SC crystals of porous PLA via thermally–induced phase separation: Effects of process conditions, solvent composition and nucleating agent

Abstract

The formation of stereo-complex crystals (SC) in porous poly (lactic acid) (PLA) material is intricately linked with improving its comprehensive properties. In this work, the effects of process conditions, solvent composition and additional nucleating agent on SC crystals during the fabrication of porous PLA through thermally-induced phase separation method were studied. Crystallization behavior of SC crystals during the pore-forming process is systematically investigated, revealing that higher quenching temperature and longer quenching period facilitate the formation of SC crystals. Additionally, the addition of deionized water to the solvent effectively enhances SC crystals formation by reducing solution viscosity and prolonging the phase separation time. The highest crystallinity of SC crystals (XSC) can be achieved, reaching 30.6%, when the water content is controlled at 1.6%. Furthermore, the introduction of carbon nanotubes (CNTs) as a nucleating agent exhibits a pronounced effect on the formation of SC crystals. When incorporating a 3 wt% content of CNTs, XSC reaches its peak value at 37.7%. This work is helpful to provide reference for improving mechanical properties and heat resistance of porous PLA, thereby expanding its potential outdoor applications.