Solid-State NMR of Melamine Phosphates,

A. Brinkmann, V. Brodski, D. J. A. De Ridder, K. Goubitz, R. Peschar, R. B. Helmholdt, H. Schenk, V. M. Litvinov, A. Braam, B. Coussens, S. Jahromi, N. Aelmans, and A. P. M. Kentgens,
44th Experimental NMR Conference, Savannah, Georgia, USA (Mar. 2003), poster.

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For many applications, polymer based materials have to pass fire retardance tests. Frequently, halogenated compounds are used as fire retardant additives, which suffer from the disadvantage of being environmentally hazardous under the influence of heat. Therefore it is of great interest to develop environmentally friendly flame retardants, which may be incorporated into polymers. A promising group of flame retardants is considered to be melamine phosphates. An important goal to improve flame retardants is to relate their chemical composition and structure to their mechanism of functioning.

We used proton spectroscopy under magic-angle-spinning conditions to gain detailed information about the proton positions, proximities and the hydrogen bonding network in melamine monophosphates, pyrophosphates and polyphosphates. The experimental results were obtained by applying homonuclear decoupling sequences to record high-resolution proton and heteronuclear correlation spectra of types 1H-13C, 1H-15N and 1H-31P. The experimental results are combined with the approximate powder structures obtained by X-ray diffraction together with a molecular modeling-Rietveld refinement approach. A model for the proton positions in the different melamine phosphates is presented.

Dr. Andreas Brinkmann
National Research Council Canada
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