Matrix
The role of the matrix in a composite profile is partly to bind the reinforcement together, and partly to hold the reinforcement in place at the right points in relation to the cross section for optimal utilization of the mechanical properties. The type of matrix also determines properties such as corrosion resistance, electrical insulation properties, and fire and temperature resistance. The following three types of matrix are fundamentally well suited to the pultrusion process: polyester, epoxy and phenol.
Polyester
Polyester is the most frequent matrix, as it gives a composite good all-round properties.
Unsaturated polyester can be divided into three main groups: orthopolyester, isopolyester and vinylester. In relation to orthopolyester, isopolyester increases impact resistance, provides greater flexibility, and increases resistance to temperatures. It also increases corrosion resistance.
Vinyl ester has even better corrosion-resistant and thermal properties. Since vinyl ester has greater elongation properties than ortho- and isopolyester, it also provides a composite with better impact resistance and improved fatigue properties.
Epoxy
Epoxy is used primarily for carbon-reinforced profiles, giving composites better fatigue and mechanical properties. Epoxy is more resistant to thermal influences and has better electrical properties.
Phenol
Phenol is used when there are requirements to high fire resistance, temperature resistance, low smoke generation, and flame retardation when subjected to fire.
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