Functionalization of graphene oxide with poly(ε-caprolactone) for enhanced interfacial adhesion in polyamide 6 nanocomposites

Abstract

Because interfacial adhesion between polymer chains and a nanofiller strongly influences the properties of polyamide nanocomposites, various approaches have been described to improve it. Here, we investigate the covalent functionalization of graphene oxide (GO) with poly(ε-caprolactone) and its application for the in situ synthesis of polyamide 6 nanocomposites. For the functionalization, GO moieties were used to initiate the polymerization of ε-caprolactone, which was followed by the separation of ungrafted polymer chains. TGA and FTIR confirmed covalent bonding between the GO and poly(ε-caprolactone). The synthesis of the nanocomposites was carried out by the in situ polymerization of ε-caprolactam containing either untreated or functionalized GO. TEM and AFM images of the nanocomposites containing the functionalized GO revealed the presence of single exfoliated nanofiller layers. DMA showed that the functionalized GO had a higher reinforcing effect than the untreated one. Thus, the obtained results suggest that our method is simple and effective for enhancing the interfacial adhesion between GO and polyamide 6.