EP/POSS/SiO2纳米复合材料性能研究

以自制的两种不同黏度的环氧基倍半硅氧烷(POSS)为改性剂,对双酚A型环氧树脂(EP)/4,4’–二氨基二苯砜(DDS)进行改性,制备EP/POSS杂化材料。再以纳米SiO2为填料制备了EP/POSS/SiO2纳米复合材料。结果表明,与EP相比,杂化材料和纳米复合材料的弯曲强度和弯曲弹性模量都有所提高,其中纳米复合材料(分别添加低黏度和高黏度的POSS)的弯曲弹性模量分别提高了15.03%和9.44%,添加高黏度的POSS和纳米SiO2后其杂化材料和纳米复合材料体系的弯曲强度均有所提高,杂化材料和纳米复合材料的最大分解温度和在高温时的热残留量都有所提高。     

PF/MCMB/石墨/CF复合材料燃料电池双极板的研制

针对目前机加工燃料电池石墨双极板、金属双极板的不足,研究了采用酚醛树脂(PF)、中间相碳微球(MCMB)、石墨和碳纤维(CF)为原料通过模压成型、渗碳烧结工艺制备复合材料双极板。结果表明,所研制的复合材料双极板具有更佳的综合性能,其制造成本低、效率高,碳元素含量达95%,压缩强度大于100MPa,弯曲强度大于30MPa,体积电阻率小于50×10-6Ω·m,所组装的单电池能满足燃料电池苛刻工作条件和性能上的要求。     

聚丙烯/纳米碳酸钙复合材料性能的研究

利用双螺杆挤出机制备了聚丙烯(PP)/活性纳米碳酸钙(nano-CaCO3)复合材料,并用注射机注射了标准拉伸、弯曲及冲击样条。研究了不同纳米碳酸钙质量含量(1%～8%)对复合材料流动性能及力学性能的影响,利用扫描电镜观察了复合材料冲击断面的形貌。研究结果表明在实验范围内,与纯PP相比,加入纳米碳酸钙后,复合材料的拉伸强度有所降低,而弯曲强度、冲击强度以及硬度增加。当纳米碳酸钙含量为3%时复合材料呈现比较好的综合性能。实验条件下,纳米碳酸钙对复合材料的流动性能影响不大。     

聚双环戊二烯/蒙脱土纳米复合材料的性能

采用反应注射成型工艺制备了聚双环戊二烯／有机蒙脱土纳米复合材料,用X射线衍射仪、透射电子显微镜等研究了纳米复合材料的结构,测试了复合材料的力学性能。结果表明,制备的材料为剥离型纳米复合材料,有优越的拉伸强度和弯曲强度,并且具有良好的韧性。     

双马来酰亚胺/环氧树脂/纳米SiO2复合材料的制备与性能研究

研究了纳米二氧化硅（SiO2）的含量对双马来酰亚胺（BMI）/环氧树脂(EP)/2,2′二烯丙基双酚A(DBA)/纳米SiO2复合材料的耐热性能、力学性能和吸水性能的影响。结果表明,当纳米SiO2的含量为2.0 %(质量分数,下同)时,BMI/EP/DBA/纳米SiO2复合材料具有较高的强度和良好的韧性,其拉伸强度、弯曲强度和缺口冲击强度比BMI/EP/DBA复合材料分别提高了22.8 %、39.0 %和37.8 %;同时,纳米SiO2含量为 2.0 %时,BMI/EP/DBA/纳米SiO2复合材料具有优异的耐热性,其玻璃化转变温度、初始热分解温度和最大热分解温度分别为204、 410、451 ℃。     

芳纶/碳纤维混杂机织复合材料的力学性能研究

分别以芳纶和碳纤维(CF)为经、纬向纱,采用小样织机制备了不同经纬密度的芳纶/CF混杂平纹织物;以环氧树脂为基体,采用真空辅助树脂转移成形方法制备芳纶/CF混杂织物增强复合材料(简称复合材料);分析了复合材料的力学性能。结果表明:在经向纱(简称经纱)、纬向纱(简称纬纱)的纤维种类分别相同时,复合材料的弯曲强度随经向密度增大而增大;以芳纶为经纱时,复合材料的弯曲模量和拉伸模量随着经纱的密度增大而减小,而复合材料的拉伸强度和断裂伸长率随着经纱密度的增大而增大;以CF为经纱时,复合材料的弯曲模量随着经纱密度的增大而增大,且弯曲强度和弯曲模量均高于以芳纶为经纱时的复合材料。     

HDPE/LLDPE/OMMT纳米复合材料的结构与性能

采用直接注射法制备HDPE/LLDPE/OMMT纳米复合材料,采用透射电子显微镜研究 HDPE/LLDPE/0MMT纳米复合材料的微观结构,研究有机蒙脱土含量对纳米复合材料性能的影响.透射电子显微镜结果显示,制备的HDPE/LLDPE/OMMT纳米复合材料是一种半剥离型的纳米复合材料.结果表明:蒙脱土的加入大大提高了纳米复合材料的力学性能和热变形温度.当有机蒙脱土质量含量仅为6%时,屈服强度和拉伸模量分别提高14.0%和59.7%,弯曲强度和弯曲模量分别提高了14.2%和60.O%.     

