English Abstract

Now Consider Again Real Structure and the Characteristics of Cross-linked Rubber Part I. Vague Images of Real Structure of Cross-linked Rubber that have been Made Apparent Recently

Yoshihide FUKAHORI
Queen Mary, University of London
Nippon Gomu Kyokaishi,(2024),97(1),9-15 General Review in Japanese

Recent studies concerning structure of cross-linked rubber verified experimentally and theoretically are summarized, where is shown that the real structure is different significantly from a molecular cross-linked model known conventionally. (1) Cross-linked rubber consists of heterogeneous structure of cross-linked phase and uncross-linked phase where both the phases are separated making co-continuous structure. Volume fraction in the system is 65~70% for the cross-linked phase and 30~35% for the uncross-linked phase. (2) The cross-linked phase is crosslinked tightly in a molecular scale, then it hardly deforms at an external deformation. In contrast, the uncross-linked phase seems not to be crosslinked keeping the original uncross-linked and liquid state, thus it mainly deforms under the external deformation and absorbs most solvents in a swelling test. (3) AFM image describes the crosslinked structure of rubber almost correctly, where the phase-separated structure is shown clearly as indicated by the simulation.

Keywords: Structure of Cross-linked Rubber, Rubber Elasticity Theory, Phase Separation, Co-continuous Structure, Cross-linked Phase, Uncross-linked Phase, AFM Image