Study On The Properties Of Toughening And Strengthening Of Polypropylene With Muscovite, Wollastonite And POE

PP is one kind of general purpose plastic, which has a number of properties and so it is widely used in a plenty of application. It is the best material which has excellent properties, and which has arisen great emphasis in research and industry fields. Common PP might just as well play the role of engineering plastic in many applied fields through the reasonable toughened and enhanced modification. The influence of muscovite, wollastonite, PP-g-MAH and POE on the strength and toughness properties of PP was discussed.Surface activity of mineral particle was modified by modifying the surface of muscovite and wollastonite, so as to improve the caking capability between mineral particles and PP. The proper modification agent, dosage and modified technology have been decided. The PP composite has been prepared through a twin screw extruder with maleated polypropylene as compatibilizer, POE as impact modifier and muscovite&wollostonite as reinforcing agents. The optimum processing conditions is determined by orthogonal test and single factor experiments. Through the researches of the mechanical properties, flowablity and thermal properties, we have found that tensile strength, flexural strength, flexural modulus, Rockwell hardness and vicat softing point are increased, from 24.87MPa,18.87MPa,681.06MPa, 15.3,73.4℃to 30.16MPa, 31.13MPa, 1220.11MPa, 18.76, 91.7℃. However the Charpy notched impact strength keeps steady and the fracture elongation decreases dramatically.The interface between the fillers and the matrix and the cause which improves their performance are explained through analyzing the surface morphology of the impact fracture by means of SEM. The analysis of the specimen fracture also indicates that the interface between the muscovite and wollastonite and the matrix is strong enough to transmit loads to the mineral particles so as to play the reinforcing role of the mineral particles. We also find that the layered distribution of muscovite which has large particle-size and the orientation of the wollastonite which has lager LD ratio are apt to improve the strength of the composite. POE is distributed in the matrix in the form of spherical particle and boned well with the matrix, so as to improve the impact strength. And POE could't improve the caking capability of the mineral particles and PP.DSC is used to characterize the melting and crystallization behavior of the composites. The results of non-thermal crystallization data show that the composites have a higher crystallinity, and are increased from 33% to36.273-40.40%. And the inorganic particles have an obvious induced crystallization of PP during cooling, so it is theoretically explained the cause of improved properties. We can see from the non isothermal heating curves that the melting temperature and heat resistance are enhanced.Toughening mechanism of the composite was preliminary investigated, founding that the improved strength and toughness was not the result of wollastonite, mica or POE,but the outcome of synergisms of the three.