Interfacial Optimization and Performance Enhancement of CGF / PA Filaments: Insights From Controlled Heat Treatment of Glass Fibers

ABSTRACT Aimed at the key problems of the performance and application of continuous fiber reinforced composite filaments in additive manufacturing, this study clarified that fiber desizing was a key variable affecting the impregnation quality, interface bonding and final filament performance. By systematically characterizing the mechanical properties, microstructure and surface chemistry of glass fibers at different heat treatment temperatures, and analyzing the effects of desizing temperature, mold temperature and traction speed on the forming quality of filaments, the interaction mechanism between fiber surface state and impregnation process conditions was revealed. It was found that the tensile strength of glass fiber decreased significantly after heat treatment above 200°C, and the strength decreased to 787.15 MPa at 350°C, a decrease of 52.12%, which was mainly attributed to the internal structure damage and surface defects of the fiber. Moderate heat treatment (such as 100°C) could increase fiber surface active groups, improve the interface bonding, and improve the comprehensive performance of the filament. This study decoupled the relationship between fiber surface modification, process parameters and composite properties, and provided new insights and experimental basis for directional regulation of composites properties and further improvement of its engineering application potential.