A New Method for Determining the Vulcanization Characteristics of Rubber Compounds

The complete course of the vulcanization curve is obtained by measuring the values of the dynamic shear modulus during a period while the test sample is held at the vulcanization temperature. The measurements are made about the position of zero distortion. The curves are in good agreement with those obtained by a step-cure method, and scorch data agree well with those obtained with the Mooney apparatus. The method has the following advantages and disadvantages. A. Advantages 1) The course of the vulcanization curve is established on a single sample without curing in stages. 2) Minimum material is required. 3) The test is quickly performed. 4) Good reproducibility is observed. 5) The unit lends itself readily to automatic recording so that one man can easily operate several instruments. B. Disadvantages 1) The apparatus should be operated by trained workers. 2) The cost of the apparatus is rather high.