Rapid preparation and continuous processing of polylactide stereocomplex crystallite below its melting point

Herein, a feasible protocol for the rapid preparation of polylactide (PLA) stereocomplex (SC) crystallite by extrusion was shown, in which a processing temperature lower than its melting point was chosen to suppress the thermal degradation and homocrystallization of PLA. Meanwhile, flexible and biodegradable poly(butylene adipate-co-terephthalate) (PBAT) was introduced to improve the processability of solid SC crystallite. The exclusive formation of SC crystallite with high crystallinity (~ 50 to 60%) was realized without further thermal treatment, which was clearly confirmed by wide-angle X-ray diffraction and different scanning calorimeter tests. It was found that certain amount of PBAT actually facilitates the stereocomplexation process, rendering the extrusion much smooth with 30 wt% more PBAT, thus making it promising to industrially achieve SC crystallite. Furthermore, the as-prepared PBAT/SC blend could be processed easily at a relatively low temperature, desirably allowing its scalable application. This work delivers a facile method for the efficient preparation and wider application of SC crystallite, which could be of great value to fabricate nucleating agents or heat-resistant PLA parts.