Dielectric properties of thermosetting material nanocomposites

• Published in: Journal of applied polymer science Vol. 106; no. 1; pp. 205 - 213
• Main Authors: Luiz Dias Filho, Newton, Adolfo de Aquino, Hermes, Souza Pereira, Denise, Rosa, André H.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05-10-2007; Wiley
• Subjects: Applied sciences; Chemical properties; dieletric relaxation; Exact sciences and technology; nanocomposite; Polymer industry, paints, wood; Properties and testing; spherosilicate; Technology of polymers; thermoset material; Dielectric loss; dieletric relaxation; thermoset material; Dielectric properties; Epoxy resin; Mechanical properties; spherosilicate; Tensile property; Silsesquioxane copolymer; Curing (plastics); Experimental study; Property processing relationship; Dielectric relaxation; Fracture toughness; Dynamic mechanical properties; Nanocomposite; Permittivity; Activation energy
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.26393

The dieletric relaxation properties of thermosetting material nanocomposites based on spherosilicate nanoplatforms were studied from room temperature to 170°C, varying the frequency from 10 to 1000 KHz. Permittivity (ε′), dielectric loss (ε″), and activation energy (Ea) were calculated. The results of dielectric relaxation were confirmed by those of the final properties. The dielectric loss amplitude decreases with increasing ODPG content until about 70–73 wt % and slightly increases at higher ODPG content. This means that the increasing of the ODPG content in the composite samples decreases the number of pendants groups and/or increases crosslink density, causing decreased motion of organic tethers, and subsequently decreasing of the dipolar mobility. The results of apparent activation energy, fracture toughness and tensile modulus mechanical properties show the same profile with respect to ODPG content, in the sense that they exhibit maxima around 70 wt % ODPG. For the ODPG/MDA composites, this formulation of 70 wt % ODPG containing excess of amine is not composition where the highest crosslinked density is reached. This implies that the best mechanical properties and Ea are provided by some degree of chain flexibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007