Conductive composites prepared via a propagating polymerization front

Abstract

A novel material, a conducting composite with variable temperature coefficient of electrical conductivity, was prepared in a propagating front of an addition polymerization. Graphite and zinc particles were incorporated into an acrylamide-triethylene glycol dimethacrylate copolymer. Specific electric resistance values of the materials yielded were measured at room temperature and also conductivity measurements were performed in the range of 20-220°C. The basic recipe was modified by doping the conductive composite materials with microscopic-scale-size particles of several inorganic and organic compounds, resulting in significantly different conductivity features of the composite. Scanning electron microscopy was performed to study the morphology of materials yielded. No percolative patterns containing zinc particles were found to support the conductive behavior of the composite. In accordance with to the modifying effect of doping materials we suspect that the acrylamide-triethylene glycol dimethacrylate copolymer plays a specific role in the electric conductivity behavior of the composite material. ZUSAMMENFASSUNG:Ein neues elektrisch leitfahiges Verbundmaterial mit variablem Temperaturkoeffizient der elektrischen Leitfahigkeit wurde durch eine ,,propagating front"-Copolymerisation von Acrylamid und Triethylenglykoldimethacrylat in Gegenwart von Graphitund Zinkpartikeln hergestellt. Der spezifische elektrische Widerstand der Polymeren wurde bei Raumtemperatur bestimmt; Leitfahigkeitsmessungen wurden zwischen 20 und 220 "C durchgefiihrt. Die Leitfahigkeitseigenschaften der Copolymeren wurden durch Dotierung mit mikroskopischen Teilchen einiger organischer und anorganischer Substanzen modifiziert. Die Morphologie der Composite wurde mit der Rasterelektro-* Correspondence authors. 0 1996 Hiithig & Wepf Verlag, Zug CCC OOO3-3146/96/$07.00 J. Szalay, I. P. Nagy, I. Barkai, M. Zsuga nenmikroskopie untersucht. Dabei wurden keine das Leitfahigkeitsverhalten beeinflussende zinkhaltigen Perkolationsstrukturen gefunden. Es wird vermutet, daB das Acrylamid/Triethylenglykoldimethacrylat-Copolymere eine entscheidende Rolle im elektrischen Leitfahigkeitsverhalten der Verbundmaterialien spielt.

Free‐Radical Frontal Copolymerization: The Dependence of the Front Velocity on the Monomer Feed Composition and Reactivity Ratios

“…Next, we derive an integral expression for the velocity, u. By dividing Equation (15d) and (15a) and multiplying by Equation (19) we get…”

“…functionally gradient polymeric materials, [15] temperature-sensitive hydrogels, [16] thermochromic composites, [17,18] and conductive composites. [19] A great deal of attention has also been devoted to the instability of polymerization fronts. The studies focused on linear stability analyses, [20,21] convective instabilities, [22,23] and nonlinear dynamics of polymerization waves.…”

Frontal polymerization accelerated by continuous conductive elements

“…However, these studies have largely focused on propagation through homogenous media. Although some research has involved the presence of nonreactive fillers or gels, these discrete materials have been evenly distributed throughout the solution. The effect of continuous elements that span the length of an object has not been explored.…”

Preparation of Polymer‐Metal Composites via In Situ Decomposition of Metal Salts by Frontal Polymerization

“…The specific direct‐current resistance of composites containing powdered zinc and graphite changes with the TGDMA/AA molar ratio. The electrical resistance decreases with the molar ratio of monomers 3. The values of the specific direct‐current resistance of samples containing zinc acetate were lower by several magnitudes compared to samples containing metallic zinc.…”

“…Frontal polymerization is a special, one‐step method to produce polymers, and is solvent‐free and fast 3. The reaction front self‐propagates through the mixture of monomers, leaving the polymer behind when the monomer(s) and initiator are appropriately chosen.…”