Analysis of MF Resins, 1996 Plastic Laminates Symposium Proceedings

The influence of condensation var-iables, such as F/M ratio, pH and condensation temperature, on the chemical structure of liquid MF resins was studied with the aid of high resolution 13 C solid and liquid NMR, HPLC and Raman spectroscopy. These techniques can be used to ob-tain qualitative as well as quanti-tative information about the chemical composition of MF resins. Where necessary, these analytical tools were further developed. The degree of condensation of MF resins can be studied by quantitatively measuring the amount of water released, via 1 H NMR, or by measuring the total number of bridges via 13 c NMR. Quantitative 13 C NMR measurements have revealed a strong relation between water tolerance and the number of ether and bridges in the MF methylene resin. This relation can be used to estimate ether and methylene bridge concentrations in MF resins with a known F/M ratio, solids content, and condensation pH for all measured water tolerance values. Quantitative HPLC measurements reveal chemical structure information during the initial stage of the melamine-formaldehyde condensation. Raman spectroscopy is anoutstanding technique for measuring e.g. the amount of free melamine in cured MF resins.