AQUALON®
`
`Sodium
`Carboxymethylcellulose
`
`Physical
`and
`Chemical
`Properties
`
`C M
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`C M C
`M C
`
`ALKERMES Exh. 2034
`Luye v. Alkermes
`IPR2016-1096
`
`

`

`AQUALON® CMC
`An Anionic Water-Soluble Polymer
`
`CONTENTS
`
`PAGE
`
`AQUALON CMC — AN ANIONIC
`WATER-SOLUBLE POLYMER . . . . . . . . . . . . . . 2
`APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 3
`CHEMISTRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
`GRADES AND TYPES . . . . . . . . . . . . . . . . . . . . 6
`Grades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
`Degree of Substitution . . . . . . . . . . . . . . . . . . . 6
`Viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
`Particle Size . . . . . . . . . . . . . . . . . . . . . . . . . . 7
`Product Coding . . . . . . . . . . . . . . . . . . . . . . . . 7
`PROPERTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
`Moisture Absorption . . . . . . . . . . . . . . . . . . . . . 8
`Physiological Properties . . . . . . . . . . . . . . . . . . 8
`DISPERSION AND DISSOLUTION OF CMC . . . . 9
`Solvent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
`Type of CMC . . . . . . . . . . . . . . . . . . . . . . . . . . 9
`Shear Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
`Dispersion Methods . . . . . . . . . . . . . . . . . . . . . 9
`Theory of Polymer Dissolution . . . . . . . . . . . . . 11
`PROPERTIES OF CMC SOLUTIONS . . . . . . . . . 13
`Viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
`Effect of Concentration . . . . . . . . . . . . . . . . 13
`Effect of Blending . . . . . . . . . . . . . . . . . . . . 13
`Blending Chart . . . . . . . . . . . . . . . . . . . . . . 13
`Effect of Shear . . . . . . . . . . . . . . . . . . . . . . 16
`Pseudoplasticity . . . . . . . . . . . . . . . . . . . 16
`Thixotropy . . . . . . . . . . . . . . . . . . . . . . . . 17
`
`Effect of Temperature . . . . . . . . . . . . . . . . . 20
`Effect of pH . . . . . . . . . . . . . . . . . . . . . . . . . 20
`Effect of Mixed Solvents . . . . . . . . . . . . . . . 20
`Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
`Microbiological Attack . . . . . . . . . . . . . . . . . 21
`Chemical Degradation . . . . . . . . . . . . . . . . . 21
`Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . 22
`Effect With Salts . . . . . . . . . . . . . . . . . . . . . 22
`Monovalent Cations . . . . . . . . . . . . . . . . . 22
`Polyvalent Cations . . . . . . . . . . . . . . . . . . 23
`Gelation of Solutions . . . . . . . . . . . . . . . . . . . . 23
`Effect With Water-Soluble Nonionic Gums . . . . 23
`PROPERTIES OF CMC FILMS . . . . . . . . . . . . . . 24
`PACKAGING AND SHIPPING . . . . . . . . . . . . . . . 25
`MICROBIOLOGICAL INFORMATION AND
`REGULATORY STATUS FOR USE IN FOODS,
`DRUGS, COSMETICS, AND TOILETRIES . . . . . 25
`Microbiological Information . . . . . . . . . . . . . . . 25
`Food Status . . . . . . . . . . . . . . . . . . . . . . . . . . 25
`Food Labeling . . . . . . . . . . . . . . . . . . . . . . . . . 26
`Pharmaceutical Use . . . . . . . . . . . . . . . . . . . . 26
`Cosmetics and Toiletries . . . . . . . . . . . . . . . . . 26
`APPENDIX—METHODS OF ANALYSIS . . . . . . . 27
`Viscosity of Solution . . . . . . . . . . . . . . . . . . . . 27
`Moisture Determination . . . . . . . . . . . . . . . . 27
`Solution Preparation . . . . . . . . . . . . . . . . . . 27
`Viscosity Measurement . . . . . . . . . . . . . . . . 28
`
`© Hercules Incorporated, 1999.
`
`1
`
`

