- Email: [email protected]
Wear and Friction Properties of Epoxy- Polyamide Blend Nanocomposites Reinforced by MWCNTs
Energy Procedia 00 (2018) 000–000
Available online at www.sciencedirect.com
www.elsevier.com/locate/procedia
ScienceDirect Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available Energy Procedia 00 (2018) 000–000
ScienceDirect ScienceDirect Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18, 19–21 September 2018, Athens, Greece Energy Procedia 157 Energy Procedia 00(2019) (2017)1561–1567 000–000 www.elsevier.com/locate/procedia
www.elsevier.com/locate/procedia
Wear and Friction Properties of Epoxy- Polyamide Blend Technologies andNanocomposites Materials for RenewableReinforced Energy, Environment and Sustainability, TMREES18, by MWCNTs 19–21 September 2018, Athens, Greece Yousif Abid Al Shaabania*
The 15th International Symposiumof on EpoxyDistrict Heating and CoolingBlend Wear and Friction Properties Polyamide Opened Educational College, Ministry of Education, IRAQ Nanocomposites Reinforced by MWCNTs Assessing the feasibility of using the heat demand-outdoor Abstract Yousif Abid Al Shaabania* temperature function for a long-term district heat demand forecast
In this paper, multi-walled carbon nanotubes (MWCNTs) were dispersed in a hardener to mixing it with an epoxy- polyamide Opened Educational College, Ministry of Education, IRAQ a,b,c a percentages ofa MWCNTs was studied. c fabricated by mechanical blend. TheI. influence of several weight ratio samples were Andrić *, A. Pina , P. Ferrão , J. Fournierb., B. The Lacarrière , O. Le Correc moulding method with axillary ultrasonic technique. The MWCNTs ratio was various between 0.1 and 0.9 wt% to find the a optimum filler ratio. The results obtained that the adding- Instituto of MWCNTs tribological properties. ThePortugal superior IN+ Center for Innovation, Technology and Policy Research Superiorimproved Técnico, Av.the Rovisco Pais 1, 1049-001 Lisbon, Abstract b tribological properties were 0.5 wt. Recherche (%) MWCNTs. Veolia & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France c et Environnement Atlantique, rue AlfredtoKastler, Nantes, France polyamide In this paper, Département multi-walledSystèmes carbon Énergétiques nanotubes (MWCNTs) were- IMT dispersed in a 4hardener mixing44300 it with an epoxyblend. The influence of several weight ratio percentages of MWCNTs was studied. The samples were fabricated by mechanical moulding method with axillary ultrasonic technique. The MWCNTs ratio was various between 0.1 and 0.9 wt% to find the optimum filler ratio. The results obtained that the adding of MWCNTs improved the tribological properties. The superior Abstract tribological properties were 0.5 wt. (%) MWCNTs. © 2018 The Authors. Published by Elsevier Ltd. heating networks are by commonly addressed in the literature as one of the most effective solutions for decreasing the ©District 2019 The Authors. Ltd. This is an open accessPublished article under Elsevier the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) greenhouse gasaccess emissions thethe building sector. These systems require high investments which are returned through the heat This is an open articlefrom under CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Selection andtopeer-review under responsibility of and the scientific Technologies and Materials Renewable Energy, sales. Due the changed climate conditions building committee renovationofpolicies, heat demand in thefor future could decrease, Environment and Sustainability, TMREES18. Environment andinvestment Sustainability, TMREES18. prolonging the return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand Keywords: MWCNTs nanostructures, resin, polyamide, tribological properties. ©forecast. 2018 The Authors. byepoxy Elsevier The districtPublished of Alvalade, locatedLtd. in Lisbon (Portugal), was used as a case study. The district is consisted of 665 This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district Selection and peer-review under responsibility of the scientific Technologies andobtained Materialsheat for demand Renewable Energy, renovation scenarios were developed (shallow, intermediate, committee deep). To of estimate the error, values were Environment and Sustainability, TMREES18. compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications Keywords: (the errorMWCNTs in annualnanostructures, demand wasepoxy lowerresin, thanpolyamide, 20% for tribological all weatherproperties. scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the * Corresponding author.considered). Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and E-mail address: Email:[email protected] improve the accuracy of heat demand estimations. 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. © 2017 The Authors. Published Elsevier Ltd. license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This is an open access article under thebyCC BY-NC-ND Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . and Sustainability, TMREES18. Cooling. E-mail address: Email:[email protected] Keywords: Heat demand; Forecast; Climate change 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18. 10.1016/j.egypro.2018.11.322
