Radiation induced grafting of N,N-dimethylacrylamide onto polyester film

Radiation induced grafting of N,N-dimethylacrylamide onto polyester film has been studied by means of immersion method. Polyester film was immersed in the aqueous solution of N,N-dimethylacrylamide containing potassium ferricyanide as homo-polymerization inhibitor and chloroform as swelling and activation agent for polyester film, and was irradiated with gamma ray at a temperature between 00C and 500C. Radiation induced grafting of N,N-dimethylacrylamide onto polyester film by means of immersion method took place when small amount of chloroform was contained in the aqueous solution. The relation between grafting ratio and irradiation time t is shown as follows. G equals kt, where G: grafting ratio (%), t: irradiation time (hr), k: constant. Grafting ratio was constant for the grafting system where the aqueous solution was saturated with chloroform. The apparent activation energy was determined to be 10.6 kcal/mole between 00C and 400C for the mixture of N,N-dimethylacrylamide-chloroform-water. From the observation of X-ray diffraction pattern, cross-section microphotograph and differential scanning calorimetry, it was suggested that N,N-dimethylacrylamide was grafted in the amorphous region of polyester film and penetrated through the whole section of the film, and grafted N,N-dimethylacrylamide itself was in amorphous state. Water content of the N,N-dimethylacrylamide grafted polyester increased with increase of grafting ratio. S equals 0.22G, where s: swelling ratio, G: grafting ratio (%). (author)