The Effect of Plasticization of Isoprene Rubber on the Cohesive Strength of its Rubber Compounds. Part 2. The Role of the Chemical Nature of Macromolecules

Abstract

The work on studying the conditions of plasticization of isoprene rubber (SKI-3) on the cohesive strength of its rubber compounds (σ_k) has been continued. As a result, it was found out that the plasticization of SKI-3, on average, over the temperature range of plasticization 30–130 °C and the duration of its conduct from 30 to 600 s, leads to a decrease in σ_k. A theoretically justified and experimentally confirmed way of increasing the σk from 0,47 to 0,57 MPa is proposed. It was found that the mechanoactivated oxidative destruction of SKI-3 macromolecules, carried out at a low temperature, promotes the growth of the σ_k of the rubber mixture. Mechanocreaking of SKI-3 macromolecules significantly reduces the σ_k. Recombination of macroradicals of different nature, formed during the plasticization
of SKI-3 at 130 °C and a time of no more than 5 minutes, leads to a significant increase in the σ_k of rubber compounds. A number of equations describing the dependence of σ_k on the molecular weight and the degree of mechanodestruction of various types of chemical nature of SKI-3 macromolecules, formed during its plasticization, are obtained.