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Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
1. Introduction The study of tribological properties is very significant to avoid the failure for any application by choosing the convenient material, structure, design of component and processing issues [1]. Polymer blends have been identified as the greatest multipurpose and economical process to produce new multiphase polymer materials that are able to satisfy the complex demands for performance and application [2]. Polymer composites have gained great attention as high-performance materials for aerospace, automotive, defense, marine and civil engineering applications over the past few decades. This is because of the dimensional stability with high strength to stiffness ratio and worthy thermal, electrical, mechanical and tribological properties [3]. Polymer Matrix Composites (PMCs) are one of the most diverse composites materials due to their ability to contain a number of different filler materials. The past decade has been witnessed important advancement in production and application of carbon nanotube (CNT) since their discovery in 1991 [4], carbon nanotube, which have unique topological hollow tubular structure, because of the very excellent property, such high length diameter ratio, unique electronics property, mechanical performance and high thermal stability. CNT can be used to make the nanocomposites with admirable tribological properties. Comparatively few studies interconnected to tribological properties of polymer composite reinforced with CNT have been reported so far [5]. In this work MWCNTs were dispersed in the hardener, using sonication, and stirring techniques for mixing the hardener with the epoxy – polyamide resins. The effect of different weight ratio on the tribological properties of MWCNTs/ epoxy – polyamide nanocomposites was investigated. Wear and friction coefficients of the nanocomposites were calculated for all samples. According to the conditions of the disc – on – disc machine the wear rate (WR) in (g/cm), wear volume (WV) in (mm3/cm) and specific wear rate (WS) in (mm3/Nm) are calculated according to the following equations respectively [6]: 𝑊𝑊� � 𝑊𝑊� � 𝑊𝑊� �
∆𝑊𝑊 � � � � ��� 𝑆𝑆� 𝑊𝑊� � � � � ��� 𝜌𝜌
∆𝑉𝑉 � � � � � � ��� 𝐿𝐿𝐿𝐿𝐿�
Where: ΔW is the weight loss of the specimen before and after the wear test (gm). ΔV is the volume loss of the specimen before and after the wear test (mm3). L is the normal load (N). SD: is the sliding distance (m). Wear coefficient can be calculated using the Archard’s equation [7]: 𝑊𝑊����� �
∆𝑉𝑉𝑉𝑉𝑉� � � � � � � ��� 𝐿𝐿𝐿𝐿�
Where WCoeff is wear coefficient and HV is the hardness. Hardness can be defined as the resistance to permanent indentation or penetration. According to the conditions of disc – on – disc machine, the coefficient of friction can be calculated by using the following relationship: ��
𝜏𝜏 � � � � � � � ��� �𝐿 � 𝐿𝐿
Where is coefficient of friction, τ is friction torque in (mN), r is the radius of counter face steel disc in (m), and L is the applied normal load in (N). The friction torque value is obtained from the integrating disc counter before and after the wear test.
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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2. Materials and Methods The polymer epoxy resin type (DGEBA) (diglycidyl ether of bisphenol A) is a viscous liquid, white color, it supplied by Fosroc Jorden, commercially well-known as Nitocote EP (405), in the form of liquid, medium viscosity, good adhesion. The ratio between resin and hardener for this study is 5:1 by weight. Polyamide polymer is mixed with epoxy resin to have a blend matrix with weight ratio epoxy to polyamide (4:1). The MWCNT that used as a nano filler is supplied by Zhengzhou Dongyao Material Co.,LTD China. The outer diameter of MWCNT tube is 13 nm, the length of the carbon tube is equal (3-12) nm, the tube wall thickness is 4.1 nm, and the number of layer is 815. Figure (1) illustrated the TEM of MWCNT that taken by production company.
Fig. 1. TEM of MWCNT (Zhengzhou Dongyao Material Co.,LTD ).
