Graphene for flame-retarding elastomeric composite foams having strong interface

It is a great challenge to make elastomeric polymer foams antistatic, flame-retardant and mechanically robust. The challenge was addressed herein by in situ polymerizing polyvinyl alcohol, formaldehyde and graphene sheets. The graphene sheets - each in average being ∼5 nm thick - had a carbon to oxygen atomic ratio of 9.8 and a Raman ID/IG of 0.03. The sheets proved to react with formaldehyde building up a strong interface for the composites, and the reaction promoted the exfoliation and dispersion of graphene sheets in the matrix. They were found to create a large number of fine pores to the composites. Graphene sheets at 0.12 vol% increased the foam water retention rate from 346% to 784%. These composites had a percolation threshold of electrical conductivity at 0.023 vol%. The composites reached a limiting oxygen index of 59.4, implying an exceptional self-extinguishing performance.