Optimization of physical and mechanical properties of rubber compounds by a response surface methodological approach

Response surface methodology was used for optimizing the ratio of vegetable oil and carbon black and occluded volume fraction of rubber in the compoun d. Central composite design for two variables was chosen as the experimenta l design. The data obtained from measurement of properties was fitted as a two variable second-order equation, and were plotted as contours using soft ware developed from MATLAB v.5.1. From contours it is observed that at the ratio of 0.06 of vegetable oil and carbon black, there is maximum coupling, and a further increment in vegetable oil and carbon black ratio shows less coupling and more plasticizing effect. The ultimate failure properties lik e tensile and tear strength and elongation decreases with an increase in oc cluded volume fraction, reaches a minima at the central region, followed by an increase, whereas 300% modulus and hardness decreases throughout. (C) 2 001 John Wiley & Sons, Inc.