Reactive compatibilization of high-impact poly(lactic acid)/ethylene copolymer blends catalyzed by N,N-dimethylstearylamine

The inherent brittleness of poly(lactic acid) (PLA) limits its wide application in many fields. Here, high-impact PLA/ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (EMA-GMA) blends were prepared with the addition of a small amount of N,N-dimethylstearylamine (DMSA) catalyst. It was found that the notched impact resistance of various PLA/EMA-GMA blends could be considerably improved by adding DMSA. In particular, the notched Izod impact strength of the blend with 20 wt% EMA-GMA increased from 35.6 to 83.5 kJ m(-2) by adding 0.2 wt% DMSA. Reactive compatibilization between PLA and EMA-GMA with DMSA was studied using Fourier transform infrared spectroscopy. The results indicated that DMSA promoted the reaction between the epoxide group of EMA-GMA and end groups (-OH, -COOH) of PLA. This considerably improved the interfacial adhesion, leading to better wetting of the dispersed phase by the PLA matrix and finer dispersed EMA-GMA particles. Therefore, the significant increase in notched impact strength was attributed to the effective reactive compatibilization promoted by DMSA. (C) 2013 Society of Chemical Industry