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

摘要

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 40oC. 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 180oC, the tensile strength (b), elongation at break (εb), the work of rupture (W) and impact strength (αcU) were only 19MPa, 1.8%, 0.15J, and 2.8kJ/m2, respectively while those of the SPCs prepared at 130~160oC were 47~65MPa, 15~32%, 9~22J, and 14.9~67.2kJ/m2, respectively. With the increase of hot-pressing temperature, the b, W and αcU decreased.