TGA/FTIR studies of segmented aliphatic polyurethanes and their nanocomposites prepared with commercial montmorillonites

• Published in: Polymer degradation and stability Vol. 94; no. 10; pp. 1666 - 1677
• Main Authors: Cervantes-Uc, J.M., Espinosa, J.I. Moo, Cauich-Rodríguez, J.V., Ávila-Ortega, A., Vázquez-Torres, H., Marcos-Fernández, A., San Román, J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2009; Elsevier
• Subjects: Applied sciences; Composites; Degradation; Exact sciences and technology; Forms of application and semi-finished materials; Nanocomposites; Nanomaterials; Nanostructure; Polymer industry, paints, wood; Polyurethane resins; Polyurethane/montmorillonite nanocomposites; Segmented polyurethanes/Closites composites; Segments; Technology of polymers; TGA/FTIR; Thermal decomposition; Thermal degradation; Thermal stability; Segmented polyurethanes/Closites composites; Polyurethane/montmorillonite nanocomposites; Thermal decomposition; TGA/FTIR; Thermal degradation; Clay; Organic clay; Montmorillonite; Thermoplastic rubber; Dispersion reinforced material; Experimental study; Composite material; Thermal stability; Polyurethane elastomer; Segmented polyurethanes/Closites composites; Quaternary ammonium compound; Thermal properties; Butene oxide copolymer; Cyclic ether copolymer; Concentration effect; Reaction mechanism; Nanocomposite; Etherurethane polymer
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2009.06.022

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.