Functionalized graphenes as nanofillers for polylactide: Molecular dynamics simulation study

摘要

This simulation studied graphene functionalized with methyl (-CH3), hydroxyl (-OH), carboxyl (-COOH), and amine (-NH2) groups as potential nanofillers for polylactide (PLA) biodegradable polymers. Key properties including the structure and dynamics of polymer chains, interaction energy and interfacial shear force between the polymer matrix and the filler, and glass transition temperature (T-g) of the nanocomposites were investigated. Results indicated that graphene functional groups play important roles in the interfacial bonding characteristics between polymer matrix and the filler. Among the fillers studied, graphene modified by -COOH groups provided the strongest enhancement of interfacial interaction and shear force between the PLA matrix and the filler. The presence of nanofillers resulted in a moderate shift of the composite T-g compared to the unfilled polymer. The system with stronger interfacial interaction possessed higher T-g due to lower mobility of chain segments induced by the interaction strength between the polymer and the filler.