Degradation of Poly(L: -Lactic Acid) and Bio-Composites by Alkaline Medium Under Various Temperatures
2011
Tisserat, B. | Finkenstadt, V. L.
Ribbons of poly(lactic acid) (PLA) and PLA containing 10 or 25% Osage Orange (OO) biocomposites of various sized heartwood particles were exposed to non-composting soil conditions either outdoors or in a greenhouse. No appreciable degradation was evident after 208Â day treatments. An artificial alkaline degradation test system was developed to reduce the study time required to evaluate PLA compositional properties on degradation. Ribbons of PLA and PLA-OO biocomposites of various sized particles were subjected to hydrolysis in alkaline concentrations (0, 0.05, 0.1, 0.15, and 0.25Â M NaOH) under various temperatures (15, 20, 25, 30, 35, 40, and 80Â °C) up to 56Â days. Higher concentrations of NaOH (e.g., 0.25Â M) caused more dramatic and rapid deterioration of PLA and PLA-OO composites than lower NaOH concentrations for all temperatures tested. Incubation in either the low temperatures (15 and 20Â °C) or the highest temperature (80Â °C) was consistently more effective in PLA-OO degradation than employing 35 or 40Â °C. Several alkaline and temperature test combinations are offered to study accelerated PLA degradation. Ribbons immersed in NaOH were examined with the scanning electron microscope to analyze for morphological alterations.
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