Processing of Hollow Glass Sphere/Polyester/Glass Fiber Sheet Molding Composites

摘要

The development of lightweight polymer-glass fiber (GF) composites is a major step towards more environmentally sustainable automobiles. By altering the commonly used industry polymer Unsaturated Polyester Resin (UPR) with hollow glass spheres (HGS) of various characteristics, one can create a novel resin matrix for glass fiber composites. The different glass bubbles, with their low densities ranging from 0.28-0.46 g/cm3, allow for an increase in glass fiber loading while still decreasing the weight of the final composite produced using sheet molding compounds (SMC). Thorough calibration of the SMC line’s glass fiber and resin mass flow rate settings is a crucial step in achieving the desired glass fiber loading and composite density. Once completed, any changes in density of the composite can be solely attributed to the addition of hollow glass spheres. It is necessary to achieve proper dispersion of each of the types of glass spheres in order to minimize aggregates which may cause stress concentrations and, thus, decreased mechanical properties. Dispersion of HGS and GF is characterized with Scanning Electron Microscopy and optical imaging, while acetone dissolution is utilized to assess the GF loading of the SMC prior to compression molding.