PET-ran-PLA Partially Degradable Random Copolymers Prepared by Organocatalysis: Effect of Poly(l-lactic acid) Incorporation on Crystallization and Morphology

PET is a non-biodegradable polymer whose hydrolytic degradation can take decades. Intensive research is been performed to accelerate its hydrolytic degradation without significantly affecting its properties. In this work, PET was combined with PLA, a well-known biodegradable polymer, and the effect of PLA content in the crystallization of the PET component has been investigated in detail. In order to make the process sustainable, PET was polymerized using monomers that can be derived from PET chemical recycling (dimethyl terephthalate) and using organocatalysis (metal-free catalysts). First, low molecular weight telechelic PLA was prepared from the organocatalyzed ROP of L-lactide followed by step-growth copolymerization with PET oligomers. The random copolymerization was confirmed by FTIR and 1H NMR. We found that PET-ran-PLA copolymers are able to crystallize up to 24 mol % of PLA. WAXS and SAXS demonstrated that PLA units interrupt the average crystallizable PET sequences, decreasing its lamellar thick...