Study On The Modification And Crystallization Behavior Of Polypropylene

Polypropylene(PP),as a very mature thermoplastic,has many excellent performances,such as good mechanical properties,innocuity,low relative density,good heat resistance,strong chemical resistance,high electrical insulation and easy processing and molding.In addition,raw materials are easy to get and the price is relatively low,so they are widely applied in the field of light industry and chemical industry,such as home appliances,buildings,automobiles and packaging,and are the fastest growing,innovative and active varieties of general synthetic resins.However,polypropylene still has shortcomings and shortcomings such as low rigidity,high brittleness and low impact strength to the notch,which seriously affects the expansion of the application scope of polypropylene.Therefore,the technology of post processing modification with general polypropylene(PP)has become the most important thing in the polyolefin industry.The alloy was prepared by melt blending of polypropylene(PP),propylene-ethylene copolymer(PEC)with various proportions of PP and PEC.The results showed that the PEC particles dispersed uniformly in the continuous PP matrix by scanning electron microscope,and the PP/PEC blend system was pretty compatible.The differential scanning calorimeter also shows that the PP and PEC elastomers are partially compatible.The tensile test showed that PP/PEC blends showed obvious ductile fracture,that is,PEC elastomers had good toughening effect on PP,and the elongation at break increased largely.The advantages and effectiveness of beta crystalline form in isotactic polypropylene(iPP)for the development of high performance polypropylene plastics are completely studied.Here,the sustainable eggshell powder Pimelic acid calcium(DES),is at a high temperature between the surface of the eggshell calcium pimelate an interaction of the preparation of PP effective nucleating agent.The reaction can be clearly FTIR and DSC data analysis is the formation reaction of eggshell powder surface calcium pimelate.Then,the effect of eggshell powder can be obtained through the influence of isothermal and non isothermal crystallization behavior,namely the research of melting characteristics and crystal structure.The results of the obtained non isothermal crystallization experiments show that the crystallization temperature of polypropylene is greatly improved by the support of beta nucleating agent.In addition,the melting characteristics of IPP and DES blends can be seen in the melting temperature range from 190-250 C under multiple scanning conditions.Interestingly,from the investigation of isothermal crystallization and subsequent melting behavior,it is found that DES is a crystallization nucleating agent which relies on temperature to selectively induce iPP.When a high or low crystallization temperature is used,the main alpha crystalline or beta crystal can be formed.These results show that the ratio of alpha and beta crystal can be fitted by selecting the isothermal crystallization conditions.The crystallization mechanism based on the thermodynamic and kinetic factors is further discussed.