Benign Fabrication of Fully Stereocomplex Polylactide with High Molecular Weights via a Thermally Induced Technique

A reproducible and environmentally friendly method for the preparation of high molecular-weight stereocomplex polylactide (HMW SCPLA) is achieved. Poly(l-lactide) and poly(d-lactide) were simply dissolved in an environmentally friendly solvent, dibasic ester (DBE), at 110 °C. Then, the two solutions were mixed and cooled to room temperature, and the HMW SCPLA spontaneously precipitated in the form of fine powder consequently. The presence of the DBE reduced the reaction temperature and improved the molecular mobility of the polymers; thus, the degradation problems and the molecular diffusion issue in the process of the formation of the stereocomplex could be overcome. The relationship among the concentration of the mixture, degree of stereo-complexation, and thermal properties of SCPLA powders was also established. Moreover, porous membrane and film SCPLA material with good thermal properties were also obtained using this thermally induced technique. This method could be a good approach to expand the SCPLA applications.