架橋CRの分子運動性と金超微粒子充てん効果

抄録

The molecular mobility of vulcanized chloroprene rubber (CR) was examined by ¹H pulsed NMR. The spin-spin relaxation time (T₂) of ¹H showed that the vulcanized CR consisted of three components of rubber molecules. The component with the longest T₂ (M3 component) appeared at above 90°C, and its molecular mobility was similar to that of liquid. The M3 component was thought to be composed of branch structures such as dangling chains and endchains. For the CR filled with ultrafine gold particles, the temperature at which the M3 component appeared became higher with the increase of gold content. The molecular mobility of the branch structures was reduced by the interaction between the surface of the gold particles and the end groups of rubber molecules such as the metal-sulfur bond. The gold particles did not change the stress-strain and the viscoelastic behaviors of CR, but improved its fatigue property at higher temperature.