A clean approach for potential continuous mass production of high-molecular-weight polylactide fibers with fully stereo-complexed crystallites

摘要

A clean and cost-effective method for 100% stereo-complexation in polylactide (PLA) fibers with molecular weight (MW) as high as 6 x 10(5) demonstrates good potential for industrial-scale continuous manufacture. Polylactide, a widely recognized biodegradable and renewable biopolymer, has a negligible share of plastic markets due to its poor hydrolytic and thermal resistance. Stereo-complexation is effective in overcoming these challenges. However, current stereo-complexation approaches usually require solvents and/or external nucleation reagents, and are expensive and complicated. Moreover, high-MW PLAs favored for developing durable products are difficult to be stereo-complexed. In this research, enantiomeric PLAs both with MW up to 6 x 10(5) were completely stereo-complexed via a facile thermal treatment on pilot-scale devices. Neither solvent nor nucleation agent was used. For poly(L-lactide) (PLLA) fibers with MW of 6 x 10(5), percentage retention of MW and percentage retention of tensile strength after hydrolysis under simulated textile dyeing condition increased from 39% to 93% and from 20% to 89%, respectively, after complete stereo-complexation. The melting point, softening point and percentage retention of MW after hydrolysis of stereo-complexed PLA (sc-PLA) fibers were up to 51 degrees C, up to 59 degrees C and up to 183% higher than that of PLLA fibers with the same MW, respectively. The mechanism of thorough stereo-complexation in high-MW PIA fibers was proposed and verified. It is promising to use this approach to broaden industrial applications of renewable and degradable biopolymers for sustainable development of material industries. (C) 2017 Elsevier Ltd. All rights reserved.