The pre‐irradiation grafting of styrene onto cotton cellulose using gamma rays

The grafting of styrene onto cotton cellulose initiated by pre‐irradiation with gamma rays, from Cobalt 60, has been studied in some detail. The build‐up and decay of radicals have been followed both by electron spin resonance measurements and by the decrease of grafting yields after storage of the irradiated cellulose. It was found that a second order decay process was approximately followed. The yield of grafted polymer and the corresponding decrease in the radical content have been followed during the grafting process. The results obtained indicate that the grafting is initiated by trapped radicals. The overall process has been described by a simple non‐steady state kinetic scheme. Good agreement between theory and the experimental results was obtained. Some evidence was found for the occurrence of peroxide initiated grafting when higher polymerization temperatures were used. The peroxides formed may arise from reaction of the cellulose with water rather than oxygen during the irradiation.