Preparation and characterization of nanocomposites based on polylactides tethered with polyhedral oligomeric silsesquioxane

A series of polylactides tethered with polyhedral oligomeric silsesquioxane (POSS–PLAs) were synthesized via the ring‐opening polymerization of L ‐lactide with 3‐hydroxypropylheptaisobutyl polyhedral oligomeric silsesquioxane (3‐hydroxypropylheptaisobutyl POSS) at a concentration of 0.02–2.00 mol % in the presence of a stannous(II) octoate catalyst. 1 H‐NMR spectra and a composition analysis of the POSS–PLA hybrids confirmed that 3‐hydroxypropylheptaisobutyl POSS served as an initiator for L ‐lactide in the ring‐opening polymerization. X‐ray diffraction patterns evidenced that polyhedral oligomeric silsesquioxane (POSS) molecules of POSS–PLA hybrids were well dispersed without the formation of their crystalline aggregates. The POSS–PLA hybrid with 0.50 mol % POSS content was solution‐blended with a neat polylactide (PLA) homopolymer to obtain PLA/POSS–PLA nanocomposites with various POSS–PLA contents of 1–30 wt %. The X‐ray diffraction results of the PLA/POSS–PLA nanocomposites demonstrated that the POSS–PLA was well dispersed in the neat PLA matrix. The thermal and thermooxidative degradation properties of the nanocomposites were found to be improved at POSS–PLA contents of 1–20 wt %, compared to the neat PLA. The crystallization rates and crystallinities of the PLA/POSS–PLA nanocomposites were faster and higher, respectively, with increasing POSS–PLA content because of the nucleation effect of the POSS molecules in the neat PLA matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010