Verification of the Method on Thick Rubber Samples

Blocks of rubber 150 mm in diameter and 25 mm thick were compression molded at temperatures from 120 to 180°C for different lengths of time, and quenched in cold water. To obtain the cure distribution through the thickness of the slab obtained under the conditions of temperature and time, a cylindrical plug 20 mm in diameter was taken from the center of each block when cold, and this plug was mounted on a lathe and cut into sections 1 mm thick. These sections were swollen in toluene in order to determine the degree of cure. 

The temperature history at equally spaced points through the thickness of the rubber sample was calculated, giving the temperature profiles obtained at a time when the sample is heated in the mold at a constant temperature. The degree of cure was then evaluated from this temperature-time history. 

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