Remarkable Progress in Self-reinforcement of Elastomers Generated through Strain-induced Crystallization (Part 2);“Real Image of Strain-induced Crystallization and Self-reinforcement in Cross-linked NR proved by the Newest Observation”

English Abstract

Remarkable Progress in Self-reinforcement of Elastomers Generated through Strain-induced Crystallization (Part 2);“Real Image of Strain-induced Crystallization and Self-reinforcement in Cross-linked NR proved by the Newest Observation”

Yoshihide FUKAHORI

Department of Materials Science, Queen Mary, University of London, Mile End Road, London, UK

Nippon Gomu Kyokaishi,(2011),84(7),215-222 General Review in Japanese

The newest observation revealed the real image of the self-reinforced structures constructed through straininduced crystallization in cross-linked NR. Strain-induced crystallization occurs within the uncross-linked phase in cross-linked rubber under extension, thus the continuous uncross-linked phase becomes the continuous super network by changing its character from soft and weak to hard and strong with increasing extension. The continuous super networks of strands of extended molecules interconnected with strain-induced crystals are constructed in the front of crack (the strongest stress field), and thus they support the whole stress field of the system, resulting in the high tensile strength of cross-linked NR together with knotty tearing. These newest observations support the model proposed by the author experimentally.

Keywords: Natural Rubber, Strain-induced Crystallization, Super Network, Strand of Extended Molecules, Knotty Tear