CARBOXYMETHYL CELLULOSE

Carboxymethyl cellulose (CMC) or cellulose gum is a cellulose derivative with Carboxymethyl cellulose (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. 
Carboxymethyl cellulose often used as its sodium salt, sodium carboxy methyl cellulose. 

CAS Number: 9004-32-4
EC Number: 618-378-6

Other names: Carmethose, Cellofas, Cellufresh, Cellugel, Celluvisc, Collowel, Ethoxose, Cellpro, Lovosa, Sarcell tel, Cellofas B, Cellofas C, Cellogel C, Cellogen PR, Glikocel TA, CMC sodium salt, Nymcel S, Tylose C, Blanose BWM, Lovosa TN, Tylose CR, Unisol RH, Cellofas B5, Cellofas B6, Cellogen 3H, Sodium CMC, Tylose CB series, Tylose DKL, Carbose 1M, 9004-32-4, Majol PLX, Carboxymethylcellulose sodium, Cellofas B50, Courlose F 4, Courlose F 8, Tylose CBR series, Courlose F 20, Copagel PB 25, Sanlose SN 20A, Cellufix FF 100, Courlose A 590, Courlose A 610, Courlose A 650, Courlose F 370, Modocoll 1200, Nymcel ZSB 10, Nymcel ZSB 16, Tylose 666, Tylose C 30, Tylose CBS 30, Tylose CBS 70, Tylose CR 50, Blanose BS 190, Tylose CB 200, Tylose CBR 400, Tylose C 300, Tylose C 600, Courlose F 1000G, Daicel 1150, Daicel 1180, Tylose C 1000P, Cellulose sodium glycolate, Sodium cellulose glycolate, Sodium glycolate cellulose, CMC 7MT, CMC 7H, CMC 7H3SF, CMC 7M, Lovosa 20alk., Sodium carboxmethylcellulose, CMC 3M5T, 7H3SF, CMC 2, KMTs 212, KMTs 300, KMTs 500, KMTs 600, Carboxymethyl cellulose, sodium salt, CMC 41A, CMC 4H1, CMC 4M6, CMC 7L1, S 75M, Cellulose glycolic acid, sodium salt, Sodium salt of carboxymethylcellulose, E0DNV5JJHX, 6ZQ8V6YVNK, 0F4M8SIS5K, 6YYV7VRE59, 72QQR5RYU4, D7SXM450NR, FC40A8XAJ3, M8VP63K8FU, RYZ9SHL900, Y3R0RA1Q8S, YGX74DKE74, 0Z2R7OG99L, 8UX21M67IJ, 8W25JI0G3V, M9J9397QWS, R05Y0B55JY, S5517JT8YS, V5U74HSL76, X075FT70UI, ZY4732LP1O, Refresh Plus, Cellufresh Formula, 0891BL4S3D, 1RD48779FJ, 379M03VC9O, 4J4P6L645M, 75KU4500GF, 97W605BIK0, 99H65D77XY, K679OBS311, Carboxymethylcellulose sodium [USP], 93O70285VH, KX442849T5, Carboxymethylcellulose sodium (USP), Sodium, Carmellose, Sodium, Croscarmellose, Blandlax, Carboxymethylcellulose, Sodium, Sodium, Carboxymethylcellulose, Refresh tears, Lubricant Drops, Gppe paste, Lubricant Eye, Refresh Celluvisc, Dry Eye Relief, CVS Lubricant Eye, TheraTears Lubricant, Equate Restore Tears, Kroger Lubricant Eye, Up and Up Lubricant, Cmc daicel 2450, EyS-ED, REFRESH PLUS, Denvercel ph 2008a, Daicel 2450, Refresh Tears Lubricant, Walgreens Lubricant Eye, Lubricant Eye Rite Aid, Ins no.466, CVS Lubricant Eye Drops, HEB Lubricant Eye Drops, Restore Plus Single Vial, Rugby Lubricant Eye Drops, Carboxmethylcellulose sodium, Leader Lubricant Eye Drops, Meijer Lubricant Eye Drops, Carboxymethylcellulose soduim, Ins-466, Up and Up Lubricant Refreshing, Gentle Eyes Lubricant Eye Drops, CVS Lubricant Eye Drops 30 ct, Equate Restore Plus Lubricant Eye, Medics Choice Lubricant Eye Drops, Signature Care Lubricant Eye Drops, Topcare Health Lubricant Eye Drops, Carboxymethylcellulose Sodium 0.5%, Equate Day and Night Restore Tears, Publix Moisturizing Relief Eye Drops, Lubricant Eye Drops Preservative Free, Foster and Thrive Lubricant Eye Drops, Equate Restore Plus Lubricant Eye Drops, Well at Walgreens Sterile Lubricant Eye, Leader Lubricant Eye Drops Soothing Relief, Walgreen Sterile Lubricant Drops 30 Count, Walgreen Sterile Lubricant Drops 70 Count, E 466, E 468, E-466, Equate Lubricant Eye Drops Preservative-Free, Equate Moisturizing Comfort Lubricant Eye Drops, Walgreens Lubricant Eye Drops Preservative Free, Good Sense Lubricating Plus Lubricant Eye Drops, Rugby Carboxymethylcellulose Sodium 0.5% Eye Drops, Lubricant Eye Drops Preservative free 30 Single Use Container, Mineral Oil, White Petrolatum and Carboxymethylcelluose Sodium, 618-378-6, Cellulose, carboxymethyl ether, sodium salt, RefChem:887391, Sodium carboxymethyl cellulose, Croscarmellose sodium, 9085-26-1, Edifas B, Aquaplast, Sodium carboxymethylcellulose, Aquacel, Nymcel slc-T, Cellogen WS-C, Avicel RC/CL, NaCm-cellulose salt, Sodium CM-cellulose, AC-Di-sol. NF, CM-Cellulose sodium salt, Aku-W 515, CCRIS 3653, Cellulose carboxymethyl ether sodium salt, UNII-E0DNV5JJHX, UNII-6ZQ8V6YVNK, UNII-6YYV7VRE59, UNII-72QQR5RYU4, UNII-D7SXM450NR, UNII-FC40A8XAJ3, UNII-M8VP63K8FU, UNII-RYZ9SHL900, UNII-Y3R0RA1Q8S, UNII-YGX74DKE74, UNII-0Z2R7OG99L, UNII-8UX21M67IJ, UNII-8W25JI0G3V, UNII-M9J9397QWS, UNII-R05Y0B55JY, UNII-S5517JT8YS, UNII-V5U74HSL76, UNII-X075FT70UI, UNII-ZY4732LP1O, B 10, UNII-0891BL4S3D, UNII-1RD48779FJ, UNII-379M03VC9O, UNII-4J4P6L645M, UNII-75KU4500GF, UNII-97W605BIK0, UNII-99H65D77XY, UNII-K679OBS311, UNII-93O70285VH, UNII-KX442849T5, Carmellose sodium, low-substituted, Cellulose carboxymethyl ether, sodium salt, UNII-0F4M8SIS5K, CHEBI:234035, DPXJVFZANSGRMM-UHFFFAOYSA-N, Cellulose, carboxymethyl ether, sodium salt, low-substituted, JAA08526, CARBOXYMETHYLCELLULOSESODIUMSALT, AKOS015915206, NS00013438, A843419, CARBOXYMETHYLCELLULOSE SODIUM, LOW-SUBSTITUTED, Sodium carboxymethyl cellulose, viscosity 600-3000 mPa.s

