Conductive Sheet Molding Compound with Carbon Based Nanomaterials
Graphite is a layered material and the stiffest material found in nature--significantly higher than clay that could be displaced by this invention in related applications. Graphite has excellent electrical and thermal conductivity. MSU has developed an inexpensive process to produce exfoliated graphite nanoplatelets (xGnP) which when added to polymers can produce nanocomposites with superior mechanical and conductivity properties, low permeability, scratch resistance, and reduced flammability.
There are vast uses of polymer composites for automotive and electronic structural applications. For example, sheet molding compound (SMC) is a widely used composite material. However, SMC is not a conductive material and requires expensive surface preparation to receive a conductive primer prior to painting. xGnP can be incorporated into SMC through a novel approach to provide sufficient conductivity for subsequent painting or adhesion to other materials.
Description of Technology
This technology is a method of making conductive polymer nanocomposites for lower cost integration into sheet molding compound (SMC) for subsequent manufacturing processes. Graphite is exfoliated and dispersed in an SMC to provide surface conductivity for painting and adhesion and other attributes desired in manufacturing. The exfoliated graphite can be dispersed in the neat resin, can coat the glass fibers, and/or can coat calcium carbonate particulates within the compound. Only a small amount of exfoliated graphite (<5%) is added to achieve dramatic increases in electrical conductivity.
- Lower cost: Graphite is a relatively low cost starting material. Production and integration of a small amount of xGnP nanocomposites into SMC results in the desired surface conductivity and at a significantly lower cost than current methods for processing the surface for subsequent painting or adhesion.
- More versatile: xGnP nanocomposites provide additional valuable traits such as low permeability, good thermal conductivity, good scratch resistance, and reduced flammability.
Applications include many large scale manufacturing processes (e.g., automotive and electronic devices industries), which use bulk materials that require surface modification or nonstructural functionality such as electrical and thermal conductivity including SMC, reinforced fiberglass, fillers, pigments, UV stabilizers, and catalysts.
Many prototypes exist; proof of concept demonstrated.
US 2008/0118736 A1 (filed Aug 31, 2007)
Lawrence Drzal, Wanjun Liu, Hiroyuki Fukushima, Inhwan Do
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Michigan State University