Optimisation of material compositions for flammability characteristics in rice husk/polyethylene composites

Abstract

A parametric study on the flammability characteristics of rice husk-reinforced polyethylene composites with various material compositions was conducted to find the “best” composites’ formulation for fire retardancy. Composites were manufactured using rice husk, maleated anhydride polyethylene and linear medium density polyethylene. The blends for manufacturing of composites were selected using mixture design approach. The individual effects of each constituent material on the fire performance of composites by cone calorimeter were studied using trace and contour plots for the various thermal and flammability properties. Regression coefficients were also estimated for each measured response. The cone calorimetry results show that the addition of rice husk improved fire retardancy of composites. The addition of maleated anhydride polyethylene did not influence the flammability properties much, except for mass loss rate and specific extinction area. The optimum mixture of rice husk, maleated anhydride polyethylene and linear medium density polyethylene for overall “best” flammability properties of the composites was also determined by multiple response optimisation using the regression models in Design Expert software. The optimum mixture for overall “best” fire retardant properties was found to be 50 wt% of rice husk, 5.6 wt% of maleated anhydride polyethylene and 44.4 wt% of linear medium density polyethylene. The flammability properties measured from composites manufactured with this formulation closely matched the values predicted by the model.