`

`AQUALON® CMC
`AN ANIONIC WATER-SOLUBLE POLYMER
`
`Aqualon® sodium carboxymethylcellulose (CMC) has a
`minimum purity of 99.5%. An anionic water-soluble polymer
`derived from cellulose, it has the following functions
`and properties:
`• It acts as a thickener, binder, stabilizer, protective colloid,
`suspending agent, and rheology, or flow control agent.
`• It forms films that are resistant to oils, greases, and
`organic solvents.
`• It dissolves rapidly in cold or hot water.
`• It is suitable for use in food systems.
`• It is physiologically inert.
`• It is an anionic polyelectrolyte.
`These properties and functions make it suitable for use in
`a broad range of applications in the food, pharmaceutical,
`cosmetic, paper, and other industries. To serve these diverse
`industries, the polymer is available in three grades: food,
`pharmaceutical, and standard, and in many types based
`on carboxymethyl substitution, viscosity, particle size, and
`other parameters.
`
`This booklet describes basic chemical and physical properties
`of Aqualon CMC in all its forms. The wide variety of types
`produced and the typical uses for this versatile polymer are
`also discussed. The contents page will guide the reader to
`subjects of special interest.
`
`Technical or semi-refined grades of sodium carboxymethyl-
`cellulose are also available and are described in Booklet
`250-3, available from Aqualon by request.
`
`2
`
`

`

`APPLICATIONS
`
`Since its commercial introduction in the United States by
`Hercules Incorporated in 1946, sodium carboxymethyl-
`cellulose has found use in an ever-increasing number of
`applications. The many important functions provided by
`this polymer make it a preferred thickener, suspending aid,
`stabilizer, binder, and film-former in a wide variety of uses.
`
`The wide range of viscosity and substitution types available
`from Aqualon for the highly purified grades and the less
`highly purified technical grades of CMC continues to expand
`the uses for this product line.
`
`APPLICATIONS FOR PURIFIED CMC(1)
`
`A representative listing of the many applications for sodium
`carboxymethylcellulose is given below and on the following
`page. Many of these applications do not require the use of
`the highly purified grade, and a technicalgrade of CMC is
`available for certain applications. Aqualon’s chemists and
`engineers continue to tailor-make various grades and types
`to meet the needs of specific customers and industries
`requiring water-soluble polymers.
`
`Types of Uses
`
`Specific Applications
`
`Properties Utilized
`
`Cosmetics
`
`Toothpaste
`
`Thickener; flavor stabilizer; suspending aid; binder
`
`Shampoos; foamed products
`
`Creams; lotions
`Gelled products
`Denture adhesives
`
`Suspending aid; thickener; foam stabilizer;
`high water-binding capacity
`Emulsion stabilizer; film-former; thickener
`Thickener; gelling agent; film-former
`Wet tack; long-lasting adhesion
`
`Foods
`
`Frozen desserts; soft-serve
`
`Pet food
`
`Protein foods
`Baked goods
`
`Beverages
`
`Desserts; icings; toppings
`
`Low-calorie foods
`Syrups
`Dressings; sauces
`Animal feed;
`extrusion products
`
`Controls ice crystal growth; improves mouthfeel, body,
`and texture
`Water binder; gravy thickener; extrusion aid; binder
`of fines
`Retains water; improves mouthfeel
`Batter viscosifier; improves moisture retention
`and texture
`Suspending aid; rapid viscosifier; improves mouthfeel
`and body; protein stabilizer in acidified drinks
`Odorless and tasteless; thickens; controls sugar crystal
`size; improves texture; inhibits syneresis
`No caloric value(2); thickens; imparts body and mouthfeel
`Clear; thickens; imparts favorable mouthfeel and body
`Thickener and suspending aid; imparts mouthfeel
`Lubricant; binder; film-former
`
`Pharmaceuticals
`
`Stabilizer; thickener; film-former
`Ointments; creams; lotions
`Thickener; gelling agent; protective colloid, film-former
`Jellies; salves
`Tablet binder; granulation aid High-strength binder
`Bulk laxatives
`Physiologically inert; high water-binding capacity
`Syrups
`Thickener
`Suspensions
`Thickener; suspending aid
`
`(1)For these applications, food grades (designated “F”) or pharmaceutical grades (designated “PH”) are used.
`These types may be referred to as “cellulose gum.”
`(2)Depends on test method.
`
`3
`
`

