Methylol cellulose

Mechanisms for Formation and Hydrolysis of Finishes. The general mechanism for acid-catalyzed formation and hydrolysis of. ZV-methylol cellulose cross-links has been shown to pass through a carbonium ion intermediate as in equations 4 and 5 (41) ... 

Notations CELL, cellulose P4VPy, poly(4-vinyl pyridine) MC, methylolated cellulose PVP, poly(N-vinyl pyrrolidone) PVA, poly(vinyl alcohol) PAN, poly(acrylonitrile) PCL, poly(e-caprolactone) Ny6, nylon 6. 

Baker, T. J., Schroeder, L. R., and Johnson, D. C. (1978). Dissolution of cellulose in polar aprotic solvents via formation of methylol cellulose. Carbohydr. Res. 67 C4-C7. 

Patton, P. Gilbert, R.D. Anisotropic solutions of methylol cellulose. Polym. Preprints (American Chemical Society, Division of Polymer Chemistry)... 

Many cellulose derivatives form lyotropic liquid crystals in suitable solvents and several thermotropic cellulose derivatives have been reported (1-3) Cellulosic liquid crystalline systems reported prior to early 1982 have been tabulated (1). Since then, some new substituted cellulosic derivatives which form thermotropic cholesteric phases have been prepared (4), and much effort has been devoted to investigating the previously-reported systems. Anisotropic solutions of cellulose acetate and triacetate in tri-fluoroacetic acid have attracted the attention of several groups. Chiroptical properties (5,6), refractive index (7), phase boundaries (8), nuclear magnetic resonance spectra (9,10) and differential scanning calorimetry (11,12) have been reported for this system. However, trifluoroacetic acid causes degradation of cellulosic polymers this calls into question some of the physical measurements on these mesophases, because time is required for the mesophase solutions to achieve their equilibrium order. Mixtures of trifluoroacetic acid with chlorinated solvents have been employed to minimize this problem (13), and anisotropic solutions of cellulose acetate and triacetate in other solvents have been examined (14,15). The mesophase formed by (hydroxypropyl)cellulose (HPC) in water (16) is stable and easy to handle, and has thus attracted further attention (10,11,17-19), as has the thermotropic mesophase of HPC (20). Detailed studies of mesophase formation and chain rigidity for HPC in dimethyl acetamide (21) and for the benzoic acid ester of HPC in acetone and benzene (22) have been published. Anisotropic solutions of methylol cellulose in dimethyl sulfoxide (23) and of cellulose in dimethyl acetamide/ LiCl (24) were reported. Cellulose tricarbanilate in methyl ethyl ketone forms a liquid crystalline solution (25) with optical properties which are quite distinct from those of previously reported cholesteric cellulosic mesophases (26). 

Poly-O-(hydroxymethyl) Methylol cellulose [37353-59-6] Synth, from cellulose and. Poly-0-(2-hydroxyethyl) HEC Natrasofi . Tylose H . Cellozise. Cellobond ... 

Methyl-5 -0-methyluridine, U-6 A -Methylmoranoline, H-175 6 -C-Methylneplanocin A, M-275 Methylol cellulose, C-48... 

Laminarin Insoluble-/orm, L-20 Laminarin Soluble-/orm, L-20 Laminarin, L-20 Latosillan, L-26 Lentinan, L-29 Leucosin, L-32 Levan, L-34 Lichenan, L-39 Mannan, M-22 Melanocidin A, M-126 Melanocidin B, M-127 Methyl cellulose, C-48 Methylol cellulose, C-48 Mucoran, M-320 Nadroparin, N-1 Neoschizophyllan, N-26 Nitrocellulose, C-48 Nucleoticidin, N-85 Parnaparin sodium, P-11 Pectic acid, P-14 Pelvetian, P-15 Peptidoglycan, P-50 Pestalotan, P-51... 

Cellulose can be converted into a hemiacetal derivative, methylol cellulose , by reacting with formaldehyde in methyl sulphoxide. Other aprotic solvents, such as pyridine, AA-dimethylformamide, AA-dimethylacetamide, A-methyl-2-pyrrolidinone, and thiolane-1-oxide can be substituted for methylsulphoxide for this conversion. More concentrated solutions of methylol cellulose could be obtained when cellulose and paraformaldehyde were heated together in the solvent than when formaldehyde gas was bubbled through a suspension of cellulose in the solvent. Solutions of 10% cellulose in methylsulphoxide could be obtained by this method. During the swelling of cellulose in ethanolamine, ethylenediamine, and methyl sulphoxide, the solvent retention capacity of cellulose at 20—120°C decreased by 10—20%, depending on the solvent."... 

