A Self-Healing System for Polydicyclopentadiene Thermosets.

Area of Science:

• Polymer Science and Engineering
• Materials Science
• Chemical Engineering

Background:

• Self-healing polymers enhance material lifespan and durability but face manufacturing challenges, especially for thermosets requiring high processing temperatures.
• Existing self-healing systems are often incompatible with thermoset processing conditions like frontal polymerization (FP).

Purpose of the Study:

• To develop a self-healing microcapsule system compatible with frontal polymerization (FP) for structural thermosets.
• To create a thermally stable self-healing system that can be integrated into thermoset manufacturing processes.

Main Methods:

• A two-part microcapsule system was designed, containing a thermally latent Grubbs-type catalyst and a Cu(I) co-reagent with dicyclopentadiene (DCPD) monomer.
• The system's stability and performance were evaluated under FP conditions (≈200 °C).
• Lap-shear tests and tapered double cantilever beam tests were used to assess interface strength and self-healing efficiency.

Main Results:

• The self-healing system demonstrated thermal stability during FP, with the catalyst activated by the Cu(I) co-reagent.
• The microcapsule system enabled efficient polymerization of DCPD upon matrix damage.
• Self-healing efficiencies exceeding 90% were achieved in the tough polyDCPD thermoset, restoring mechanical properties.

Conclusions:

• A novel self-healing microcapsule system compatible with FP manufacturing of thermosets has been successfully developed.
• The system utilizes a thermally latent catalyst activated by a co-reagent, enabling efficient healing of polyDCPD.
• This approach offers a viable solution for incorporating self-healing capabilities into structural thermoset materials.