Mechanically Robust Polylactide Fibers with Super Heat Resistance via Constructing in situ Nanofibrils

All-PLA fibers with excellent comprehensive performance and recycling convenience are realized efficiently.High molecular weight poly(D-lactide)(HPDLA)is incorporated into poly(L-lactide)(PLLA)matrix to construct in situ nanofibrils structure by taking advantages of the microphase separation between HPDLA and PLLA.The tensile strength of HPDLA/PLLA composite fibers(HDL-8)is enhanced from 2.1 cN/dtex of neat PLLA-8 fibers up to 2.9 cN/dtex.Its boiling water shrinkage(BWS)and shrinkage in hot air(HAS)significantly decrease to 7.8%and 2.8%,respectively.The abundance of in situ nanofibrils creates a grille-like structure that is crucial for both heat and hydrolysis resistance.More strikingly,a hybrid shish-kebab structure induced by the in situ nanofibrils serves as a mechanical reinforcement.This work paves a new way for heat resistance and self-reinforcement modification of PLA materials.