Comparison study of the bio-degradation property of polylactic acid (Pla) green composites reinforced by kenaf fibers

Abstract

Degradation of polylactic acid (PLA) was studied to investigate the best method of degradation to assist in reducing environmental pollution. Two condition of testing were conducted, which are natural weathering and landfill burial test. The rate of degradation was determined by weight loss, which was calculated once a month for six months. Natural weathering was achieved by exposing the samples to the natural environment, and this method was adopted according to ASTM D1435. Landfill burial testing was conducted by adopting ASTM G160-12 with a few modifications. The result shows that degradation was faster in a landfill burial condition. This was determined by the calculated weight loss, which was 2-4% of the total weight loss of PLA and its composites after six months' exposure to a natural weathering environment. In contrast, the landfill burial condition showed 4-17% weight loss after six months. The addition of natural fiber, whether bast or core fiber, assisted in the degradation of the composites. As well, the addition of natural fiber led to a 0.3-1.3% higher weight loss among the composites compared to neat PLA following natural weathering, while an 11-13% weight loss was recorded for composites exposed to the landfill burial condition. Natural weathering and landfill burial testing provide a time frame for the degradation of composite products. This is a good information for commercial composting facilities, providing data on the time frame required for material biodegradation.