Dynamic vulcanization of rubberwood-filled polypropylene/natural rubber blends

The effects of dynamic crosslinking on mechanical properties, water absorpt ion and morphology of rubberwood-filled polypropylene (PP)/natural rubber ( NR) blends were studied. The blends were prepared at 180 degreesC using a r otor speed of 50 rpm for 12 min. Sulfur concentration was steadily increase d from 0 to 2.0 (wt%) in order to study the vulcanization effect. It was fo und that dynamic crosslinking has enhanced the tensile strength, stress-at- peak, Young's modulus, flexural modulus and stabilization torque (at the en d of the mixing stage) of the rubberwood-filled PP/NR blends. This has been attributed to the increase in crosslink density which was indicated by a r eduction of weight gain (water absorption) and weight loss of the blends wi th increasing sulfur concentration. (C) 2001 Elsevier Science Ltd. All righ ts reserved.