偶联剂对石墨/酚醛树脂复合双极板性能的影响

Effect of Coupling Agent on the Properties of Phenolic Resin/Graphite Composite Bipolar Plates

针对石墨/酚醛树脂复合双极板存在的强度低、脆性大等问题,采用偶联剂改性方法来增强复合双极板的界面结合,提高其抗弯强度.研究了偶联剂的种类、添加方式及用量对石墨/酚醛树脂复合材料双极板力学性能和电学性能的影响.结果表明:采用石墨改性法可提高石墨/酚醛树脂复合双极板的抗弯强度,但导电性能有所降低;而采用树脂改性法制备的石墨/树脂复合双极板同时具有较高的电学和力学性能.因此树脂改性法更适合制备复合双极板.当偶联剂质量分数均为0.7%,采用树脂改性法分别以硅烷偶联剂和钛酸酯偶联剂改性时,石墨/树脂复合材料双极板抗弯强度和电导率分别为33.3 MPa,70.3 S·cm-1和32.1 MPa,73.8 S·cm-1,均满足燃料电池用石墨/酚醛树脂复合双极板的技术要求.

The problems of phenolic resin/graphite composite bipolar plates are their brittleness and poor mechanical strength. In this study, coupling agent was used to enhance the interfacial adhesion of composite and thus improve the flexural strength. The influence of the types, treating methods and content of coupling agent on the properties of bipolar plates were investigated. Results have shown that a sharp increase of flexural strength was observed for bipolar plates prepared by graphite modification, while the conductivity decreased modestly. Meanwhile, the bipolar plates prepared by resin modification offer high conductivity and excellent flexural strength. Therefore, it can be concluded that resin modification is more suitable for the fabrication of composite bipolar plates. When 0.7wt% of the coupling agent is added to the composite by resin modification, the composite bipolar plate modified by silane coupling agent has a conductivity of 70.3 S·cm^-1 and a flexural strength of 33.3 MPa. And for the composite bipolar plate modified by titanate coupling agent, the conductivity and flexural strength are 73.8 S·cm^-1 and 32. 1 MPa, respectively. These values well satisfy the requirements of composite bipolar plates.