The Study Of Polypropylene Fiber Self-reinforced Polypropylene Resin

This paper took polypropylene fibers as warp and weft yarn prepared plain weave and twill polypropylene continuous fibric. Using compression molding method added textile fabrics into the polypropylene to make polypropylene continuous fiber self-reinforced composite polypropylene. Discussing the organizational structure、fiber distribution shape、 fiber conten、preparation of process parameters of different fineness (900D and 300D) on the effect of the composite tensile properties, modulus of elasticity, impact resistance, flexural properties, thermal properties, dynamic mechanical properties. And by scanning electron microscopy (SEM) to observe the cross-section and low-temperature brittle tensile fracture of the composite materials. The main findings:(1) In certain cases, the mechanical properties of composite materials would be affected by the molding process. As the hot-pressing time, hot-pressing temperature, hot-pressing pressure gradually increased, the tensile strength, elastic modulus and bending strength of the composite materials all showed a trend of increase and then decrease.This was mainly decided by polypropylene resin infiltration degree of polypropylene, arrangement of polypropylene fiber and polypropylene fiber stress. The optimum technological of Polypylene fiber/polypropylene composites was determined by the experiment, hot-pressing temperature was 185 ℃, hot pressing time was 3 min, hot-pressing pressure was 5 mpa.(2) Different forms of fabrics was provided with different infiltration performance, directly affected the mechanical properties of composite materials. Tensile properties and elasticity modulus of twill polypropylene fiber composites were better than plain fabric. But the impact strength was on the contrary. From SEM photos,15%(mass fraction) of polypropylene fiber and PP resin has good compatibility, and twill intervals between polypropylene fiber and matrix was smaller than plain. DMA analysis showed that the loss factor (tan delta) moved to high temperature direction gradually, the glass transition temperature (Tg) of twill fabric composite was the largest.(3) Polypropylene fiber content on the effect of properties of composite materials. Results showed that when hot-pressing temperature was 185℃, polypropylene fiber mass fraction was 15%, the composite had an optimum mechanical properties, the tensile strength increased by 39% than pure PP. Notched impact strength are reduced, but the reduction is not big, composite materials are still into ductile fracture. As can be seen from the SEM photos, polypropylene fiber and PP resin had a good compatibility, the composite material had excellent mechanical properties. DMA analysis showed that with the increase of the content of polypropylene, composite materials storage modulus obviously increased as well. Loss factor (tan delta) moved to high temperature gradually, when the fiber content was 15%, the glass transition temperature (Tg) reached the largest.