ABSTRACT
A polymer is a natural or synthetic compound of usually high molecular weight consisting of many repeating units of smaller molecules that can be linked in linear, branched, or cross-linked form. Thermosets are polymers that chemically react under suitable environment, such as high temperature, to a permanently solid and infusible state. Thermoplastics are those polymers that can be repeatedly softened by application of heat and hardened by cooling. Epoxy resins are a class of thermosetting polymers that have found extensive applications in industrial, aerospace, and other high-end sectors. The base resin in an epoxy system is chemically an organic compound containing epoxide molecules. An epoxide molecule has an epoxide group in its molecular structure. In the initial "green" or uncured state, the epoxide molecules do not normally react with each other at room temperature. In an epoxy formulation, modifiers are added to the base epoxy resin and the hardener to impart specific physical and mechanical properties.
