On the stress relaxation of nylon 6

• Published in: Journal of polymer science 1958, Vol.27 (115), p.335-347
• Main Authors: Yoshitomi, Tatsuya, Nagamatsu, Kazuo, Kosiyama, Kiiti
• Format: Article
• Language: English
• ISSN: 0022-3832; 1542-6238
• DOI: 10.1002/pol.1958.1202711527

The stress relaxation of low‐crystallinity nylon 6 is measured by torsional method at various temperatures in three (0, 40, and 75%) relative humidities. As the whole procedures are very accurate, the results contain little experimental error. The relaxation data at 0 and 75% relative humidity can be reduced to respective master curves by Ferry's reduction method. Considering the changes of structure by difference in humidity, it is found that these two master curves are reduced further to one single general master curve by the aid of some molecular theory of the crystalline polymers. By the use of first‐order approximation, the relaxation time spectrum of this crystalline polymer is obtained for a very wide time scale range, more than 1021 sec. The resultant spectrum is fairly high and flat, reflecting the characteristic features of crystalline polymers. It has, however, two weak but distinct maxima, corresponding to the so‐called “wedge” and “box” distributions in the relaxation time spectrum of the amorphous polymers. Based on the existence of this box distribution in the spectrum, it is suggested that there should exist some sort of clusters effective in the mechanical behavior of the crystalline polymers.