干法制备燃料电池用模压膨胀石墨/树脂复合板的性能

Performances of Expanded Graphite/Resin Composite Plates for Fuel Cells Prepared by Dry Mixing and Molding

选用膨胀石墨(EG)为导电填料,树脂为粘结料,采用干法混合及模压成型工艺制备复合板;该工艺保持了石墨蠕虫原有的三维网状结构,使其在具备良好导电导热性的同时还有良好的柔韧性、气密性及机械强度。考察了不同含量的聚酰亚胺(PI)、苯并恶嗪(BZ)、酚醛树脂(PF)和聚偏氟乙烯(PVDF)所制备的复合板的电导率、气密性和抗弯强度等重要指标。结果表明,当PI、BZ和PVDF含量为30%或40%(质量分数)时,所制得的复合板的电导率最小值为136.6S·cm-1,氢气渗透率最大值为1.938×10-6 cm3·cm-2·s-1,抗弯强度最小值为58.8MPa,各指标均满足DOE的要求。

Expanded graphite was selected as conductive filler and resins as matrices. The expanded graphite and a resin were first dry mixed and then compression molded. This processing approach allowed the graphite worms to keep three-dimensional network structures, and thus leading to the composite plate having not only good electrical and thermal conductivity, but also excellent flexibility, gas permeability and mechanical strength. Four resins, polyi- mide （PI）, polybenzoxazine （BZ）, phenolic resin （PF） and polyvinylidene fluoride （PVDF）, were evaluated and for each resin its weight ratio to expanded graphite was also examined. The prepared composite samples were tested in electrical conductivity, gas permeability and flexural strength. The results showed that when the content of PI, BZ or PVDF was 30 wt% or 40 wt%, the lowest electrical conductivity is 136.6 S · cm-1, the highest gas permeability is 1. 938×10-6cm2·cm-2·s-1 and the minimum flexural strength is 58. 8 MPa among all of the composite plates, therefore all of them can meet the DOE targets.