Carboxymethyl cellulose used to be marketed under the name Tylose, a registered trademark of SE Tylose.
Carboxymethyl cellulose synthesized by the alkali-catalyzed reaction of cellulose with chloroacetic acid. 
The polar (organic acid) carboxyl groups render the cellulose soluble and chemically reactive.

Following the initial reaction, the resultant mixture produces about 60% Carboxymethyl celluloseplus 40% salts (sodium chloride and sodium glycolate). 
This product is the so-called technical Carboxymethyl cellulose which is used in detergents. 
A further purification process is used to remove these salts to produce the pure Carboxymethyl cellulose used for food, pharmaceutical, and dentifrice (toothpaste) applications. 
An intermediate "semipurified" grade is also produced, typically used in paper applications such as restoration of archival documents.

The functional properties of Carboxymethyl cellulose depend on the degree of substitution of the cellulose structure , as well as the chain length of the cellulose backbone structure and the degree of clustering of the carboxymethyl substituents.

Carboxymethyl cellulose is used in food under the E number E466 or E469 (when it is enzymatically hydrolyzed) as a viscosity modifier or thickener, and to stabilize emulsions in various products including ice cream. 
Carboxymethyl cellulose also a constituent of many non-food products, such as toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, reusable heat packs, and various paper products. 

