Research On Grafting Modification Of Polypropylene In Solid-phase And Water Suspension Methods

Polypropylene(PP)is one of the most widely used plastics,due to its excellent physical and chemical properties along with low cost.However,PP has its inherent disadvantages such as low surface energy,lack of chemical functionality and poor compatibility with synthetic polar polymers,which restrict its further applications.This can be resolved through grafting copolymerization,a well established method for modification of polyolefins properties.We select two optimum methods to study on the modification of PP with polar monomer on the basis of previous work.The hydroperoxidant PP was obtained by the oxidation of PP by BPO in the dry air.The storage time of HPP was investigated and the effects of co-monomer on maleic anhydride(MAH)solid-phase grafted onto HPP backbone were studied.Effects of different experimental conditions about St and MAH grafted PP were investigated.The grafting samples were investigated by Fourier transform infrared spectroscopy(FTIR),thermal gravimetric analysis(TG),melt flow rate(MFR)measurements and contant angle measurements.The co-monomer St can improve remarkably MAH grafted PP and produce little gel.The optimum technical parameter is that PP/monomer(100/6)were swelled under room temperature for one hour and reacted 2.5 hour at 100?.FTIR results of grafted products indicate that the monomers were indeed grafted onto PP chains.TG and MFR results show thermal properities of grafting samples decrease with the grafting percentage increase.The data of contant angle indicate that the polarity of grafted products improve significantly.Besides,grafting monomers onto PP in water suspension system were investigated.The optimum technical parameter is that swelling time was 60 min,the concentration of monomer was 8%(the percentage of weight of PP),the reaction time was 150 min,the reaction temperature was 100? and the concentration of initiator was 0.5%(the percentage of weight of PP).FTIR results of grafted products indicate that the monomers are indeed grafted onto the backbone of PP chains.TG results show thermal properties of grafted products improve significantly with the grafting percentage increase.The MFR results show that grafting products remain its versatile physical properties.Compared to the traditional solid-graft method,the grafting reaction reacted in water suspension system has these merits:higher grafting percentage,grafting efficiency and excellent performance.