Research On The Modification Of Vinyl Acetate Grafting Onto Chlorinated Polypropylene

Chlorinated polypropylene is a widely used thermoplastic resin in printing ink industry, and should be dissolved in benzene solvents when used. However, along with our country promoted environmental printing ink, it is urgent to carry out research on the modification of ester solubility chlorinated polypropylene. And this is a research of theoretical and economic significance.In this study, modified chlorinated polypropylene was prepared through radical grafting reaction by solution method in chloroform, using vinyl acetate as grafting monomer, azodiisobutyronitrile as initiator. The ester solubility modified CPP is prepared. Concrete research contents and outcomes are as follows:(1) The modified product CPP-g-VAc was prepared by grafting reaction, and IR spectrum comfirmed that vinyl acetate had grafted onto chlorinated polypropylene. The optimum reaction conditions were as follows: monomer feeding mode is adding into reaction mixture dropwise; reaction temperature is61℉; reaction time is7h; monomer concentration is m(VAc):m(CPP)=0.1956; initiator concentration is m(AIBN):m(CPP)=0.1. Under the optimum reaction condition, graft degree of the modified products was11.77%and the graft efficiency is55.02%.(2) Analysis method of determining accurate graft degree was established.And the RSD=1.17%.(3) TG showed that the thermal stability of the modified CPP did not change significantly compared with raw materials CPP, which illustrated the introduction of VAc will not affect the CPP application performance in the printing ink industry.(4) The solubility performance of modified products was studied. The modified product CPP-g-VAc of graft degree6.02%was prepared to a mixture system in different solvents (20%wt), and it can be completely dissolved in the methyl isobutyl ketone, cyclohexanone, and butyl acetate. What’s more, the highest solubility in butyl acetate can reach23%, which can meet the requirements of ester solvent ink system. In addition, the solubility parameter of raw material CPP and modified CPP was measured by intrinsic viscosity. The solubility parameters of CPP was19.16(J.cm-3)1/2, and solubility parameter of modified products was19.21(J.cm-3)1/2, which means the polarity of modified products increases.