Abstract
A rapid compositive analysis of melamine-formaldehyde resins (MFR) and urea-formaldehyde resins (UFR) by proton magnetic resonance spectrometry was proposed.
MFR and UFR free of water were examined in dimethylsulfoxide-d6 solution without any chemical pretreatments. The relative mole number of melamine nucleus [M] was obtained by the next equation.
[M] =1/3 {[>NH] + [NH2] + [>N-] =1/3 {A1+ (A2/2) + (A4/4)}
Similarly, the relative mole number of urea nucleus [U] was obtained by the next equation.
U=1/2 {[>NH] + [-NH2]+ [>N-]} = 1/8 (2A1+2A2+A4)
In these equations, A1 and A2 are represented as the signal areas correspond to monosubstituted and non substituted amine groups, respectively and A4 about MFR and A4 about UFR are represented as the signal areas correspond to -N (-CH2-) 2 group and total methylene group, respectively.
By this method it is possible to determine the contents of free methylol, total methylene, nonsubstituted, monosubstituted and disubstituted amine groups in amino resins rapidly, but the accuracy was not so good