Esterification of OH groups in methylol cellulose was studied. Ultimately, we wished to add long graft-like chains to the cellulose, so acid chlorides were the reactants of choice. Acetyl chloride was used as a model reactant. Here, DMSO cannot be used as a solvent because of its reactivity with acid chlorides. Esterifications were carried out by two methods, one involving direct reaction of acetyl chloride with methylol cellulose in DMF/LiCl using pyridine as acid acceptor. The pyridine was probably not necessary, though its equilibrium involvement with the acid chloride caused no apparent problem. 

The other method involved a two-step treatment, first with sodium hydride, then with acetyl chloride. The presence of about 3% DMSO in the methylol cellulose caused some problems, manifested by less than theoret al yield of acetate incorporation, but still materials with DS in acetyl of 0.2 to about 1 were prepared reproducibly under homogeneous reaction conditions. 

Chemistry of A Methylol Agents. The reaction of dimethylolurea and cellulose is illustrated in equation 3 ... 

Cellulose dissolved in suitable solvents, however, can be acetylated in a totally homogeneous manner, and several such methods have been suggested. Treatment in dimethyl sulfoxide (DMSO) with paraformaldehyde gives a soluble methylol derivative that reacts with glacial acetic acid, acetic anhydride, or acetyl chloride to form the acetate (63). The maximum degree of substitution obtained by this method is 2.0 some oxidation also occurs. Similarly, cellulose can be acetylated in solution with dimethylacetamide—paraformaldehyde and dimethylformamide-paraformaldehyde with a potassium acetate catalyst (64) to provide an almost quantitative yield of hydroxymethylceUulose acetate. 

Chemical compounds that contain methylol groups (-CH2 OH) form stable, covalent bonds with cellulose fibers. Those compounds are well known and widely used in textile chemistry. Hydrogen bonds with cellulose can be formed in this reaction as well. The treatment of cellulose with methylolmelamine compounds before forming cellulose unsaturated polyesters (UP) composites decreases the moisture pickup and increases the wet strength of reinforced plastic [48,49]. 

Paraformaldehyde/DMSO dissolves cellulose rapidly, with neghgible degradation, and forms the hydoxymethyl (methylol) derivative at Ce [ 140-142]. Therefore, cellulose derivatives at the secondary carbon atoms are easily obtained after (ready) hydrolysis of the methylol residue. Additionally, fresh formaldehyde may add to the methylol group, resulting in longer methylene oxide chains, that can be functionahzed at the terminal OH group, akin to non-ionic, ethylene oxide-based surfactants [143,144]. 

Substituted triazinyl derivatives of DAS are usually chosen for pad-dry-bake application to cotton in conjunction with an easy-care or durable-press finish. In these mildly acidic conditions (pH about 4) the FBA must show appreciable resistance towards the catalyst (usually magnesium chloride) necessary to cure the resin. The less substantive products in the upper half of Table 11.1 are important in this respect, as are compounds of type 11.9 where R = OCH3 or CH3NCH2CH2OH. It is likely that the hydroxyethylamino groups present in many of these compounds participate in condensation reactions with N-methylol groups in the cellulose-reactant resin. The performance of an FBA applied in conjunction with a resin finish can be modified and improved by careful formulation of the pad liquor but this lies beyond the scope of the present chapter. Alternatively, FBA and resin can be applied in two separate steps most DAST-type brighteners would be suitable if applied in this way. 

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... 

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. 

Kamogawa, and Sekiya (54) studied the graft polymerization of acrylamide onto cotton fabric using ceric ammonium nitrate as the catalyst. Similarly to Kulkarni et al. (35) the authors performed subsequent cross-linking with formaldehyde amd methylol compounds. From precipitation studies by acidification of cuprammonium solutions on mixtures of polyacrylamide and cellulose on the one hand and polyacrylamide-cellulose grafts on the other the authors conclude that chemical bonds must exist between the two polymers in the grafted product. 

The first synthetic plastics were the phenol-formaldehyde resins introduced by Baekeland in 1907 [1], Melamine and urea also react with formaldehyde to form intermediate methylol compounds which condense to cross-linked polymers much like phenol-formaldehyde resins. Paper, cotton fabric, wood flour or other forms of cellulose have long been used to reinforce these methylol-functional polymers. Methylol groups react with hydroxyl groups of cellulose to form stable ether linkages to bond filler to polymers. Cellulose is so compatible with these resins that no one thought of an interface between them, and the term reinforced composites was not even used to describe these reinforced systems. 

The key role of C6 in stabilizing the native cellulose lattice is supported by recent findings concerning the mechanism of action of the dimethyl-sulfoxide-paraformaldehyde solvent system, which is quite effective in solubilizing even the most crystalline of celluloses. The crucial step in the mechanism proposed for the action of this system is substitution of a methylol group on the primary hydroxyl at the C6 carbon (26, 27). 

The methylol groups are very reactive, condensing with each other, with the N-H groups in urea, and with the -OH groups in cellulose. 

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