The Effect of Plasticization of Isoprene Rubber on the Tangent of the Angle of Mechanical Losses of its Vulcanizates at 60 °C. Part 2. The Role of the Chemical Nature of Macromolecules

Abstract

The article is devoted to the study of the influence of the different nature of macromolecules formed during the plasticization of (Р) isoprene rubber (SKI-3) on the tanges of mechanical losses at 60 °C of its sulfur vulcanizates (tg60). It was found that the oxymacroradicals formed during the oxidative destruction of SKI-3 macromolecules at 130 °C contribute to a decrease in the value of tg60 with an increase in their molecular weight (MM) and the degree of oxidation. In the case of P SKI-3 in the temperature conditions of mechanocreaking dominance, the emerging alkyl and allyl macroradicals sharply reduce the value of tg60, and with an increase in their MM and the degree of mechanocreaking, this effect increases. Recombination of macroradicals of various types formed during P significantly increases tg60. Equations are obtained that allow calculating the values of tg60 of sulfur vulcanizates based on different types of macromolecules, depending on the magnitude of their MM and the degree of P. Practical recommendations for reducing tg60 are given.