ABSTRACT: L-Lactide/trimethylene ca

ABSTRACT: L-Lactide/trimethylene carbonate copolymers have beenproduced as multifilament fibers by high-speed melt-spinning. Therelationship existing between the composition, processing parametersand physical properties of the fibers has been disclosed by analyzinghow the industrial process induced changes at the macromolecularlevel, i.e., the chain microstructure and crystallinity development. Apoly(L-lactide) and three copolymers having trimethylene carbonatecontents of 5, 10 and 18 mol % were synthesized with high molecularweight (Mn) up to 377 kDa and narrow dispersity. Their microstructure, crystallinity and thermal properties were dictated by thecomposition. The spinnability was then assessed for all the as-polymerized materials: four melt-spun multifilament fibers withincreasing linear density were collected for each (co)polymer at a fixed take-up speed of 1800 m min−1 varying the massthroughput during the extrusion. A linear correlation resulted between the as-spun fiber properties and the linear density. Theas-spun fibers could be further oriented, developing more crystallinity and improving their tensile properties by a second stageof hot-drawing. This ability was dependent on the composition and crystallinity achieved during the melt-spinning and theparameters selected for the hot-drawing, such as temperature, draw ratio and input speed. The crystalline structure evolved to amore stable form, and the degree of crystallinity increased from 0−52% to 25−66%. Values of tensile strength and Young’smodulus up to 0.32−0.61 GPa and 4.9−8.4 GPa were respectively achieved.