Epoxidized cardanol-based prepolymer as promising biobased compatibilizing agent for PLA/PBAT blends

Epoxidized cardanol-based prepolymer (ECP) generated from cashew nut shell liquid (CNSL) was successfully used as biobased compatibilizer/chain extender for poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) (80:20 wt%) blends. The reactive compatibilization effectiveness of different amounts of this biobased additive was compared with that of a petroleum-derived glycidyl-based copolymer, namely Joncryl ADR4300 (ADR) in term of mechanical, dynamic-mechanical and thermal properties, as well as rheological and morphological aspects. The addition of 3 wt% of ECP resulted in significant improvement of yield stress, elongation at break, Young modulus and toughness. The results obtained with this additive were similar or even superior to those observed for ADR. A sea-island-type morphology with very small PBAT domains was also reached with the compatibilization, as indicated by scanning electron microscopy (SEM). The compatibilization was also suggested from the slight increase of the glass transition temperature of the PBAT phase and also a decrease in crystallinity degree of PLA phase. The results presented in this work open new possibilities for developing cost-effective biobased and/or biodegradable materials for food packaging applications.