The bulk density is 0.06 g/cm3. The surface area is 200 m2/g. The purity of MWCNTs is more than 90%. Figure 1 shows the (TEM) of MWCNTs that carried out by production Company. Nanocomposites are prepared by dispersing (MWCNTs) to achieve best state of dispersion the nanomaterial were treated with hardener medium for the deagglomeration of the nanomaterial by ultra-sonication for half hour at room temperature. The hardener having nanomaterial’s are additional to the blend resin (epoxy 405/polyamide) with weight ratio (5:1) with different ratio of MWCNTs and mixed for 2 minutes by hand made. The mixture was molded and cured for 24 h. The samples are treated at (353K) for 6 h in the oven to complete the cure process. The surfaces of the samples are polished mechanically to minimize the influence of surface defects, mainly the porosity. To prepare the nanocomposite samples, molds are made from Teflon. The mold muddy by oil before the mixture is poured into the mold. To calculation the weight of blends resin and MWCNTs sensitive electronic balance were used. The density of samples was calculated by Archimedean method. The specimens are weighted in air then weight in liquid (water) using Sartorius BL 210S (d = 0.1mg) balance to weigh the nanocomposite samples. The measurements of density must to be very accuracy since it very important for calculation of the tribological properties. Wear test have been accomplished in the disc – on - disc type wear and friction which was used to evaluate the wear behavior of the nanocomposite, against hardened ground stainless steel disc. In this test the curve end of disc specimen (40 mm) diameter was fixed vertically with the rotation disc throughout the test. The load 40 Newton was applied to the disc against the surface of rotating stainless steel disc. Every specimen was weighed before and after the test by a sensitive digital balance (0.1) milligram. The time of the test was measured by digital watch. [Disc - on – disc] test equipment’s which designed by tribological dynamic machine (TDM) to measure the wear rate of the prepared samples. The disc was used is made from stainless steel. The wear tests were performed in air at room temperature. The testing time (t) is (20) min.
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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3. Results and Discussion
ρ (gm/cm³)
The experimental values of density for epoxy- polyamide nanocomposites are illustrated in Figure (2). The experimental density values are measured by employing the Archimedean base [8]. Figure (3) illustrated the variations of micro hardness with addition of MWCNTs to epoxy- polyamide nanocomposites. The hardness values of nanocomposites are gradually increased when MWCNTs were added to the epoxy- polyamide blend matrix. The addition of MWCNTs, which have relatively higher material properties, donates to the increase in hardness of the epoxy- polyamide nanocomposites. The continuous increasing of micro hardness come from increasing the number of high strength nanomaterial inside the matrix, it caused increasing their hardness property. This result exhibit with that obtained by R. Zhou, et al. [9]. The increasing of the hardness was come from the effect of interface between the epoxy- polyamide blend matrix and the MWCNTs, As well as the high adhesion between them. 1.494 1.492 1.49 1.488 1.486 1.484 1.482
Fig. 2. The experimental density values of epoxy- polyamide blend /MWCNTs wt% ratio.
This Figure shows that the experimental values of density decreased with increasing the weight ratio of MWCNTs.
Vicars Hardens MPa
20 15 10 5 0
Fig. 3. The micro hardness values of epoxy- polyamide blend /MWCNTs wt% ratio.
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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0.1
WR 10ˉ⁶ gm/cm
0.08 0.06 0.04 0.02 0
Fig. 4. The wear rate values of epoxy- polyamide blend /MWCNTs wt% ratio.
The blend nanocomposites filled with different amounts of (MWCNTs) exhibits excellent wear properties. The wear results show that the reinforced specimens have enhanced wear resistance than the unreinforced specimens. It is clear from Figure 4 that the increasing of weight ratio of MWCNTs improved the wear resistance of unreinforced epoxy- polyamide blend. This improvement comes from the transfer film to the disc. The transferal film of a uniform thin film gives protection to the nanocomposite surfaces from aggressive damage of hard metal asperities which causes lessen wear rate. Specific wear rate of epoxy- polyamide blend /MWCNTs illustrated in Figure 5. 1.4
Ws 10¯¹² mm³/N.cm
1.2 1
0.8 0.6 0.4 0.2 0
Fig. 5. The specific wear rate values of epoxy- polyamide blend /MWCNTs with wt% ratio.
