MECHANICAL PROPERTIES OF GLASS FIBER/BASALT FIBER REINFORCED POLYPROPYLENE HYBRID COMPOSITES FABRICATED BY DIRECT FIBER FEEDING INJECTION MOLDING PROCESS

摘要

This paper mainly discussed the mechanical properties of glass fiber/basalt fiber reinforced polypropylene hybrid composites which were made through a new method called the direct fiber feeding injection molding (DFFIM) process. The DFFIM process means that continuous basalt fibers were directly fed into the barrel of injection molding machine while using the glass fiber/polypropylene pellets to make composites materials. Basalt fibers were fed into the melt polymer by the shearing motion of the screw of injection molding machine during plasticization process. Thus, the fiber attrition during extrusion will be eliminated. This is a fundamental industry change and it eliminates the compounding step and the cost of reinforcing compounded pellet, so it could lower the cost of fiber reinforced polymer composites. Then, fiber orientations in the composites which made by both DFFIM process and normal injection were evaluated to get fiber orientation factor, respectively. Fiber volume fractions and residual fiber lengths of both glass fiber which from GFPP pellet and basalt fiber which from direct roving feeding method were investigated and analyzed. The interfacial shear strength between fiber and polypropylene in composites was analyzed by utilizing the modified Kelly-Tyson equation. The effect of the basalt fiber in GF/hybrid PP composites was discussed based on the mechanical properties testing results which include tensile test, three point flexural test, Izod impact test and single edge notch tensile test. Scanning electron microscope was conducted on the fracture surface of the tensile tested specimen to see the cross-section morphology to know fiber status in the composites.