Cellulose is composed ofglucoseComposed macromoleculesPolysaccharide。Insoluble in water and general organic solvents.yesPlant cell wallThe main components of.Cellulose is the most widely distributed and abundant polysaccharide in nature, accounting for more than 50% of the carbon content in the plant kingdom.cottonIts cellulose content is close to 100%, which is the most pure natural cellulose source.In general, cellulose accounts for 40~50% of the wood, and there are 10~30% hemicellulose and 20~30% hemicelluloseLignin。
Cellulose is the main structural component of plant cell wall, which is usually combined with hemicellulose, pectin and lignin. Its combination mode and degree have a great impact on the texture of plant derived food.The texture changes of plants at maturity and after ripening are caused by changes in pectin substances.Cellulase does not exist in human digestive tract. Cellulose is an important dietary fiber.The most widely distributed and abundant polysaccharide in nature.[1]
At room temperature, cellulose is insoluble in both water and general organic solvents, such asalcohol、Ether、acetone、benzeneIt is also insoluble in dilute alkali solution and soluble in copper ammonia Cu (NHthree)four(OH)twoSolution and copper ethylenediamine [NHtwoCHtwoCHtwoNHtwo]Cu(OH)twoSolution, etc.Therefore, it is relatively stable at room temperature, because there are cellulose moleculeshydrogen bond。[2]
Cellulose hydrolysis
Under certain conditions, cellulose reacts with water.During the reaction, the oxygen bridge is broken, and water molecules are added at the same time. Cellulose changes from long chain molecules to short chain molecules until all the oxygen bridges are broken and become glucose.[3]
Cellulose andOxidantA chemical reaction takes place to produce a series of substances different from the original cellulose structure. This reaction process is called cellulose oxidation.The base ring of cellulose macromolecule isD-glucosewithBeta-1,4 glycoside bondIts chemical composition contains 44.44% carbon, 6.17% hydrogen and 49.39% oxygen.Due to different sources, the number of glucose residues in cellulose molecules, namelyDegree of polymerization(DP) In a wide rangeVascular plant、Lichen plantAnd the main components of some algal cell walls.Acetobacter(Actobaeter)Capsule, and caudateCapsuleCellulose is also found in,cottonIt is high purity (98%) cellulose.so-calledα - cellulose(α - cellulose) This name refers to the part that cannot be extracted from the original cell wall standard sample of complete cellulose with 17.5% NaOH.Beta cellulose(β - cellulose) and γ - cellulose are corresponding tohemicelluloseCellulose.Although α - cellulose is usually mostly crystalline cellulose, β - cellulose and γ - cellulose chemically contain not only cellulose, but also various polysaccharides.Cellulose in the cell wall forms microfibers.The width is 10-30 nanometers, and some are several microns long.applicationX-ray diffractionandNegative staining(Negative staining method). According to the observation of electron microscope, the crystalline parts of chain molecules arranged in parallel constitute basic microfibers with a width of 3-4 nanometers.It is speculated that these basic microfibers together constitute microfibers.Cellulose can be dissolved in Schwitzer reagent or concentrated sulfuric acid.Although it is difficult to hydrolyze with acid, dilute acid orcellulaseIt can make cellulose produce D-glucoseCellobioseandoligosaccharide。In acetic acid bacteria, there is an enzyme that transfers glycosides from UDP glucose primer to synthesize cellulose.Standard samples of granular enzymes with the same activity have been obtained in higher plants.This enzyme usually uses GDP glucose to mix beta-1,3 bonds when transferred by UDP glucose.The formation site of microfiber and the mechanism controlling the arrangement of cellulose are still unclear.On the other hand, as far as the decomposition of cellulose is concerned, it is estimated that when the primary cell wall extends and grows, part of the microfibers will be decomposed due to the action of cellulase and become soluble.