Figure 5 shows that the values of specific wear rate decreases by increasing the weight ratio percentage of MWCNTs but it increases with wt% more than 0.5wt%, because the agglomeration of nanomaterial. The superior value of specific wear rate at 0.5 wt% . This manner exhibits a good agreement with O. Jacobs et al. [10].
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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a
b
Fig. 6. Optical microscope image of epoxy- polyamide blend /MWCNTs with wt% a: (0.5 wt%) and b: the neat epoxy- polyamide blend.
Figures 4 and 5 show the decreasing of wear that occurred as a result of friction between the specimen and the rotation disc for all samples of epoxy- polyamide blend - MWCNTs as compare with neat epoxy- polyamide blend. Figure 6 shows the decreasing the blackout of material that occurred on the surface of epoxy- polyamide blend nanocomposite. The coefficient of friction of MWCNTs nanocomposites was decreasing for the samples (0.1, 0.3, and 0.5) wt% then the coefficient of friction increased as shown in Figure 7 because of the roughness of the surface that in contact with disc as a result of agglomeration that associated the increasing of weight ratio percentage of MWCNTs in epoxy- polyamide blend matrix. The optimum value of coefficient of friction is at 0.5 wt% ratio. The decrease in coefficient of friction is attributed to the presence of MWCNTs acting as a solid lubricant.
coefficient of friction μ
0.2 0.15 0.1 0.05 0
Fig. 7. The coefficient of friction values of epoxy- polyamide blend /MWCNTs with wt% ratio.
4. Conclusions The adding MWCNTs to the epoxy- polyamide blend improve the tribological properties. The increasing of weight ratio of MWCNTs improved the wear resistance of unreinforced epoxy- polyamide blend. This improvement comes from the transfer film to the disc. The transferal film of a uniform thin film gives protection to the
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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nanocomposite surfaces from aggressive damage of hard metal asperities which causes lessen wear rate.The optimum value of wt% of MWCNTs is (0.5) wt %. Increasing of wt% of MWCNTs increases the values of Vickers hardness continually. The increasing of the hardness was come from the effect of interface between the epoxypolyamide blend matrix and the MWCNTs, As well as the high adhesion between them. 5. References [1] William D. Callister, Jr David and G. Rethwisch, "Material science and engineering an introduction", Eight editions,. John Wiley and sons Inc., (2009): 25 – 37. [2] Charef Harrats, Sabu Thomas and Gabriel Groenincks, "Micro and nano structured multiphase polymer blend system phase morphology and interfaces", Taylor & Francis Group, ( 2006): 80 – 85. [3] Chowdhury F.H., Hosur M.V. and Jeelani S., “Studies on the flexural and thermomechanical properties of woven carbon/nanoclay-epoxy laminates”, Materials Science and Engineering A, 421(1-2), (2006): 298–306. [4] S. Iijima, "Helical microtubules of graphitic carbon", Nature, 354, (1991): 56–58 . [5] Yeong-Seok Zoo, Jeong-Wook An, Dong-phil Lim and Dae-Soon Lim, "Effect of carbon nanotube addition on tribological behavior of UHMWPE", Tribology Letter, 16, (2004): 305–309. [6] Sudhakar Majhi, S.P.Samantarai and S.K.Acharya, "Tribological Behavior of Modified Rice Husk Filled Epoxy Composite", International Journal of Scientific &Engineering Research, 3(6), (2012): 2229-5518. [7] Phildelphia, USA, "ASTM standards Annual hand book", Section 3,03,02, ASTM G-99, (1995). [8] Agarwal B. D. and Broutman L. J., "Analysis and Performance of Fiber Composites", Second Edition, Jhon Wiley & Sons, Inc. New York, (1990): 128 - 154. [9] Jiang D. and Q. N. Li, “Mechanical properties and erosion Wear resistance of polyurethane matrix composites”, Wear, 259, (2005): 676– 683. [10] O. Jacobs A., W. Xub, B. Scha dela and W. Wu, "Wear behaviour of carbon nanotube reinforced epoxy resin composites", Tribology Letters, 23 (1), (2006): 65 - 75.