Carboxymethyl cellulose used primarily because it has high viscosity, is nontoxic, and is generally considered to be hypoallergenic as the major source fiber is either softwood pulp or cotton linter. 
Carboxymethyl cellulose is used extensively in gluten free and reduced fat food products. 
In laundry detergents,Carboxymethyl cellulose used as a soil suspension polymer designed to deposit onto cotton and other cellulosic fabrics, creating a negatively charged barrier to soils in the wash solution. 
In ophthalmology, Carboxymethyl cellulose is used as a lubricant in artificial tears to treat dry eyes. 
Extensive treatment may be required to treat severe dry eye syndrome or Meibomian gland dysfunction (MGD).

Carboxymethyl cellulose is also used as a thickening agent, for example, in the oil-drilling industry as an ingredient of drilling mud, where it acts as a viscosity modifier and water retention agent. 
Sodium Carboxymethyl cellulose (Na CMC) for example, is used as a negative control agent for alopecia in rabbits.
Knitted fabric made of cellulose (e.g. cotton or viscose rayon) may be converted into Carboxymethyl cellulose and used in various medical applications.[citation needed]

Device for epistaxis (nose bleeding). A poly-vinyl chloride (PVC) balloon is covered by Carboxymethyl cellulose knitted fabric reinforced by nylon. 
The device is soaked in water to form a gel, this is inserted into the nose and the balloon inflated. 
The combination of the inflated balloon and the therapeutic effect of the Carboxymethyl cellulose stops the bleeding.
Fabric used as a dressing following ear nose and throat surgical procedures.

Water is added to form a gel, and this gel is inserted into the sinus cavity following surgery.
Insoluble microgranular Carboxymethyl celluloseis used as a cation-exchange resin in ion-exchange chromatography for purification of proteins. 
Presumably, the level of derivatization is much lower, so the solubility properties of microgranular cellulose are retained, while adding sufficient negatively charged carboxylate groups to bind to positively charged proteins.
Carboxymethyl cellulose is also used in ice packs to form a eutectic mixture resulting in a lower freezing point, and therefore more cooling capacity than ice.

Aqueous solutions of Carboxymethyl cellulose have also been used to disperse carbon nanotubes. 
The long Carboxymethyl cellulose molecules are thought to wrap around the nanotubes, allowing them to be dispersed in water. 
In conservation-restoration, it is used as an adhesive or fixative (commercial name Walocel, Klucel).

Carboxymethyl cellulose is used to achieve tartrate or cold stability in wine. 
This innovation may save megawatts of electricity used to chill wine in warm climates. 
Carboxymethyl cellulose more stable than metatartaric acid and is very effective in inhibiting tartrate precipitation. 
Carboxymethyl cellulose reported that KHT crystals, in presence of CMC, grow slower and change their morphology. 

Their shape becomes flatter because they lose 2 of the 7 faces, changing their dimensions. 
Carboxymethyl cellulose molecules, negatively charged at wine pH, interact with the electropositive surface of the crystals, where potassium ions are accumulated. 
The slower growth of the crystals and the modification of their shape are caused by the competition between Carboxymethyl cellulose molecules and bitartrate ions for binding to the KHT crystals.
In veterinary medicine , Carboxymethyl cellulose is used in abdominal surgeries in large animals, particularly horses, to prevent the formation of bowel adhesions.

Carboxymethyl cellulose is sometimes used as an electrode binder in advanced battery applications (i.e. lithium ion batteries), especially with graphite anodes.
Carboxymethyl cellulose's water solubility allows for less toxic and costly processing than with non-water-soluble binders, like the traditional polyvinylidene fluoride (PVDF), which requires toxic n-methylpyrrolidone (NMP) for processing. 
Carboxymethyl cellulose is often used in conjunction with styrene-butadiene rubber (SBR) for electrodes requiring extra flexibility, e.g. for use with silicon-containing anodes.

Carboxymethyl cellulose powder is widely used in the ice cream industry, to make ice creams without churning or extreme low temperatures, thereby eliminating the need for the conventional churners or salt ice mixes. 
Carboxymethyl cellulose is used in preparing bakery products such as bread and cake. 
The use of Carboxymethyl cellulose gives the loaf a much improved quality at a reduced cost to the baker, by economizing on the fat component. 
Carboxymethyl celluloseis also used as an emulsifier in high quality biscuits. 

By dispersing fat uniformly in the dough, it improves the release of the dough from the moulds and cutters, achieving well-shaped biscuits without any distorted edges. 
Carboxymethyl cellulose can also help to reduce the amount of egg yolk or fat used in making the biscuits, thus achieving economy. 
Use of Carboxymethyl cellulose in candy preparation ensures smooth dispersion in flavour oils, and improves texture and quality. 
Carboxymethyl cellulose is used in chewing gums, margarines and peanut butter as an emulsifier. It is also used in leather crafting to burnish the edges.

