unsaturated polyester reinforced coconut fiber. Unsaturated polyester composites reinforced coconut fiber 0% Coconut fiber 5% Coconut fiber 10% Coconut fiber 15% Coconut fiber
Average Tensile strength (MPa) 17.6 22.8 22.3 24.5
Average max. strain (%) 2.2 1.6 1.7 2.2
Average modulus elasticity (MPa) 830.9 1328.5 1275.6 1096.9
Fig. 4. Types of the fiber reinforcement that are found at the fracture surface of the composite of the polyester reinforced randomly with 3 cm coconut fiber.
The fiber reinforcement of the matrix in the composite usually in the form of overload, pullout, delamination and matrix flow [13]. Observation of fracture surface indicate that all method reinforcement of fiber on the matrix are occurred in the composite of unsaturated polyester reinforce coconut fiber. As for r example, Fig. 4 is the fracture surface of composite that is reinforced randomly with 10% of coconut fiber. All type of reinforcement such overload, pullout, delamination and matrix flow are found clearly on the fracture surface
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4. Conclusion The coconut fiber can be released from coconut coir by alkali treatment of 5% NaOH for 2 hour and drying at 90oC. The resulting fiber having average of tensile strength of 130.9 MPa, failure (maximum) strain 22.4 %, and modulus of elasticity 681.4 MPa. Randomly addition of 3 cm length of coconut fiber with fraction 15% in to the unsaturated polyester give maximum reinforcement that reach tensile strength of the composite about 24.5 MPa. All type of fiber reinforcement of the composite such overload, pullout, delamination, and matrix flow are found clearly on the fracture surface. Acknowledgements This research is supported by grant research of Program Karya Ilmiah Mahasiswa (PKM) from the ministry of research technology and higher education (Ristekdikti) The Republic of Indonesia. References [1] P. Sathish, R.Kesavan, and N. Mahaviradhan."Coconut Fiber Reinforced Composites: A Review. "International Journal for Research in Applied Science & Engineering Technology 5 (3)(2017):171-172. [2] A. Singh, S. Singh and A. Kumar."Study of Mechanical Properties and Absorption Behaviour of Coconut Shell Powder-Epoxy Composites."International Journal of Materials Science and Applications 2(5)(2013):157-161. [3] T. B. Reddy."Mechanical Performance of Green Coconut Fiber/HDPE Composites International."Journal of Engineering Research and Applications 3(6)(2013):1261-1270. [4] P. N. E. Naveen and M. Yasaswi."experimental analysis of coir-fiber reinforced polymer composite materials."International Journal of Mechanical Engineering and Robotic research 2(2) (2013):10-18. [5] A.Y.P. Wardoyo, U.P. Juswono, and S. Riyanto."Developing Particulate Thin Filter Using Coconut Fiber for Motor Vehicle Emission."AIPConf Proc, 1719(2016):030043.1-030043.4. [6] F. Destyorini, Indriyati, N. Indayaningsih, B. Prihandoko and A. Z. Syahrial." Properties of carbon composite paper derived from coconut coir as a function of polytetrafluoroethylene content."Materials Science and Engineering316(012054)(2018):1-7. [7] N. Babu, B. Shivasai, V. Mahesh, and P. Reddy." Design and analysis of coconut fiber reinforced polyester composite leafspring."International Journal of Mechanical Engineering and Technology 8(6)(2017):544–552. [8] V. Balaji , and K. S. Vadivu."Mechanical Characterization of Coir Fiber and Cotton Fiber reinforced Unsaturated Polyester Composites for Packaging Applications." Journal of Applied Packaging Research 9(2)(2017):12-19. [9] S.Natsa, J. O Akindapo and D. K Garba."Development of a military helmet using coconut fiber reinforced polymer matrix composite."European Journal of Engineering and Technology3 (7)(2015):55-65. [10 ]ASTM C 1557 -03."Standard Test Method for Tensile Strength and Young’s Modulus of Fibers." ASTM international (2003), PA, United State. [11]ASTM D 3039."Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials."ASTM international (2002) PA, United State. [12]M. Arsyad."Effect of alkali treatment on the coconut fiber surface."ARPN Journal of Engineering and Applied Sciences 12( 6)(2017):18701875. [13]B. R. Charlie and A. Choudury."Failur Analysis of Engineering Materials."(2002) McGraw-Hill,Inc.
