3,288 research outputs found
The application of thermal analysis to the study of epoxyâclay nanocomposites
This is a copy of the author 's final draft version of an article published in the journal Journal of thermal analysis and calorimetry. The final publication is available at Springer via http://dx.doi.org/10.1007/s10973-016-5278-0The development of polymer layered silicate (PLS) nanocomposites goes back over 20 years now, and yet they still have not achieved their full potential. A principal reason for this is the difficulty of obtaining a truly exfoliated nanostructure. The fabrication procedure for such PLS nanocomposites based upon epoxy resin includes several stages, including dispersion of the clay in the resin, intercalation of the resin into the clay galleries, and finally curing of the nanocomposite system. Many attempts have been made to improve the degree of exfoliation in the final nanostructure by modifying the procedures involved in these fabrication stages, and the usual approach is to examine the nanostructure, by techniques such as small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), as a function of the fabrication procedure. We show here, however, that thermal analytical techniques, and in particular differential scanning calorimetry, can complement the techniques of SAXS and TEM in the search for ways in which to achieve improved degrees of exfoliation in PLS nanocomposites based upon epoxy resin.Peer ReviewedPostprint (author's final draft
Globalisation, concentration and footloose firms: in search of the main cause of the declining labour share.
Over the last two decades the share of national income which accrues to labour has followed a marked downward trend across a host of industrialised countries. This paper attempts to assess the importance of several potential causes of this phenomenon. We investigate compositional effects, the effect of declining trade costs, changes in the market structure (concentration) and the effect of low-wage competition between countries. Overall, the findings suggest that lower trade costs and factors related to economic integration such as industry concentration, the market power of firms and increased international low-wage competition indeed affect the labour share. However, their effect has been quite limited when compared to changes in the sectoral composition, the effects of technological change, cyclical factors and changes in the prices of intermediary goods.
Non-isothermal cure and exfoliation of tri-functional epoxy-clay nanocomposites
The non-isothermal cure kinetics of polymer silicate layered nanocomposites based on a tri-functional epoxy resin has been investigated by differential scanning calorimetry. From an analysis of the kinetics as a function of the clay content, it can be concluded that the non-isothermal cure reaction can be considered to consist of four different processes: the reaction of epoxy groups with the diamine curing agent; an intra-gallery homopolymerisation reaction which occurs concurrently with the epoxy-amine reaction; and two extra-gallery homopolymerisation reactions, catalysed by the onium
ion of the organically modified clay and by the tertiary amines resulting from the epoxy-amine reaction. The final nanostructure displays a similar quality of exfoliation as that observed for the isothermal cure of the same nanocomposite system. This implies that the intra-gallery reaction, which is responsible for the exfoliation, is not significantly inhibited by the extra-gallery epoxy-amine cross-linking reaction.Peer ReviewedPostprint (published version
Strategic consultation on the FE workforce and Initial Teacher Education workforce for the Education & Training Foundation
A research project undertaken on behalf of the Education and Training Foundation exploring barriers to attracting candidates with higher qualifications and skills to the FE sector and to explores if ITE predominantly attracts people from a humanities background. The report suggests that people move into FE teaching through opportunity. The issue if dual professionalism is an important element of identity. Those becoming teacher educators tend to drift into the role. Discussions were focused less on the background of people but on the space they have to deliver a curriculum which includes pedagogy theory and the extent to which ITE need to have subject specialisms to prepare teachers for effective classroom practice.Education and Training Foundatio
A novel comparative study of different layered silicate clay types on exfoliation process and final nanostructure of trifunctional epoxy nanocomposites
© 2016. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/The effect of three different organically modified layered silicate clays (Nanomer I.30E, Cloisite 30B and Nanofil SE 3000) on the exfoliation process and on the thermal properties and nanostructure of cured trifunctional epoxy resin based nanocomposites was studied. Optical microscopy showed that the best and poorest qualities of clay distribution in the epoxy matrix were obtained with Nanofil SE 3000 and Nanomer I.30E, respectively. However, the isothermal differential scanning calorimetry scans show that, of the three systems, it is only the Nanomer clay that promotes intra-gallery reaction due to homopolymerisation, appearing as an initial rapid peak prior to the cross-linking reaction. This rapid intra-gallery reaction is not present in the curing curve for the Cloisite and Nanofil systems. This fact implies that the fully cured nanostructure of the Cloisite and Nanofil system is poorly exfoliated, which is confirmed by small angle X-ray scattering which shows a scattering peak for these systems at around 2.53°, corresponding to about 3.5 nm d-spacing.Peer ReviewedPostprint (author's final draft
The continuing relevance of George L. Mosse to the study of nationalism
This article explores four aspects of George L. Mosseâs legacy in the field of nationalism. First, it examines his wrestling with the normative complexities of nationalism, reflected in his horror of integralist nationalism (exemplified in fascism) that was in tension with his sympathy with liberal Zionism. Second, it discusses Mosseâs innovative anthropological approach to nationalism as a form of culture that aligns him with the ethno-symbolic school of nationalism, associated with Anthony D. Smith. A third contribution was his pioneering studies of the rituals of war commemoration and their changing forms as central to national legitimation. Finally, Mosse has been recognised by leading feminists as an important early investigator of sexuality as it relates to the construction of repressive national codes of respectability. What links these topics is Mosseâs tendency to view nationalism as reinforcing the coercive aspects of modern industrial societies. In none of these areas was Mosse a systematic thinker, but the interdisciplinary character of his work and his concern with fundamental problems of identity continues to inspire research into these issues
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