Research On The Impregnation Mechanism Of Glass Fabirc/Polypropylene Composites And Interface Bonding Performance

With the excellent design ability, high specific strength and stiffness, high damage tolerance, long prepreg storage cycle, short molding cycle, recyclability, low manufacturing and maintenance cost, fiber reinforced thermoplastic composites(FRTC) are popular with academia and industry. Thermoplastic polymer is pseudoplastic fluid, which displays shear thinning behavior when flowing through the fiber porous media. One of the key factors to prepare manufacture FRTC is how to characterize the non-Newtonian viscosity behavior of thermoplastic melt accurately. The interface of composites is a bridge which transmits stress from polymer matrix to fiber. The performance of glass fiber reinforced Polypropylene (PP) is dependent to a great extent on the properties of glass fiber/PP composites. The synergistic reinforcing and toughening of composites is hard to realize in the traditional interface modification. The two above problems are studied by focusing on the impregnation theory, molding process and new interface design which comprehensive investigating the impregnation theory and new interface design method.The main focus of the impregnation theory of GFRPP is the viscosity property of the power law fluid flowing in fibrous porous medium. The impregnation model of GFRPP was deduced in this work, the impregnation model is based on Darcy’s law and takes into account the processing parameters and material properties. The impregnation model was validated by a series of experiments, and two kinds of different viscosity PP was used in this work. In order to guide industrial production, the cause of key parameters effect on the impregnation is studied by the experiment and model, and the pressure, dwell time, temperature and the infiltration front were main focus of this part.Because of the synergistic reinforcing and toughening of nano particles, the nano-silica was introduced onto the surface of glass fiber by KH550 silane coupling agent using chemical grafting with two step modifying process. Then the modified glass fiber/PP composites were fabricated using film staking procedure. In order to guide industrial production of fiber reinforced polyolefin polymer composites, the performance of the composites was characterized by interfacial shear strength (IFSS), interfacial fracture toughness (Guc), tensile strength, flexural Strength and dynamic mechanical analysis (DMA).