PMI Foam Core
Polymethacrylimide structural foam core of the Rohacell class, used in motorsport sandwich and aero parts.
Overview
PMI (polymethacrylimide) foam is a closed-cell structural core used where sandwich parts must survive autoclave or high-temperature prepreg cures that would collapse PVC or PET foams. The Rohacell-class grades are the motorsport and aero default for wings, dive planes, floor sections and body-in-black sandwich. Fine cell structure, high specific compressive strength and compatibility with epoxy prepreg make PMI the core of choice on many Formula 1, LMDh and hypercar aero packages. It machines cleanly, takes film adhesive well, and can be thermoformed to mild curvature before cure. It is a specialised polymer foam, not a honeycomb: isotropic crush, no cell-directionality, and a different damage mode. Cost and limited recyclability keep it on LVHV and racing programmes rather than high-volume body structures.
Automotive Applications
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Properties
Category
Type
Structural Foam Core
Available Forms
Key Properties
- Autoclave-stable closed-cell foam
- High specific compressive strength
- Compatible with epoxy prepreg
- CNC-machinable
- Limited recyclability
- Higher cost than commodity foams