Visco-Elastic Modulus and Intercalation of Polymer Chains in Epoxy Nano-Composites

摘要

Polymer nano-composites (PNC) are polymers which are reinforced with less than 5% by volume of nano-sized particles with high aspect ratios (L/h > 300). Compared to conventional composites, where the reinforcement is on the order of microns, the nano-composites are reinforced on the order of a few nanometers with advantages in processing and toughness. Nano-composites of epoxy clay have been studied where epoxy is mixed at high shear rates with clay . In our method of making nano-composites, an epoxy, Diglycidyl ether of bisphenol (DGEBA) A was mixed under high shear with organically modified mica type silicate (OMTS) either of benzyl dimethyl stearyl ammonium (BDSMA) or of methyl bishydroxyethyl stearyl ammonium chloride ion exchange with sodium montmorillonite. Nano-composites of epoxy cured with hexahydrophthalic anhydride (70%) with polyether polyol (25%) were made also under high shear both at 90C and 120C. Heat of reaction and transition temperature of epoxy nano-composite was compared with cured epoxy nano-composite. Analysis by X-Ray Diffraction was used to determine peaks, spacing and interfacial region. Dynamic visco-elastic measurements were used to distinguish between the nano-composites from two organically modified mica type silicates. Effect of increase in concentration and temperature on visco-elastic modulus of nano-composites was analyzed in terms of intercalation of polymer chains.