Methyl cellulose (or methylcellulose) is a
compound derived from
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
. It is sold under a variety of trade names and is used as a thickener and
emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althoug ...
in various food and cosmetic products, and also as a bulk-forming
laxative
Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation.
Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...
. Like cellulose, it is not digestible, not toxic, and not an
allergen
An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies.
In technical t ...
.
In 2020, it was the 422nd most commonly prescribed medication in the United States, with more than 100thousand prescriptions.
Uses
Methyl cellulose has a wide range of uses.
Medical
Constipation
Methyl cellulose is used to treat
constipation
Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel moveme ...
.
[ Effects generally occur within three days.][ It is taken by mouth and is recommended with sufficient water.][ Side effects may include abdominal pain.][ It is classified as a ]bulk forming laxative
Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation.
Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubr ...
. It works by increasing the amount of stool present which improves intestinal contractions.
It is available over the counter
Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...
.[ It is sold under the brand name Citrucel among others.][
]
Artificial tears and saliva
The lubricating property of methylcellulose is of particular benefit in the treatment of dry eyes
Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS), is the condition of having dry eyes. Other associated symptoms include irritation, redness, discharge, and easily fatigued eyes. Blurred vision may also occur. Symptoms rang ...
. Solutions containing methyl cellulose or similar cellulose derivatives are used as substitute for tears
Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The different types of ...
or saliva
Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can ...
if the natural production of these fluids is disturbed.
Medication manufacturing
Methyl cellulose is used in the manufacture of drug capsules; its edible and nontoxic properties provide a vegetarian alternative to the use of gelatin
Gelatin or gelatine (from la, gelatus meaning "stiff" or "frozen") is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also ...
.
Consumer products
Thickener and emulsifier
Methyl cellulose is occasionally added to hair shampoos, tooth pastes and liquid soaps, to generate their characteristic thick consistency. This is also done for foods, for example ice cream
Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It may be made from milk or cream and is flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit such as ...
or croquette
A croquette is a deep-fried roll consisting of a thick binder combined with a filling, which is breaded and deep-fried; it is served as a side dish, a snack, or fast food worldwide.
The binder is typically a thick béchamel or brown sau ...
. Methyl cellulose is also an important emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althoug ...
, preventing the separation of two mixed liquids because it is an emulsion stabilizer.
Food
The E number
E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...
of methyl cellulose as food additive is E461. E464 is hydroxypropylcellulose and more soluble in water.
Methyl cellulose, as a gel
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...
, has the unique property of setting when hot and melting
Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which in ...
when cold.
Methyl cellulose is used as an ingredient in some meat analogues
A meat alternative or meat substitute (also called plant-based meat or fake meat, sometimes pejoratively) is a food product made from vegetarian or vegan ingredients, eaten as a replacement for meat. Meat alternatives typically approximate qua ...
that are intended to replicate the texture of meat.
Lubricant
Methyl cellulose may be used in personal lubricant.
Construction materials
Methyl cellulose finds a major application as a performance additive in construction materials. It is added to mortar dry mixes to improve the mortar's properties such as workability, open and adjustment time, water retention, viscosity, adhesion to surfaces etc. Construction grade methyl cellulose is not to be identified with food and pharmaceutical grade methyl cellulose and hydroxypropyl methyl cellulose, as it may be cross-linked with glyoxal
Glyoxal is an organic compound with the chemical formula OCHCHO. It is the smallest dialdehyde (a compound with two aldehyde groups). It is a crystalline solid, white at low temperatures and yellow near the melting point (15 °C). The li ...
for easy dispersion in water.
The construction materials can be cement-based or gypsum-based. Notable examples of dry mixture mortars which utilize methyl cellulose include tile adhesives, EIFS, insulating plasters, hand-trowelled and machine-sprayed plaster, stucco, self-leveling flooring, extruded cement panels, skim coats, joint & crack fillers, and tile grouts. Typical usage is about 0.2% – 0.5% of total dry powder weight for dry mixtures.
Derivatives of methyl cellulose which improve performance characteristics include hydroxypropyl methyl cellulose (HPMC) and hydroxyethyl methyl cellulose (HEMC). These derivatives typically improve the characteristics such as water retention, vertical surface slip resistance, open time, etc.
Glue and binder
Methyl cellulose can be employed as a mild glue
Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation.
The use of adhesives offers certain advant ...
which can be washed away with water. This may be used in the fixing of delicate pieces of art as well as in book conservation to loosen and clean off old glue from spines and bookboards.
