Preparation And Application Of Polypropylene Grafted MAH

Reactive extrusion is a technology of polymeric reaction processing, which integrates the technology of chemical reaction with extrude process. It is a new edge science subject. This dissertation not only introduced the specialty of reactive extrusion, but also presented the theory. The kinetics equation and energy balance equation were discussed and the equipments were recommended.We used this technology to prepare coupling agents of PP-g-MAH. The raw material was PPT30S which was produced by QiLu petrochemical company. Well-defined maleic anhydride(MAH) was chosen by testing and analyzing. Studied the effect of monomer contents on properties of PP-g-MAH. Based on the results of DSC, graft degree of MAH, the decompose temperature and activate energy, we determined the best initiator was DCP. Studied the effect of initiator contents on properties of PP-g-MAH. Firstly, the prescription and technics were got by orthogonal-experiments. Studied the effect of equipments on graft degree of PP-g-MAH, The results showed that the closely intermeshing co-rotating twin-screw extruder with longer L/D should be better for grafting reaction. The crystal degree of PP-g-MAH was bigger than PP by microscope WAXD and DSC, so did the crystal temperature. But the crystal configuration of main molecule chain had not changed. Secondly, Based rheological behavior of PP-g-MAH, as a result, PP-g-MAH still be a kind of non-Newtonian pseudo plastic fluid, the shear viscosity decreased rapidly with shear rate. The shear viscosity and shear stress of PP-g-MAH was weaker than pure PP. This result proved the fact that PP-g-MAH was not sensitive to temperatures. It would improve processing property of polymer compounds.Summing up the properties of obtained products, the properties hadreached the level of same products of domestic and foreign county.Application of PP-g-MAH in the blend materials of wood fibres and polypropylene was discussed. When the PP-g-MAH was interfused into the compounds, the melt flow rate and tensile strength were increased, and then the elongations at break were decreased. The more contents of PP-g-MAH, the bigger of flexural strengths. However, when the flexural module reached high to a value, the flexural module remained the same. With increasing the contents of PP-g-MAH, the impact strength was increased firstly, and then it was decreased rapidly. The effect of PP-g-MAH which was used alone was better than that it was mixed with other chemical coupling agent. The shear stress and shear visc was increased slightly when PP-g-MAH had been put in;the rheological behavior of the compound system had no big difference with the contents of PP-g-MAH, this showed the fact that the compatibility of filler and PP had been improved, the unite intension had been increased. When the contents of PP-g-MAH was below 10%, Based on analyzing the SEM photos, we found that phase between wood fibres and PP was distinctness when PP-g-MAH was not joined in. It also had no difference when it was mixed with other chemical coupling agents. When PP-g-MAH was putted in, the interfaces were invisible. Wood fibres and PP were wraped together. The surface of two phase were faintness which were companying with something of strip. The SEM image hence demonstrated that the compatibiliser PP-g-MAH had successfully reacted with the wood fibres, resulting in clearly enhanced fibres-polymer adhesion. This was proved the compatibility between wood fibers and PP had been improved, so did the mechanical strengths. The properties of car inner decorated planks which were made of this compounds measured up to national standards.In CaCO₃/PP compounds, Effects of PP-g-MAH were discussed. When a amounts of PP-g-MAH was added into the compounds, the melt flow rate wasincreased, so did the tensile strength and impact strength. Moreover, the flexural module of this compounds material was enhanced. The rheological behavior of the compounds had been studied, the results showed that when PP-g-MAH were put in, the shear stress and shear viscosity values was decreased slightly, the shear visC of the compound system had no big difference with contents of PP-g-MAH, PP-g-MAH was different from the other coupling agents, Not only the PP-g-MAH could improve the adhere ability, but also it had lubricate function. When CaC03 was filled in PP, the crystal temperature was raised, so did the crystal degrees. This was because CaC03 could be as nucleating agent in PP. However, addition of PP-g-MAH decreased this nucleation level, so crystal degree fell down. But it still be bigger than the crystal degree of pure PP. In the state of melting, the PP-g-MAH had function of plastic. In the state of solid, non-active molecule chains of PP-g-MAH and PP chains developed crystal together, the surface of two phase remained strong link together. Thus, the properties of the compounds were improved. PP-g-MAH also could enhance the polarity of the compounds and improve the spray- paint property. The automobile tyres covers which was made of this compounds materials were better than the same products in domestic market.The PP-g-MAH is low cost and high profit. The reactive extrusion machines is simple, It has good effects in compounds. It has bright future in market.