Closed-cell foam structures contain sealed microscopic cells that prevent water, vapor, and air movement through the material. This structural feature greatly influences:
- Moisture resistance
- Thermal insulation
- Mechanical stability
- Long-term durability
XPS foam is known for its highly uniform closed-cell structure, giving it excellent thermal insulation and low water absorption. PVC foam also uses a closed-cell structure but is engineered for structural strength rather than insulation alone.
In marine and outdoor applications, closed-cell materials are essential because water ingress can:
- Increase weight
- Reduce mechanical strength
- Promote adhesive degradation
- Accelerate aging
Closed-cell foam cores also maintain more stable compressive strength under humid conditions compared to open-cell systems.
From a thermal engineering perspective, trapped gas within closed cells reduces heat transfer, making these foams effective insulators.
