Change of Glass Transition Temperature (T_g) and Moisture Adsorption Behaviour of Nylon 6 Fiber Induced by Exposure of Ultra-Violet Ray

摘要

Differential scanning calorimetry (DSC) andsorption isotherm of water vapor were measured for Nylon6specimens exposed by Ultra-Violet (UV) Ray with various periods up to 32 hours.The crystallinity of specimens did not change and UVirradiation did not effect on the crystalline itself in the range of experiment.Thus it was thought that the molecular scission and closs-linkingreaction take place in the amorphous region.The difference of the specific heat capacities of specimensmeasured below and above T_g showed a tendency of decreasewith increasing exposure time. The rate of decrasing of specificheat capacity was lowered with higher crystallinity. The factseemed to suggest that the cross-linking giving rise to lessmolecular motion, would precede in the amorphous region witha higher cohesive energy density compared to that with a lowercohesive energy density.The comparison of sorption isotherms for specimens before andafter irradiation also supported the assumption mentioned above.