Carboxymethyl cellulose has also been used extensively to characterize enzyme activity from endoglucanases (part of the cellulase complex). 
Carboxymethyl cellulose is a highly specific substrate for endo-acting cellulases, as its structure has been engineered to decrystallize cellulose and create amorphous sites that are ideal for endoglucanase action. 
Carboxymethyl cellulose is desirable because the catalysis product (glucose) is easily measured using a reducing sugar assay, such as 3,5-dinitrosalicylic acid. 

Using Carboxymethyl cellulosein enzyme assays is especially important in regard to screening for cellulase enzymes that are needed for more efficient cellulosic ethanol conversion. 
However, Carboxymethyl cellulose has also been misused in earlier work with cellulase enzymes, as many had associated whole cellulase activity with CMC hydrolysis.
As the mechanism of cellulose depolymerization has become better understood, exo-cellulases are dominant in the degradation of crystalline (e.g. Avicel) and not soluble (e.g. CMC) cellulose.

Carboxymethyl cellulose is a derivative of cellulose, containing Carboxymethyl cellulose groups that are generated via the reaction of cellulose with chloroacetate in alkali to produce substitutions in the C2, C3, or C6 positions of glucose units . 
As a result, Carboxymethyl cellulose is water soluble and more amenable to the hydrolytic activity of cellulases. 
Carboxymethyl cellulose is therefore a useful additive to both liquid and solid medium for the detection of cellulase activity, and its hydrolysis can be subsequently determined by the use of the dye Congo red, which binds to intact β-d-glucans. 

Zones of clearing around colonies growing on solid medium containing Carboxymethyl cellulose, subsequently stained with Congo red, provides a useful assay for detecting hydrolysis of Carboxymethyl cellulose and therefore, β-d-glucanase activity . 
The inoculation of isolates onto membrane filters placed on the surface of Carboxymethyl cellulose agar plates is a useful modification of this technique, as the filter may subsequently be removed allowing visualization of clear zones in the agar underneath cellulolytic colonies.

Carboxymethyl cellulose (CMC), a derivative of cellulose , is a cheaper, nontoxic, biodegradable, and renewable polymer. 
The drawback of Carboxymethyl cellulose film is its poor mechanical properties. 
Due to its superior mechanical properties, low flammability, impressive biocompatibility, and greater biodegradability, silk fibroin has been identified as a potentially convenient biomaterial. 
Depending on the requirements for various applications it can be modified to a hydrogel, film, scaffold, or nonwoven mat.
 
GO is a suitable filler in composites that enhances the mechanical properties . 
Abdulkhani et al.  
synthesized biopolymer nanocomposite films by mixing reduced graphene oxide (RGO) to sodium Carboxymethyl cellulose(Carboxyl methly cellulose)/silk fibroin matrix. 
The result showed that RGO is useful for composites due to its high performance and low cost. 
These nanocomposites are used in food packaging.

Carboxymethyl cellulose sodium is a viscous polysaccharide that belongs to a high molecular weight category. 
Carboxymethyl cellulose has mucoadhesive property and is used during eye surgery. 
Carboxymethyl cellulose sodium promotes re-epithelialization of the epithelial cells in corneal wounds. 
Carboxymethyl cellulose useful for the study of attached cell and three-dimensional tissue culture models.

Carboxymethyl cellulose sodium has been used as a vehicle for tamoxifen citrate, sorafenib, and savolitinib. 
Carboxymethyl cellulose has also been used as a component of serum-free medium (SFM) for the suspension of human umbilical vein endothelial spheroids.
Useful for the study of attached cell and three-dimensional tissue culture models.

Pharmaceutical secondary standards for application in quality control provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.

Sodium Carboxymethyl cellulose(Na CMC) is used for its thickening and swelling properties in a wide range of complex formulated products for pharmaceutical, food, home, and personal care applications, as well as in paper, water treatment, and mineral processing industries. 
To design Na Carboxymethyl cellulose solutions for applications, a detailed understanding of the concentration-dependent rheology and relaxation response is needed. 
We address this here by investigating aqueous Na CMC solutions over a wide range of concentrations using rheology as well as static and dynamic light scattering. 

The concentration dependence of the solution specific viscosities ηsp could be described using a set of three power laws, as predicted from the scaling theory of polyelectrolytes. 
Alternatively, a simpler approach could be used, which interpolates between two power law regimes and introduces only one characteristic crossover concentration. 
We interpret the observed behavior as a transition from the semidilute nonentangled to the entangled concentration regimes; this transition behavior was not observed in the solution structure, as determined using static light scattering. 

