Identification of nanostructural development in epoxy polymer layered silicate nanocomposites from the interpretation of differential scanning calorimetry and dielectric spectroscopy

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• 作者：Frida Romá ; n ^{roman@mmt.upc.edu} ; Yolanda Calventus ^{calventus@mmt.upc.edu} ; Pere Colomer ^{colomer@mmt.upc.edu} ; John M. Hutchinson ; ^{hutchinson@mmt.upc.edu}
• 关键词：Cure kinetics ; Differential scanning calorimetry (DSC) ; Dielectric spectroscopy ; Epoxy ; Glass transition ; Nanocomposites
• 刊名：Thermochimica Acta
• 出版年：2012
• 期刊代码：110_00406031
• 类别：ch
• 出版时间：10 August, 2012
• 卷：541
• 期：Complete
• 页码：76-85
• 文件大小：1181 K

摘要

The effect of nanoclay on the non-isothermal cure kinetics of polymer layered silicate nanocomposites based upon epoxy resin is studied by calorimetric techniques (DSC and TGA) and by dielectric relaxation spectroscopy (DRS) in non-isothermal cure at constant heating rate. The cure process takes place by homopolymerisation, initiated anionically using 3 wt%dimethylaminopyridine (DMAP), and the influence of the nanoclay content has been analysed. Interesting differences are observed between the nanocomposites with 2 wt%and 5 wt%clay content. At low heating rates, these samples vitrify and then devitrify during the cure. For the sample with 2 wt%clay, the devitrification is accompanied by a thermally initiated homopolymerisation, which can be identified by DRS but not by DSC. The effect of this is to improve the exfoliation of the nanocomposite with 2 wt%clay, as verified by transmission electron microscopy, with a corresponding increase in the glass transition temperature. These observations are interpreted in respect of the nanocomposite preparation method and the cure kinetics.