`

`APPLICATIONS FOR STANDARD GRADE OF CMC
`
`Types of Uses
`
`Specific Applications
`
`Properties Utilized
`
`Adhesives
`
`Wallpaper paste
`
`Water-binding aid; adhesion; good open time;
`nonstaining
`
`Starch-corrugating adhesive
`
`Thickener; water-binding and -suspending aid
`
`Latex adhesives
`
`Thickener; water-binding aid
`
`Aerial-drop fluids
`
`Insecticides
`
`Thickener; binder; suspending aid
`
`Ceramics
`
`Drift-control agent
`
`Glazes
`Porcelain slips
`Vitreous enamels
`Refractory mortars
`
`Thickener
`
`Binder for green strength; thickener; suspending aid
`
`Welding rod coatings
`
`Binder; thickener; lubricant
`
`Coatings
`
`Foundry core wash
`
`Binder; thickener; suspending aid
`
`Detergents
`
`Lithography
`
`Paper and paper
`products
`
`Latex paints; paper coatings
`
`Rheology control; suspending aid; protective colloid
`
`Laundry
`
`Whiteness retention through soil suspension
`
`Fountain and gumming
`solutions
`
`Water-based inks
`
`Internal addition
`
`Surface addition
`
`Hydrophilic protective film
`
`Binder; rheology control; suspending aid
`
`High-strength binder; improves dry strength of paper
`
`High-strength binder; oil-resistant film-former; provides
`control of curl and porosity and resistance to oils
`and greases
`
`Pigmented coatings
`
`Thickener; rheology control; water-retention aid
`
`Textiles
`
`Laundry and fabric sizes
`
`Film-former
`
`Latex adhesives; backing
`compounds
`Printing pastes and dyes
`
`Warp sizing
`
`Rheology control; thickener; water binding and holdout
`
`High film strength; good adhesion to fiber; low
`BOD value
`
`Tobacco
`
`Cigar and cigarette adhesive Good wet tack; high film strength
`
`Reconstituted sheet
`
`High-strength binder and suspending aid
`
`4
`
`

`

`Figure 1
`Structure of Cellulose
`
`OH
`
`H
`
`O
`
`H O
`
`H
`
`OH
`
`CH2OH
`
` H
`
` H
`
` H H
`
`O
`
`O
`
`OH
`
`H
`
`n-2
`2
`
`HO
`
`H
`
`H
`
`OH
`
`H
`
`CH2OH
`
`OH
`
`CH2OH
`
` H
`
` H
`
` H H
`
`O
`
`O
`
`OH
`
`H
`
`O
`
`H
`
`H
`
`O
`
`H
`
`OH
`
`H
`
`OH
`
`H
`
`CH2OH
`
`Figure 2
`Idealized Unit Structure of CMC, With a DS of 1.0
`
`H
`
`OH
`
`H
`
`OH
`
`H
`
`H
`
`O
`
`O
`CH2OCH2COONa
`
`CH2OCH2COONa
`O
`
`O
`
`H
`
`H
`
`H
`
`OH
`
`H O
`
`H
`
`H
`
`H
`
`Table I — Typical Molecular Weights for Representative
`Viscosity Types of Aqualon CMC
`(DS = 0.7 in All Cases)
`
`Viscosity
`Type
`
`High
`Medium
`Low
`
`Degree of
`Polymerization
`
`3,200
`1,100
`400
`
`Molecular
`Weight
`
`700,000
`250,000
`90,000
`
`CHEMISTRY
`
`CMC is a cellulose ether, produced by reacting alkali
`cellulose with sodium monochloroacetate under rigidly
`controlled conditions.
`
`Figure 1 shows the structure of the cellulose molecule; it is
`visualized as a polymer chain composed of repeating cello-
`biose units (in brackets). These, in turn, are composed of
`two anhydroglucose units (β-glucopyranose residues). In
`this structure, n is the number of anhydroglucose units
`(which are joined through 1,4 glucosidic linkages), or the
`degree of polymerization, of cellulose.
`
`Each anhydroglucose unit contains three hydroxyl groups,
`shown in white. By substituting carboxymethyl groups for
`some of the hydrogens of these hydroxyls, as shown in
`Figure 2, sodium carboxymethylcellulose is obtained. The
`average number of hydroxyl groups substituted per anhy-
`droglucose unit is known as the “degree of substitution,” or
`DS. If all three hydroxyls are replaced, the maximum theo-
`retical DS of 3.0 (impossible in practice) results.
`
`9004-32-4
`CASRN:
`CAS Name: Cellulose, carboxymethyl ether,
`sodium salt
`
`Optimum water solubility and other desirable physical prop-
`erties of CMC are obtained at a much lower degree of sub-
`stitution than 3. The most widely used types of Aqualon®
`CMC have a DS of 0.7, or an average of 7 carboxymethyl
`groups per 10 anhydroglucose units. Higher degrees of
`substitution result in CMC products having improved
`compatibility with other soluble components.
`
`Cellulose ethers, such as CMC, are long-chain polymers.
`Their solution characteristics depend on the average chain
`length or degree of polymerization (DP) as well as the degree
`of substitution. Average chain length and degree of substi-
`tution determine molecular weight of the polymer. As
`molecular weight increases, the viscosity of CMC solutions
`increases rapidly. Approximate values (weight averages) for
`the degree of polymerization and molecular weight of sev-
`eral viscosity types of Aqualon CMC are given in Table I.
`
`The degree of neutralization of carboxymethyl groups also
`impacts viscosity. In solution, the degree of neutralization is
`controlled by the pH.
`
`At the end of the carboxymethylation, the reaction mixture
`contains a slight excess of sodium hydroxide, which is usu-
`ally neutralized. Although the neutral point of CMC is pH
`8.25, the pH is generally adjusted to about 7-7.5. If the pH
`to which the CMC is neutralized is 6.0 or less, the dried
`product does not have good solubility in water; solutions
`are hazy and contain insoluble gel particles. If the pH is
`4 or below, the dried product is insoluble in water.
`
`5
`
`

