抄録
The variation of creep and creep recovery with temperature and the ultimate tensile properties under constant load were studied for acrylonitrile-methylacrylate copolymeric fibers containing different amounts of methylacrylate (MA), and the effects of the copolymer composition on the ultimate tensile properties are discussed. The composite curves of the tensile strength against the time to break plotted double logarithmically exhibit an identical shape being independent of the copolymer composition, so that a critical condition for rupture may be assumed as equivalent. The temperature dependency of the shift factor along the logarithmic axis of the time to break and the values of a characteristic temperature are identical among samples, at least practically. Therefore, it is assumed that the composition of amorphous phase is essentially equivalent within the region of the MA fraction (6_??_12wt. %) used. The “failure envelope” over the transition zone and the rubbery and/or leathery zone changes to a more sharply convexed shape with increasing the MA fraction. On the other hand, it is obtained from the experiments of the creep and creep recovery that the response against external force becomes more sensitive with increasing the MA fraction. The variation of the “failure envelope” with the copolymer composition may be explained by a constancy of critical condition and the variation of the response against external force.
