Use of Marble Waste in the Rubber Industry: Part II (SBR Compounds)

Abstract

An attempt has been made to utilise marble powder as a filler for rubber. The marble was derived from the slurry produced by a Gangsaw machine while cutting the big marble blocks in north-western India. The marble powder has been used in styrene butadiene rubber (SBR): (1) as a cheapening filler, (2) as a semi-reinforcing filler; this involved chemical treatment of the slurry; and (3) as a partial replacement for carbon black filler, to reduce the cost of the compounds. One other motivation was the need to find a way of disposing of the powder, which is creating a serious threat to the local environment. The methodology consisted of: (i) collection of the marble powder (ii) its characterisation (iii) its evaluation in rubber compounds (iv) treatment of the marble powder to enhance its reinforcing characteristics both by chemicals and by electron beam (EB) radiation and (v) evaluation of the filled material in end-products. It was found that the marble powder could be used as a cheapening filler in styrene butadiene rubber, in place of other commercial fillers like whiting. However, no significant improvement was obtained by chemical treatment or by electron beam (EB) radiation of the marble powder. It could be used as a partial replacement for carbon black (up to 10 phr) in various rubber products, which are used under static conditions (not under dynamic situations). These findings were consistent with those previously observed for natural rubber compounds.