super(13)C-NMR, super(13)C- super(13)C gCOSY, and ESI-MS characterization of ether-bridged condensation products in N,N'-dimethylurea-formaldehyde systems

• Published in: Journal of applied polymer science Vol. 128; no. 6; pp. 3957 - 3963
• Main Authors: Kibrik, Eleonore J, Steinhof, Oliver, Scherr, Guenter, Thiel, Werner R, Hasse, Hans
• Format: Journal Article
• Language: English
• Published: 01.06.2013
• Subjects: Condensates; Condensation resins; Mass spectroscopy; Polymers; Reproduction; Resins; Spectra; Ureas
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.38630

The reaction of urea with formaldehyde is the basis for the production of urea-formaldehyde (UF) resins which are widely applied in the wood industry. The presence of ether-bridged condensation products in the UF resin reaction system is an open question in the literature. It is addressed in the present work. The N,N'-dimethylurea-formaldehyde model system was studied since it is chemically similar to the UF resin reaction system but allows for a simple elucidation of all reaction products. It was analyzed by super(13)C-NMR spectroscopy and ESI-MS. In corresponding NMR and MS spectra, peaks due to methoxymethylenebis(dimethyl)urea and its hemiformal were observed. super(13)C- super(13)C gCOSY analysis was conducted using labeled super(13)C-formaldehyde. The correlation spectra showed evidence for an ether-bridged compound and mass spectra exhibited peaks agreeing with labeled methoxymethylenebis(dimethyl)urea and its hemiformal. Methoxymethylenebis(dimethyl)urea was characterized in N,N'-dimethylurea-formaldehyde systems in acidic and slightly basic media. As urea is very similar to N,N'-dimethylurea, the results of this work strengthen the assumption that ether-bridged condensation products are likely to form in UF resins. [copy 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013