Study On The Effect Of Ionomer On The PP/EVA TPV As A Compatibilization

At present, the propylene/ethylene-vinyl acetate copolymer ?PP/EVA? thermoplasic vulcanizate ?TPV? was restricted in using because the compatibility between PP and EVA was not well. In our study, two kind of compatilizers were prepared. Then the effect of different compatilizers on PP/EVA TPV were compared.Adopting sodium maleate ?MANa? as a grafting monomer, dicumyl peroxide ?DCP? as an initiator, ionomer ?PP-g-MANa? was prepared by grafting MANa onto polypropylene ?PP?based on melt-grafting. The ionomer was characterized by fourier transform infrared spectroscopy ?FTIR?. The characteristic peaks of the carboxylate C=O between 1585.47cm^-1 and 1560.83cm^-1 demonstrated that the MANa and PP has grafted. The effect of the monomer amount, initiator amount on the grafting yield of PP-g-MANa was analyzed. When adding 24phr MANa and 0.4phr DCP to PP, the grafting ratio of PP-g-MANa was 36.4%.The grafted MANa onto saponified EVA ?EVAL-g-MANa? was prepared by molting method and the ionomer was characterized by the test of FTIR. The characteristic peaks of the C=O at 1575cm^-1 demonstrated that MANa was successfully grafted onto EVAL. The influences of monomer amount, reaction temperature, reaction time and the rotational speed of torque rheometer on the grafting degree were analyzed by the orthogonal experimental design. The results showed that the grafting ratio of EVAL-g-MANa was 21.4% when monomer amount, reaction time, temperature and rotational speed of torque rheometer was 6phr, 10min, 150? and 30r/min, respectively.The mechanical property, processability, crystallization property and microstructure of PP-g-MANa, EVAL-g-MANa and the mixture of PP-g-MANa with EVAL-g-MANa on PP/EVA TPV were studied systematically. The tensile strength, elongation at break, impact strength, modulus of elasticity and flexural stress of the TPV increased by 11.10%, 2.89%,18.00%, 35.71% and 97.16% respectively when the mixture of ionomer amount was 6 phr.Simultaneously, the melt flowing rate of the TPV was two times as before. The size of composite crystal decreased obviously and crystal beam crossed. The outlines of crystal became not obvious as before. The interior of crystal was arranged loosely. We can caught sight of the size of dispersed phase in the composite decreased from SEM graph. The phase interface became fuzzy and dispersed phase distribution was more even. The comprehensive properties of thermoplastic vulcanizates have been improved.