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

ANIBAL BHER; ILKE UYSAL UNALAN; RAFAEL AURAS; MARIA RUBINO; CARLOS E. SCHVEZOV

POLYMER DEGRADATION AND STABILITY

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2019

0141-3910

Biobased reactive films produced from poly(lactic acid) (PLA), thermoplastic cassavastarch (TPCS), and reinforced with graphene nanoplatelets (GRH) were evaluated for biodegradation in compost and inoculated vermiculite under composting conditions for up to 120 days. Molecular weight was determined to understand the abiotic degradation process. A reduction of the neat PLA and PLA fraction of each film, following a first order relationship, indicated the presence of hydrolytic degradation. A priming effect was observed in compost for the physical blend of PLA with TPCS; however, this effect was not evident in inoculated vermiculite. A high biodegradation rate was observed for the TPCS fraction in each tested sample. In inoculated vermiculite, the presence 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, the incorporation of GRH at 0.1% wt. also resulted in a decreased abiotic degradation rate for PLA and increased mineralization. Lower rate constants determined for films containing GRH in compost were associated with a longer lag-phase and a lower water retention capability of compost compared with vermiculite. Reactive blends produced can be used as new compostable blends for industrial applications.