Peroxide vs. sulfur crosslinking

Advantages of peroxide crosslinking in comparison with sulfur cure

• Simple formulation
• Storage of the peroxide-containing compound without bin scorch
• High processing temperature
• Rapid vulcanization without reversion
• Good compression set, particularly at elevated temperatures
• High temperature resistance
• Limited extractable constituents from final product
• No staining of of the finished parts
• No discoloration of crosslinked product by contact with metals and PVC
• Most peroxides do not cause blooming
• Co-vulcanization of saturated and unsaturated elastomers
• Co-vulcanization of elastomers and thermoplastics
• Copolymerization with polymerizable plasticizers or co-agents to give controlled hardness and stiffness, coupled with easy processing

Points of attention for peroxide crosslinking 

• Sensitivity to oxygen under curing conditions
• Certain components of the rubber compound such as fillers, extender oils, antioxidants and resins must be selected with care because they may, under certain conditions, consume peroxide free radicals
• Usually, tensile and tear strength properties are reduced by 15%, when compared to a conventional sulfur based crosslinking system
• Scorch and cure time are less flexible, since they are determined mainly by the temperature
• During cure, some peroxides may lead to distinct odors
• Post cure may be necessary