is added. The compounding ingredients were added according to the formulation in Table 3.
The viscous foaming liquid was then poured into a mould and vulcanised in a steam oven. After vulcanisation, the foam was stripped from the mould and the process was completed by washing and drying. Foam rubber samples of 1 inch thickness were produced.
Determination of foam density. Density of uncured foam was determined by calculation from the mass and volume of the specimen. A representative specimen with skins on the top and bottom surface measuring at least 0.01 m2 in area by full-part thickness was cut from an area free of voids. The density was calculated in grams per cubic centimeter as follows: