Polylactide single-polymer composites with a wide melt-processing window based on core-sheath PLA fibers

Polylactide (PLA) single polymer composites (SPCs) were prepared using PLA nonwovens made of core-sheath PLA fibers as raw materials by hot-pressing. The core and sheath materials were poly(L-lactide) (PLLA) and PLA with D-lactide of about 10 mol% (PLA90), respectively. The melt processing window of PLA SPCs reached more than 40 degrees C. The effects of hot-pressing temperature on the crystallinity, the size distribution of crystallites, the lamellar thickness and mechanical property of PLA SPCs were significant while those of hot-pressing pressure were small. The strong interfacial adhesion between matrix and reinforcement led to high mechanical properties of PLA SPCs. For pure PLA materials prepared at 180 degrees C, the tensile strength (sigma(b)), elongation at break (epsilon(b)), the work of rupture (W) and impact strength (alpha(cU)) were only 19 MPa, 1.8%, 0.15 J, and 2.8 kJ/m(2), respectively while those of the SPCs prepared at 130-160 degrees C were 47-65 MPa, 15-32%, 9-22 J, and 14.9-67.2 kJ/m(2), respectively. With the increase of hot-pressing temperature, the sigma(b), W and alpha(cU) decreased. (c) 2017 Elsevier Ltd. All rights reserved.