The Influence of the Structural Organisation of Nitrile Butadiene Rubbers on their Vulcanisation

Abstract

A comparative analysis of features of the vulcanisation of nitrile butadiene rubbers containing 18 wt% units of acrylic acid nitrile with different distributions of the AAN units along the macromolecules is carried out. The content of cis-1,4-, trans-1,4-, and 1,2-units was determined by IR spectroscopy (Bruker Equinox 55 Fourier spectrometer) from the intensity of the 730, 970, and 910 cm−1 absorption bands respectively. The dynamic viscosity at temperatures of 85 and 130°C and at shear rates of 1.13–42.23 s−1 and also the vulcanisation kinetics were determined on an Alpha Technologies RPA 2000 unit. The physicomechanical characteristics were determined using a Gotech AI-3000 instrument. The vulcanising system contained sulphur, ZnO, stearic acid, and an accelerator. The influence of the content of stearic acid on the properties of the vulcanisates was studied, and it was shown that the rubbers investigated can be divided into three groups. The authors suggest that the vulcanisation parameters and the physicomechanical characteristics of the elastomers are most influenced by the size of the alternating unit nanoformations.