High Molecular Weight Tri-substituted Phenol as an Antioxidant for Rubber

Abstract

Long aliphatic chain containing substituted phenols like (9-(2-hydroxy 3,5-dinonylphenyl) methyl stearate (DNPMS), (9-(2-hydroxy 3,5-dicumyl phenyl) methyl stearate (DCPMS) and (9-(4-hydroxy 3,5-ditertiary butyl phenyl) methyl stearate (DTBPMS) have been prepared by Friedel Crafts alkylation of hindered phenols such as 2,4-dinonyl phenol (DNP), 2,4-dicumyl phenol (DCP) and 2,6-ditertiary butyl phenol (DTBP) respectively with methyl oleate in presence of AlCl₃ at room temperature. To study the efficacy of these compounds as antioxidants, natural rubber mixtures have been prepared. The physical and mechanical properties of the rubbers were determined. The effects of the prepared compounds on the mechanical properties after ageing were evaluated. It was found that the synthesized compounds showed good antioxidant behaviour compared with the industrially used conventional antioxidant styrenated phenol (SP). In the second part, we have studied the effect of antioxidant DTBPMS which is having structural similarity with Irganox 1076, on the ageing of NR-SBR blend vulcanizates Hawai footwear application. It was found that the DTBPMS showed delayed initial crack formation and other mechanical properties were comparable to those of vulcanizates containing Irganox 1076.