Available online at www.sciencedirect.com
www.elsevier.com/locate/procedia
ScienceDirect Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available Energy Procedia 00 (2018) 000–000
ScienceDirect ScienceDirect Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18, 19–21 September 2018, Athens, Greece Energy Procedia 157 Energy Procedia 00(2019) (2017)1561–1567 000–000 www.elsevier.com/locate/procedia
www.elsevier.com/locate/procedia
Wear and Friction Properties of Epoxy- Polyamide Blend Technologies andNanocomposites Materials for RenewableReinforced Energy, Environment and Sustainability, TMREES18, by MWCNTs 19–21 September 2018, Athens, Greece Yousif Abid Al Shaabania*
The 15th International Symposiumof on EpoxyDistrict Heating and CoolingBlend Wear and Friction Properties Polyamide Opened Educational College, Ministry of Education, IRAQ Nanocomposites Reinforced by MWCNTs Assessing the feasibility of using the heat demand-outdoor Abstract Yousif Abid Al Shaabania* temperature function for a long-term district heat demand forecast
In this paper, multi-walled carbon nanotubes (MWCNTs) were dispersed in a hardener to mixing it with an epoxy- polyamide Opened Educational College, Ministry of Education, IRAQ a,b,c a percentages ofa MWCNTs was studied. c fabricated by mechanical blend. TheI. influence of several weight ratio samples were Andrić *, A. Pina , P. Ferrão , J. Fournierb., B. The Lacarrière , O. Le Correc moulding method with axillary ultrasonic technique. The MWCNTs ratio was various between 0.1 and 0.9 wt% to find the a optimum filler ratio. The results obtained that the adding- Instituto of MWCNTs tribological properties. ThePortugal superior IN+ Center for Innovation, Technology and Policy Research Superiorimproved Técnico, Av.the Rovisco Pais 1, 1049-001 Lisbon, Abstract b tribological properties were 0.5 wt. Recherche (%) MWCNTs. Veolia & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France c et Environnement Atlantique, rue AlfredtoKastler, Nantes, France polyamide In this paper, Département multi-walledSystèmes carbon Énergétiques nanotubes (MWCNTs) were- IMT dispersed in a 4hardener mixing44300 it with an epoxyblend. The influence of several weight ratio percentages of MWCNTs was studied. The samples were fabricated by mechanical moulding method with axillary ultrasonic technique. The MWCNTs ratio was various between 0.1 and 0.9 wt% to find the optimum filler ratio. The results obtained that the adding of MWCNTs improved the tribological properties. The superior Abstract tribological properties were 0.5 wt. (%) MWCNTs. © 2018 The Authors. Published by Elsevier Ltd. heating networks are by commonly addressed in the literature as one of the most effective solutions for decreasing the ©District 2019 The Authors. Ltd. This is an open accessPublished article under Elsevier the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) greenhouse gasaccess emissions thethe building sector. These systems require high investments which are returned through the heat This is an open articlefrom under CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Selection andtopeer-review under responsibility of and the scientific Technologies and Materials Renewable Energy, sales. Due the changed climate conditions building committee renovationofpolicies, heat demand in thefor future could decrease, Environment and Sustainability, TMREES18. Environment andinvestment Sustainability, TMREES18. prolonging the return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand Keywords: MWCNTs nanostructures, resin, polyamide, tribological properties. ©forecast. 2018 The Authors. byepoxy Elsevier The districtPublished of Alvalade, locatedLtd. in Lisbon (Portugal), was used as a case study. The district is consisted of 665 This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district Selection and peer-review under responsibility of the scientific Technologies andobtained Materialsheat for demand Renewable Energy, renovation scenarios were developed (shallow, intermediate, committee deep). To of estimate the error, values were Environment and Sustainability, TMREES18. compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications Keywords: (the errorMWCNTs in annualnanostructures, demand wasepoxy lowerresin, thanpolyamide, 20% for tribological all weatherproperties. scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the * Corresponding author.considered). Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and E-mail address: Email:[email protected] improve the accuracy of heat demand estimations. 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. © 2017 The Authors. Published Elsevier Ltd. license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This is an open access article under thebyCC BY-NC-ND Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . and Sustainability, TMREES18. Cooling. E-mail address: Email:[email protected] Keywords: Heat demand; Forecast; Climate change 1876-6102 © 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18. 10.1016/j.egypro.2018.11.322
