Melamine–formaldehyde resins: Constitutional characterization by fourier transform ¹³C‐NMR spectroscopy

Abstract

Abstract The random chemical structures of melamine–formaldehyde resins, including methylated melamine–formaldehyde resins and urea–melamine formaldehyde resins, were investigated by 13 C‐NMR spectroscopy (Fourier transform). All the combined formaldehydes, methylol and methyl ether groups, methylene structures, and dimethylene ether structures were assigned. A 13 C chemical shift of methylene carbon occurred by substitution of other constituents of the methylene group for a proton of the adjacent monosubstituted nitrogen atom, as shown in a 13 C‐NMR spectrum of urea–formaldehyde resins. It was found that the chemical shift of each corresponding carbon of both melamine resins and urea–melamine resins was almost superimposed with that of urea resins.