Graphene modifies the biodegradation of poly(lactic acid)-thermoplastic cassava starch reactive blend films

Abstract

Biobased blend films produced from poly(lactic acid) (PLA), thermoplastic cassava starch (TPCS), and reinforced with graphene nanoplatelets (GRH) were evaluated in compost and inoculated vermiculite under composting conditions for 120 days. A reduction of the molecular number of the PLA fraction in the blends indicated early hydrolytic degradation. A priming effect was observed in compost for the physical blend of PLA with TPCS. A high biodegradation rate was observed for the TPCS fraction in each tested sample. In inoculated vermiculite, the addition of GRH resulted in a decreased hydrolytic degradation rate for PLA-GRH, attributed to the natural barrier offered by GRH to diffusion of water into the PLA matrix. In compost, incorporation of GRH at 0.1% wt. also resulted in a decreased abiotic degradation rate for PLA. Films containing GRH were associated with a longer lag-phase.