Influence of the Fractional Composition and Molecular Characteristics of Titanium, Gadolinium and Neodymium 1,4-cis Polyisoprene Rubbers on the Properties of Their Rubber Mixtures and Vulcanizates. Part 2. Influence on Vulcanization Properties

Abstract

The article is devoted to the study of the fractional composition (FC) and molecular characteristics (MC) of titanium (SPI-Ti), gadolinium (SPI-Gd) and neodymium (SPI-Nd) 1,4-cis-polyisoprene on the vulcanization properties of rubber mixtures made according to the ISO 2303 formulation. It was found that the value of the minimum torque (M_L) of rubber mixtures stretches with an increase in the content of ultra-high-molecular and high-molecular fractions and a decrease in the low-molecular fraction. The M_L rubber compound from SPI-Ti was the smallest by this criterion. The degree of vulcanization of rubber mixtures is dissolved in the SPI-Ti ˂ SPI-Nd ˂ SPI-Gd series and decreases with increasing content of the low-molecular fraction in them. The time to reach the optimum vulcanization of the rubber mixture (t₉₀) of SPI-Nd and SPI-Gd is shorter than that of SPI-Ti due to the presence of fractions containing macromolecules of the star topology. The vulcanization resistance (t_S1) of the rubber compound varies symbiotically compared to t₉₀. Separately, the question of the influence of FC and MC of natural rubber NR on the indicators M_L, degree of vulcanization, t₉₀ and t_S1 is considered. A number of equations describing the above patterns were obtained.