Effect of antioxidants on aging of the chloroprene rubber/butadiene rubber (CR/BR) blends

Abstract

Thermal degradation of blends containing chloroprene rubber (CR) and butadiene rubber (BR) cross-linked with copper(II) oxide (CuO) with the addition of anti-aging substance ((N-(1.3-dimethylbutyl)-N-phenyl-p-phenylenediamine (6PPD), polymerized 2.2.4-trimethyl-1.2-dihydroquinoline (TMQ), or 2-mercaptobenzimidazole (MBI)) under high temperature was investigated using a Fourier Transform Infrared spectroscopy (FTIR) spectroscopy and color measurement. Additionally, changes in mechanical properties (such as tensile strength, elongation at break, hardness, tear resistance) causes by aging factors have also been investigated. The results indicated that the 6PPD and the MBI provided better protection of the CR/BR/CuO vulcanizates against degradation at elevated temperature than the TMQ. As a result of thermo-oxidative aging, in an infrared spectrum, a peak assigned to stretching vibration of carbonyl groups was observed. Differences in protection against thermo-oxidative aging by the anti-aging substance are caused by their different structure, consequently, by the differences in their protection mechanism.