Tailoring the Thermomechanical Properties of High Performance Aerospace & Automotive Composite Materials

There is a rising need to create high performance, lightweight and strong yet tough materials for use in industries including aerospace, automotive and others. The use of composite materials to meet this need is now common for several reasons. These include significant weight savings over traditional materials and design flexibility.

The matrix phase in such composite materials plays several important roles, including binding the reinforcement together, maintaining shape and stress transfer onto the reinforcements but also it enhances properties. While fibres are excellent at improving tensile stiffness and strength, a well-chosen matrix will provide shear and compressive stiffness but also, toughness. The ability to survive impact is one of the most important questions requiring research in composites today.

Strategies for improving the existing toughness in thermosetting polymers include the addition of rubber particles and dissolved/phase separated thermoplastic polymers. Whilst using these approaches will increase the toughness it is often difficult to correspondingly maintain the strength and stiffness of the material. However, high performance epoxy resins have some natural toughness courtesy of the reacted epoxy ring or cooperative rotation of the backbone phenyl rings. This provides a mechanism to dissipate energy and so improves the toughness of the material.

As part of a wider research effort into this phenomenon, this project will investigate the effect of systematically altering the chemistry of a model epoxy resin composite matrix. A structure property map will be built allowing the properties of not only the matrix phase, but also the composite itself, to be tailored. A variety of resin and composite samples will be manufactured and tested in order to build the map. This in turn will lead to insight into the properties of both the matrix and composite, and also allow composite designers to use these materials more efficiently in the future.