Preparation and characterization of cellulose reinforced natural rubber / tapioca starch composite foam

Cellulose pulp-reinforced natural rubber/tapioca starch composite foams were prepared by baking process. The effect of storage relative humidity on the physical and flexural properties of composite foams was investigated. For nonreinforced system, both specific flexural strength and specific flexural modulus were found to decrease with increase the natural rubber content while maximum flexural strain appeared to be improved with addition of 50% by weight of natural rubber. For reinforced system, the 30% by weight of natural rubber content composite foams were reinforced with cellulose pulp. All flexural properties, specific flexural strength, specific flexural modulus and maximum flexural strain were found to increase with increase fiber content. Moreover, the scanning electron micrographs revealed that the average cell sizes for all foam compositions decrease with the increasing of natural rubber and cellulose pulp contents. As result of the smaller average cell size, thicker cell wall, higher desity, and the presence of reinforcing fibers, cellulose pulp-reinforced natural rubber / tapioca starch composite foams appeared to exhibit much improvement in the mechanical properties.