EPOXIDIZED NATURAL OILS AS THE ALTERNATIVE SAFE PROCESS OILS IN RUBBER COMPOUNDS

Abstract

Abstract Due to the toxicity of aromatic oils derived from polycyclic aromatic hydrocarbons (PAHs), safe process oils are required for a replacement in rubber compounds. The properties of tire tread compounds filled with high abrasion furnace black (HAF) when epoxidized palm oil (EPO) and epoxidized soybean oil (ESBO) are used as the processing oils, in comparison with the use of conventional distillate aromatic extract (DAE) were investigated. The oil characteristics were analyzed by spectroscopic techniques (FTIR and NMR), differential scanning calorimetry and elemental analysis. Influence of the oils on the properties of natural rubber (NR), NR/styrene butadiene rubber (SBR) blend, and SBR compounds was investigated. All compounds with the EPO and DAE oils have similar cure characteristics (i.e., scorch and cure times, torque differences) and processing properties (i.e., minimum torques and Mooney viscosities). However, the use of ESBO oil clearly retards the curing reaction, resulting in lower extent of crosslinking, and thus inferior vulcanizate properties. The mechanical properties, e.g., hardness, modulus, tensile strength, elongation at break, tear, and abrasion resistance, of the compounds utilizing the EPO and DAE oils are comparable and superior to those of the ESBO added compound. In addition, the use of EPO results in similar dynamic mechanical properties of rubber vulcanizates when compared with conventional DAE. The results indicate that EPO is a potential candidate for the placement of DAE oil in rubber compounds.