Effect of hydration conditions in thermal and mechanical properties of injection-molded glass fiber/polyamide-6

Engineering polymers are used in a multitude of load-bearing applications where structural integrity and long-term reliability are of the utmost importance. In this study, two different commercial composites (Durethan and Technyl) of polyamide-6 reinforced with 30 wt% of glass fiber were manufactured by injection molding and different hydration conditions were tested. All composites were characterized chemical and mechanically (tensile, flexural, impact and toughness). The fractured surface morphology was analyzed microscopically. According to the infrared spectra, the chemical structures of the composites were not altered by the hydration conditions tested and there were no significant effects on the degree of crystallinity of the samples evaluated. The toughness and impact tests evidenced that the best hydration condition was an immediate immersion, followed by the one performed after 24 h the injection, where for the impact resistance test the Durethan composites was 27.84% higher than Technyl. Wet Pack hydration method, showed similar behavior with samples that were not hydrated, exhibiting low toughness and impact resistance. In general, Durethan composites hydrated by immediate immersion showed the best mechanical performance, being the most suitable to be used in the industry as a stretcher junction component.