Kinetics Of Chloride Induced Grafting Of Maleicanhydride Onto PE And The Impact Of Styrene On The Grafting System

The mechanism and kinetics of in-situ chlorinating-graft copolymerization (ISCGC) of grafting maleic anhydride (MAH) on high-density polyethylene (HDPE) in gas-solid phase was investigated in this paper. Based on the assumption that single radical termination is the main way of termination reaction of radical solid phase graft polymerization, the kinetics and mechanism of the ISCGC of maleic anhydride in the presence of polyethylene are studied over the temperature range 50-100℃. A kinetic scheme is proposed and the experimental results are critically compared with it. The data yield apparent active energy (Ea) is 48.72KJ/mol. which, although subject to high uncertainty, are consistent with the fact that in-situ chlorinating graft copolymerization can be carried out at lower temperatures, which would then have to have an unusually low activation energy.Attempts to enhance the grafting degree (GD) of maleric anhydride (MAH) onto high density polyethylene (HDPE) in the presence of styrene (St) by ISCGC were made in this paper. The product composed of MAH/St copolymer as grafted chains and polyethylene as backbone (only containing trace chlorine) was named as PE-cg-(MAH/St). The feasibility of preparing PE-cg-(MAH/St) was identified by both FTIR and 1H-NMR spectrum. The structure of the graft copolymer was characterized by FTIR,1H-NMR, DSC and GPC. The gel content (GC) close to zero showed that there was no cross-link reaction in MAH/St grafted onto PE by ISCGC. The effects of reaction temperature, mass ratio, total monomer concentration, chlorine flow rate on the GD of MAH were also investigated, and the experimental results show that the addition of the second monomer St can significantly increased the GD of MAH. In the case of setting the reaction temperature 80～90℃, the mass ratio of MAH and St about 9:7, the total monomer is 16 parts per hundreds of resin (phr), and chlorine flow 29 mmol/min, GD is up to 3.56%. Additionally, the mechanical properties of PE-cg-(MAH/St) were explored primarily.Finally, the hydrophilic lipophilic properties, thermal stability and mechanical properties of the graft polymer PE-cg-(MAH/St) were studied. The factors in the mechanical properties of grafted polymer were also investigated.