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Polyacrylonitrile 공중합체 섬유의 고리화 반응
Cyclization Reaction of Polyacrylonitrile Copolymer Fiber
HWAHAK KONGHAK, December 1986, 24(6), 451-457(7), NONE
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Abstract
Polyacrylonitrile(PAN) 공중합체 섬유의 산화공정에서 발생하는 고리화 반응의 정도를 상대고리화도로 측정하여 비교하였다. 대체로 180 ℃이후 1 ℃/min의 승온속도로 가열하면 약 210 ℃부터 급격한 반응이 시작되고 260 ℃이후에는 섬유의 끊어지는 현상이 나타났으며 최대 상대고리화도는 약 0.52였다. 그러나 210∼250 ℃에서 등온 열처리하면 처리시간에 따라 상대고리화도 값을 0.9 이상으로도 증가시킬 수 있었지만 최적 산화처리 조건으로는 240 ℃에서 2시간 또는 250 ℃에서 1시간이 선정되었다. 그리고 이러한 조건에서의 고리화 반응은 1차반응으로서 활성화에너지 E는 약 21.44 kcal/mol 반응속도상수의 빈도인자, Ko는 약 2.2×105 sec-1 이었다.
Cyclization reaction degree and optimum heat treatment conditions of polyacrylonitrile-copolymer fiber during the oxidation process were investigated by the relative cyclization grade method. When the raw fiber was heated at 1 ℃/min, cyclization reaction started slowly at about 180 ℃, and progressed rapidly after 210 ℃. But there was a tendency of breaking off the cyclized fiber above 260 ℃ and the maximum relative cyclization grade was about 0.52. The relative cyclization grade of oxidized fiber could be increased above 0.9 by selecting isothermal treatment, but it is recommended to maintain about 0.7-0.9 during the oxidation process. With isothermal treatment, cyclization was the first-order reaction, the activation energy and the frequency factor were 21.44 kcal/mol and 2.2×105 sec-1 respectively in the range of 210 ℃-250 ℃.