Graft Modification Of PP Based On Near-critical DEM Swelling-insertion

The solid-phase grafting of polypropylene started in the late 1980 s.The solid-phase grafting products are prone to ?-bond rupture and severe degradation,which is not conducive to surface printing,dyeing,and development of polymer alloys and blended composite materials,limits the application of PP.To overcome the shortcomings of solid-phase grafted polypropylene and expand the application range,it is of great significance to use near-critical dimethyl ether to assist the solid-phase grafting reaction.The research objective of this subject is to synthesize graft products with controlled grafting rate and uniform monomer distribution under mild conditions,and optimize the reaction conditions and processes for preparing functionalized PP to make it easy to achieve industrialization.In this paper,the near-critical DME embedding technology was used to insert the modified monomer and initiator 2,2'-azobis(isobutyronitrile)(AIBN)into the PP matrix by swelling PP film.After the swelling agent was removed,the modified monomer and initiator 2,2'-azobis(isobutyronitrile)(AIBN)were heated at the appropriate temperature,and the graft product was obtained by the free radical reaction.The swelling degree of different polypropylene matrix materials was studied in the glycidyl methacrylate graft polypropylene system,glycidyl methacrylate graft polypropylene system and styrene co-monomer graft polypropylene system and near-critical DME system.Determine swelling,swelling temperature,reaction time,reaction temperature,monomer ratio,monomer and initiator dosage for relative grafting rate and the effect of contact angle,and characterization of graft product,Fourier infrared spectra showed that monomers were successfully grafted onto the PP matrix,and then quantitative analysis of the graft product,to represent the relative size of grafting rate calculation of water contact angle method for characterization of the graft hydrophilic.Thermogravimetric analysis of thermal stability of graft products.The experimental results showed that the polypropylene spline,polypropylene film and polypropylene particles were swelling at 55? for 24 h with near-critical dimethyl ether as the swelling agent.The swelling degree of different polypropylene substrates was investigated.The results showed that the swelling degree of polypropylene film was the highest.In glycidyl methacrylate grafted onto polypropylene system,the swelling of 55? temperature,swelling time was 3 h,dosage of monomer GMA was 6 par based on PP,a dosage of initiator AIBN was 0.5 par based on PP,the reaction temperature was 85?,reaction time was 3 h when the maximum relative grafting rate 2.91%,the water contact angle of grafted product was 69.75 °.In glycidyl methacrylate and styrene grafted onto polypropylene system grafting polypropylene system,swelling time 3 h,the swelling temperature of 55?,3 h reaction time,reaction temperature 85?,a dosage of initiator AIBN was 0.6 par based on PP,and the monomers(the mol ratio of GMA and St was 1: 1)total amount was 10 par with 5.86% relative grafting ratio and contact angle was 67.19 ° of the grafted product.The thermal analysis experiment shows that the heat resistance of PP is reduced by adding monomer.