Water can cause limited swelling of cellulose, and some acid, alkali and salt aqueous solutions can penetrate into the fiber crystal area to produce infinite swelling and dissolve cellulose.Cellulose will not change significantly when heated to about 150 ℃, and will gradually coke due to dehydration if the temperature exceeds this temperature.Cellulose hydrolyzes with concentrated inorganic acid to produce glucose, reacts with concentrated caustic solution to produce alkali cellulose, and reacts with strong oxidant to produce oxidized cellulose.[3]
Compliance
Cellulose has poor flexibility and is rigid because:
(1) Cellulose molecules have polarity and strong interaction between molecular chains;
(2) The six membered pyran ring structure in cellulose makes internal rotation difficult;
(3) Cellulose can form hydrogen bonds within and between molecules, especially intramolecular hydrogen bondsGlycosidic bondIt cannot rotate, which greatly increases its rigidity.[3]
Preparation method
Announce
edit
Production method 1: Cellulose is the most abundant natural macromolecular compound in the world. The raw materials for production are wood, cotton, cotton linter, wheat straw, rice straw, reed, hemp, mulberry bark, broussonetia papyrifera and bagasse.Due to the shortage of forest resources in China, 70% of cellulose raw materials come from non wood resources.The average cellulose content of softwood and hardwood in China is about 43-45%;The average cellulose content of grass stems is about 40%.The industrial process of cellulose isSulfiteCooking plant raw materials with solution or alkali solution is mainly to remove lignin, which is called sulfite process and alkali process respectively.The materials obtained are called sulfite pulp and alkaline pulp.The residual lignin is further removed through bleaching, and the bleached pulp obtained can be used for papermaking.Further removing hemicellulose can be used as raw material for cellulose derivatives.
Production method 2: use fiber plant raw materials and inorganic acid to pound into slurry to make α - cellulose, and then treat it to make cellulose partially depolymerize, and then remove the amorphous part and purify it.
Production method 3: loosen the selected industrial wood pulp board, and then feed the 1%~10%hydrochloric acidThe reaction kettle (5%~10% of the dosage) is used for heating and hydrolysis. The temperature is 90~100 ℃, and the hydrolysis time is 0.5~2h. After the reaction, it is cooled and sent to the neutralization tank. It is neutralized with liquid alkali. After filtering, the filter cake is dried at 80~100 ℃, and finally it is crushed to obtain the product.
Production method 4: cellulose made from wood pulp or cotton pulp.It is refined after bleaching and mechanical dispersion.[3]
effect
Announce
edit
Cellulose is the oldest and most abundant natural polymer on the earth. It is inexhaustible and the most precious natural renewable resource for mankind.Cellulose chemistry and industry began more than 160 years ago, which is the main research object during the birth and development of polymer chemistry. The research achievements of cellulose and its derivatives arePolymer PhysicsAnd the creation, development and enrichment of chemistry.[3]
Physiological function
There is no β - glycosidase in the human body, so cellulose cannot be decomposed and utilized, but cellulose can absorb a lot of water, increase the amount of feces, promote intestinal peristalsis, accelerate the excretion of feces, shorten the stay time of carcinogens in the intestinal tract, and reduce the adverse stimulation to the intestinal tract, thus preventing the occurrence of intestinal cancer.[3]
dietary fiber
Cellulose in human diet is mainly contained in vegetables and rough processed cereals. Although it cannot be digested and absorbed, it can promote intestinal peristalsis, facilitate fecal excretion and other functions.Herbivores rely on symbiotic microorganisms in their digestive tract to decompose cellulose, so as to be absorbed and utilized.Food cellulose includes crude fiber, semi crude fiber and lignin.Food cellulose is a substance that cannot be digested and absorbed. It was considered as "waste" in the past. In 2013, it was considered to play an important role in protecting human health and prolonging life.Therefore, it is called the seventh nutrient.
Dietary fiber is generally high-purity dietary fiber extracted from natural foods (konjac, oats, buckwheat, apples, cactus, carrots, etc.).The main functions of dietary fiber are:
(1) Treat diabetes
Dietary fiber can improve the sensitivity of insulin receptorinsulinUtilization rate of;Dietary fiber can wrap the sugar of food, make it gradually absorbed, and balance the blood sugar after meal, so as to regulate the blood sugar level of diabetic patients and treat diabetes.
(2) Prevention and treatment of coronary heart disease
The increase of serum cholesterol level will lead to coronary heart disease.The excretion of cholesterol and bile acid is closely related to dietary fiber.Dietary fiber can combine with cholic acid, so that cholic acid can be rapidly discharged from the bodydietary fiberThe combination with cholic acid will promote the conversion of cholesterol to cholic acid, thus reducing the cholesterol level.
(3) Hypotensive effect
Dietary fiber can absorb ions and exchange with sodium and potassium ions in the intestinal tract, thus reducing the ratio of sodium to potassium in the blood, thus playing a role in lowering blood pressure.