ScienceDirect www.materialstoday.com/proceedings Materials Today: Proceedings 22 (2020) 300–305
2018 2nd International Conference on Nanomaterials and Biomaterials, ICNB 2018, 10–12December 2018, Barcelona, Spain
Tensile Properties of coconut Coir single fiber with alkali treatment and reinforcement effect on unsaturated polyester polymer Arya Widnyanaa, I Gde Riana, I Wayan Suratab, Tjokorda Gde Tirta Nindhiab,* a
Under graduate student at Study Program ofMechanical Engineering, Engineering Faculty, Udayana University, Jimbaran, Bali, 80361, Indonesia b
Study Program ofMechanical Engineering, Engineering Faculty, Udayana University, Jimbaran, Bali, 80361, Indonesia
Abstract Many reports related with alkali treatment on coir of coconut are available but the data related with the stress-strain curve is not provided. In this research stress-strain curve of tensile test data of the coconut single fiber obtained from alkali treatment with 5% NaOH is provided. Seven repetitions was conducted. The results indicate that the fiber is linier elastic with no indication as ductile material. The average of tensile strength is 130.9 MPa, failure (maximum) strain is 22.4 % and modulus of elasticity is 681.4 MPa. Randomly addition of 3 cm length of coconut fiber with fraction 15% in to the unsaturated polyester give maximum reinforcement that reach tensile strength of the composite about 24.5 MPa © 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the 2018 2nd International Conference on Nanomaterials and Biomaterials.
Keywords: Coconut, single, fiber, tensile, strength, reinforcement, unsaturated polyester
1. Introduction Composites material can be made in various way, one of that is by a polymer resin reinforced by fibers, merging physical enactment of polymer such as the appearance, bonding, physical properties of polymers and mechanical properties of the fiber. For these purpose the exchange of industrial fibers with natural fibers could be considered. Natural fibers traditionally employed in sacking, ropes and weaving that present various abilities to be used as
* Corresponding author. Tel.: +62-08179405539; fax: +62-0361-4746071. E-mail address:[email protected] 1876-6102© 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the 2018 2nd International Conference on Nanomaterials and Biomaterials.
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301
reinforcement elements in composites. The usage of synthetic fibers is confined due to high production cost whereas natural fibers apart from being cheap in cost, it is also amply available, less weight and strong [1]. Coconut coir is available in abundance in tropical countries as a waste product after consumption. Such abundance can fulfill the demand of filler based composites while reducing waste. Processing and procurement of coconut coir is cost effective than other artificial fillers [2]. Coconut coir belongs to the category fibers/fibrous materials, have high cellulose content and thus high lignin content, which it is strong, and highly durable and resilient. Coconut fiber is obtained from the Mesocarp of the fruit of Cocas nucifera, from the coconut palm tree, which belongs to the Palme. The lightness of the fibers is due to the cavities arising from the dried out sieve cells [3]. Coconut fiber having green properties of 36.52% lignin, 33.61% cellulose 33.61%, 29,27 % pentosan, ash 0.61%. Meanwhile the dry properties as 29.23% lignin, 26.00 %total water soluble, 23.81 cellulose, 8.50 % hemicelluloses [3]. The highest percentage in the coconut fiber which is lignocelluloses material is lignin which makes the fiber having very high and stiffer when compare to other natural fiber. The lignin provide the plant tissue and the individual cells with compressive strength and also stiffness the cell wall of the fiber. The lignin content influences the structure, hydrolysis rate, properties, flexibility. High lignin content appear to be more flexible and finer [3]. Coconut fiber is widely use for many application and still in progress for many other purpose. It is the only fruit fiber that usable in the textile industry [3]. Addition of coconut fiber in to the matrix polymer is found increasing damping ratio that make composite not only suitable for strength related properties but also for giving advantage to the structure in reducing the high resonant [4]. Coconut fiber is potential to be develop as filter for ultrafine particle emitted by motor vehicles [5]. Interestingly coconut coir have potential use for carbon paper of gas diffusion layer (GDL) in proton exchange membrane fuel cells (PEMFC) [6]. Recently coconut fiber is developed for leaf spring. The main objective of this project is to reduce the weight of an automobile by replacing its steel leaf spring with composite leaf spring that would produce same deflection when the load applied is constant [7]. Research also pay attention on coconut fiber composites that can become a substitute for plywood and medium density fiber boards used in packaging application [8]. Composite with coconut fiber as reinforcement was initiated also for military helmet [9]. For many application above mentioned, coconut coir need to be treated by using alkali treatment in order to obtain fine fiber of coconut. It is the purpose of this research to provided tensile properties data of coconut coir single fiber with alkali treatment and observe reinforcement effect on unsaturated polyester polymer. 2. Experimental The section coconut coir is soaked in alkali (5 % NaOH) for 2 hours and gently stirring until the fiber well separated. The reason of selection of this 5% concentration of NaOH solution was because previous research indicated that with concentration 5%NaOH resulting the highest surface roughness (4 mm) comparing to other higher concentration (10%, 15% and 20%) [10]. The fiber obtained was washed with distillated water. Clean fiber was dried in the oven at 90oC. The diameters of coconut fiber of each tested material were measured. Optical microscope is used to measure the diameter of the coconut single fiber. The diameter measurements were performed on coconut single fiber at three different equidistant points of the fiber. The average of the fiber diameter represented the mean diameter value for each single fiber that was investigated. The tensile strength test analysis has been carried out following standard test method for tensile strength and modulus of elasticity of fiber [11]. Tensile testing has been performed to evaluate the tensile strength, modulus elasticity, and strain (ϵ) of coconut single fiber. Seven times repetition of valid tensile tests were conducted. The average value of tensile test will be provided. A mounting tab (Fig. 1) is used for specimen mounting. Suitable adhesive is placed on the mounting tab with define gage length. The fiber is bond to the mounting tab. The gauge length in this research is 50 mm.
