Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Antioxidant 1010 and processing-parameter regulation were combined to improve PLA melt spinning stability. Under optimized conditions of 0.3–0.5 wt% antioxidant, 190°C processing temperature, and a draw ratio of 15, thermo-oxidative degradation was suppressed, molecular weight retention and melt stability were improved, thereby enhancing filament consistency, elongation, and mechanical uniformity during continuous processing.

ABSTRACT
This study used polylactic acid (PLA) as the base material and applied melt spinning process to examine the effects of antioxidant 1010 on the thermal stability, molecular weight retention, rheological behavior, and mechanical uniformity of PLA fibers during processing. By adjusting antioxidant content, draw ratio, processing temperature, and residence time, together with the melt flow behavior, the effects of the antioxidant on reducing thermal degradation and improving spinning uniformity, as well as the influence of processing parameters on fiber uniformity, were investigated. The results show that adding a suitable amount of antioxidant (0.3–0.5 wt%) improves the thermal stability of the PLA melt. Under these conditions, molecular weight retention increases by about 15%, the polydispersity index (PDI) decreases, and molecular chain degradation is reduced. Less chain degradation also leads to better fiber elongation and more uniform mechanical properties, with the coefficient of variation of tensile strength and elongation reduced to about 7%. This study determined suitable processing parameters for single-screw spinning of the PLA/antioxidant system (antioxidant content of 0.3–0.5 wt%, processing temperature of 190°C, and draw ratio of 15), which support stable processing and structural control of PLA fibers with high uniformity.