Rheological and mechanical properties of natural rubber reinforced with agricultural byproduct

Cocoa pod powdered (CP) and Carbonized Cocoa pod powdered (CCP) sieved through 150 μm mesh were characterized in terms of loss on ignition, surface area, moisture content, and oil absorption and used as filler in compounding natural rubber and vulcanized using efficient vulcanization system. The processing and curing characteristics of the compound mixes were determined on a Monsanto Rheometer. Physical‐mechanical properties of the vulcanizates were measured as a function of filler loading. It was found that vulcanizates with 40–50% filler loading showed maximum tensile strength of 8.4 MPa for CP, and 9.5 MPa for CCP. Hardness showed increased with increased filler loading for all the compounds. The reinforcing ability of the cocoa pod husk is not much inferior when compared to Carbon Black, N330. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3718–3722, 2003