Characterization of the mechanical and thermal properties and morphological behavior of biodegradable poly(L-lactide)/poly(ε-caprolactone) and poly(L-lactide)/poly(butylene succinate-co-L-lactate) polymeric blends

Two series of biodegradable polymer blends were prepared from combinations of poly(L-lactide) (PLLA) with poly(ε-caprolactone) (PCL) and poly(butylene succinate-co-L-lactate) (PBSL) in proportions of 100/0, 90/10, 80/20, and 70/30 (based on the weight percentage). Their mechanical properties were investigated and related to their morphologies. The thermal properties, Fourier transform infrared spectroscopy, and melt flow index analysis of the binary blends and virgin polymers were then evaluated. The addition of PCL and PBSL to PLLA reduced the tensile strength and Young's modulus, whereas the elongation at break and melt flow index increased. The stress-strain curve showed that the blending of PLLA with ductile PCL and PBSL improved the toughness and increased the thermal stability of the blended polymers. A morphological analysis of the PLLA and the PLLA blends revealed that all the PLLA/PCL and PLLA/PBSL blends were immiscible with the PCL and PBSL phases finely dispersed in the PLLA-rich phase.