MODEL COMPOUND VULCANIZATION - 3. THE RELATIONSHIPS BETWEEN SULFIDIC PRODUCT YIELD AND STRESS-STRAIN PROPERTIES.

In the reported study, twenty accelerators were compared by model compound vulcanization (MCV). A relationship was established between total sulfidic product yield and tensile modulus (300%) of natural rubber vulcanizers. In previous work, two types of accelerators were distinguished by MCV on the basis of thier distributions of the isomeric monosulfide reaction products. Type A accelerators consist of a wide range of functional compounds such as sulfenamides and guanidines. Type B accelerators contain a thiocarbamyl or a thiophosphate group. These types of accelerators can also be distinguished on the basis of their relationship between sulfidic product yield in MCV and tensile modulus. The difference between these two types of accelerators can also be derived from thier relationship betweeen tensile modulus and failure properties such as tear strength and tensile strength. Type A accelerators show a somewhat higher tear and tensile strength at a given tensile modulus value. The difference is attributed to the different distribution of sulfidic crosslinks, and possibly to chain scission in vulcanizates of type B accelerators.