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Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
1. Introduction The study of tribological properties is very significant to avoid the failure for any application by choosing the convenient material, structure, design of component and processing issues [1]. Polymer blends have been identified as the greatest multipurpose and economical process to produce new multiphase polymer materials that are able to satisfy the complex demands for performance and application [2]. Polymer composites have gained great attention as high-performance materials for aerospace, automotive, defense, marine and civil engineering applications over the past few decades. This is because of the dimensional stability with high strength to stiffness ratio and worthy thermal, electrical, mechanical and tribological properties [3]. Polymer Matrix Composites (PMCs) are one of the most diverse composites materials due to their ability to contain a number of different filler materials. The past decade has been witnessed important advancement in production and application of carbon nanotube (CNT) since their discovery in 1991 [4], carbon nanotube, which have unique topological hollow tubular structure, because of the very excellent property, such high length diameter ratio, unique electronics property, mechanical performance and high thermal stability. CNT can be used to make the nanocomposites with admirable tribological properties. Comparatively few studies interconnected to tribological properties of polymer composite reinforced with CNT have been reported so far [5]. In this work MWCNTs were dispersed in the hardener, using sonication, and stirring techniques for mixing the hardener with the epoxy – polyamide resins. The effect of different weight ratio on the tribological properties of MWCNTs/ epoxy – polyamide nanocomposites was investigated. Wear and friction coefficients of the nanocomposites were calculated for all samples. According to the conditions of the disc – on – disc machine the wear rate (WR) in (g/cm), wear volume (WV) in (mm3/cm) and specific wear rate (WS) in (mm3/Nm) are calculated according to the following equations respectively [6]: 𝑊𝑊� � 𝑊𝑊� � 𝑊𝑊� �
∆𝑊𝑊 � � � � ��� 𝑆𝑆� 𝑊𝑊� � � � � ��� 𝜌𝜌
∆𝑉𝑉 � � � � � � ��� 𝐿𝐿𝐿𝐿𝐿�
Where: ΔW is the weight loss of the specimen before and after the wear test (gm). ΔV is the volume loss of the specimen before and after the wear test (mm3). L is the normal load (N). SD: is the sliding distance (m). Wear coefficient can be calculated using the Archard’s equation [7]: 𝑊𝑊����� �
∆𝑉𝑉𝑉𝑉𝑉� � � � � � � ��� 𝐿𝐿𝐿𝐿�
Where WCoeff is wear coefficient and HV is the hardness. Hardness can be defined as the resistance to permanent indentation or penetration. According to the conditions of disc – on – disc machine, the coefficient of friction can be calculated by using the following relationship: ��
𝜏𝜏 � � � � � � � ��� �𝐿 � 𝐿𝐿
Where is coefficient of friction, τ is friction torque in (mN), r is the radius of counter face steel disc in (m), and L is the applied normal load in (N). The friction torque value is obtained from the integrating disc counter before and after the wear test.
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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2. Materials and Methods The polymer epoxy resin type (DGEBA) (diglycidyl ether of bisphenol A) is a viscous liquid, white color, it supplied by Fosroc Jorden, commercially well-known as Nitocote EP (405), in the form of liquid, medium viscosity, good adhesion. The ratio between resin and hardener for this study is 5:1 by weight. Polyamide polymer is mixed with epoxy resin to have a blend matrix with weight ratio epoxy to polyamide (4:1). The MWCNT that used as a nano filler is supplied by Zhengzhou Dongyao Material Co.,LTD China. The outer diameter of MWCNT tube is 13 nm, the length of the carbon tube is equal (3-12) nm, the tube wall thickness is 4.1 nm, and the number of layer is 815. Figure (1) illustrated the TEM of MWCNT that taken by production company.
Fig. 1. TEM of MWCNT (Zhengzhou Dongyao Material Co.,LTD ).