`

`GRADES AND TYPES
`
`To serve its diverse markets, Aqualon produces CMC in
`several grades and in a wide variety of types, based on
`the degree of substitution, viscosity, particle size, and
`other parameters.
`
`DEGREE OF SUBSTITUTION
`Aqualon CMC is produced with the following degrees
`of substitution:
`
`GRADES
`Aqualon® CMC is available in the three grades outlined below.
`
`Grade
`Food
`
`Pharmaceutical
`
`Designation
`F
`P*
`PH**
`
`Standard
`
`None
`
`*P (1.2 D.S. types and CMC 7L2P)
`**PH (0.7 and 0.9 D.S. types)
`
`Intended Use
`Food, cosmetic,
`pharmaceutical
`Cosmetic,
`pharmaceutical
`Industrial
`
`Type
`
`7
`9
`12
`
`Substitution
`Range(a)
`0.65-0.90(b)
`0.80-0.95
`1.15-1.45
`
`Sodium
`Content, %
`
`7.0-8.9
`8.1-9.2
`10.5-12.0
`
`(a)Ranges shown in this table are not necessarily current
`specifications.
`(b)ln 7S types, the upper limit of substitution is 0.95.
`
`Higher degrees of substitution give improved compatibility
`with other soluble components such as salts and nonsol-
`vents. Generally, the number given in the product desig-
`nation is approximately 10 times the DS.
`
`Table II — Some Types of Aqualon CMC
`
`Viscosity Range at 25°C,(c) cps (mPas)
`
`Designations for Indicated Substitution Types
`7
`9
`12
`
`High—at 1% Concentration
`2,500-6,000
`1,000-2,800
`1,500-3,000
`
`Medium—at 2% Concentration
`800-3,100
`1,500-3,100
`400-800
`200-800
`100-200
`
`Low(d)—at 2% Concentration
`25-50
`
`—at 4% Concentration
`50-200
`
`9H4
`
`9M31
`9M8
`
`12M31
`
`12M8
`
`7H4
`7H3S, 7HOF
`7H
`
`7M
`7M8S
`7M2
`
`7L
`
`7L2
`
`(c)Ranges shown in this table are not necessarily current specifications.
`(d)Some even lower viscosity types are available. Contact your technical representative for additional information.
`
`6
`
`

`

`VISCOSITY
`CMC is manufactured in a wide range of viscosities. High-
`viscosity types are prepared from high viscosity cotton lin-
`ters. Medium-viscosity types are prepared from wood pulp
`of specified viscosity. Low-viscosity types are prepared by
`aging the shredded alkali cellulose and by using chemical
`oxidants. The foregoing methods of regulating the viscosity
`are based on controlling the DP. It is also possible to attain
`high viscosity by decreasing the solubility so that the product
`is highly swollen but not completely dispersed. This can be
`accomplished by decreasing the uniformity of the reaction
`and lowering the DS. For example, products at DS 1.2 do
`not have solution viscosities as high as products of DS 0.7
`prepared in substantially the same way. However, the solu-
`tions of the higher-substituted products are much smoother.
`
`The viscosity ranges of some types are listed in Table II.
`Others are available to meet specific needs. Regular viscos-
`ity types with a DS of 0.7 meet most needs and are desig-
`nated by the number 7, followed by the letter H (high), M
`(medium), or L (low). All other types are designated by an
`additional number following the letter which, when multiplied
`by a factor, gives the approximate upper viscosity limit. The
`factor and applicable concentration appear below.
`
`Viscosity Type
`
`Factor
`
`Concentration, %
`
`High
`Medium
`Low
`
`1,000
`100
`10
`
`1
`2
`2
`
`Solutions of all CMC types display pseudoplastic behavior.
`(See page 16.) Some types, particularly those of higher
`molecular weight and lower substitution, also show thixo-
`tropic behavior in solution. (See page 17.) These thixotropic
`solutions will possess varying amounts of gel strength and
`are used where suspension of solids is required. The “S,” 9,
`and 12 types produce solutions with little or no thixotropy,
`and are utilized where smooth solutions without structure
`are required.
`
`Specific properties are available in certain other types. For
`example, the “O” type, 7HOF, provides the best solubility
`and storage stability in acid media.
`
`PARTICLE SIZE
`Aqualon® CMC is available in several different particle sizes
`to facilitate handling and use in processing operations such
`as solution preparation and dry-blending. Screen analysis is
`given here for three of the types. Other types are available.
`Particle Size(e)
`
`Designation Description
`
`None
`
`Regular
`
`Coarse
`
`On U.S. 30, %, max
`On U.S. 40, %, max
`
`On U.S. 20, %, max
`Through U.S. 40,
`%, max
`Through U.S. 80,
`%, max
`
`1
`5
`
`1
`
`55
`
`5
`
`C
`
`X
`
`Fine
`
`On U.S. 60, %, max 0.5
`Through U.S. 200,
`%, min
`
`80
`
`(e)AII screens are U.S. Bureau of Standards sieve series.
`
`PRODUCT CODING
`An example of the coding used for ordering Aqualon CMC
`follows:
`For cellulose gum Type 7H3SCF:
`7 means that the typical degree of substitution is
`approximately 0.7.
`H means high viscosity.
`3 means that the viscosity of a 1% solution is in the
`range of 3,000 cps.
`S means smooth solution characteristics.
`C means coarse particle size.
`F means food grade.
`
`Aqualon can tailor the chemical and physical properties of
`CMC to meet special requirements. Users are encouraged
`to discuss their needs with their technical representative,
`or to call the 800 number shown on the back cover for
`product information.
`
`7
`
`

