Manufacturing Challenges of Creating Unsaturated Polyester Syntactic Foams with Glass Fiber Reinforcements

Abstract

Market demand for fuel efficient automobiles is motivating the push towards lightweight autobodies. The manufacturing of unsaturated polyester resin (UPR)-glass fiber (GF) Sheet Molding Compound (SMC) composites with hollow glass sphere (HGS) fillers creates a “syntactic foamâ€. This is a step towards achieving composites with densities of less than 1.5 g/cm3, with the goal of replacing the industry standard 1.9 g/cm3 density composites. While the physical replacement in the resin paste formula of calcium carbonate, the most dense filler (2.71 g/cm3), with lightweight HGS (0.28-0.46 g/cm3), can be done with relative ease, there are manufacturing challenges that must be addressed. Rheology, differential scanning calorimetry, and optical microscopy were used to assess changes in production parameters, such as resin maturation time and compression molding pressure. These characterization techniques will allow for the examination of UPR-GF-HGS as a promising alternative to current UPR-GF composites in the automotive industry.