Improvement in Crystallization and Toughness of Poly(L-lactide) by Melt Blending with Poly(L-lactide)-b-polyethylene glycol-b-poly(L-lactide) in the Presence of Chain Extender

Poly( L -lactide)/poly( L -lactide)- b -polyethylene glycol- b -poly( L -lactide) (PLLA/PLLA-PEG-PLLA) blends with various PLLA-PEG-PLLA ratios and chain-extender contents were prepared by melt blending. PLLA-PEG-PLLA was used with the aim to improve crystallization and toughness of the PLLA matrix in the blends. PLLA/PLLA-PEG-PLLA blends exhibited a homogeneous phase. PLLA-PEG-PLLA enhanced crystallization of the PLLA matrix as investigated from non-isothermal and isothermal crystallization studies. Impact strength of the blends increased with the PLLA-PEG-PLLA ratio. Chain extension reduced the melt flow properties and improved impact strength of the blends but suppressed crystallization of the PLLA matrix. The overall results indicated that the crystallizability, toughness and melt flow characteristics of PLLA-based blends can be tailored by PLLA-PEG-PLLA blending and addition of chain extender.