CHO, SH PARK, JS LEE, WS CHUNG, IJ 2024-01-21T22:31:45Z 2024-01-21T22:31:45Z 2022-01-11 1993-06 0170-0839 https://pubs.kist.re.kr/handle/201004/146031 The structural changes of polyacrylonitrile fibers have been studied through the effect of heat treatment on dynamic mechanical relaxation of undrawn and drawn fibers. It is generally accepted that polyacrylonitrile has two transition temperatures. This study showed that the activation energies of the low temperature transition and the high temperature transition were about 53 and 155kcal/mole, respectively. The latter was related to the intermolecular diploe-dipole dissociation of the nitrile groups in the amorphous region and the former was related to the molecular motion in the paracrystalline region. English SPRINGER VERLAG DIELECTRIC-RELAXATION TRANSITION EFFECT OF HEAT-TREATMENT ON STRUCTURAL-CHANGES AND DYNAMIC-MECHANICAL RELAXATION OF POLYACRYLONITRILE FIBERS Article 10.1007/BF00300034 1 POLYMER BULLETIN, v.30, no.6, pp.663 - 668 POLYMER BULLETIN 30 6 663 668 scie scopus A1993LP06500007 2-s2.0-0027459708 Polymer Science Polymer Science Article DIELECTRIC-RELAXATION TRANSITION