An assessment of Rice Husk Ash modified, Marble Sludge loaded Natural Rubber hybrid composites

Marble sludge (MS) and rice husk have been collected from marble industry and rice processing mill. MS was dried, ground and passed through 10µm size sieve. Rice husk was treated with hydrochloric acid solution at 105˚ C, and burned at 650 ˚ C for four hours, pulverize and passed through 10µm size sieve. Both powders were characterized by the X-ray fluorescence and then incorporated in the natural rubber (NR), according to recipe for various hybrid compositions. Compounding was carried out on a two-roll mill with total filler loading of 60 parts per hundred rubber (phr). The composites were vulcanized at 155o C. The effects of partial or complete replacement of MS by rice husk ash (RHA) on mechanical and swelling properties of MS/RHA/NR hybrid composites before, and after ageing were analyzed. Results show that tensile strength, 100% modulus, 300% modulus, tear strength, hardness, crosslink value, volume fraction and shear modulus increases while elongation at break, compression set, rebound resilience, abrasion loss, swelling coefficient and the average molecular weight of the polymer between cross-links decreases with increasing RHA weight ratio in hybrid composites. The ageing characteristic of corresponding hybrid composites was evaluated at 70˚ C and 100˚ C temperatures for 96 hours.