`

`Figure 3
`Effect of Relative Humidity on Equilibrium Moisture
`Content of Aqualon CMC at 25°C
`
`12M31P
`
`7HF
`
`20
`
`60
`40
`Relative Humidity, %
`
`80
`
`40
`
`30
`
`20
`
`10
`
`Equilibrium Moisture Content, %
`
` 0
`
` 0
`
`PHYSIOLOGICAL PROPERTIES
`Dermatological and toxicological studies by independent
`laboratories demonstrate conclusively that sodium carboxy-
`methylcellulose shows no evidence of being toxic to white
`rats, dogs, guinea pigs, or human beings. Feeding, metabo-
`lism, and topical use studies also show that CMC is physio-
`logically inert. Patch tests on human skin demonstrated that
`sodium carboxymethylcellulose was neither a primary irritant
`nor a sensitizing agent. Additional information is available
`from Hercules Incorporated.
`
`PROPERTIES
`
`Typical properties of Aqualon® CMC polymer and in solution
`and film form are shown in Table III. These are not necessar-
`ily specifications.
`
`Table III—Typical Properties of Aqualon CMC
`Polymer
`Sodium carboxymethylcellulose—
`dry basis, %, min . . . . . . . . . . . . . . . . . . . . 99.5
`Moisture content (as packed), %, max . . . . . . . 8.0
`Browning temperature, °C . . . . . . . . . . . . . . . . 227
`Charring temperature, °C . . . . . . . . . . . . . . . . . 252
`Bulk density, g/ml
` . . . . . . . . . . . . . . . . . . . . . .0.75
`Biological oxygen demand (BOD)(f), ppm
`7H type . . . . . . . . . . . . . . . . . . . . . . . . . 11,000
`7L type . . . . . . . . . . . . . . . . . . . . . . . . . . 17,300
`
`Solutions
`pH, 2% solution . . . . . . . . . . . . . . . . . . . . . . . . 7.5
`Surface tension, 1% solution,
`dynes/cm at 25°C. . . . . . . . . . . . . . . . . . . . . . 71
`Specific gravity, 2% solution . . . . . . . . . . . . 1.0068
`Refractive index, 2% solution . . . . . . . . . . . . 1.336
`
`Typical Films (Air-Dried)
`Density, g/ml
` . . . . . . . . . . . . . . . . . . . . . . . . . 1.59
`Refractive index . . . . . . . . . . . . . . . . . . . . . . 1.515
`Thermal conductivity, W/mK. . . . . . . . . . . . . . 0.238
`
`(f)After 5 days’ incubation. Under these conditions, cornstarch has
`a BOD of over 800,000 ppm.
`
`MOISTURE ABSORPTION
`CMC absorbs moisture from the air. The amount absorbed
`and the rate of absorption depend on the initial moisture
`content and on the relative humidity and temperature of
`the surrounding air. Figure 3 shows the effect of relative
`humidity on equilibrium moisture content of three types
`of Aqualon CMC.
`
`As Aqualon CMC is packed, its moisture content does not
`exceed 8% by weight. Because of varying storage and ship-
`ping conditions, there is a possibility of some moisture
`pickup from the “as-packed” value.
`
`8
`
`

