Thermoset polymers form the matrix in filled plastics and fiberreinforced composites used in a diversity of products. These range from consumer items and auto body panels to advanced composites for printed circuit boards (PCBs), aerspace structural components such as the Space Shuttle payload bay door and jet engine cowls and ducts, and expensive, high-performance sports equipment. Also, thermosets are used extensively as adhesives, molding compounds, and surface coatings, including protective solder masks for PCBs.