Cografting kinetics of styrene and ethyl acrylate onto polyethylene

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Abstract
Kinetic studies of cografting reactions of styrene (St) and ethyl acrylate (EA) onto preirradiated polyethylene (PE) have been investigated by means of bromine labeling and infrared spectroscopy. Kinetic data obtained from these methods, that is, the percent grafting, the number of graft chains, and growing rates, were obtained at temperatures of 0, 20, 40, and 50°C. The graft percent was virtually influenced by the degree of swelling. At 0°C, the mixing ratio of ethyl acrylate and styrene monomer before the beginning of the reaction was equal to the existence ratio in the graft chains after the reaction. Therefore, this reaction is considered to be diffusion‐controlled. On the contrary, at 20 and 40°C, the existence ratio in graft chains after the reaction. Therefore, this reaction is considered to be diffusion‐controlled. On the contrary, at 20 and 40°C, the existence ratio in graft chains agreed with the theoretical curve calculated from monomer reactivity ratio. The number of active graft chains for given times were 3∼5 × 10−7 mole/g PE and it decreased with temperature; 0 > 20 > 50°C. While the total number of graft chains is 5∼15 × 10−7 mole/g PE and it increased with temperature; 0 < 20 < 50°C. The growing rate were 1∼5 monomer/site/sec for 0°C, 2∼15 for 20°C.
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