Poly(L-lactide) nanocomposites containing octaglycidylether polyhedral oligomeric silsesquioxane: Preparation, structure and properties

Abstract

Poly(L-lactide)s (PLLA) tethered with octaglycidylether polyhedral oligomeric silsesquioxane (OPOSS) with contents of 0.02-1.00 mol% were successfully prepared by solution ring-opening polymerization of L-lactide in the presence of Sn(Oct) 2 catalyst. Fourier transform infrared (FTIR) and proton nuclear magnetic resonance 1H-NMR spectroscopic techniques confirm the formation of secondary hydroxyls due to the reaction between PLLA main chains and OPOSS cages. X-ray analyses prove that the presence of OPOSS does not alter the packing structure of PLLA chain in the crystals but enhances the crystallinity of PLLA hybrids. PLLA/PLLA-OPOSS nanocomposites with PLLA-OPOSS contents of 1-30 wt% were prepared by solution-mixing of the neat PLLA polymer with various contents of the PLLA-OPOSS hybrid with 0.50 mol% OPOSS. It is found that the glass transition temperature of the PLLA/PLLA-OPOSS nanocomposites remains the same as that of pristine PLLA and the thermooxidative stability of the nanocomposites is improved with the PLLA-OPOSS content of 1-20 wt%, as compared to that of the neat PLLA polymer. PLLA/PLLA-OPOSS nanocomposites, except for PLLA/PLLA-OPOSS 1, has higher crystallization rate at 120°C. The nucleation density increases with increase in the content of PLLA-OPOSS. © BME-PT.