Properties of short glass fiber–reinforced polyethylene terephthalate composites: effects of fiber length & surface modification

Abstract Fiber length and interface properties have significant effects on the mechanical characteristics of fiber-reinforced composites. In this work, effects of screw speed and fiber content on glass fiber (GF) length during the process of twin-screw extruder were investigated. And the influences of GF length on the mechanical characteristics of composites (PET/GF) were also studied. The GF surface was modified by the silane coupling agent (KH-550) with different concentrations of KH-550 solution. The results reveal that increasing the screw speed from 20 to 40 rpm at the same GF content leads to a decrease in GF length in PET/GF composites, resulting in reduced tensile strength and flexural strength. Moreover, a 3 wt% concentration of KH-550 enhances the tensile strength, flexural strength, and impact strength of PEF/KGF composites by 21.4 %, 3.1 %, and 26.6 %, respectively.