Polypropylene modification by the radiation graft polymerization of N-vinylcaprolactam

The radiation graft polymerization of N-vinylcaprolactam onto polypropylene films was studied. The radiation graft polymerization was performed with preirradiation in air (peroxide method) or using a direct method in aqueous solutions and organic solvents. The effects of radiation dose, reaction time, monomer concentration, and homopolymerization inhibitor on the radiation graft polymerization were studied. It was found that the radiation graft polymerization from a monomer emulsion in water occurred at the highest rate. The IR spectra of grafted polymers were obtained. With the use of differential scanning calorimetry and equilibrium swelling in water, it was found that the modified polymers of polypropylene with grafted poly(N-vinylcaprolactam) chains exhibited thermoresponsive properties.