Dynamic light scattering revealed three relaxation modes. 
The two fastest relaxations were assigned as the “fast” and “slow” relaxation modes typically observed in salt-free or not fully screened polyelectrolyte solutions within the semidilute concentration range. 
The third, typically weak mode, was attributed to the presence of a small amount of poorly dissolved cellulose residuals. 

Since filtration altered the solution behavior, without sufficiently removing the residuals, data collection and processing were adapted to account for this, which facilitated a detailed light scattering investigation of the original solutions, relevant for industrial applications. 
The relaxation time characterizing the fast mode, τf, was concentration independent; whereas the relaxation time of the slow mode, τs, demonstrated similar crossover behavior as observed for the specific viscosity, further demonstrating the dynamic nature of the crossover.

Polyaniline is a conducting polymer which has been subject of intensive research on the exploitation of new products and applications. 
The main aim of the work is the development of a conductive bacterial cellulose (BC)-based material by enzymatic-assisted polymerization of aniline. 
For this, we study the role of Carboxymethyl cellulose(CMC) as a template for the in situ polymerization of aniline. 
Bacterial cellulose was used as the supporting material for the entrapment of CMC and for the in situ oxidation reactions. 
The amount of Carboxymethyl cellulose entrapped inside BC was optimized as well as the conditions for laccase-assisted oxidation of aniline. 

The new oligomers were evaluated by spectrometric techniques, namely 1H NMR and MALDI-TOF, and the functionalized BC surfaces were analyzed by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and reflectance spectrophotometry. 
The conductivity of the developed materials was evaluated using the four-probe methodology. 
The oligomers obtained after reaction in the presence of CMC as template display a similar structure as when the reaction is conducted only in BC. 

Though, after oxidation in the presence of this template, the amount of oligomers entrapped inside BC/CMC is considerably higher conferring to the material greater electrical conductivity and coloration. 
The use of Carboxymethyl cellulose as a template for aniline oxidation on BC seems to be a promising and cheap strategy to improve the yield of functionalization and increment the properties of the materials, namely electrical conductivity and coloration.

Conductive materials have been gaining scientific attention due to the increasing need for new technologies for the exploitation of electronic sensor devices, energy-storage, and intelligent clothing. 
Bacterial cellulose (BC) has been used to develop composites containing a conductive polymer, such as polyaniline (PANi), polypyrrole and polythiophene, and others . 
The use of templates, like sulfonated polystyrene as sodium salt (SPS), the calcium salt of ligninosulfonate, micelles composed by sodium dodecylbenzenesulfonate (SDBS), or vesicles made-up of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) have been described as favoring the polymerization of aniline. 

These molecules are composed by sulfonate groups and, in oxidation conditions, aniline is oxidized to a conductive product, emeraldine salt . 
The templates, due to a localization of the reaction in their vicinity, direct the regioselectivity of the monomer coupling reaction, favoring para-over ortho-coupling of oxidized aniline.  
These compounds have dopant action (counter ions), which balance the positive charge on the PANi, thereby stabilizing the PANi-Emeraldine salt structure, crucial for electrical conductivity. 
Together with templates, the laccase/O2- assisted polymerization of aniline has been studied as an environmentally friendly route to produce conductive.
 
Laccase has been applied for the aniline polymerization in situ inside BC nano fibers under mild conditions replacing the chemical oxidants that are normally used, such as ammonium peroxydisulfate, potassium dichromate or ferric chloride . 
The use of templates is crucial to reduce the undesired coupling reactions, as side-chain branching, and to ensure the polymerization of linear head-to-tail aniline . 
The template works by forming polymer–polymer complexes which are stabilized via non-covalent binding forces among hydrogen bonds, electrostatic and hydrophobic interactions during polymerization  .

Carboxymethyl cellulose (CMC), a soluble derivative of cellulose, is an example of an efficient template for aniline polymerization. 
Carboxymethyl cellulose adsorbs irreversibly to cellulose fibers under specific conditions increasing their negative charge . 
Carboxymethyl cellulose contains –COO– groups which supply anionic locations to react with electropositive molecules (positively charged cations) via electrostatic interactions, favoring the polymerization of aniline . 
BC has considerable amount of hydroxyl groups which, due to their high reactivity, can be easily modified. 

However, the reactivity of the hydroxyl groups can be restricted by intramolecular and intermolecular hydrogen bonds during polymerization events . 
When Carboxymethyl cellulose is introduced inside BC, the –COO– groups of Carboxymethyl cellulose can form intermolecular interactions with the hydroxyl groups of BC. 
The loss of some –OH groups by BC, able to interact with other compounds, can be counterbalanced by the presence of Carboxymethyl cellulose, which is composed by hydroxyl and carboxylate groups.

