Selecting coagents for use in peroxide-cured elastomers

摘要

Peroxide curing is an alternative to sulfur vulcanization that offers superior heat-aged performance. Curing with peroxide alone, however, is inferior to sulfur vulcanization in areas such as wear resistance and dynamic properties. The addition of crosslinking coagents with the peroxide overcomes these deficiencies, while maintaining the improvement in heat-aged performance. By using the appropriate coagent, final properties such as dynamic flexibility, tear resistance, and tensile strength are comparable or superior to sulfur-cured systems with much better heat-aged performance. In addition, certain coagents also have the added benefit of significantly improving adhesion to metal and fiber reinforcing materials when vulcanized. A wide range of coagents is available and proper selection of coagent is critical in achieving optimum performance. Saret~® Coagents are examples of coagents based on acrylic chemistry and are classified as Type Ⅰ coagents. Ricon~® Resins are low molecular weight polybutadiene resins that contain high vinyl functionality and are classified as Type Ⅱ coagents. A comparison of these coagents in peroxide cure formulations is presented in this paper.