White Paper

Geopolymer matrix composites (GMCs) are a group of materials which bridge the temperature performance gap between reinforced polymers and ceramic matrix composites (CMCs). In high temperature environments where reinforced polymers would fail and need to be replaced with metals, GMCs offer a lightweight alternative suitable for service temperatures up to 1000°C whilst providing a non-brittle failure mechanism. GMCs are produced in a similar manner to carbon fibre reinforced epoxy composites whereby woven fibres are impregnated with a resin which sets to form a structure. In comparison to typical ceramic matrix composites which are sintered at high temperatures, GMCs need only mild processing conditions of below 100°C, allowing a simple route to manufacture. In addition, this low temperature processing route facilitates the inclusion of additives in the matrix which would otherwise decompose or deteriorate at typical processing temperatures for manufacturing conventional ceramic matrix composites.

This white paper details the processing considerations for manufacturing GMCs, the remarkable properties of such materials, applications where GMCs have been successful, and potential opportunities to exploit untapped markets. The properties and processing conditions of GMCs are compared to that of conventional CMCs, detailing the pros and cons of each material system. Suitable geopolymer formulations for GMCs are discussed, with detail provided on the compositional requirements to ensure thermal and chemical compatibility between the geopolymer matrix and ceramic fibre.