English Abstract

Fracture Reveals Real Structure and Characters of Rubber
Part 6: Real Structure and a Generalized Concept of Rubber Reinforcement
(Second): What is the Essence of Stress-upturn in Cross-linked NR ?

Yoshihide FUKAHORI
Queen Mary, University of London
Nippon Gomu Kyokaishi,(2015),88(8),309-316 General Review in Japanese

The cross-linked phase in real cross-linked rubber behaves as not the non-Gaussian but the Gaussian. The stressupturn and high tensile strength can be realized by the contribution of the co-continuous uncross-linked phase. The uncross-linked phase changes to the bundle of the extended molecules under large extension at a low temperature and high velocity depending on the molecular packing, which supports the main part of the stress of the system. For NR, due to its high molecular stereo-regularity, the molecular packing in the uncross-linked phase increases greatly as extension increases, and thus the stress-upturn and high tensile strength will be well generated even at room temperature.

Keywords: Gaussian, Non-Gaussian, Cross-linked Phase, Uncross-linked Phase, Molecular Stereo-regularity, Molecular Packing