Alternative Natural Rubber Cross-Linking Utilizing a Disulfide-Containing Bismaleimide

Area of Science:

• Materials Science
• Polymer Chemistry
• Rubber Technology

Background:

• Natural rubber (NR) requires effective cross-linking for engineering applications.
• Developing recyclable elastomers with tunable properties is a key challenge.
• Disulfide bonds offer potential for dynamic covalent networks in rubber.

Purpose of the Study:

• To investigate a disulfide-selective cross-linking strategy for NR.
• To evaluate the impact of metal coordination on disulfide metathesis kinetics.
• To develop high-performance, recyclable elastomeric materials.

Main Methods:

• Synthesis of a disulfide-containing bismaleimide (BIS) cross-linker.
• Compounding NR with BIS and different copper-based additives (CuCl2, CuMA).
• Rheological, mechanical, and thermal stability testing of formulations.

Main Results:

• CuCl2 formulations exhibited degradation and brittleness.
• CuMA formulations showed improved torque, tensile strength, and thermal stability.
• CuMA-based compounds demonstrated partial recyclability and effective cross-linking.

Conclusions:

• Copper(II) methacrylate (CuMA) is a promising additive for creating recyclable NR elastomers.
• Metal coordination, especially with CuMA, modulates disulfide metathesis for network rearrangement.
• This work provides a foundation for designing dynamic covalent networks in elastomers.