Epoxidized vegetable oils as processing aids and activators in carbon-black filled natural rubber compounds

This study investigated the suitability of epoxidized vegetable oils as additives in place of aromatic processing aids and activators in natural rubber based truck tyre tread compounds. The processability and cure characteristics of the compounds and physical properties of the vulcanizates were compared with those of the standard vulcanizate, which was prepared with a standard mineral oil -Dutrex R. Epoxidation of the oils was carried out (formed in situ) using the peracetic acid method and epoxidation was confirmed using 1H NMR and 13C NMR spectra. Epoxidized vegetable oils (EVO) were used at a fixed dose in the compounding process as processing aids. These oils were used in the compounding process to ascertain the possibility of using them as activators and processing aids.

Epoxidized palm oil (EPO) showed better processing properties, polymer filler interaction and dispersion properties and best heat resistance ability. Epoxidized sunflower oil (ESFO) can be used as an accelerator with the combination of sulphenamide to overcome the problem of reversion. Epoxidized soya bean oil (ESBO), EPO and ESFO were better alternative processing aids than petroleum based aromatic oils, which have been reported as carcinogenic. The cure characteristics and physical properties of the vulcanizate based on EPO suggested that this oil could be used as an activator in rubber compounding.

Keywords: Activator, epoxidation, palm oil, processing aid, soya bean oil, sunflower oil.

Doi: 10.4038/jnsfsr.v39i3.3628

J.Natn.Sci.Foundation Sri Lanka 2011 39 (3):243-250