In this work, we developed conductive BC composites by entrapping Carboxymethyl cellulose inside BC membranes followed by the in situ aniline polymerization by laccase. 
The Carboxymethyl cellulose was entrapped inside BC to serve as template for polymerization and laccase was used as reaction catalyst. 
Potassium hexacyanoferrate (II) (KHCF), a radical initiator, and bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT), a surfactant, were used as additives for aniline oxidation. 

The role of Carboxymethyl cellulose on aniline polymerization was evaluated through the quantification of the amount of polymer formed. 
The polymerization of aniline was evaluated by UV/Visible spectroscopy and the new oligomers were characterized by spectrometric techniques, namely 1H NMR and MALDI-TOF. 
BC/PANi and BC/CMC/PANi composites were monitored by FTIR, SEM, TGA, and XRD analysis. 
The conductivity of the developed materials was assessed through the four-probe method and the color of BC samples was evaluated spectrophotometrically.

The linear polymer Carboxymethyl cellulose(CMC) as a polyelectrolyte is an object of consideration in this review. 
The emphasis is on the electric properties of Carboxymethyl celluloseboth as a free chain in solution and adsorbed on the solid surface. 
A special attention is paid to the mobility of counterions, electrostatically associated with the CMC polyelectrolyte chain

Carboxymethyl cellulose[C6H7O(OH)3−x(OCH2COOH)x]n is a derivative of the regenerated cellulose [C6H10O5]n with hydroxy-acetic acid (hydroxy ethanoic acid) CH2(OH)COOH or sodium monochloroacetate ClCH2COONa. 
The CMC backbone consist of D-glucose residues linked by β-1,4-linkage. 
The molecular mass of one glucose unit in CMC chain is mCMC = 146.14 + 75.04 x, where x ≤ 3 is the degree of substitution (DS). 
As a rule CMC is produced as sodium salt [C6H7O(OH)3−x(OCH2COONa)x]n with DS = 0.4−1.2, then the molecular mass per unit is mNaCMC = 146.14 + 97.03 x ≈ 185−263 g/mol.

As derivative of the cellulose (poly-β-D-glucose) Carboxymethyl cellulosehas inherited its main structural peculiarities: 
(a) rigidity of the glucose units (6-atoms rings in “armchair” conformation); 
(b) an almost fully extended conformation owing to impossibility for rotation round the C−O−C bonds between the glucose residues because of strong steric limitations (a consequence of the β-configuration at C-1 atom in 1,4-linkage); 
and (c) orientation of the bigger constituent groups (−OH, −CH2OH and −OCH2COOH) in the equatorial plane out of the saccharic ring. 

The cross-sectional dimension of the Carboxymethyl cellulosechain is a sum of the diameter of the glucose ring (0.5 nm) and the size of the carboxymethyl group (0.4 nm, situated on the both side of the chain); the effective diameter of the chain is rather higher because the glucose residues are oriented not line in line but somewhat tilted along the backbone line.
 
The replacement of the H-atom of −OH-group with −CH2COO− causes a loss of the possibility of parallel association of Carboxymethyl cellulosechains in sheet-like structures (a characteristic of the cellulose structure leading to supramolecular organization in microfibrils ) because of both steric hindrance and electrostatic repulsion but that does not exclude the possibility of intra- and intermolecular interaction by hydrogen bonds between the unsubstituted −OH groups.

In the literature the polymer unit of Carboxymethyl cellulose chain is denoted as consisting of one or two glucose rings following the manner applying to the cellulose. 
The one unit way is chemically well-founded according the cellulose contents because all the glucose units are chemically identical (except those on the two ends of the chain). 

According to the conformation of the cellulose chain a more thought-out manner is the two glucose residues unit because this way allows distinguishing the cellulose (poly-β-D-glucose) and the amylose (poly-α-D-glucose), both linear chains of chemically identical glucose residues. 
The conformation of the polymer chains of these two polysaccharides differs drastically owing to the configuration at the anomeric C-1 atom: the β-1,4-linkage in the cellulose leads to inversed orientation of every second glucose ring according the previous one and to sterically conditioned full extended conformation because of impossible rotation round the C−O−C bonds between C-1 and C-4 atoms of the neighbour rings. 

In the case of the amylose the α-configuration at C-1 atom leads to uniform orientation of the glucose rings and to impossibility of extended conformation; due to the α-1,4-linkage amylose chain has a tendency to spiral conformation . 
Since the linear charge density of the CMC chain is determined by the number of −COO− groups per glucose unit independently of its orientation, in this chapter the one glucose residue is accepted to denote the monomeric unit.

