Ionic liquid modification of graphene oxide and its role towards controlling the porosity, and mechanical robustness of polyurethane foam

Abstract

Fabrication of polymeric foam with controlled porosity, good mechanical properties and electrical conductivity is demanding. However, developing such a porous system has remained a major challenge till today. Herein, we synthesized 1-methyl imidazole chloride ionic liquid grafted graphene oxide (G[MIM]Cl) and utilized it as an effective agent for controlling the strength, distribution and dimension of the pores of polyurethane foam system (ILF). On the contrary, the polymeric foams fabricated with pristine expandable graphite (GF) and the neat polymer (PUF) demonstrated a distorted cell structure and an uneven distribution of the pores. Additionally, the mechanical properties of GF and PUF were found to be inferior compared to those of ILF. The effect of surface modification of filler on the dispersion in the polyurethane matrix was also studied and compared with the dispersion of the un-functionalized filler. The ILF exhibited higher electrical conductivity over the GF and the PUF. Compressive stress-strain behavior and dynamic mechanical properties indicated that ILF demonstrated significant mechanical robustness compared to GF and PUF. These findings can be readily extended to the development of complex three dimensional polymeric architecture where controlled porosity is required.