Gas Barrier and Biodegradable Properties of Poly(L-lactide) Nanocomposites Compounded with Polyhedral Oligomeric Silsesquioxane Grafted Organic Montmorillonite

摘要

A novel organic montmorillonite (OMMT) was prepared by reacting the aminopropyllsobutyl polyhedral oligomeric silsesquioxane (POSS) with the OMMT that had already been modified by cationic surfactants. The layer spacing of OMMT increased from 1.68 to 3.43 nm after being intercalated by POSS. Poly(L-lactide) (PLLA) based nanocomposites with montmorillonites were produced by melt compounding. The PLLA nanocomposites with POSS modified OMMT were comprised of a random dispersion of intercalated/exfoliated aggregates of layered silicates throughout the PLLA matrix. The incorporation of POSS modified OMMT resulted in a significant increase in decomposition temperature for 5 % weight loss in comparison with the virgin PLLA. Gas permeation analysis showed that the increase of the montmorillonite concentration in the polymer matrix led to an expected decrease in permeation values. Gas barrier properties of the nanocomposites were compared with those predicted by phe-nomenological models such as the Nielsen model and Cussler model. Incorporation of the POSS on OMMT improved significantly mechanical properties of PLLA. The biodegradability of the neat PLLA and corresponding nanocomposite was studied under compost, and the rate of biodegradation of PLLA increased after nanocomposite preparation.