Thermo-physical responses of polymeric composites tailored by electric field

Applying an electric field to a liquid suspension redistributes the inclusions, arranges them in chain-like structures and/or orients fibrous inclusions or chain-like structures parallel to electric field. The present paper shows micro-tailored polymer composites including orthotropic structures and describes physical mechanisms influencing the microstructure in an electric field. Mechanical and thermal properties of orthotropic and random composites containing glass-fiber or graphite particles in an epoxy are measured. Both the glass-fiber and graphite chains in epoxy response mechanically as one would anticipate for orthotropic materials. However, while thermal expansion response of the aligned glass-epoxy composite is orthotropic, that of the aligned graphite composite is essentially isotropic. Thermal expansion, thermal conduction, and optical property of tailored graphite-epoxy composites are tested for various compositions, orientation directions of contacted particles' chains.