Effects of photodegradation performance with PLA‐containing samples on double injection molding

Abstract

The influence of different overlay layers (ABS, PC, and PLA) is investigated on the photodegradation behavior of poly(lactic acid) (PLA)‐containing samples in double injection molding, and PLA/PLA samples serve as the control group. In terms of microstructure, an analysis is conducted on the chemical structure, thermal performance, crystallinity, and molecular weight of the base layer of samples. The carbonyl index and molecular weight of the base layer of PLA/PLA samples decrease rapidly, and the trend of crystallinity change is also fast. Among them, the number of molecular chain scissions decreases to 0.61, and the crystallinity increases to a maximum of 17.93%, which indicates that the photodegradation degree of the base layer of PLA/PLA samples is greater than that of the other two samples. The microscopic surface morphology change of the base layer of three PLA‐containing samples is analyzed. The base layer of PLA/PLA samples becomes rougher after 600 h of UV degradation. Meanwhile, compared with other PLA‐containing samples, the percentage of tensile strength loss of PLA/PLA samples is higher, decreasing by 16.64%. In summary, using acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) materials as overlay layers for double injection molding can mitigate the photodegradation of the base layer of PLA‐containing samples in double injection molding.