Investigations of the chemical structure of sulfonated amino‐formaldehyde resins. V. ¹³C‐NMR analysis of sulfonated urea–melamine–formaldehyde resins

Abstract

13C‐NMR spectroscopy was used to characterize the chemical structure of sulfonated urea–melamine–formaldehyde resins, prepared by a three‐step procedure (addition, sulfonation, condensation). Each of the three reaction steps was investigated separately and the average number of functional groups, obtained after each step, was determined quantitatively. The effect of the reactant ratios on the chemical structure was studied.

Reactions between melamine formaldehyde resin and cellulose: Influence of pH

“…Up to about 20% RH we observe a drastic increase of w ∞ ; from 20% < RH < 70% the w ∞ varies linearly with RH and for 70% < RH the w ∞ increases drastically with the RH. These variations are expected for a cellulosic material22 and are characteristic of the water sorption by a porous material. Up to 70% RH the water sorption is described by a modified dual mode sorption 33–36.…”

“…13 C‐NMR spectroscopy was widely used to characterize the chemical structures of different modified melamine formaldehyde resins,22–25 but only recent works such as those of Mercer and Pizzi26, 27 are devoted to the characterization of resin/cellulose mixtures. These authors focused their works on melamine formaldehyde/wood particleboard and melamine‐urea‐formaldehyde/wood particleboard.…”

Superhydrophilic mesoporous sulfonated melamine–formaldehyde resin supported palladium nanoparticles as an efficient catalyst for biofuel upgrade

“…These assignments are in good agreement with those reported previously. 51 Notably, the signal at 70 ppm assigned to the methylene-ether linkage (CH 2 -O-) is undetectable, which is consistent with the only methylene linkage in the sample. The methylene linkage is very important in the polymer network because this linkage is more stable than the methylene-ether linkage.…”

“…The strong peaks at 155 and 165 ppm could be assigned to the triazine rings, while the strong peak at 57 ppm is related to the species of -NH-CH 2 -SO 3 -. 51,52 The shoulder peak at 53 ppm is proposed to the species of -NH-CH 2 -NH-. These assignments are in good agreement with those reported previously.…”

Synthesis of sulfonyl fluorinated macro emulsifier for low surface energy emulsion polymerization application

“…Especially, hydrophilic ceramic with a rough surface had a high WCA up to 141° after treatment by Lm, exhibiting the huge potential of hydrophobic application. Based on the chemical character of hydrophilic sulfonyl groups, crosslinking agent containing melamine formaldehyde can be added in the emulsions to crosslink sulfonyl groups and may constrain the migration of hydrophilic groups. It should be mentioned that the crosslinking effect of sulfonyl groups are the focus of our following research.…”