Effects of intensive microbial metabolism on starch-filled polyethylene films in controlled compositing windows.

Abstract

Low density (LDPE) and high density (HDPE) polyethylene films filled with starch up to a maximum level of 20% by weight were tested for biodegradation under different environmental conditions. Composting windrows consisting of various putrescible waste and assembled for controlled biostabilization management under static conditions were used. The physical and chemical deterioration of the polyethylene-starch films exposed to a controlled composting environment were recorded and analyzed with respect to the different composting evolution and were compared with the data collected in pure culture systems and in bench scale tests simulating an aerobic biostabilization process. Evidences are presented on the partial removal of starch from the different films as a consequence of massive surface colonization by various microorganisms. Loss of starch is accompanied by a small but significant drop in the average molecular weight and decrement in mechanical strength. In the case of a composting trial experiencing prolonged severe temperature conditions, a small but spectroscopically detectable oxidation of the polyethylene matrix was also observed. Efficiency of the controlled composting systems can be claimed in assessing reproducible conditions in an accelerated biostabilization of putrescible matter and hence versatility in the evaluation of the degradation of plastic manufacts.Polyolefins such as polyethylene with a degree of polymerization higher than 20 are particularly recalcitrant to microbial attack (1,14,26). Biodegradation of polyethylene as well as of many other thermoplastic polymers (e.g. polypropylene, polyvinyl chloride, polystyrene) has been indeed considered as a phenomenon to be

Photocatalytic Degradation of Polystyrene Plastic under Fluorescent Light

“…Moreover, both M w and M n decrease rapidly at the initial stage of the irradiation, and then the decrease becomes slow with the reaction proceeding. In polymer degradation where chain scission occurs at random, one always can see a rapid initial molecular weight decrease, which slows down as the process continues ( , ).

3 Weight loss of PS−TiO 2 and PS−(TiO 2 /CuPc) samples at different irradiation times.

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High‐density polyethylene/natural rubber blends filled with thermoplastic tapioca starch: Physical and isothermal crystallization kinetics study

“…Because the (natural resources)-based filler is biodegradable and conventional thermoplastic like polyolefin is nonbiodegradable, the combination of these two materials is classified as a partially biodegradable system. On exposure to the microbial activities, the starch-based materials are weakened as a result of degradation, thus leading to a partial breakdown process referred to as biofragmentation [1]. Production of partially or fully biodegradable materials has offered a possible solution to the polymer waste disposal problem associated with the petroleum-based plastics.…”

“…On exposure to the microbial activities, the starch-based materials are weakened as a result of degradation, thus leading to a partial breakdown process referred to as biofragmentation [1]. Production of partially or fully biodegradable materials has offered a possible solution to the polymer waste disposal problem associated with the petroleum-based plastics.…”