Chitosan from Muga silkworms (Antheraea assamensis) and its influence on thermal degradation behavior of poly(lactic acid) based biocomposite films

摘要

The research work is focused on extraction of chitin from Muga silkworms (MS) and its conversion into chitosan by chemical treatment process. The extracted amount of chitin and chitosan from MS were obtained similar to 8 wt % and similar to 7 wt %, respectively. Potentiometric titrations, conductometric titrations, elemental analysis, H-1-NMR and FTIR analyses were employed to calculate the degree of deacetylation of chitosan (extracted at 80 degrees C after 10 h) and found as 77% +/- 2, 81% 1.8, 82% +/- 2.4, 97.77% +/- 0.3, and 82% +/- 1.8, respectively. The deacetylation process of chitin showed pseudo-first order reaction kinetics and activation energy was estimated as similar to 15.5 kJ/mole. The extracted chitosan (at 80 degrees C after 10 h) showed higher crystallinity and improved thermal stability with respect to chitosan extracted from other marine sources. Subsequently, poly(lactic acid) (PLA) and extracted chitosan dispersed biocomposite films were prepared by solution casting method. Significant dispersion of chitosan (extracted at 80 degrees C after 10 h) micro-particles were observed in biocomposite films using FESEM analysis. Due to chitosan interaction with PLA, significant reduction in thermal degradation and activation energy was observed during nonisothermal degradation scan of such films using Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose models. (C) 2016 Wiley Periodicals, Inc.