The −CH2COOH group can be attached to every of the three hydroxyl groups of the cellulose monomer unit, so theoretically the degree of substitution (DS) can reach 3, but usually DS does not exceed 2. The distribution of −CH2COOH groups in the glucose unit and along the CMC chain is accepted to be random in the model  proposed to give the monomer composition of a sample with known DS. 

The model is based on the supposition that the substitute reaction occurs at random, i.e. each of the three −OH groups (at C-2, C-3 and C-6 position) of every monomer unit can be substituted in equal probability independently on the presence of another constituent in the same glucose unit. 
The experimental investigations  of the mole fraction of substituted monomers of CMC confirm the hypothesis for random distribution of the constituents. 
For example, at DS = 1.3 the mole fractions are about 0.2, 0.4, 0.3 and 0.1 for unsubstituted, mono-, di- and trisubstituted, respectively. 

On the base of these results it can be concluded that the −CH2COO− groups are also randomly distributed along the CMC chain and practically there are no regions containing more than one or two uncharged monomer units when DS is higher than 1−2. 
The absence of long uncharged segments allows accepting that the negative charges are almost evenly distributed along the CMC chain at high linear charge density (high DS and high degree of dissociation); that is important condition for applying the model of uniformly charged cylinder to CMC chain.

The distance between two glucose units in CMC chain is 0.515 nm . 
The contour length Lc (the length of the chain backbone if it is fully stretched but without deformation of the valence angles and bonds) is determined as a product of the number of monomers n and the length of one unit: Lc = 0.515 n (nm).

In this section the characteristics of CMC as a free polyelectrolyte chain are overlooked, i.e. the chain has conformational freedom that does not or depends on the presence of other macromolecules, respectively in diluted solution or semi-concentrated ones. 
The chain is immersed in salt-free medium or in electrolyte with valency z. In the first case the counterions originate from the ionizable group of the chain: 
H+ or Na+ (in the case of CMC or its sodium salt NaCMC). 
A part of counterions can be electrostatically adsorbed losing their freedom; the rest are scattered by the thermal energy kT and are randomly distributed around the chain forming an ions cloud.

The effective dissociation constant Ka (respectively pKa = −logKa) of a weak polyelectrolyte depends on the neighbour electric charges in the chain and in the medium. 
The presence of other negative charges in the vicinity of a given COO− group leads to increasing of the electric field intensity and the local concentration of H3O+ ions. 

As a result the probability of protonation of the COO− group increases; respectively the equilibrium of the reaction COOH↔COO− +H+ is shifted to the non-dissociated form. 
That is why the dissociation capability of the ionizable groups in the polyelectrolyte chain can not be characterized by a constant like in the case of a simple (monomeric) acid (pKa = pH at α = 1/2). 
The apparent (effective) dissociation “constant” pKa = f(x,α,μ) of COOH groups in CMC chain is a function of the degree of substitution x, the degree of dissociation α (determined by pH of the medium), and the ionic strength μ; the first two factors determine the linear charge density of the chain.

Methylcellulose (MC) and sodium Carboxymethyl cellulose (sod. CMC) have many other uses besides those in conservation. 
A brief rummage through your medicine cabinet may come up with such products as toothpaste, laxatives, or diet pills each of which may contain either MC or sod. Carboxymethyl cellulose. 
Other products include ice cream, water-based paints, detergents and a variety of paper products to name but a few. 
Characteristics which make them useful are: high viscosity in low concentrations, defoaming abilities, surfactant, and bulking abilities. 
They are not toxic and do not promote allergic reactions in humans

These cellulose polymers can be purchased in grades ranging from coarse to fine particles and in varying viscosities. 
In solution, Hercules Carboxymethyl cellulose 7H and Culminal (MC from Talas) are quite clear while Cellofas B3500 from Conservation Materials is hazy.

The easiest way to make up any of the MCs or sod. 
Carboxymethyl celluloses is to measure out the desired quantity of the powder, fill a blender with the right amount of deionized or distilled water, turn on the blender to the lowest speed, and pour the powder in a steady stream into the vortex. 

As soon as all of the powder is in the water, turn off the blender. 
Over-blending can result in a loss of viscosity. 
No preservative is necessary as long as purified water is used and the storage container is airtight. 
After blending, Carboxymethyl cellulose  best to leave the solution at least one hour before using.

