SILANIZATION OF TREAD RUBBER COMPOUNDS OF PASSENGER TIRES P.II. STUDY OF RELAXATION SPECTRUM OF A TREAD RUBBER BY THE METHOD OF STRESS RELAXATION: φ - AND δ-PROCESSES

Abstract

Tread rubbers of composition described in P.I have been studied by method of stress relaxation under static condition at tension ε = 30 % and temperatures 20–110 ºС, also the same as in P.I. The existence of φ- and δ-processes besides of λ-process is sown. Their characteristics are analyzed. Several φ-processes associated with different types of structures formed with the participation of fillers, were found in the time range 10²–10⁶ s. Several different δ-relaxation processes caused by the changes in the chemical structure of the studied rubbers were also revealed. Activation energies U and radius R of particles, assumed to be ball-formed, connected with φ- and δ-processes, are calculated. Conclusions are presented about the effect of the ratio of carbon black (TU) and silica (DS) on the characteristics of φ- and δ-processes. In particular, under reduce of the ratio TU:DS the rate of φ-process of higher rate increases, R also increases, and U decreases. Silanization results in nearly threefold reduce of R i.e. in increase of dispersity of DS observed earlier. Lower R and higher U are shown for δ-processes. Effect of rubbers type in composition of tread rubbers, including their crystallization ability, on R and U changes in dependents of TU:DS ratio and silanization presence is under discussion.