Fabrication and Testing of Biobased and Synthetic Sheet Molding Compound (SMC)
- Douglas Gardner
- Adriaan van Heiningen
- Ryan Mills
- Department of Energy
- AOC: World Leader in Resin Technology
Solids fiberglass plastics are used in the automobile industry for exterior parts. By characterizing woody fiber types, the glass reinforcement may be replaced by natural fibers. This would lighten the car parts and help fuel economy. The fiberglass plastics are a combination of various plastic components. The hemicellulose from wood has the potential of replacing a plastic material used to keep the part from shrinking during processing. The use of hemicellulose would create a market for the Hemicellulose extracted from pulp chips.
Sheet Molding Compound, (SMC), is a composite material comprised of an unsaturated crosslinked polymer, reinforcing fiber, thermoplastic processing aids, mineral fillers, and lubricant (release agent). SMC reinforced with natural fibers is currently researched to determine if natural fibers compete with synthetic fibers. To achieve the mechanical properties required for the SMC material with natural fibers, the surface energy of the polyester composite and reinforcement needs to be understood. Inverse gas chromatography, (IGC), is a technique that is used to characterize the surface energy and polar characteristics of materials. After determining surface characteristics of the composite and fibers, chemical or mechanical modifications are made to enhance the interaction of the fibers with the composite matrix. After modification, a crosslinked material is made. To test the material, hygrothermal aging is used to accelerate normal environmental aging and dynamic mechanical thermal analysis, (DMTA), is used to study the material changes as a function of hygrothermal aging. Results indicate that the cohesion of natural fibers to the polyester matrix should outperform glass.
What’s New on this Project?
Hand sheets of dicyclopentadiene based SMC has been fabricated with both glass and Kenaf reinforcements. Hemicellulose extracted from wood chips will be introduced into the SMC and compounded with glass for testing. The testing experimental protocol has been developed with previous SMC and accepted for publication on July 11, 2007 in the journal of materials science. Inverse gas chromatography analysis of the Kenaf fiber and 14 other fiber types have been completed and from this data styrene maleic anhydride (SMA) was the sizing agent selected for surface sizing of the Kenaf fiber. The Kenaf reinforcement has been saturated with styrene and SMA for both bulk fiber and surface conditioning.