Electrospun non-woven mats from stereocomplex between high molar mass poly(l-lactide) and poly(d-lactide)-block-poly(butylene succinate) copoly(ester urethane)s

Abstract

By applying electrospinning new fibrous materials from a stereocomplex formed between a high molar mass poly(l-lactide) (HPLLA) and a copoly(ester urethane) (CPEU) based on poly(d-lactide) (PDLA) and poly(butylene succinate) (PBS) blocks (PDLA-b-PBS) were prepared. The stereocomplex formation was evaluated by means of differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses. In contrast to electrospun mats of HPLLA and HPLLA/PDLA-OH in which the polymers were in the amorphous state, it was found that the presence of PBS allowed the formation of a crystalline phase in the fibrous materials from HPLLA/PDLA-b-PBS. Annealing at 100°C for 8h enabled reorganization of the polymer segments within the fibers and the appearance for all of the samples of crystalline diffractions in the XRD patterns. A melting temperature of about 200°C was registered in the DSC thermograms of pristine and annealed mats from HPLLA/PDLA-OH and HPLLA/PDLA-b-PBS; evidence for stereocomplex formation. It was shown that besides stereocomplex crystallites PBS and PLA crystallites existed as well when using CPEUs with a higher PBS content. The obtained data from the thermogravimetric analysis (TGA) showed that the thermal stability of the stereocomplex-based fibrous materials depended on the PBS content.