Shrinkage reduced polyimide-graphene oxide composite aerogel for oil absorption

This work investigates the role of graphene oxide (GO) in mitigating shrinkage in polyimide (PI) aerogels and on enhancement of oil absorption capacity by the aerogel materials. The study considers grafting of GO particles with pyromellitic dianhydride (PMDA) to obtain GO-modified PMDA prior to reaction with 2,2'-dimethylbenzidine to obtain polyamic acid. The polyamic acid chains are crosslinked using 1, 3, 5-tris (4-aminophenyl) benzene and chemically imidized using acetic anhydride and pyridine to obtain polyimide gel. The resulting aemgel specimens, obtained by supercritical drying of the gels, show significant reduction of diameter shrinkage from 9.0% for unmodified monoliths to 0.8% in the presence of 5.2 wt% GO, 9.1% reduction in surface energy compared to unmodified aerogel, high surface area (>504 m(2)/g), high porosity (>93%), and low bulk density (<0.0905 g/cm(3)). These aerogels show large enhancement of hydrocarbon oil absorption capacity.