Study On Two-step Solid Phase Grafting Modiifcation Of Polyethylene With Dual Monomer

Polyethylene (PE) is a plastic widely used in the industrial production, due to itpossesses such advantages as rich raw materials resources, low cost, good chemical stability,excellent cold temperature resistance and electrical insulation property. However, PE has itsinherent disadvantages such as low surface energy, poor compatibility with synthetic polarpolymers, photo oxidation and thermal oxidation take place easily, crosslink and chain fractureappeared after irradiation, which restrict its further applications. This can be resolved throughgrafting copolymerization, a well established method for modification of polyethyleneproperties. Modification of polyethylene with binary-monomer(GMA/St) was studied by twomethods, which were supercritical CO2(SC-CO2)assisted modification of polyethylene bysolid-state and impregnation assisted modification of polyethylene by solid-state.Modification of polyethylene by grafting of glycidyl methacrylate (GMA) and styrene(St) as co-monomer and benzoylperoxide (BPO) as initiator using supercritical carbon dioxideas a solvent and swelling agent. The effects of swelling pressure, swelling temperature,swelling time, reaction temperature, reaction time and initiator concentration etc. on graftingreaction were studied. The maximum grafting degree of5.65%was reached when initiatordosage is0.7%, and reacted at100℃for2hours after3hours impregnation at8.0MPa and40℃. The FTIR results confirmed that both glycidyl methacrylate and styrene were graftedonto PE.Modification of polyethylene by grafting of glycidyl methacrylate in solid state wascarried out, using styrene as co-monomer. PE was impregnated in an organic solution of themonomers and initiator for sometime. The grafting reaction was taken place after removal oforganic solvent. The effects of co-monomer type, molar ratio of two monomers, monomerdosage, impregnation time, reaction temperature and time, initiator concentration, interfacialagent species and stirring speed on grafting reactions were investigated in details. Themaximum grafting degree of6.43%was reached when monomers dosage is7%, molar ratioof two monomers（GMA：St）is three to one, the interfacial agent dosage is8.6%, and reactedat100℃for2hours after6hours impregnation at room temperature.. The FTIR resultsconfirmed that both glycidyl methacrylate and styrene were grafted onto PE.