Polymer Chemistry

Presence of nanofillers in a polymer matrix can significantly improve properties of resultant nanocomposites. To achieve such improvement, a homogenous dispersion of nanofiller in matrix and strong interfacial adhesion between them are prerequisites. In this presentation, I want to introduce our approaches to enhance these parameters for in situ intercalative polymerization of ε-caprolactam/graphene oxide dispersion to yield polyamide-based nanocomposites. In first procedure, an improvement was achieved by addition of ε-caprolactone to mentioned dispersion followed by anionically initiated polymerization. As a result of improved dispersibility, tensile modulus increased with higher nanofiller concentration. The second procedure consisted in utilization of graphene oxide functionalized by poly(ε-caprolactone). Functionalization was carried out by polymerization of ε-caprolactone initiated by graphene oxide functional groups that resulted in partial covalent attachment of poly(ε-caprolactone) chains to graphene oxide. Polyamide 6 nanocomposites containing functionalized graphene oxide showed higher dynamic modulus and higher exfoliation level than nanocomposites with an initial graphene oxide. As presence of ε-caprolactone/poly(ε-caprolactone) proved to be effective for achieving better dispersibility and interfacial adhesion, I also want to outline one-pot method for covalent functionalization of graphene oxide. This method consists in ε-caprolactone polymerization in dimethylformamide/graphene oxide dispersion directly followed by Steglich esterification to introduce covalent bonds between poly(ε-caprolactone) and graphene oxide.