Effect of Screw-Axial Vibration on Structure and Properties of Short Glass Fiber Reinforced High-Density Polyethylene Composites

Abstract

Interfaces between resins and glass fibers perform concernful roles in mechanical and physicochemistry properties in composites. Additionally, the increase of the glass fiber orientation can drastically strengthen the mechanical qualities of composites. Here we employ the screw-axial vibration force field (VFF) via the self-devised electromagnetic dynamic plastics injection-molding machine to demonstrate the effects of the orientation and distribution state of short glass fibers (SGFs) and the distribution state of interfacial modifiers, compared with steady-state injection molding. We thus fabricated the samples of SGF reinforced high-density polyethylene with graftomer, plasticizer and other additives under screw-axially superposing vibration force field. The composite samples experience tensile testing, impact testing, scanning electronic micrograph techniques and the mathematical calculation of orientation of short glass fibers. The results betray that VFF with the vibrational frequency f = 3 Hz and amplitude A = 0.2 mm considerably enhances the orientation of SGFs along the melt flow direction, even at the core, compared with steady-state injection molding. Likewise, VFF dramatically improves the distribution state of short glass fibers and interfacial modifiers. Therefore, the tensile strength and impact strength of specimens are both significantly heightened, in contrast with those of conventional injection molding specimens.