Study On Composites Of Continuous/Long Fiber Reinforced IPC

A mould of melt impregnation was designed, it overcome that the fiber only got two dimensional force in the impregnation process, and got a circumferential force. So the fiber should well dispersed and impregnated. The composites of continuous glass fiber reinforced impact polypropylene copolymer (IPC) were prepared, and then pelletized for injection mold. The mechanical properties (tensile, impact, flexural) and physical properties (shrinkage, hardness) were tested after the injection molding. At the same time, the submicroscopic morphology of impact fracture surface and the dynamic mechanical behavior of the composites were investigated by scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA), respectively.The results of mechanical experiments show that the tensile strength, flexural modulus of the composites increased obviously with the increase of fiber content, which achieved maximum at the fiber content of55wt%, and improved respectively500%and1100%compared to pure IPC. However, the impact strength of the puer IPC was obviously higher than the composites. And the impact strength achieved maximum when the fiber content was45wt%. At the same time, the addition of the maleic anhydride grafted polypropylene (MAH-g-PP) greatly improved the mechanical properties of the composites, which achieved maximum when the MAH-g-PP content was8wt%. Test results of physical performance show that the hardness of long glass fiber/IPC composites increased with the increase of fiber content, and the shrinkage rate was significantly lower than the IPC.Stress-strain curves of the composites were analysed and fit, and the areas under the curves were calculated by integral theorem for the toughness modulus of the composites. The results show that the toughness modulus and the ability to anti-deform gradually increased with the increase of the fiber content, but the elongation decreased gradually. In addition, both the toughness modulus and ability to anti-deform for the materials were improved with the addition of MAH-g-PP.The analysis of SEM shows that the addition of the MAH-g-PP could improve the interfacial bond, which enhanced the mechanical properties of the composites. The analysis of DMA shows that the incorporation of long glass fibers and MAH-g-PP improved obviously the stiffness and interfacial adhesion of the composites, which led to the increases of mechanical properties and storage modulus (E'). However, they decreased slowly when the MAH-g-PP content exceeded8wt%due to a slippage caused by the self-entanglement of MAH-g-PP. Further, tanδ value of the composites decreased attributed to the incorporation of long glass fiber and the improvement of the interfacial adhesion effectively restricted the movement of polymer molecules. In addition, both the Tg of iPP and EPR shifted to higher temperatures with the increase of fiber content, but only the Tg of iPP shifted to higher temperature with the increase of MAH-g-PP content, which indicates that MAH-g-PP could obviously improve interaction between glass fiber and iPP.