Force-Temperature Behavior of Nylon Filaments at Fixed Extensions

Abstract

By use of the thermodynamic equations for elasticity, force-temperature measurements on nylon filaments at fixed extensions in water have been related to the molecular mechanism of elasticity. Drawn fibers at low extensions were found to have an entropy force component larger than the total force. This effect was less pronounced in undrawn fibers, but persisted over a wider range of extensions. For undrawn nylon, a transition in the force-temperature behavior has been found which differs markedly from the second-order transition in rubber; rubberlike elasticity was found below rather than above the transition temperature. The transition temperature was ca. 47°C for 5% extension, and increased rapidly with increasing extension. Both nylon 6-6 and nylon 6 were found to have the same force-temperature be havior, except that the former showed evidence of impending glasslike elasticity near 0°C.