EFFECT OF MICRO-SIZED MARBLE SLUDGE ON PHYSICAL PROPERTIES OF NATURAL RUBBER COMPOSITES

Marble waste as sludge was collected from the marble industry, as a way of solving the environmental problem of industrial waste. The sludge was dried, ground and passed through the desired sieves (10, 15, 20, 37 and 75 mu m). This powder was characterized by X-ray fluorescence and then incorporated in the formulation of NR composites with different loading of micro-sized MS particles (20, 40, 60, 80 and 100 parts per hundred of rubber, phr). The cure characteristics, mechanical properties and swelling properties of MS/NR composites were evaluated. The results indicate that minimum torque, maximum torque, tensile strength, modulus, tear strength, hardness, crosslink density increased, while the scorch time, cure time, cure rate, cure rate index (CRI), elongation at break, compression set, rebound resilience, abrasion loss, swelling coefficient, average molecular weight and filler-rubber interaction decreased with increasing MS loading.