Methyl cellulose is the main ingredient in many wallpaper paste Adhesive flakes that are mixed with water to produce wallpaper paste
Wallpaper adhesive or wallpaper paste is a specific adhesive, based on modified starch, methylcellulose, or clay used to fix wallpaper to walls.
Wallpaper pastes have a typical ...
s. It is also used as a binder in pastel crayons and also as a binder in medications. Hydroxypropyl methylcellulose (HPMC) is an FDA-approved water-soluble adhesive, has been used in various wet-adhesion applications in construction products, paints, and drug delivery for 70 years.HPMC adheres strongly to all wet surfaces, regardless of hydrophobicity.
Paint
Methyl cellulose is used as a rheological modifier in paint to prevent 'sagging'.
Paper and textile sizing
Methyl cellulose is used as sizing
Sizing or size is a substance that is applied to, or incorporated into, other materials—especially papers and textiles—to act as a protective filler or glaze. Sizing is used in papermaking and textile manufacturing to change the absorptio ...
in the production of papers and textiles as it protects the fibers from absorbing water or oil. When applied to several pieces of paper, methyl cellulose will bind the layers together, often to create a more durable or multicolored sheet. In addition, origami
) is the Japanese art of paper folding. In modern usage, the word "origami" is often used as an inclusive term for all folding practices, regardless of their culture of origin. The goal is to transform a flat square sheet of paper into a f ...
artists use it to coat their origami models, as the compound will stiffen and protect the paper against time.
Dust control
Hydroxypropyl methyl cellulose (HPMC) and hydroxyethyl methyl cellulose (HEMC) is used as a binder in dust control technologies. They mitigate fugitive dust released from arid/semi-arid area as well as improve commercial face mask when used as a filtering material.
Cell culture
Methyl cellulose is also used in cell culture
Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment. The term "tissue culture" was coined by American pathologist Montrose Thomas Burrows. This tec ...
to study viral replication. It is dissolved in the same nutrient-containing medium
Medium may refer to:
Science and technology
Aviation
* Medium bomber, a class of war plane
* Tecma Medium, a French hang glider design
Communication
* Media (communication), tools used to store and deliver information or data
* Medium ...
in which cells are normally grown. A single layer of cells is grown on a flat surface, then infected with a virus for a short time. The strength of the viral sample used will determine how many cells get infected during this time. The thick methyl cellulose medium is then added on top of the cells in place of normal liquid medium. As the viruses replicate in the infected cells, they are able to spread between cells whose membranes touch each other, but are trapped when they enter the methyl cellulose. Only cells closely neighboring an infected cell will become infected and die. This leaves small regions of dead cells called plaques in a larger background of living uninfected cells. The number of plaques formed is determined by the strength of the original sample.
Bacterial and protozoal motility inhibitor
Aqueous methyl cellulose solutions have been used to slow bacterial and protozoal cell motility for closer inspection. Changing the amount of methyl cellulose in solution permits the adjustment of the solution's viscosity.
Stem cell differentiation
Methyl cellulose is used in the most common approaches to quantify multiple or single lineage-committed hematopoietic progenitors, called colony-forming cells (CFCs) or colony-forming units (CFUs), in combination with culture supplements that promote their proliferation and differentiation, and allow the clonal progeny of a single progenitor cell to stay together and thus form a colony of more mature cells.
Chemistry
It is a hydrophilic
A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press.
In contrast, hydrophobes are n ...
white powder in pure form and dissolves in cold (but not in hot) water, forming a clear viscous solution or gel.
Methyl cellulose is used as a buffer additive in capillary electrophoresis
Capillary electrophoresis (CE) is a family of electrokinetic separation methods performed in submillimeter diameter capillaries and in micro- and nanofluidic channels. Very often, CE refers to capillary zone electrophoresis (CZE), but other electr ...
to control electroosmotic flow Electroosmotic flow (or electro-osmotic flow, often abbreviated EOF; synonymous with electroosmosis or electroendosmosis) is the motion of liquid induced by an applied potential across a porous material, capillary tube, membrane, microchannel, or an ...
for improved separations.
