Acrylate-modified gamma-irradiated olive stones waste as a filler for acrylonitrile butadiene rubber/devulcanized rubber composites

Abstract

Olive stones waste (OSW) from Egazi olive cultivar was ground mechanically then surface treated. The treatment of OSW was carried out by impregnation in acrylate monomer; trimethyl-propane trimethacrylate (TMPTMA) under gamma irradiation. OSW, either treated or untreated was introduced to acrylonitrile butadiene rubber (NBR)/ devulcanized waste rubber (DWR) blend for investigations. Waste rubber powder was devulcanized chemically by using spindle oil to obtain devulcanized waste rubber (DWR). The latter was blended at different ratios with acrylonitrile butadiene rubber (NBR). Upon testing the prepared blends; NBR/DWR (70/30) blend showed the optimum mechanical properties. The prepared composites were assessed with scanning electron microscopy, tensile properties, X-ray diffraction, dynamic mechanical thermal analysis (DMTA), water uptake and abrasion resistance. The mechanical results indicated that treated OSW showed better results than untreated ones. In addition, composites loaded by 10 phr treated OSW exhibited the highest enhancement in tensile and DMTA properties. Samples with untreated OSW exhibited higher water uptake than treated ones. Generally, water uptake or abrasion loss increased proportionally with increasing OSW loading, either untreated or treated ones.