Determination of volume of shrinkage. The dimension of the mould and finished foam rubber sample was measured. The difference in dimension between the mould and the foam sample was calculated as a percentage of volume shrinkage.
Mechanical properties of latex foam rubber. The tensile strength and elongation at break values of the foam samples were determined using an Instron 5565 Testing Machine with a crosshead speed of 500 mm/min. The test was conducted at room temperature (25 ± 1ºC) and parallel sided test pieces were cut.
Hardness of the latex foam rubber was determined using the indentation test. The indentor foot was first brought into contact with the test specimen, the test sample was then indented until 25% of its initial thickness was reached. The force necessary to produce a 25% indentation in the latex foam was observed.