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Fig. 1. Single fiber arrangement for tensile test.
The tensile strength test analysis has been carried out following standard test method for tensile strength and modulus of elasticity of fiber [11]. Tensile testing has been performed to evaluate the tensile strength, modulus elasticity, and strain (ϵ) of coconut single fiber. Seven times repetition of valid tensile tests were conducted. The average value of tensile test will be provided. A mounting tab (Fig. 1) is used for specimen mounting. Suitable adhesive is placed on the mounting tab with define gage length. The fiber is bond to the mounting tab. The gauge length in this research is 50 mm. The tensile strength (σ) was calculated by using Equation 1. Where F is force to failure (N), A is a cross sectional area fracture plane normal to fiber axis (m2). The tensile strain (ϵ) was measure by using Equation 2 [11].
σ =
F A
(1)
The tensile strain (ε) was measure by using Equation 2. Where Δl is elongation of the gage length(mm) and l0 is the gage length (mm) [11]
ε=
Δl l0
(2)
Young’s modulus (E) of the fiber was calculated by using Equation 3[11].
E=
σ ε
(3)
The research was continued to understand the reinforcement effect of addition coconut fiber obtained with alkali treatment to unsaturated polyester polymer. The coconut fiber is cut around 3 cm in length and mixed randomly in to unsaturated polyester polymer with metiletilketon peroxide as hardener. The tensile test sample for this purpose was followed ASTM D3090 standard [12]. It was prepared 4 variations (mass %) of sample for this purpose namely: 0%, 5%, 10%, and 15% . The curing temperature is 60oC for 2 hours. The graph of strain versus strain was presented to analyze the reinforcement mechanism. Fractography of fracture surface was observed by using optical microscope.
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3. Result and discussion The coconut fiber can be released from coconut coir by alkali treatment as introduced in this research. The release is caused by reaction of the alkali solution with lignin and hemicelluloses as reported in previous publication [10]. The result of tensile test for single fiber of coconut that is treated with alkali treatment (5% NaOH) is presented in Fig. 2 and the value can be found in Table 1. For all 7 samples that are tested, all reveal linier elastic properties with no indication as ductile fiber. The average tensile strength is found about 130.9 MPa with average failure strain 22.4 %. The Average of modulus elasticity (E) is 681.4 MPa. The tensile strength and failure strain that is obtained in this research were found lower than previous report [10]. This is could be due to in this research, the immersion time in alkali solution is for 2 hours. Immersion time in the alkali treatment in the previous report is 3 hours. Other reason is due to different source of coconut.
Fig. 2. Graph of stress-strain curves of 7 coconut single fibers with alkali treatment.
Table 1. The averages of tensile strength, maximum strain and Modulus Elasticity of coconut single fiber with alkali treatment (5% NaOH). Average Tensile strength (MPa)
Average max. strain %
130.9
22.4
Average modulus elasticity (MPa) 681.4
Addition of coconut fiber is found yield a positive effect for reinforcement of unsaturated polyester as can be seen in Fig. 3. In general, for all variation of coconut fiber fraction (5%, 10%, and 15% of coconut fiber) in to the matrix of unsaturated polyester, yield a higher tensile strength compared to one that without coconut fiber reinforcement (Table 2). The highest tensile strength is found at the sample with composition of 15% coconut fiber with average value reach 24.5 MPa. The values of failure strain are found decrease with the addition of coconut fiber until addition of 10% coconut fiber. If the addition coconut fiber is added until about 15 %, the value of average failure strain was found the same with the one without addition of coconut fiber which is reach 2.2%.