纳米CaCO_3对PE–HD/CF复合材料力学性能的影响

针对高密度聚乙烯(PE–HD)/碳纤维(CF)二元复合材料随CF含量的增加,拉伸强度和弯曲强度增大、冲击强度却逐渐下降的情况,在二元体系中添加纳米CaCO3制得PE–HD/CF/CaCO3三元复合材料,对比分析了两种复合材料的力学性能,并采用扫描电子显微镜对三元复合材料的冲击断面进行观察。结果表明,纳米CaCO3的加入使得三元复合材料的拉伸强度略有降低,但弯曲强度和冲击强度在一定范围内增大;当纳米CaCO3含量为10份时,复合材料的综合力学性能最佳。     

环氧树脂/炭纤维布/铝复合材料的力学性能和导热系数研究

使用硅烷偶联剂对纳米铝粉的表面进行了改性.采用共混和热压成型方法制备了环氧树脂/炭纤维布和环氧树脂/炭纤维布/铝粉复合材料,并研究了复合材料的力学性能和导热性能.结果表明,复合材料的弯曲强度和冲击强度随着炭纤维布用量的增加而显著增大;纳米铝粉的添加进一步提高了复合材料的弯曲强度和冲击强度.当炭纤维布用量从0层增加到4层...     

聚苯醚/聚苯乙烯/纳米二氧化硅复合材料的制备及其结构与性能

通过熔融共混法制备了聚苯醚(PPE)/聚苯乙烯(PS)/纳米二氧化硅(SiO2)复合材料,并采用透射电子显微镜、扫描电子显微镜、力学性能测试及Hakke流变仪等研究了复合材料的结构与性能。结果表明,纳米SiO2均匀分散在PPE/PS基体中,粒径随着SiO2含量的增加而增大;随着纳米SiO2含量的增加,复合材料的拉伸强度、断裂伸长率和缺口冲击强度呈现先增大后降低的趋势,弯曲强度和玻璃化转变温度逐渐增大,蠕变量则逐渐降低。     

Low Cost and Rapidly Processed Randomly Oriented Carbon/Carbon Composite Bipolar Plate for PEM Fuel Cell

The objective of the present work is to develop carbon/carbon (C/C) composite bipolar plate at low cost with rapid processing time by a novel process. Carbon/carbon composite was developed using exfoliated carbon fiber reinforcement, isroaniso as primary matrix precursor, and resole type phenolic resin as secondary matrix precursor. Randomly oriented hybrid carbon fiber (T‐800 and P‐75) reinforced hybrid carbon matrix composite was fabricated. The slicing and channel forming were carried out using simple and conventional machines. The competency of the material was investigated by characterizing and analyzing density, scanning electron miscroscopy (SEM), compressive strength, compressive modulus, flexural strength, tensile strength, impact strength, hardness, electrical conductivity, thermal conductivity, coefficient of thermal expansion, permeability, and corrosion current. The C/C composite bipolar plate with exfoliated carbon fibers offered bulk density 1.75 g cm⁻³, tensile strength 45 MPa, flexural strength 98 MPa, compressive strength 205 MPa, electrical conductivity 190 (through‐plane) and 595 S cm⁻¹ (in‐plane), and thermal conductivity 24 (through‐plane) and 51 W m⁻¹ K⁻¹ (in‐plane). Further, single cell test was performed to evaluate the effectiveness of the C/C composite bipolar plate in the PEM fuel cell and the performance was compared with the commercial graphite bipolar plate at different operating temperatures.     

Differences in physico-mechanical behaviors of resol(e) and novolac type phenolic resin based composite bipolar plate for proton exchange membrane (PEM) fuel cell

Composite bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) are prepared by compression molding technique using polymer as binder and graphite as electric filler material with some other reinforcements. Study on the effect of resole and novolac type phenolic resin on the properties of composite bipolar plate, such as bulk density, porosity, bulk conductivity, hardness, flexural strength, etc. shows that both of the resin shows different physico-mechanical properties. Moreover, single cell performance analysis also shows variation for resole and novolac based composites. A novel concept of triple continuous structure to provide graphite polymer blends with high electrical conductivity, high shore hardness, high flexural strength, less porosity and low density has been proposed and study on the effect of different types of phenolic resin on the properties and performance of bipolar plate reveals that novolac type powdered phenolic resin gives better mechanical properties than resole type phenolic resin. However, resole type phenolic resin compound has slightly higher electrical conductivity due to more number of polar -OH group presents on its cured form. But due to the less porosity and higher mechanical strength, bipolar plates with novolac type phenolic resin gives better performance in I-V analysis than bipolar plates with resole type phenolic resin.     

