Jan 3, 2012 - degradation mechanism of organophosphorus flame-retardant poly(methyl methacrylate) .... using mixed GaussianeLorentzian line shapes.
Polymer Degradation and Stability 97 (2012) 273e280
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Thermal degradation of organophosphorus flame-retardant poly(methyl methacrylate) nanocomposites containing nanoclay and carbon nanotubes Tugba Orhan a, Nihat Ali Isitman b, c, Jale Hacaloglu a, c, *, Cevdet Kaynak b, c a
Department of Chemistry, Middle East Technical University, TR-06531 Ankara, Turkey Department of Metallurgical and Materials Engineering, Middle East Technical University, TR-06531 Ankara, Turkey c Department of Polymer Science and Technology, Middle East Technical University, TR-06531 Ankara, Turkey b
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Article history: Received 23 August 2011 Received in revised form 31 October 2011 Accepted 24 December 2011 Available online 3 January 2012
Filler nanoparticles pave the way for the development of novel halogen-free flame-retardant polymers. The aim of this study was to investigate the thermal degradability, and in particular, the thermal degradation mechanism of organophosphorus flame-retardant poly(methyl methacrylate) (PMMA) nanocomposites containing nanoclay (NC) and multi-walled carbon nanotubes (CNT). For this purpose, thermogravimetry and direct pyrolysis mass spectrometry analysis were utilized. The onset of degradation was delayed through increased maximum degradation temperature and suppressed mass loss corresponding to initial degradation stage with carbon nanotubes and nanoclays, respectively. Possibility of reactions of melamine and/or melamine derivatives and interactions between carbonyl groups of PMMA and phosphinic acid leading to thermally more stable products was increased owing to the barrier effect of filler nanoparticles. In the presence of NC better flame retarding characteristics was detected as anhydride formation, leading to charring being more effective. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Thermal degradation Direct pyrolysis mass spectrometry Organophosphorus compound Carbon nanotube Organoclay Nanocomposite
1. Introduction Filler nanoparticles, e.g. organically modified layered silicates (nanoclays) and single- or multi-walled carbon nanotubes have been shown to reduce the flammability of polymeric materials when incorporated at low loading levels (generally
