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By Application: Architectural Laboratory Water Treatment Marine Air Handling |
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anneal acrylic
The gamma-ray induced graft copolymerization of methacrylic acid on synthetic fibers, such as nylon, acrylic, polyester, and polyethylene fibers, by a pre-irradiation technique in air was studied. The order of easiness of the grafting was as follows: nylon> acrylic> polyethylene > polyester. In nylon, the rate of grafting was observed to be proportional to 0.5 power of the dose, and it became higher with increasing polymerization temperature. The activation energy for the decomposition of peroxides was found to be about 20 kcal/mole. The amount of grafting on the irradiated fibers after storage at room temperature in air depended on the kinds of fibers. No decrease of the amount of grafting on nylon, but a considerable decrease on acrylic fiber was observed after storage. In nylon, when treated immediately after irradiation, the amount of grafting did not depend on the irradiation temperatures from -78 deg C to +30 deg C. In acrylic fiber it became larger with the decrease of the irradiation temperature. It was concluded that the formation of trapped radicals able to induce graft copolymerization is difficult in nylon and easy in acrylic fiber. The effect of the pH value in aqueous solution was studied. The rate of grafting was high at below pH 4, and lowered between pH 4 and pH 6, showing a minimum value at pH 7 and increasing again at pH 9. These results could be explained by the effect of pH value on the homopolymerization rate of methacrylic acid in aqueous solution. The mechanical and thermal properties of the grafted fibers were investigated, and it was found that the thermal properties of acrylic fiber were improved by the grafting.
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