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

Abstract

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 1 H-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.

Star-Shaped and Linear POSS-Polylactide Hybrid Copolymers

“…Dubois et al applied aminopropylheptaisobutyl POSS as an effective initiator in polymerization of lactide and formation of block copolymers with a polycaprolactone- b -polylactide chain [ 21 ]. Syntheses of POSS hybrid star systems, bearing eight chains of polylactide or polylactide- b -(poly(N-izopropylacrylamide) were initiated from POSS bearing octa(glicydyl ether) [ 22 ] and octa(3-hydroxypropyl) [ 12 ] moieties, respectively. This approach known as core-first method relies on initiation of polymerization by eight functional groups of POSS.…”

Phenyl hepta cyclopentyl – polyhedral oligomeric silsesquioxane (ph,hcp-POSS)/Polystyrene (PS) nanocomposites: the influence of substituents in the phenyl group on the thermal stability

“…composites [23][24][25][26][27][28][29]. The general formula of POSSs is (RSiO 1.5 ) n , or R n T n , where organic substituents (R = alkyl, aryl or any other) are attached to silicon cage.…”

Recent Advances in Nanocomposites Based on Aliphatic Polyesters: Design, Synthesis, and Applications in Regenerative Medicine

“…On the contrary, the influence of nanoparticles on the polymer glass transition is less evident. In some cases, no variation has been recorded [13,80,82], in others a slight T g increase has been detected and ascribed to a good interaction between polymer matrix (PLA) and nanofillers, which restricted the macromolecular mobility by hydrogen bonding and electrostatic interactions [79].…”