Influence of the nanoparticle type on the thermal decomposition of the green starch/poly(vinyl alcohol)/montmorillonite
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Influence of the nanoparticle type on the thermal decomposition of the green starch/poly(vinyl alcohol)/montmorillonite nanocomposites Manuela-Tatiana Nistor • Cornelia Vasile
Received: 1 February 2012 / Accepted: 24 September 2012 / Published online: 4 November 2012 Ó Akade´miai Kiado´, Budapest, Hungary 2012
Abstract In this study, some aspects concerning the thermal decomposition of starch/poly(vinyl alcohol) (PVA)/ montmorillonite (MMT) nanocomposites with 2 wt% nanoclay, prepared by melt mixing method, were studied. For these loadings, the inorganic fillers are well dispersed through the PVA/starch matrix, i.e., the nanocomposites formed are mostly intercalated hybrids. The aim of this article is to establish the effect of the nanofiller nature on the thermal decomposition of the starch/PVA/MMT nanocomposites. The thermal behavior of the 50 wt% starch/50 wt% PVA blend and its nanocomposites with 2 wt% nanoclay has been investigated by thermogravimetric analysis coupled with Fourier transform-infrared spectroscopy and mass spectrometry (MS). The volatile compounds resulting during the thermal degradation were studied by in situ vapor phase FT-IR spectroscopy and MS technique under a controlled temperature/time program. Apart from the identification of the volatile compounds, some conclusions on the nanoclays effect on the degradation mechanism and formation of the volatile compounds in accordance with the previously developed general mechanisms for PVA and starch degradation have been formulated. The clay–PVA/starch nanocomposites show completely different degradation product distribution patterns, which may be attributed to the presence of the head-to-head structures and Si–O–C linkages formed between clay and blend components. Keywords Nanocomposites Decomposition Mechanism TG FT-IR MS
M.-T. Nistor C. Vasile (&) Department of Physical Chemistry of Polymers, ‘‘Petru Poni’’ Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley, 700487 Iasi, Romania e-mail: [email protected]
Introduction Polymer/layered silicate nanocomposites have attracted strong interest in today’s materials research, as it is possible to achieve impressive enhancements of the material properties compared to the pure polymers. Polymer/clay nanocomposites preparation involves high temperatures irrespective of the fabrication route and also most polymeric materials require prolonged service in air at high temperatures. If the processing temperature is higher than the thermal stability of the organic components used for montmorillonite (MMT) modification or matrix components, the decomposition will take place, leading to variations in material structure. Thus, the determination of the onset temperature of the degradation, the resulting compounds of the degradation and the stability of the polymer in the presence of layered silicates as well as understanding the relationship between the molecular structure and the thermal stability (decomposition temperature, rate, and the degradation products) of the organic modifier in th
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