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TGA/FTIR studies of segmented aliphatic polyurethanes and their nanocomposites prepared with commercial montmorillonites
Ist Teil von
Polymer degradation and stability, 2009-10, Vol.94 (10), p.1666-1677
Ort / Verlag
Kidlington: Elsevier Ltd
Erscheinungsjahr
2009
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
Nanocomposites prepared with segmented polyurethane (SPU) and commercially available nanoclays (Cloisite™ Na
+, Cloisite™ 15A, Cloisite™ 30B) were studied using thermogravimetric analysis coupled with Fourier Transform Infrared Spectroscopy (TGA/FTIR). The results showed that the thermal degradation of unfilled SPU and the 4, 6 and 10
wt% hand mixed nanocomposites occurred in two stages being the first due to degradation of hard segments and the second due to the degradation of soft segments. It was also found that the thermal stability of these nanocomposites was not improved by increasing nanoclay concentration except for SPU/Cloisite™ 15A nanocomposites were a 40
°C increase was observed. In a similar manner, FTIR spectra of the evolved gases obtained after the thermal degradation of these nanocomposites were qualitatively similar to the unfilled polymer except in those containing Cloisite™ 30B where isocyanate absorptions were detected. In contrast, SPU/Cloisite™ 30B nanocomposites prepared by
in-situ polymerization, exhibited higher thermal stability than the corresponding hand mixed nanocomposites. In addition, these nanocomposites exhibited the presence of carbon dioxide in the evolved gases during its second degradation stage which was not observed in the hand mixed nanocomposites. In this case, it can be said that the presence of clays in the nanocomposites has a significant effect on the thermal degradation pathways.