(4) Anticancer effect
Since the 1970s, there have been more and more reports on the research of dietary fiber in anti-cancer, especially the relationship between dietary fiber and digestive tract cancer.Early surveys in India showed that people living in northern India consumed much more dietary fiber than those living in southern India, and the incidence of colon cancer was also much lower than that in southern India.According to this survey, scientists have made more in-depth research and found that dietary fiber can prevent and treat colon cancer for the following reasons: some saprophytic bacteria in the colon can produce carcinogens, while some beneficial microorganisms in the intestine can use dietary fiber to produce short chainsfatty acid, such short chain fatty acids can inhibit the growth of saprophytic bacteria;Cholic acid and goose bile acid in bile can be metabolized by bacteria into carcinogens and mutagens of cells. Dietary fiber can bind bile acid and other substances and expel them from the body to prevent the production of these carcinogens;Dietary fiber can promote intestinal peristalsis, increase stool volume, and shorten emptying time, thus reducing the chance of carcinogens in food contacting the colon;The beneficial bacteria in the intestine can use dietary fiber to produce butyric acid, which can inhibit the growth and proliferation of tumor cells, induce tumor cells to transform into normal cells, and control the expression of oncogenes.
(5) Weight loss treatment of obesity
Dietary fiber replaces part of the amount of nutrients in food, and reduces the total food intake.Dietary fiber promotes the secretion of saliva and digestive juice, plays a filling role in the stomach, and at the same time, absorbs water to expand, which can produce a sense of fullness and inhibit eating desire.Dietary fiber combines with some fatty acids, which makes fatty acids cannot be absorbed when they pass through the digestive tract, thus reducing the absorption rate of fat.
(6) Treat constipation
Dietary fiber has strong water holding capacity, and its water absorption rate is up to 10 times.After absorbing water, it increases the volume of intestinal contents, loosens and softens the stool, and makes it more smooth and labor-saving when passing through the intestinal tract.At the same time, dietary fiber, as a foreign body in the intestine, can stimulate the contraction and peristalsis of the intestine, accelerate the excretion of stool, and have the effect of treating constipation.[4]
research findings
Announce
edit
An international team, including researchers from the University of Gottingen in Germany, was surprised to find that although the simulated Martian atmosphere had destroyed the microbial ecology of the Kombucha culture, a cellulose producing bacterium of the genus Paecilomyces survived when studying the possibility of Kombucha surviving in a Martian like environment.This discovery was published in the recent journal Frontier of Microbiology.The results show that the cellulose produced by bacteria may be the reason for their survival under alien conditions.This also provides the first evidence that bacterial cellulose may be a biomarker of extraterrestrial life, and cellulose based membranes may be a good material for protecting life in extraterrestrial settlements.[5]
In 2014, with the support of the European Space Agency (ESA), researchers of the Biology and Mars Experiment (BIOMEX) project sent kombucha culture to the International Space Station (ISS) to better understand the robustness of cellulose as a biomarker, the genome structure of kombucha and its extraterrestrial survival behavior.These samples were reactivated on the earth, and were cultured for another two and a half years under the simulated Martian conditions outside ISS one and a half years later.[5]
Ingestion
Announce
edit
Vegetables are rich in cellulose.Cellulose free foods include: chicken, duck, fish, meat, eggs, etc;Foods with a large amount of cellulose include coarse grains, bran, vegetables, beans, etc., of which the cotton content is the highest, reaching 98%.Therefore, it is suggested that diabetics should eat more fiber rich foods such as beans and fresh vegetables.At present, most domestic plant fiber foods are made of rice bran, bran, wheat grains, beet chips, pumpkin, corn husk and seaweed, which can reduce blood sugar and blood lipids to a certain extent.[4]
Content and determination
Announce
edit
Food rich in cellulose
Although cellulose cannot be absorbed by the human body, it has a good role in clearing the intestinal tract, and is a healthy food suitable for patients with IBS (irritable bowel syndrome).The cellulose content of common foods is as follows:
Wheat bran: 31%
Cereals: 4-10%, from more to less, they are wheat grains, barley, corn, buckwheat flour, barley flour, sorghum rice, and black rice.
Cereals: 8-9%;Oatmeal: 5-6%
The cellulose content of potatoes, sweet potatoes and other potatoes is about 3%.
Beans: 6-15%, ranging from more to less: soybeans, green beans, broad beans, kidney beans, peas, black beans, red beans, mung beans.
Whether cereals, potatoes or beans, generally speaking, the more refined the processing, the less cellulose content.
Vegetables: bamboo shoots have the highest content, with 30-40% cellulose content in dried bamboo shoots and more than 40% pepper.The others with more cellulose are: bracken, cauliflower, spinach, pumpkin, cabbage, rape.
Mushroom (dry): the cellulose content is the highest, of which the cellulose content of Tricholoma matsutake is close to 50%, and those with more than 30% are listed from more to less: Lentinula edodes, Tremella fuciformis and Auricularia auricula.In addition, the cellulose content of laver is also high, reaching 20%.
