Thermal, morphological and mechanical properties of flexible poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide)/thermoplastic starch blends.

This paper reports a flexible poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) (PLLA-PEG-PLLA) melt blended with a thermoplastic starch (TPS). The crystallization, thermal stability, phase morphology and mechanical properties of PLLA-PEG-PLLA/TPS blends were evaluated and compared to PLLA/TPS blends. Addition of TPS suppressed crystallizability for both the PLLA and PLLA-PEG-PLLA matrices. The thermal stability of PLLA-PEG-PLLA was greatly increased by blending with TPS. The PEG middle-blocks enhanced phase compatibility between PLLA-PEG-PLLA and TPS phases. Tensile tests showed that the PLLA-PEG-PLLA/TPS blend films were ductile and very flexible compared to the PLLA/TPS blend films. The obtained PLLA-PEG-PLLA/TPS blends can be utilized as novel flexible bioplastics.