`

`DISPERSION AND DISSOLUTION
`OF CMC
`
`DISPERSION METHODS
`CMC particles have a tendency to agglomerate, or lump,
`when first added to water. To obtain good solutions easily,
`the dissolving process should be considered a two-step
`operation:
`
`1. Dispersing the dry powder in water. Individual par-
`ticles should be wet and the dispersion should not
`contain lumps.
`2. Dissolving the wetted particles.
`
`When the proper technique is used, good dispersion is
`obtained, and CMC goes into solution rapidly. To prepare
`lumpfree, clear solutions, a variety of methods can be used:
`
`Method 1
`Add CMC to the vortex of vigorously agitated water. The rate
`of addition must be slow enough to permit the particles to
`separate and their surfaces to become individually wetted,
`but it should be fast enough to minimize viscosity buildup of
`the aqueous phase while the gum is being added.
`
`Method 2
`Prior to addition to water, wet the powder with a water-
`miscible liquid such as alcohol, glycol, or glycerol that will
`not cause CMC to swell. Two to three parts of liquid per part
`of CMC should be sufficient.
`
`Method 3
`Dry-blend the CMC with any dry, nonpolymeric material
`used in the formulation. Preferably, the CMC should be
`less than 20% of the total blend.
`
`Method 4
`Use a water eductor (Figure 4) to wet out the polymer par-
`ticles rapidly. The polymer is fed into a water-jet eductor,
`where a high-velocity waterflow instantly wets out each
`particle, thus preventing lumping. This procedure speeds
`solution preparation and is particularly useful where large
`volumes of solutions are required. For users wishing the
`convenience of an automatic system, a polymer solution
`preparation system (PSP), which is used in conjunction
`with a water eductor, is shown in Figure 5.
`
`Special, fast-dissolving fluidized polymer suspensions of
`CMC are available to give very rapid dissolution where it is
`required or where agitation is substandard.
`
`Users are encouraged to contact their technical representa-
`tive for information on PSP units or fluidized suspensions
`of CMC.
`
`A number of factors such as solvent, choice of polymer, and
`shear rate affect dispersion and dissolution of CMC.
`
`SOLVENT
`Aqualon® CMC is soluble in either hot or cold water. The
`gum is insoluble in organic solvents, but dissolves in suit-
`able mixtures of water and water-miscible solvents, such as
`ethanol or acetone. Solutions of low concentration can be
`made with up to 50% ethanol or 40% acetone. Aqueous
`solutions of CMC tolerate addition of even higher propor-
`tions of acetone or ethanol, the low-viscosity types being
`considerably more tolerant than the high-viscosity types,
`as shown below.
`
`Tolerance of Aqualon CMC Solutions for Ethanol
`Volume Ratio of Ethanol
`to CMC Solution, 1%
`First Evident
`First Distinct
`CMC
`Haze
`Precipitate
`Type
`2.4 to 1
`3.6 to 1
`7L
`2.1 to 1
`2.7 to 1
`7M
`1.6 to 1
`1.6 to 1
`7H
`Note: In these tests, ethanol (95%) was added slowly at room
`temperature to the vigorously stirred 1% CMC solution.
`
`TYPE OF CMC
`The higher the degree of substitution, the more rapidly
`CMC dissolves. The lower the molecular weight, the faster
`the rate of solution.
`
`Particle size has a pronounced effect on the ease of dis-
`persing and dissolving CMC. “C,” or coarse, types were
`developed to improve dispersibility of the granules when
`agitation is inadequate to produce a vortex on the liquid
`surface. Solution time, on the other hand, is extended
`considerably with a coarse material.
`
`For applications requiring a rapid solution time, CMC of
`fine particle size (X grind) is best. However, special dis-
`solving techniques, such as prewetting the powder with a
`nonswelling liquid, mixing it with other dry materials, or
`using an eductor-type mixing device, are necessary to
`obtain dispersion.
`
`SHEAR RATE
`Preparing solutions by extremely low shear agitation, such
`as shaking by hand, is generally not recommended. Prop-
`erties of the resulting solution are quite different from those
`prepared by higher shear methods. The effect of shear on
`solution properties is discussed in more detail on pages 11
`and 16.
`
`9
`
`