The bulk density is 0.06 g/cm3. The surface area is 200 m2/g. The purity of MWCNTs is more than 90%. Figure 1 shows the (TEM) of MWCNTs that carried out by production Company. Nanocomposites are prepared by dispersing (MWCNTs) to achieve best state of dispersion the nanomaterial were treated with hardener medium for the deagglomeration of the nanomaterial by ultra-sonication for half hour at room temperature. The hardener having nanomaterial’s are additional to the blend resin (epoxy 405/polyamide) with weight ratio (5:1) with different ratio of MWCNTs and mixed for 2 minutes by hand made. The mixture was molded and cured for 24 h. The samples are treated at (353K) for 6 h in the oven to complete the cure process. The surfaces of the samples are polished mechanically to minimize the influence of surface defects, mainly the porosity. To prepare the nanocomposite samples, molds are made from Teflon. The mold muddy by oil before the mixture is poured into the mold. To calculation the weight of blends resin and MWCNTs sensitive electronic balance were used. The density of samples was calculated by Archimedean method. The specimens are weighted in air then weight in liquid (water) using Sartorius BL 210S (d = 0.1mg) balance to weigh the nanocomposite samples. The measurements of density must to be very accuracy since it very important for calculation of the tribological properties. Wear test have been accomplished in the disc – on - disc type wear and friction which was used to evaluate the wear behavior of the nanocomposite, against hardened ground stainless steel disc. In this test the curve end of disc specimen (40 mm) diameter was fixed vertically with the rotation disc throughout the test. The load 40 Newton was applied to the disc against the surface of rotating stainless steel disc. Every specimen was weighed before and after the test by a sensitive digital balance (0.1) milligram. The time of the test was measured by digital watch. [Disc - on – disc] test equipment’s which designed by tribological dynamic machine (TDM) to measure the wear rate of the prepared samples. The disc was used is made from stainless steel. The wear tests were performed in air at room temperature. The testing time (t) is (20) min.
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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3. Results and Discussion
ρ (gm/cm³)
The experimental values of density for epoxy- polyamide nanocomposites are illustrated in Figure (2). The experimental density values are measured by employing the Archimedean base [8]. Figure (3) illustrated the variations of micro hardness with addition of MWCNTs to epoxy- polyamide nanocomposites. The hardness values of nanocomposites are gradually increased when MWCNTs were added to the epoxy- polyamide blend matrix. The addition of MWCNTs, which have relatively higher material properties, donates to the increase in hardness of the epoxy- polyamide nanocomposites. The continuous increasing of micro hardness come from increasing the number of high strength nanomaterial inside the matrix, it caused increasing their hardness property. This result exhibit with that obtained by R. Zhou, et al. [9]. The increasing of the hardness was come from the effect of interface between the epoxy- polyamide blend matrix and the MWCNTs, As well as the high adhesion between them. 1.494 1.492 1.49 1.488 1.486 1.484 1.482
Fig. 2. The experimental density values of epoxy- polyamide blend /MWCNTs wt% ratio.
This Figure shows that the experimental values of density decreased with increasing the weight ratio of MWCNTs.
Vicars Hardens MPa
20 15 10 5 0
Fig. 3. The micro hardness values of epoxy- polyamide blend /MWCNTs wt% ratio.
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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0.1
WR 10ˉ⁶ gm/cm
0.08 0.06 0.04 0.02 0
Fig. 4. The wear rate values of epoxy- polyamide blend /MWCNTs wt% ratio.
The blend nanocomposites filled with different amounts of (MWCNTs) exhibits excellent wear properties. The wear results show that the reinforced specimens have enhanced wear resistance than the unreinforced specimens. It is clear from Figure 4 that the increasing of weight ratio of MWCNTs improved the wear resistance of unreinforced epoxy- polyamide blend. This improvement comes from the transfer film to the disc. The transferal film of a uniform thin film gives protection to the nanocomposite surfaces from aggressive damage of hard metal asperities which causes lessen wear rate. Specific wear rate of epoxy- polyamide blend /MWCNTs illustrated in Figure 5. 1.4
Ws 10¯¹² mm³/N.cm
1.2 1
0.8 0.6 0.4 0.2 0
Fig. 5. The specific wear rate values of epoxy- polyamide blend /MWCNTs with wt% ratio.