Carbon‐Polymer Composite Bipolar Plate for HT‐PEMFC

Graphene reinforced carbon‐polymer composite bipolar plate is developed using resole phenol formaldehyde resin, and conductive reinforcements (natural graphite, carbon black, and carbon fiber) using compression molding technique. Graphene is reinforced into the composite to alter various properties of the composite bipolar plate. The developed composite bipolar plate is characterized and the effect of temperature on mechanical and electrical properties is investigated with an overall aim to achieve benchmark given by US‐DOE and Plug Power Inc. The flexural strength and electrical conductivity of the composites was almost stable with the increase in temperature upto 175 °C. The composite bipolar plate maintained high in‐plane and through‐plane electrical conductivities, which is about 409.23 and 98 S cm^–1, respectively, at 175 °C. The flexural strength and shore hardness of the developed composite was around 56.42 MPa and 60, respectively, at 175 °C, and on further increase in the temperature the mechanical strengths deceases sharply. The electrical and mechanical properties of the composite bipolar plates are within the US‐DoE target. However, the various properties of the composite bipolar plate could not be sustained above 175 °C.     

Effect of the compression molding parameters on the in-plane and through-plane conductivity of carbon nanotubes/graphite/epoxy nanocomposites as bipolar plate material for a polymer electrolyte membrane fuel cell

The main challenges for commercialization of a single-filler graphite (G) polymer-matrix composite as bipolar plates are its low electrical conductivity and flexural strength. The minimum requirements set by the US Department of Energy (DOE) are the electrical conductivity and flexural strength to be greater than 100 S/cm and 25 MPa, respectively. In this study, the electrical conductivity of a G/epoxy (EP) composite (single filler) is only 50 S/cm (in-plane conductivity) at 80 wt% G. However, flexural strength is greater than 25 MPa. Using carbon nanotubes (CNTs) as the second filler at a concentration of 5 wt% in a CNTs/G/EP nanocomposite resulted in the in-plane and through-plane electrical conductivity and flexural strength being 180 S/cm, 75 S/cm, and 45 MPa, respectively. The density of the CNTs/G/EP nanocomposite is also less than that of G/EP composite, which demonstrates that a total weight reduction is achievable.     

Development of Low‐Cost Advanced Composite Bipolar Plate for Proton Exchange Membrane Fuel Cell�

The bipolar plate is one of the most imperative components of proton exchange membrane fuel cells (PEMFC) which consumes up to 80% of weight and near about 50% of the total cost of the cell. Development of cost‐effective composite bipolar plate with high electrical conductivity and high mechanical strength is both technically and economically demanding. In this paper, a low‐cost advanced composite bipolar plate is developed by bulk moulding compression (BMC) technique. It is clear from the experiments that by increasing the matrix volume fraction, bulk density and electrical conductivity of a composite bipolar plate decrease but shore hardness increases. Test results clearly show that best overall properties are achieved when a constant volume fraction of polymer matrix and natural graphite is reinforced with synthetic graphite, carbon black and carbon fibre. This bipolar plate was found to have high conductivity, less porosity and high mechanical strength. The I–V characteristics in single cell test exhibited more uniform power density at both higher and lower current densities     

Synergistic Effects of Carbon Fillers of Phenolic Resin Based Composite Bipolar Plates on the Performance of PEM Fuel Cell

The most essential and costly component of polymer electrolyte membrane fuel cells is the bipolar plate. The production of suitable composite bipolar plates for polymer electrolyte membrane fuel cell with good mechanical properties and high electrical conductivity is scientifically and technically very challenging. This paper reports the development of composite bipolar plates using exfoliated graphite, carbon black, and graphite powder in resole‐typed phenol formaldehyde. The exfoliated graphite with maximum exfoliated volume of 570 ± 10 mL g⁻¹ used in this study was prepared by microwave irradiation of chemically intercalated natural flake graphite in a few minutes. The composite plates were prepared by varying exfoliated graphite content from 10 to 35 wt.% in phenolic resin along with fixed weight percentage of carbon black (5 wt.%) and graphite powder (3 wt.%) by compression molding. The composite plates with filler weight percentage of 35/5/3/exfoliated graphite/carbon black/graphite powder offer in‐plane and trough‐plane electrical conductivities of 374.42 and 97.32 S cm⁻¹, bulk density 1.58 g cm⁻³, compressive strength 70.43 MPa, flexural strength 61.82 MPa, storage modulus 10.25 GPa, microhardness 73.23 HV and water absorption 0.22%. Further, I–V characteristics notify that exfoliated graphite/carbon black/graphite powder/resin composite bipolar plates in unit fuel cell shows better cell performance compared exfoliated graphite/resin composite bipolar plates. The composite plates own desired mechanical properties with low bulk density, high electrical conductivity, and good thermal stability as per the U.S. department of energy targets at low filler concentration and can be used as bipolar plates for proton exchange membrane fuel cells.     

