Highly Filled Graphene-Benzoxazine Composites as Bipolar Plates in Fuel Cell Applications

This research emphasizes on the development of highly filled graphene-polybenzoxazine composites and investigates thermal, electrical, and mechanical properties of the obtained composites for bipolar plate applications. The composition of graphene loading was achieved to be in the range of 10-60 wt%. The experimental results revealed that at the maximum graphene content of 60 wt% (44.8 vol%) in the poly-benzoxazine, storage moduli at room temperature of the composites were considerably enhanced with the amount of the graphene, that is, from 5.9 GPa of the neat polybenzoxazine to about 25.1 GPa at 60 wt% of graphene. Glass transition temperatures (T-g) of the obtained composites were observed to be 174-188 degrees C and the values substantially increased with increasing the filler contents. At 60 wt% of graphene content, thermal conductivity, as high as 8.0 W/mK, is achieved for the graphene-filled polybenzoxazine. Furthermore, the flexural modulus and flexural strength of the composites were found to be as high as 18 GPa and 42 MPa, respectively. Water absorption of graphene filled-composite is relatively low with the value of only about 0.06% at 24 h of water immersion. Additionally, electrical conductivity was measured to be 357 S/cm at maximum loading of the graphene. Therefore, the graphene-filled composites based on polybenzoxazine are highly attractive as bipolar plates for polymer electrolyte membrane fuel cells applications. (C) 2014 Society of Plastics Engineers