Special effects
The slimy, gooey appearance of an appropriate preparation of methyl cellulose with water, in addition to its nontoxic, nonallergenic, and edible properties, makes it popular for use in special effects for motion picture
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...
s and television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, ...
wherever vile slimes must be simulated. In the film '' Ghostbusters,'' the gooey substance the supernatural entities used to "slime" the Ghostbusters was mostly a thick water solution of methyl cellulose. The ''Aliens
Alien primarily refers to:
* Alien (law), a person in a country who is not a national of that country
** Enemy alien, the above in times of war
* Extraterrestrial life, life which does not originate from Earth
** Specifically, intelligent extrater ...
'' ooze and drip a great deal of methyl cellulose—especially the queen.
Methyl cellulose has been used to safely simulate molten materials, as well. In several of the Terminator films, it was back-lit with colored gels and films to reproduce the heated glow of iron in the large pouring ladles used to transport the metal from the smelting ovens to the various molds and forms. Methyl cellulose was also a stand-in for the lava flows in Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world ...
in ''Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often found where tectonic plates ...
'' and on the volcanic surface of Mustafar, in '' Star Wars: Episode III – Revenge of the Sith''.
Chemistry
Methyl cellulose does not occur naturally and is synthetically produced by heating cellulose with caustic solution (e.g. a solution of sodium hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions .
Sodium hydroxide is a highly caustic base and al ...
) and treating it with methyl chloride
Chloromethane, also called methyl chloride, Refrigerant-40, R-40 or HCC 40, is an organic compound with the chemical formula . One of the haloalkanes, it is a colorless, odorless, flammable gas. Methyl chloride is a crucial reagent in industria ...
. In the substitution reaction that follows, the hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydrox ...
residues (-OH functional groups) are replaced by methoxide (-OCH3 groups).
Different kinds of methyl cellulose can be prepared depending on the number of hydroxyl groups substituted. Cellulose is a polymer
A polymer (; Greek '' poly-'', "many" + '' -mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
consisting of numerous linked glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
molecules, each of which exposes three hydroxyl groups. The ''Degree of Substitution'' (DS) of a given form of methyl cellulose is defined as the average number of substituted hydroxyl groups per glucose. The theoretical maximum is thus a DS of 3.0, however more typical values are 1.3–2.6.
Different methyl cellulose preparations can also differ in the average length of their polymer backbones.
Solubility and temperature
Methyl cellulose has a lower critical solution temperature (LCST) between 40 °C and 50 °C. At temperatures below the LCST, it is readily soluble
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solubi ...
in water; above the LCST, it is not soluble, which has a paradoxical effect that heating a saturated solution of methyl cellulose will turn it solid, because methyl cellulose will precipitate out. The temperature at which this occurs depends on DS-value, with higher DS-values giving lower solubility and lower precipitation temperatures because the polar
Polar may refer to:
Geography
Polar may refer to:
* Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates
*Polar climate, the cli ...
hydroxyl groups are masked.
Preparing a solution of methyl cellulose with cold water is difficult however: as the powder comes into contact with water, a gel layer forms around it, dramatically slowing the diffusion of water into the powder; hence, the inside remains dry. A better way is to first mix the powder with hot water, so that the methyl cellulose particles are well dispersed (and so have a much higher effective surface area) in the water, and cool down this dispersion while stirring, leading to the much more rapid dissolution of those particles.
See also
* Carboxymethyl cellulose
Carboxymethyl cellulose (CMC) or cellulose gum is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used as its sodiu ...
* Ethyl cellulose
Ethyl cellulose (or ethylcellulose) is a derivative of cellulose in which some of the hydroxyl groups on the repeating glucose units are converted into ethyl ether groups. The number of ethyl groups can vary depending on the manufacturer.
It i ...
* Ethyl methyl cellulose
Ethyl methyl cellulose is a thickener, vegetable gum, foaming agent and emulsifier. Its E number is E465.
* Hydroxypropyl cellulose
Hydroxypropyl cellulose (HPC) is a derivative of cellulose with both water solubility and organic solubility. It is used as an excipient, and topical ophthalmic protectant and lubricant.
Chemistry
HPC is an ether of cellulose in which some of t ...
* Hydroxyethyl cellulose
References
Further reading
* Cathleen Baker (1984). Methylcellulose & Sodium Carboxymethylcellulose: An Evaluation for Use in Paper Conservation through Accelerated Aging. Preprints of the Contributions to the Paris Congress, 2–8 September 1984: Adhesives and Consolidants, pp. 55–59. International Institute of Conservation.
*
*
{{DEFAULTSORT:Methyl Cellulose
Cellulose
Edible thickening agents
Food additives
Laxatives
Personal lubricants
Excipients
Cellulose ethers
Food stabilizers
E-number additives