EPR imaging study of paramagnetic centre distribution in thiokol-epoxy hermetics

Abstract

The distribution of paramagnetic centres in carbon black filler in the interphase layer of the thiokol-epoxy hermetics on the border of brass or glass substrate was studied using EPR· imaging method. It was shown that the relative content of radicals decreases near the hermetic-"rigid" surface contact border. The thickness of the layer with a low concentration of radicals is estimated as 0.5±0.3 mm, The inhomogeneous distribution of radicals is more obvious in the case of hermetic hardening on a brass surface. These results are explained by a catalytic acceleration of the thiokol-epoxy polymerization reaction in the region of hermetic-metal surface contact.

Adsorption and Premicellar Aggregation of CTAB Molecules and Fabrication of Nanosized Platinum Lattice on the Glass Surface

“…Therefore, another purpose of this work is to elucidate the aggregation of surfactants at the glass surface. This part of the work is additionally stimulated by our recent investigations 35 capabilities of ESR method are depicted by its application in direct registration of decomposition products in perfluorosulfonated membranes, 37−39 investigation of micelles of classical surfactants, 40 amphiphilic calix [4]arenes 41 and polymerization with spin probe method, 42 ESR imaging of paramagnetic centers in polymers, 43 and simultaneous studies of paramagnetic intermediates by electrochemistry and ESR. 44−55 Surfactant molecules usually do not have paramagnetic properties and as a result do not give rise to ESR spectrum.…”

“…Electron spin resonance (ESR) is widely used in research of both homogeneous and microheterogeneous systems. Wide capabilities of ESR method are depicted by its application in direct registration of decomposition products in perfluorosulfonated membranes, − investigation of micelles of classical surfactants, amphiphilic calix[4]arenes and polymerization with spin probe method, ESR imaging of paramagnetic centers in polymers, and simultaneous studies of paramagnetic intermediates by electrochemistry and ESR. − Surfactant molecules usually do not have paramagnetic properties and as a result do not give rise to ESR spectrum. In order to investigate their aggregation behavior with ESR method spin probes were added into the solution.…”

ESEEM of copper complexes formed in the interlayer between thiokol-epoxy adhesive and brass substrate

“…It was found that the number of complexes depends on the free-sulphur concentration [1]. The diffusion of the copper ions from the substrate into the thiokol-epoxy polymer was studied with EPR imaging [2]. A correlation was found between the content of the free sulphur in the thiokol-epoxy adhesive and the adhesion strength to the substrate.…”

“…The study of the mechanism of adhesion of a thiokol-epoxy adhesive to a brass substrate was the subject of several investigations [1][2][3]. Electron paramagnetic resonance (EPR) studies of the interlayer between the adhesive and the brass substrate revealed the formation of square-planar copper complexes with sulphur-containing ligands.…”