`

`Figure 4
`Typical Installation of Eductor-Type Mixing Device
`
`Lightnin Mixer
`
`Polymer Feed
`
`Funnel
`
`Mix Tank
`
`Air Bleed-
`Holes
`
`Water
`Inlet
`
`Eductor
`
`Mixing Device
`
`Makeup Water
`
`Workman
`Platform
`
`Discharge
`Special Mixing Device
`This inexpensive equipment is
`most effective for quickly pre-
`paring uniform solutions of CMC.
`
`Figure 5
`Automated Polymer Solution Preparation (PSP) System
`
`Dust
`Collector
`
`Polymer Hopper
`
`Screw
`Drive
`Motor
`
`Helical Screw Feeder
`
`Polymer
`Eductor
`
`Water
`
`Air
`
`PSP Unit
`
`Eductor
`
`Preparation Tank
`
`10
`
`

`

`time-dependent phenomenon, if CMC/salt solutions are
`allowed to stand, it is very possible that the final stage of
`disaggregation will be Stage 2 and the equilibrated viscosity
`will be higher than that of CMC in distilled water. Hence, one
`cannot assume that addition of salt will lower equilibrated
`solution viscosity, only that it will inhibit polymer disaggre-
`gation. With Types 9 and 12, the slight viscosity increase in
`saturated salt is caused by the “viscosity bonus effect” dis-
`cussed on page 20.
`
`Figure 6
`Idealized Curve Showing Effect of Degree
`of Disaggregation on Viscosity of Polymer Solution
`
`2
`
`1b
`
`2a
`
`3
`
`1a
`
`1
`
`Viscosity
`
`Degree of Disaggregation
`
`THEORY OF POLYMER DISSOLUTION
`When a polymer is dispersed in a solvent, the degree of
`disaggregation—i.e., separation of polymer molecules—
`is affected by the:
`• Chemical composition of the polymer.
`• Solvating power of the solvent.
`• Shear history of the resulting solution.
`Figure 6 shows how these states of disaggregation may
`affect viscosity of the liquid. If CMC is added to a liquid
`and its degree of disaggregation reaches equilibrium, the
`polymer may:
`• Remain as a suspended powder, neither swelling
`nor dissolving (1).
`• Swell to a point of maximum viscosity without com-
`pletely dissolving (2).
`• Reach maximum disaggregation (3).
`• Exist in an intermediate state (1a, 1b, 2a).
`Depending on choice of polymer, solvent, and mechanical
`means of preparing the solution, the user of CMC can alter
`its state of disaggregation to suit his needs. Table IV shows
`the effect of these factors on the disaggregation of CMC as
`measured by solution viscosity.
`
`Increasing DS makes CMC more hydrophilic, or “water-
`loving”; hence, types having high DS are more readily dis-
`aggregated in water. Plotting solution viscosity at constant
`shear against increasing DS (Types 7 through 12) produces
`a curve similar in shape to that shown in Figure 6.
`
`Increasing electrolyte concentration reduces disaggre-
`gation, as evidenced by the lower viscosity in saltwater of
`Type 7. The viscosities listed in Table IV were measured
`under quality control conditions—that is, two hours after
`solution was complete. At this point, CMC dissolved in an
`electrolyte solution is probably in the Stage 1 section of the
`disaggregation curve. CMC dissolved in distilled water
`under quality control conditions is at Stage 3 of the curve.
`Viscosities of CMC/salt solutions measured at this point will
`be lower than the viscosities of corresponding CMC solu-
`tions prepared in distilled water. Since disaggregation is a
`
`Table IV — Factors Affecting Disaggregation of Aqualon® CMC
`(This table shows the effect of polymer composition, solvent strength, and mechanical shear on disaggregation, as
`measured by solution viscosity. All data are at 25°C. Cellulose gum was added dry to the solvents listed.)
`
`Cellulose
`Gum Type
`
`7HF
`
`7H3SF
`
`9M31F
`
`12M31P
`
`Anchor Stirrer
`Distilled
`Water
`
`4% NaCl
`
`1,680
`
`1,680
`
`215
`
`175
`
`140
`
`570
`
`160
`
`80
`
`Viscosity, cps (mPas)
`
`Saturated
`NaCl
`
`Distilled
`Water
`
`4% NaCl
`
`Saturated
`NaCl
`
`Waring Blendor
`
`760
`
`760
`
`125
`
`100
`
`1,040
`
`750
`
`95
`
`55
`
`2,440
`
`1,720
`
`235
`
`140
`
`45
`
`165
`
`225
`
`180
`
`11
`
`

