Evaluation of Some Mechanical Properties of Composites of Natural Rubber with Egg Shell and Rice Husk

Egg shell and rice husk were incorporated into natural rubber using a laboratory size two roll mixing mill. A conventional vulcanization was used for curing. The tensile strength, abrasion resistance, hardness as well as the equilibrium swelling characteristics of the vulcanizate in toluene were measured as function of filer loading. The composites were varied from 0pph to 70pph. The tensile strength of the egg and rice husk filled vulcanizates exhibited retardation with increase in filler contents. The egg shell retarded from 12.5Mpa to 6.6Mpa and the rice husk from 10.4Mpa to 4.7Mpa. The hybrid was erratic, decreased from 92Mpa to 84Mpa and thereafter increased to 14.4Mpa. The abrasion resistance showed an irregular pattern of initial decreased from 92Mpa to 84Mpa and thereafter increased to 92Mpa and finally decreased to 89Mpa with increase in filler loading for egg shell, with a maximum wear ratio of 10.8 x 10-2g/rub. The rice husk increased from 85Mpa to 80Mpa, decreased to 79Mpa, with a maximum wearratioof1.27x 10-2g/rub. The hybrid decreased from 88Mpa to 83Mpa, with a maximum wear ratio of 1.4 x 10-2g/rub as the filler load increased. Hardness of vulcanizate increased with increase in filler contents from Opph to 70pph.