Radiation-Induced Copolymerization of N-Vinylpyrrolidone with Monochlorotrifluoroethylene

The copolymerization of N-vinylpyrrolidone (NVP) with chlorotrifluoroethylene (CTFE), initiated by gamma rays from a60Co source, has been studied at temperatures of 20 to −78°C in a dose rate range of 5 × 104 to 3.8 × 105 rd/h. The copolymerization rate was proportional to the 0.5 power of dose rate and showed a maximum at the equimolar concentration of both monomers. The apparent overall activation energy of copolymerization was determined to be 5.8 kcal/mol. 1, 1-Diphenyl-2-picrylhydrazil was found to be a strong inhibitor. The composition curve indicated a strong alternating copolymerization tendency. The monomer reactivity ratios were determined to be r(NVP) = 0.38 and r(CTFE) = 0.30, respectively, by the Fineman-Ross method. The copolymer obtained is a white powder. It is soluble in such solvents as acetone, dimethylformamide, and chloroform, but insoluble in water.