Compatibility And Mechanical Properties Of Polypropylene Composites

Polypropylene （PP） is a kind of thermoplastic polymer, having rich sources, and itssynthesis process is simple. PP owes small density, low price and excellent workability. And itis used as the first choice of the high performance materials in the area of general purposeplastic. But polypropylene also posses some disadvantages, such as low impact strength.Therefore polypropylene toughening increasingly causes the attention of research andindustrial department. In recent years, research of inorganic nanometer particles and elastomerfilling with polypropylene gradually becomes the hot spot, and gets a preliminary application.Therefore, research of the polypropylene modification lays the foundation for the applicationof polypropylene.Polypropylene was intended to be toughened by nano-TiO₂and elastomer in thepaper.And the structure and performance of polypropylene composites were alsostudied,specific studies were as follows:（1） Surface modification of nanoparticlesThe key to prepare a good toughness PP/nano-TiO₂composites is to improve thedispersion of nano-TiO₂in the polypropylene matrix and the interface compatibility.In orderto solve these problems,related research was performed.The surface of nano-TiO₂wasmodified by solution grafting modification.Nano-TiO₂was grafted amphotericpolymers（silane coupling agent KH560）,and thus the surface properties of it waschanged.Then the modification effect of nano-TiO₂was characterized by infraed（FTIR） andthermogravimetric（TG） and so on.The result showed,nano-TiO₂modified in an alkalineenvironment was best,and it’s surface was coated the most amount of organic.（2） Nano-TiO₂modified polypropyleneModified nano-TiO₂was blended with polypropylene in a twin-screw extruder to preparepp/nano-TiO₂composites.And effect on the crystallization behavior and mechanicalproperties of the composites was studied.The results showed,when nano-TiO₂modified in analkaline environment was blended with polypropylene,its size was small and distributeduniformly;When it was blended with nano-TiO₂,the tensile strength,elongation at break andtensile modulus were improved at a different degree.And the elongation at break wasincreased a little.（3） Polyamide elastomer modified polypropylenePolyamide elastomer was choosed to be blended with polypropylene and polypropylenecompatibilizer （maleic anhydride-grafted polypropylene, MPP） in a twin-screw extruder. Theeffect of MPP and elastomer on crystallization and mechanical properties of polypropylenewere studied. When the elastomer content was contant, the tensile strength and elongation atbreak of polypropylene composites were increased and then decreased with the amount ofmaleic anhydride grafted polypropylene increasing, when the content of maleic anhydridegrafted polypropylene was4%,the dispersed phase elastomers in the polypropylene matrixwere dispersed evenly,interface compatibility between the dispersed phase and the matrix,the tensile strength and elongation at break of the composite system were the largest; When the content of maleic anhydride grafted polypropylene was contant, tensile strength of thepolypropylene composite was increased first and then decreased with the increasing in thecontent of elastomer, but the elongation at break was always improved, And when theelastomer content was10%,the tensile strength of the composite system was the best. As aresult, the content of elastomer was10%and maleic anhydride grafted polypropylene was4%, when polypropylene was modified by elastomer.