Most conservators regard the MCs and sod. 
Carboxymethyl celluloses primarily as adhesives. We will see in fact that they have many other uses, but let's start with their adhesive applications. 
Carboxymethyl cellulose alone is really strong enough to be used as an adhesive when a great deal of stress on the bond is encountered such as in tear repairs or hinges.

MC should also not be used for an overall backing as it is not a very polar adhesive and as such will not affect a very good bond between papers, especially smooth-surfaced papers. 
Carboxymethyl cellulose occasionally mixed with wheat starch paste in order to provide 'slip' and indeed this mixture comprises most wallpaper pastes.

Carboxymethyl cellulose on the other hand is a very polar adhesive and as such makes a very good bond between sheets of paper and is useful for overall backings where stress on the bond is not a real problem. 
Carboxymethyl cellulose could also be mixed with wheat starch paste to provide 'slip'. 
The advantage sod. 
Carboxymethyl cellulose has over wheat starch paste is that a dry backing can be done when the original work of art consists of water sensitive media or paper which is dimensionally unstable. 

This is because a 2.5% solution of say CMC 7H is very viscous but is not very 'wet' so that it can be brushed on the reverse of the original and the backing paper without either expanding too much or without much water penetrating to the surface of the origi al. 
Once the backing is complete, air drying can take place with the original face down so that water evaporates from the back reducing still further the risk of the front getting wet. 
When dry the backed original can be humidified and pressed or put out on a drying screen/board to flatten. 

The adhesive dries to a very thin even layer and is easily reversible with cold water. 
Carboxymethyl cellulose non-staining and does not become brittle upon ageing. Other applications in this section might include temporary facings, mends or backings. 
If you can use hot water for a wash bath, you might like to use MC as the temporary adhesive as it will not dissolve in hot water but is easily reversed in cold water. 
This would probably hold together a badly torn piece which could not be handled in any other way.

An extremely useful method for quickly filling small holes or losses in paper is accomplished by mixing Whatman Cellulose Powder CF11 with MC or sod.Carboxymethyl cellulose. 
The cellulose powder as sold is very white, but gradations of browns can be made by cooking the dry powder in a Teflon pan over a hot plate.

Wear a dust mask as the powder can be irritating if inhaled. 
Also be careful not to scorch the powder. 
The cooked powder can then be color matched, dry, to the original paper by adding lighter or darker shades of the powder as necessary. 
Then enough 3% MC or 2.5% sod. CMC is added to make a stiff paste. 

Carboxymethyl cellulose can then be applied to the hole or loss with a microspatula, tip of a scalpel blade, etc. Leave it to air dry. Retouching is seldom necessary if you have matched the powder color well in the first place. 
If a smoother surface is needed, small amounts of calcium carbonate can be added to the powder before the adhesive is added. 
Any excess of the cellulose powder paste left over can be allowed to dry out, and later on, rejuvenated for further use by adding a few drops of water and working up into a paste again.

These cellulose polymers also act as deflocculating agents in that they cause particles such as fibers to stay in suspension and not clump together and separate out of solution. 
This advantage can be very useful in employing wet pulp fills in a treatment, especially when using a pipette to distribute the pulp from the slurry. 
The proportions are about 1:3, .5% MC or sod. 
Carboxymethyl cellulose: pulp slurry.

In low concentrations such as .5%, these polymers can serve very well as sizing agents and indeed are used extensively in the paper industry as both internal and surface sizes. 
In paper conservation, the use of a sizing agent can perform two roles: to repel oil and/or grease and to enhance the fiber-to-fiber bonding which makes the paper stronger and more durable. 

The .5% solutions of either MC or sod. CMC can be brushed on both sides of the non-water sensitive original through tissue paper on silicone paper and left to air dry. 
They could also be brushed on the surfaces while the piece was on the vacuum suction table to enhance penetration. 
This should be done on a porous yet slick-surface material such as Hollytex, Reemay or Pellon and allowed to air dry.

Because of its surfactant properties, MC and sod. 
Carboxymethyl cellulose can be used like detergents. 
If a swab is dipped in the viscous solution and the excess wiped off, it can be used as a kind of cleaning lubricant over areas of dirt and/or staining with little or no risk of abrading the paper. 
Excess on the paper surface should be removed when the treatment is complete as both MC and sod. CMC will leave a slightly greyish film.

In conjunction with this surfactant property and because 3% or 2.5% solutions carry a lot of water but are not wet, these polymers can be used as poultice material to soak up staining, soften adhesives through paper (even varnished paper), aid in removing old adhesive residues without affecting water sensitive media, and can act as a viscous carrier for enzymes, bleach and solvents.