New evidences of accelerating degradation of polyethylene by starch

An investigation into the effects of starch on both, UV photo-oxidative degradation and biodegradation, of HDPE was focused on the interface between HDPE and starch using Synchrotron-FTIR microscope (SFTIR-M) and scanning electronic microscope (SEM). Carbonyl group detection by FTIR was conducted to evaluate the effect of degradation following exposure to UV photo-oxidative degradation. The results showed that the concentration of carbonyl groups on the interface were higher, suggesting the role of starch in accelerating the UV photo-oxidative degradation of HDPE. The interface between HDPE and starch was further observed under SEM to study the morphological changes after UV photo-oxidative degradation and biodegradation. Micro-cracking was observed on the interface between starch and HDPE after UV photo-oxidative degradation. Tensile testing after UV exposure showed that the variation rate of elongation was higher for the samples containing starch. Starch, an easily biodegradable material, can also act as initial source of nutrients for micro-organisms (bacteria, fungi, and algae) in the blend materials thus enhancing their biodegradability.