A MODEL FOR THE CREEP OF ORIENTED HIGH-MODULUS FIBERS

Recently it has been shown that the creep of oriented high-modulus fib ers satisfies a logarithmic time law over very long time intervals. Mo reover, the modulus of these fibers increases due to the creep. This w as interpreted by the annihilation of conformation defects during cree p. In structures with strong intermolecular interactions as in aramide s, however, the direct annihilation of defects is difficult to explain . Moreover a direct annihilation leads to a false time law if no furth er assumption about the properties of the defects are made. In this pa per a model for the transport of conformation defects in oriented poly mer chains imbedded into an oriented fibrillary structure with strong intermolecular interactions is presented. This modified transport mode l leads directly to the experimentally observed time law without any f urther assumptions about the defect properties.