The Studies On Properties And Application Of Glass Fiber Reinforced Polypropylene Composite

Polypropylene(PP)has been widely used because of its attractive combination of low density,good mechanical properties,heat stability and chemical resistance.Right now,short glass fiber reinforced polypropylene and long glass fiber reinforced polypropylene are the two common materials in glass fiber reinforced polypropylene,they are extensively used in appliance making and automobile making.Especially for LGF-PP,due to it’s exceptional mechanical properties,fatigue resistance and low-creepage properties,LGF-PP is usually utilized to replace engineering plastics or even the iron materials.LGF-PP can reduce the weight of the car.In this paper,the glass fiber reinforced PP with different length are studied,which are SGF-PP and LGF-PP respectively.We study the influence of different PP material on the properties of these two kind of composites.In the 30 percent short glass fiber reinforced PP,we study different screw speed and different screw configuration,which would affect the performance of the material.Then we study different content of glass fiber both in SGF-PP and LGF-PP.In addition,the glass fiber distribution of SGF-PP and LGF-PP was studied by SEM.Through these experiments,we found the effect of PP resin and glass fiber content on the properties of glass fiber reinforced PP,and we found the optimum screw speed and screw configuration,these parameters would guide us when we process the SGF-PP material.Firstly,different ratios of homopolymer PP and copolymer PP were used in different recipes,and the influence of different resin type on the mechanical properties of SGF-PP and LGF-PP composites were discussed.The results showed that both for SGF-PP and LGF-PP,when the MFI increase,the mechanical properties of the material will increase.The tensile strength of the material can be improved by the use of homopolymer PP.The impact strength of the material can be improved by the use of copolymer PP.Secondly,through different process experiments,the influence of the screw speed on the mechanical properties of 30% short glass fiber reinforced PP was studied.Then the reserved length of glass fiber at different screw speed was measured.The experimental data showed that when the machine speed is in the low range,it is not conducive to the dispersion of the glass fiber,when the screw speed is in the high range,it will cause the damage of the glass fiber and reduce the reserved length of glass fiber.Medium screw speed is the best for the SGF-PP composite.On this basis,the influence of different screw configurations on the mechanical properties of 30% SGF-PP was studied.The results showed that when the short glass fiber was added in the extruder,the dispersing ability of screw is needed.When using the TME elements in the screw,the damage of the glass fiber can be reduced,and the reserved length of the glass fiber in the material can be increased.The TME element can improve the mechanical properties of the SGF-PP composite.Finally,different glass fiber diameter and content on the mechanical performance of SGF-PP and LGF-PP composites were compared.The results showed that with the diameter of the glass fiber decrease,the mechanical properties of the SGF-PP composite are improved.Although the tensile strength of LGF-PP composite increases with the decrease of the diameter of glass fiber,the bending strength and notched impact strength will decrease.The experimental data showed that with the increase of the glass fiber content,the mechanical properties of these two composites will increase too.In addition,the impact section of SGF-PP and LGF-PP materials was characterized by SEM.In the LGF-PP material,the three-dimensional structure of the glass fiber is formed,which is conducive to the stress transfer and improve the mechanical properties of the composite.