Properties Of Polypropylene/ Maleic Anhydride-grafted Propylene-based Elastomer/glass Fiber Composites

Polypropylene(PP)is a widely used general plastic with various excellent properties,such as low cost,good mechanical properties,good chemical stability.However,its impact toughness is poor,its compatibility with inorganic filler is poor,and its mechanical properties are worse than those of engineering plastics,so its application is limited.Glass fiber(GF),which has high strength and good rigidity,is a widely used reinforcement material.GF reinforced PP is a kind of composite material with excellent properties,it has broad application prospects in the household appliance and automotive industry.The combination of GF and PP is weak due to the poor compatibility between them,which is not conducive to the improvement of the performance of the materials.Therefore,the key is to improve the compatibility between GF and PP.In this paper,GF was used as the reinforcing material and treated with silane coupling agent KH-550,VM-g-MAH and POE-g-MAH were selected as compatibilizers and impact modifiers,high performance GF reinforced PP composites were prepared by melt blending and injection molding.The effects of compatibilizers content and coupling agent treatment on the mechanical properties,heat resistance,melt flow rate and crystallization properties were investigated,and the effects of different compatibilizers were compared.The mechanical properties of the composites were tested and the interfacial bonding was observed by SEM: The treatment of glass fiber with coupling agent KH-550 cannot effectively improve the compatibility,so the mechanical properties of the material was not improved significantly.The addition of compatibilizers significantly enhanced the interfacial bonding between GF and PP,which greatly improved the mechanical properties of the material.The mechanical properties of the material were further improved by the combination of coupling agent and compatibilizers.The rigidity of the material was reduced and the toughness was improved with the increment of compatibilizers.Overall,the effect of VM-g-MAH was better than that of POE-g-MAH.When GF content was 30%,and treated by KH-550,and the content of VM-g-MAH was 10%,composite with excellent mechanical properties can be prepared,its tensile strength,flexural strength,notched impact strength were 73.7 MPa,126.1 MPa,25.7 KJ/m2.The results of VST test showed that the heat resistance of the material can be improved by the coupling agent treatment of GF.The addition of compatibilizers decreased the heat resistance of the composites,and the Vicat Softening Temperature of the composites decreased with the increase of the content of compatibilizers.The heat resistance of POE system is better than that of VM system.The results of MFR test showed that the addition of compatibilizers and coupling agent treatment had a significant effect on the MFR of the composites.If GF was not treated by KH-550,the MFR of POE system and VM system decreased with the increase of the content of compatibilizers;if GF was treated by KH-550,The MFR of VM system increased with the increase of content of compatibilizer.The melt flowability of the VM system was better than that of the POE system.The results of DSC and WAXD showed that the crystallinity of PP was little affected by compatibilizers,and the addition of compatibilizers and coupling agent treatment did not change the crystal form of PP.The difference between VM system and POE system was that the content of ? crystal of the former was lower,and the grain size of ? crystal was smaller.