Cu2O/Cu Cermet as a Candidate Inert Anode for Al Production

Cu₂O/ x Cu ( x =0–25 wt%) cermets were evaluated as a novel partially inert anode for aluminum (Al) production. The physical and mechanical properties, including the compressive strength, flexural strength, thermal expansion coefficient, thermal conductivity, and dc electrical conductivity were tested at room temperature and at temperatures up to 950°C. The coefficient of thermal expansion, compressive strength, flexural strength, thermal conductivity, and electrical conductivity of Cu₂O/Cu cermets increased with increasing Cu content. High-temperature electrical conductivity measurements showed that with increasing temperature, the electrical conductivity increased when the Cu content was below the percolation threshold, while it decreased when the Cu content was above the percolation threshold. A relatively stable CuAlO₂ layer formed on the cermet surface during electrochemical testing, and the corrosion rate of this anode was estimated to be about 1.8–1.9 cm/year in Al production.     

Electrical and thermal conductivity and tensile and flexural properties of carbon nanotube/polycarbonate resins

Adding conductive carbon fillers to insulating thermoplastic polymers increases the resulting composite's electrical conductivity. Carbon nanotubes (CNTs) are very effective at increasing composite electrical conductivity at low loading levels without compromising composite tensile and flexural properties. In this study, varying amounts (2–8 wt %) of CNTs were added to polycarbonate (PC) by melt compounding, and the resulting composites were tested for electrical conductivity (1/electrical resistivity), thermal conductivity, and tensile and flexural properties. The percolation threshold was less than 1.4 vol % CNT, likely because of CNTs high aspect ratio (1000). The addition of CNT to PC increased the composite electrical and thermal conductivity and tensile and flexural modulus. The 6 wt % (4.2 vol %) CNT in PC resin had a good combination of properties for electrical conductivity applications. The electrical resistivity and thermal conductivity were 18 Ω‐cm and 0.28 W/m · K, respectively. The tensile modulus, ultimate tensile strength (UTS), and strain at UTS were 2.7 GPa, 56 MPa, and 2.8%, respectively. The flexural modulus, ultimate flexural strength, and strain at ultimate flexural strength were 3.6 GPa, 125 MPa, and 5.5%, respectively. Ductile tensile behavior is noted in pure PC and in samples containing up to 6 wt % CNT. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Electrical,mechanical, and thermal properties of exfoliated graphite/phenolic resin composite bipolar plate for polymer electrolyte membrane fuel cell

Exfoliated graphite (EG) was synthesized from natural flake graphite by acid treatment followed by microwave irradiation. A maximum expanded volume of 560 mL/g was achieved for this exfoliation of graphite. EG/phenolic resin composite bipolar plates for polymer electrolyte membrane fuel cell were fabricated with a high loading of EG by compression molding. The composites possess low density, high electrical conductivity, high thermal stability, and high compressive strength. The composite bipolar plates were also characterized by X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and so on. The composite prepared with 50 wt% of EG has shown the desired properties for bipolar plate as per the US Department of Energy (DOE‐2015) targets. As a result, the EG–resin composites can be used as bipolar plates for polymer electrolyte membrane fuel cell applications. POLYM. ENG. SCI., 55:917–923, 2015. © 2014 Society of Plastics Engineers     

Fabrication of electrically conductive polymer composites for bipolar plate by two‐step compression molding technique

Electrically conductive polymer composites for bipolar plate were fabricated by two‐step compression molding technique. Raw materials consisted of natural graphite flakes (G), expanded graphite (EG), carbon black (CB), and phenol resin (PF). The G/EG/CB/PF composites were first compressed at a temperature lower than curing point (100°C) and then cured at a high temperature above curing point (150°C) and high pressure (10 MPa). Results showed that G and EG are oriented in the direction parallel to the composite plate surface. CB is dispersed not only in the phenol resin matrix but also in the packing and porous space of G and EG. The addition of EG and CB significantly increases number of the electrical channels and thus enhances the electrical conductivity of the composite. Under optimal conditions, electrical conductivity and flexural strength of the composite were 2.80 × 10⁴ S/m and 55 MPa, respectively, suggesting that the dipolar plates prepared by two‐step compression molding technique are adequate to meet the requirement of proton exchange membrane fuel cells. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2296–2302, 2013