Formaldehyde reaction with cellulose

Cellulose Reaction with Formaldehyde and Its Amide Derivatives... 

Amide derivatives, cellulose, reaction with formaldehyde and its, 52... 

The introduction of Calcobond dyes a few years later by American Cyanamid exploited a similar principle but incorporated the N-methylol groups into the dye molecule itself [132]. The labile chloro substituents in dichlorotriazine dyes were converted to amino groups by substitution with ammonia and the resulting melamine residue made cellulose-reactive again by reaction with formaldehyde (Scheme 7.59). A typical member of this range was Cl Reactive Red 92 (7.120). A characteristic problem of the Procion Resin process and of the... 

Crosslinking of cellulose has an important influence on its reactivity it can be achieved by several methods reaction with formaldehyde, bis-N-hydroxymethylurea, divinyl sulfone, etc. Crosslinking of cellulose greatly decreases its reactivity, probably because its ability for swelling is decreased. ... 

In 1906 Eschalier reported that cellulosic fibers had improved wet strengths after reaction with formaldehyde." Subsequently, countless publications and patents have reported investigations of the reactions of formaldehyde and of formaldehyde adducts of urea, melamine and carbamates with cellulose. Before the macromolecular structure of cellulose was generally accepted, the reaction of formaldehyde with cellulose was proposed (equation 8)" " ... 

Reactions of urea-formaldehyde products with cellulose yield products with more stable crosslinks than reaction with formaldehyde. Examples of these reactions are... 

Reaction with formaldehyde in the presence of alkalies causes temporary alterations in the physical characteristics of cellulose but it is apparent... 

Cellulosic fibers (cotton, rayon) are crosslinked by reaction of the hydroxyl groups of cellulose with formaldehyde, diepoxides, diisocyanates, and various methylol compounds such as urea-formaldehyde prepolymers, /V, /V -di tnethylol-A(A -dimethy lene urea, and trimethyl-olmelamine [Marsh, 1966]. Crosslinking imparts crease and wrinkle resistance and results in iron-free fabrics. 

It is known that low-molecular-weight esters of phosphorous acid react, in the presence of alkali catalysts, with formaldehyde to give the corresponding hydroxymethyl phosphonates. This reaction was used to synthesize cellulose hydroxymethylphosphonates (V). The structure of these compounds has been confirmed by hydrolysis to hydroxymethyl-phosphonic acid, which was identified by paper chromatography. 

Although not a measure of cellulose crosslinking, since mono functional agaits are incapable of crosslinking, the response to hydrolysis conditions of cotton fabric treated with N-methyl, N -hydroxymethylethyleieurea offers evidence of cellulose reaction. This response can be seen in Table II. Formaldehyde is released from the... 

There have been contradictory reports about the reaction of wood with formaldehyde from UF-resins. At room temperature, and up to the boiling point of water, wood absorbs only very little formaldehyde. Thus, gine chips treated with 35 wt% formaldehyde solution for 30 min at 160°C retain less than 0.01 wt% formaldehyde (3). Forest products scientists generally assume that UF resins do not bond to wood (4). However, at higher temperatures, wood absorbs formaldehyde and irreversibly changes its physical properties. Thus, after 15 hrs of exposure at 120 C, 7 wt% formaldehyde is retained by solid oak and causes a 50% reduction in swelling (5-8). Since wood cellulose is... 

The purpose of this chapter is to describe exploratory 13C-NMR studies of formaldehyde-cellulose reaction model systems. Solid state NMR spectra are still comparatively broad and do not reveal as much detail as solution spectra Ql). Furthermore, solid state NMR studies are still cumbersome, ana since no references are available on solid state studies of cellulose-formaldehyde interactions, we conducted an analysis of model systems for cellulose that are water soluble. This paper reports reactions of formaldehyde with methanol, ethyIenegIycoI, some seIect sugars, and ceI Iobi ose. 

By far the simplest possible model system for cellulose is the reaction of monovalent alcohols such as methanol with formaldehyde. This system is present in aqueous phase in commercial formalin solutions that are made by partial oxidation of methanol. These... 

Once formaldehyde reaches the bound water layer In the S-2 cell walls it is available for reaction with the cellulose surface. Our exploratory experiments indicate that such reaction is indeed expected, that it causes formation of hemiacetals, readily reaches equilibrium, and is reversible. The concentration of formaldehyde bound In form of hemiacetal will depend on the concentration of water as well as that of formaldehyde. Since the water concentration depends on relative humidity of the surrounding air, the... 

There are also patents for solid, water-insoluble products resulting from such a reaction.1276,1277 In addition there are reports of the strengthening of artificial silk, starches, and cellulose after contact with formaldehyde.1278 On the other hand model studies carried out by Tomasik and Schilling1279 on the reaction of maltodextrins with formaldehyde and pyruvaldehyde suggested that neither of these, in contrast to glyoxal and glutaraldehyde, acted as crosslinker. 

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