Novel Expandable Epoxy Beads and Epoxy Particle Foam

Area of Science:

• Materials Science
• Polymer Chemistry
• Foam Technology

Background:

• Thermoplastic-based expanded polymeric beads have limitations in high-temperature applications due to deformation and melting.
• A need exists for polymeric foams with enhanced thermal stability and complex geometry fabrication capabilities.

Purpose of the Study:

• To introduce a new method for fabricating expandable epoxy beads (EEBs) using a solid-state carbamate foaming technique.
• To expand and fuse EEBs into epoxy particle foams (EPFs) and characterize their properties.

Main Methods:

• Fabrication of EEBs by mixing epoxy, carbamate, and hardener, followed by extrusion and curing.
• Expansion and fusion of EEBs into EPFs within an aluminum mold at 160 °C.
• Characterization of EPF density, glass transition temperature (Tg), and mechanical properties (compressive and torsion storage modulus).

Main Results:

• Successfully produced EPFs with densities of 212 kg/m³ and 258 kg/m³.
• Achieved high glass transition temperatures (Tg) of 150-154 °C.
• Exhibited favorable mechanical performance with compressive modulus of 50-70 MPa and torsion storage modulus of 34-56 MPa at 30 °C.

Conclusions:

• The solid-state carbamate foaming technique is effective for producing EEBs and subsequent EPFs.
• The resulting EPFs demonstrate superior thermal stability and mechanical strength compared to conventional thermoplastic foams.
• This method enables the creation of complex-shaped epoxy particle foams suitable for demanding applications.