Low-Temperature Sintering of Stereocomplex-Type Polylactide Nascent Powder: Effect of Crystallinity

• DOI: 10.1021/acs.macromol.7b01794
• Publication Date: 2017-09-29T17:40:49Z
• Authors: Dongyu Bai; Huili Liu; Hongwei Bai; Qin Zhang; Qiang Fu
• Keywords: 01 natural sciences; 0104 chemical sciences

Stereocomplex (SC) crystallization between high-molecular-weight poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) provides a promising route to substantially improve the properties of polylactide (PLA), but conventional melt processing SC-type PLA (SC-PLA) is nearly impossible primarily due poor memory effect as well serious thermal degradation after complete melting SC crystallites with high temperatures above 220 °C. Recently, we reported an innovative low-temperature (180–210 °C) sintering technology for fabricating SC-PLA products from its nascent powder. Unfortunately, practical application has been significantly hindered by extremely pressure 1 GPa, which must be utilized ensure good surface wetting densified powder particles. With this challenge in mind, herein, role crystallinity investigated. Interestingly, first demonstrate that depressing favorable particle under much lower during densification stage powders because deformation becomes easier decrease fraction rigid crystal network. Moreover, subsequent interface welding stage, more PLLA/PDLA chains could involved interdiffusion across interfaces, thus forming large amounts new capable tightly interfaces. As consequence, sheets excellent heat resistance mechanical have successfully fabricated low 300 MPa. Overall, these fascinating findings not only provide fundamental understandings on initial also indicate avenue toward industrial-scale fabrication low-crystallinity using polymer equipment.