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Fig. 3. Graph of comparison stress-strain curve of unsaturated polyester reinforced coconutfiber with alkali treatment (5% NaOH) Table 2. The averages of tensile strength, maximum strain and modulus elasticity of unsaturated polyester reinforced coconut fiber. Unsaturated polyester composites reinforced coconut fiber 0% Coconut fiber 5% Coconut fiber 10% Coconut fiber 15% Coconut fiber
Average Tensile strength (MPa) 17.6 22.8 22.3 24.5
Average max. strain (%) 2.2 1.6 1.7 2.2
Average modulus elasticity (MPa) 830.9 1328.5 1275.6 1096.9
Fig. 4. Types of the fiber reinforcement that are found at the fracture surface of the composite of the polyester reinforced randomly with 3 cm coconut fiber.
The fiber reinforcement of the matrix in the composite usually in the form of overload, pullout, delamination and matrix flow [13]. Observation of fracture surface indicate that all method reinforcement of fiber on the matrix are occurred in the composite of unsaturated polyester reinforce coconut fiber. As for r example, Fig. 4 is the fracture surface of composite that is reinforced randomly with 10% of coconut fiber. All type of reinforcement such overload, pullout, delamination and matrix flow are found clearly on the fracture surface
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4. Conclusion The coconut fiber can be released from coconut coir by alkali treatment of 5% NaOH for 2 hour and drying at 90oC. The resulting fiber having average of tensile strength of 130.9 MPa, failure (maximum) strain 22.4 %, and modulus of elasticity 681.4 MPa. Randomly addition of 3 cm length of coconut fiber with fraction 15% in to the unsaturated polyester give maximum reinforcement that reach tensile strength of the composite about 24.5 MPa. All type of fiber reinforcement of the composite such overload, pullout, delamination, and matrix flow are found clearly on the fracture surface. Acknowledgements This research is supported by grant research of Program Karya Ilmiah Mahasiswa (PKM) from the ministry of research technology and higher education (Ristekdikti) The Republic of Indonesia. References [1] P. Sathish, R.Kesavan, and N. Mahaviradhan."Coconut Fiber Reinforced Composites: A Review. "International Journal for Research in Applied Science & Engineering Technology 5 (3)(2017):171-172. [2] A. Singh, S. Singh and A. Kumar."Study of Mechanical Properties and Absorption Behaviour of Coconut Shell Powder-Epoxy Composites."International Journal of Materials Science and Applications 2(5)(2013):157-161. [3] T. B. Reddy."Mechanical Performance of Green Coconut Fiber/HDPE Composites International."Journal of Engineering Research and Applications 3(6)(2013):1261-1270. [4] P. N. E. Naveen and M. Yasaswi."experimental analysis of coir-fiber reinforced polymer composite materials."International Journal of Mechanical Engineering and Robotic research 2(2) (2013):10-18. [5] A.Y.P. Wardoyo, U.P. Juswono, and S. Riyanto."Developing Particulate Thin Filter Using Coconut Fiber for Motor Vehicle Emission."AIPConf Proc, 1719(2016):030043.1-030043.4. [6] F. Destyorini, Indriyati, N. Indayaningsih, B. Prihandoko and A. Z. Syahrial." Properties of carbon composite paper derived from coconut coir as a function of polytetrafluoroethylene content."Materials Science and Engineering316(012054)(2018):1-7. [7] N. Babu, B. Shivasai, V. Mahesh, and P. Reddy." Design and analysis of coconut fiber reinforced polyester composite leafspring."International Journal of Mechanical Engineering and Technology 8(6)(2017):544–552. [8] V. Balaji , and K. S. Vadivu."Mechanical Characterization of Coir Fiber and Cotton Fiber reinforced Unsaturated Polyester Composites for Packaging Applications." Journal of Applied Packaging Research 9(2)(2017):12-19. [9] S.Natsa, J. O Akindapo and D. K Garba."Development of a military helmet using coconut fiber reinforced polymer matrix composite."European Journal of Engineering and Technology3 (7)(2015):55-65. [10 ]ASTM C 1557 -03."Standard Test Method for Tensile Strength and Young’s Modulus of Fibers." ASTM international (2003), PA, United State. [11]ASTM D 3039."Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials."ASTM international (2002) PA, United State. [12]M. Arsyad."Effect of alkali treatment on the coconut fiber surface."ARPN Journal of Engineering and Applied Sciences 12( 6)(2017):18701875. [13]B. R. Charlie and A. Choudury."Failur Analysis of Engineering Materials."(2002) McGraw-Hill,Inc.