Prepreg materials were once only prevalently used in the aerospace and high performance sectors of the general composite area. Recently, however, they have become increasingly more common across numerous sectors of the composites industry. The reasons for these increased uses include the mechanical performance that prepregs provide their consistent properties and their ease of use.
Within the prepreg world and also in the general composites field, there is an ongoing trend for increased thermal resistance requirements. Potential markets for these enhanced products include transportation, electronics and electrical insulation. However, the high temperature requirement for these markets needs to be achieved without a sacrifice of the other performance and/or processing advantages of the resins such as fast curing at the desired reaction temperature. Thus, the optimum balance between the already-existing performances features with the increased temperature resistance needs to be achieved to meet this developing marketplace need.
This article will discuss several recent developments in epoxies that address these requirements. Several different chemical approaches are highlighted to obtain high temperature resistance of the epoxy materials without a loss in the desirable processing features of the resins. In addition, information is provided about ways to enhance the curing features of the epoxies to make them react only at the desired reaction temperature and not during the storage and prepreg production process. The latency of the epoxies during storage is...