`

`Figure 7
`Effect of Solvent Strength on Disaggregation
`of Aqualon® CMC
`(1.75% CMC in Glycerin-Water)
`
`100,000
`
`9M8F
`
`7MF
`
`10,000
`
`12M8P
`
`Viscosity, cps
`
`In many cases, the high shear imparted by the Waring blendor
`can enhance viscosity development or disaggregation.
`
`The effect of solvent strength (polarity in binary solvent mix-
`tures) on the disaggregation of CMC is shown in Figure 7.
`Note the similarity of these curves to the curve in Figure 6.
`The data in Figure 7 and in Table IV show that an increase
`in solvating power or an increase in mechanical shear
`breaks internal associations of gel centers and promotes
`disaggregation.
`
`The effect of solutes such as salts or polar nonsolvents on
`the viscosity of CMC solutions also depends on the order of
`addition of the gum and solute. This is shown in Figure 8. If
`CMC is thoroughly dissolved in water and the solute is then
`added, it has only a small effect on viscosity. However, if the
`solute is dissolved before the CMC is added (as is the case
`with Table IV data), it inhibits breaking up of crystalline
`areas, and lower viscosities are obtained. This effect of
`solutes is less apparent with more uniformly substituted
`material containing fewer crystalline areas.
`
`1,000
`
`300
`
`0
`
`80
`60
`40
`20
`Water in Solvent, weight %
`
`100
`
`Figure 8
`Effect of Solutes on Viscosity of CMC Solutions
`
`Solute Added After CMC
`
`Solute Added
`Before CMC
`
`Solutes Used:
`NaCl
`NaCl + NaOH (pH 10.1)
`Na2So4
`Na4P2O7 • 10H2O (pH 9.5-9.8)
`KCl or LiCl
`
`300
`
`200
`
`100
`
`80
`
`60
`
`40
`
`30
`
`20
`
`Apparent Viscosity, cps
`
`10
`0.02
`
`0.4
`0.2
`0.08 0.1
`0.04
`Molal Concentration of Cation, moles/1,000 g solvent
`
`0.8 1.0
`
`12
`
`

`

`PROPERTIES OF CMC SOLUTIONS
`
`Viscosity is the single most important property of CMC solu-
`tions. Aqualon has acquired considerable information on
`factors affecting viscosity, and these data are given here.
`Stability of CMC solutions to microbiological attack and
`chemical deterioration is also discussed in this section.
`
`VISCOSITY
`Solutions of CMC can be prepared in a wide range of vis-
`cosities. Such solutions are non-Newtonian because they
`change in viscosity with change in shear rate. Consequently,
`it is essential to standardize viscosity determination methods.
`This standardization must include the type and extent of
`agitation used to dissolve the CMC, as well as precise con-
`trol of temperature, conditions of shear, and method of vis-
`cosity measurement. The procedure used in the Aqualon
`control laboratory is described in detail in the Appendix,
`page 27.
`Effect of Concentration
`The viscosity of aqueous CMC solutions increases rapidly
`with concentration. This is shown in Figure 10. The bands
`show the range of viscosity obtainable with standard
`viscosity types.
`Effect of Blending
`Two viscosity types of CMC can be blended to obtain an in-
`termediate viscosity. Because viscosity is an exponential
`function, the viscosity resulting from blending is not an
`arithmetic mean.
`
`A blending chart (VC-440), available from Aqualon, can be
`used to determine the result of blending various amounts of
`two viscosity types of CMC. It can also be used to determine
`the amount of CMC required to achieve a desired viscosity
`when blending two types of known viscosity.
`Blending Chart
`The blending technique outlined in this bulletin can be
`used eqully well for Aqualon® cellulose gum (sodium
`carboxymethylcellulose), Natrosol® hydroxyethylcellulose,
`Culminal® methylcellulose and methyl hydroxypropylcellulose
`and Klucel® hydroxypropylcellulose. This technique is useful
`when it is desirable to blend two viscosity types of the same
`water-soluble polymer in order to obtain a solution having a
`predetermined viscosity and solids concentration.
`
`Blends can be calculated directly from the equation that fol-
`lows; or, more conveniently, the blending chart in Figure 9
`can be used. From this chart, one can determine, without
`calculations, the percentage of any two viscosities that must
`be blended to secure a desired intermediate viscosity.
`Likewise, it is possible to determine the viscosity that will
`result from utilizing any blend.
`
`Equation: Because the viscosity-concentration relationship is
`an exponential function, the viscosity resulting from blending
`is not an arithmetic mean. The viscosity of a blend can, how-
`ever, be approximated by use of the equation below, which
`is derived from the Arrhenius equation that relates viscosity
`with polymer concentration.
`
`n log V1 + (100-n) log V2
`100
`Log Vs =
`where Vs = Viscosity sought
`n = Percent (by weight) of the first component of the
`blend having a viscosity of V1
`V2 = Viscosity of the second component of the blend
`Note: All viscosities must be expressed at the same polymer
`concentration and in the