Figure 5 shows that the values of specific wear rate decreases by increasing the weight ratio percentage of MWCNTs but it increases with wt% more than 0.5wt%, because the agglomeration of nanomaterial. The superior value of specific wear rate at 0.5 wt% . This manner exhibits a good agreement with O. Jacobs et al. [10].
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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a
b
Fig. 6. Optical microscope image of epoxy- polyamide blend /MWCNTs with wt% a: (0.5 wt%) and b: the neat epoxy- polyamide blend.
Figures 4 and 5 show the decreasing of wear that occurred as a result of friction between the specimen and the rotation disc for all samples of epoxy- polyamide blend - MWCNTs as compare with neat epoxy- polyamide blend. Figure 6 shows the decreasing the blackout of material that occurred on the surface of epoxy- polyamide blend nanocomposite. The coefficient of friction of MWCNTs nanocomposites was decreasing for the samples (0.1, 0.3, and 0.5) wt% then the coefficient of friction increased as shown in Figure 7 because of the roughness of the surface that in contact with disc as a result of agglomeration that associated the increasing of weight ratio percentage of MWCNTs in epoxy- polyamide blend matrix. The optimum value of coefficient of friction is at 0.5 wt% ratio. The decrease in coefficient of friction is attributed to the presence of MWCNTs acting as a solid lubricant.
coefficient of friction μ
0.2 0.15 0.1 0.05 0
Fig. 7. The coefficient of friction values of epoxy- polyamide blend /MWCNTs with wt% ratio.
4. Conclusions The adding MWCNTs to the epoxy- polyamide blend improve the tribological properties. The increasing of weight ratio of MWCNTs improved the wear resistance of unreinforced epoxy- polyamide blend. This improvement comes from the transfer film to the disc. The transferal film of a uniform thin film gives protection to the
Yousif Abid Al Shaabania / Energy Procedia 157 (2019) 1561–1567 Author name / Energy Procedia 00 (2018) 000–000
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nanocomposite surfaces from aggressive damage of hard metal asperities which causes lessen wear rate.The optimum value of wt% of MWCNTs is (0.5) wt %. Increasing of wt% of MWCNTs increases the values of Vickers hardness continually. The increasing of the hardness was come from the effect of interface between the epoxypolyamide blend matrix and the MWCNTs, As well as the high adhesion between them. 5. References [1] William D. Callister, Jr David and G. Rethwisch, "Material science and engineering an introduction", Eight editions,. John Wiley and sons Inc., (2009): 25 – 37. [2] Charef Harrats, Sabu Thomas and Gabriel Groenincks, "Micro and nano structured multiphase polymer blend system phase morphology and interfaces", Taylor & Francis Group, ( 2006): 80 – 85. [3] Chowdhury F.H., Hosur M.V. and Jeelani S., “Studies on the flexural and thermomechanical properties of woven carbon/nanoclay-epoxy laminates”, Materials Science and Engineering A, 421(1-2), (2006): 298–306. [4] S. Iijima, "Helical microtubules of graphitic carbon", Nature, 354, (1991): 56–58 . [5] Yeong-Seok Zoo, Jeong-Wook An, Dong-phil Lim and Dae-Soon Lim, "Effect of carbon nanotube addition on tribological behavior of UHMWPE", Tribology Letter, 16, (2004): 305–309. [6] Sudhakar Majhi, S.P.Samantarai and S.K.Acharya, "Tribological Behavior of Modified Rice Husk Filled Epoxy Composite", International Journal of Scientific &Engineering Research, 3(6), (2012): 2229-5518. [7] Phildelphia, USA, "ASTM standards Annual hand book", Section 3,03,02, ASTM G-99, (1995). [8] Agarwal B. D. and Broutman L. J., "Analysis and Performance of Fiber Composites", Second Edition, Jhon Wiley & Sons, Inc. New York, (1990): 128 - 154. [9] Jiang D. and Q. N. Li, “Mechanical properties and erosion Wear resistance of polyurethane matrix composites”, Wear, 259, (2005): 676– 683. [10] O. Jacobs A., W. Xub, B. Scha dela and W. Wu, "Wear behaviour of carbon nanotube reinforced epoxy resin composites", Tribology Letters, 23 (1), (2006): 65 - 75.