Nuts: 3-14%.More than 10%: black sesame, pine nut, almond;Below 10% are white sesame, walnut, hazelnut, walnut, sunflower seed, watermelon seed and peanut kernel.
Fruit: dried red fruits are the most abundant, with cellulose content close to 50%, followed by dried mulberry, cherry, wild jujube, black jujube, big jujube, small jujube, pomegranate, apple and pear.
All kinds of meat, eggs, dairy products, oil, seafood, alcoholic drinks, soft drinks do not contain fiber;The cellulose content of various infant foods is extremely low.
Cellulose is not fiber, but two concepts.Cellulose is measured with a cellulose analyzer. Generally, crude fiber is measured, and dietary fiber is also measured in food.[1]
Medicinal Introduction
Announce
edit
Natural Dietary Cellulose Tablets
(1) Edible purpose：
Moisturize intestines and relieve constipation, get a feeling of satiety, and decompose fat.
(2) Product features：
The scientific formula derived from natural ingredients is conducive to normal physiological activities;Get satiety.
Cellulose can expel disease causing toxins from the body through the digestive system.
Shorten the stay time of food in the intestinal tract and make the stool smooth.
It is composed of a variety of unique cellulose, which can decompose the fat ingested.
One to two tablets for bowel moistening and defecation, three times a day, 20 minutes before meals or boiled water after meals.[4]
Cellulose and health
Announce
edit
Not all carbohydrates can be digested and converted into glucose.The indigestible carbohydrate is called fiber.It is an indispensable part of a healthy diet. The content of fruits, vegetables, lentils, broad beans and coarse grains is high.Eating high fiber foods can reduce the risk of bowel cancer, diabetes and diverticulum disease.And it is not easy to have constipation.
Usually people think that fiber is "coarse fodder", but this is not the case. Fiber can absorb water.Therefore, it can make the food residue expand and become loose, making it easier to pass through the digestive tract.The risk of infection is reduced because the retention time of food residues in the body is shortened;Moreover, when some food, especially meat, deteriorates, it will produce carcinogens and cause cell mutation. The reduction of the retention time of food residues in the body can also reduce the possibility of this situation.The content of fiber in the diet of regular meat eaters is very low, which will increase the stay time of food in the intestines to 24-72 hours. During this period, some food may deteriorate.So if you like meat, you must make sure that your diet also contains a lot of fiber.
There are many types of fiber, some of which are proteins rather than carbohydrates.Some kinds of fibers, such as those contained in oats, are called "soluble fibers". They can slow down the absorption of carbohydrates when combined with carbohydrate molecules.In this way, they can help keep the blood sugar concentration stable.Some fibers are much more absorbent than others.Wheat fiber can expand to 10 times of its original volume in water, while glucomannan fiber in Japanese konjac can expand to 100 times of its original volume in water.Since fiber can expand food and slow down the release of energy in sugar, super absorbent fiber can help control appetite and help maintain proper weight.
The ideal intake of fiber is not less than 35 grams per day.If the food is properly selected, it is easy to reach this standard without additional supplementation.It is best to obtain fiber from a large number of different food sources, including oats, lentils, broad beans, plant seeds, fruits, and raw or lightly cooked vegetables.Most of the fiber in vegetables is destroyed during cooking, so it is better to eat vegetables raw.[4]
Common cellulose
Announce
edit
Polycellulose
The First Clinical College of Dalian Medical University and the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences (Dalian Institute of Chemical Physics for short), after years of cooperation, have completed the "Basic and Clinical Application Research on the Prevention of Tissue Adhesion by Polycellulose", which has successfully developed a new high-tech material -- polycellulose, which can be used to prevent tissue adhesion after creation and surgery,It has been proved to have good adhesive effect in basic experiments and clinical application studies.
How to make surgery not only cure diseases but also not cause serious adhesion complications is an urgent problem to be solved in today's surgery.From 1993 to 1999, a research group led by Professor Jiang Changming of the Department of Orthopaedics developed a new absorbable anti adhesion material Poly CMC, and carried out extensive basic and clinical prospective research in orthopaedics, general surgery, neurosurgery and other disciplines.In the basic research, they cooperated with Dalian Institute of Chemical Physics to successfully complete the synthesis of polycellulose and drug screening with polycellulose as raw material and polyglucose as cross-linking agent.Animal experimental studies have respectively conducted studies on the prevention of adhesion of tendon, nerve, dura, joint and abdominal cavity after surgery with polymeric fibers, proving that the effect of prevention of adhesion is obvious.The clinical application study observed the effect of poly polymer fiber on preventing muscle adhesion.Polycellulose has good biocompatibility and is an ideal anti adhesion material.It can eliminate or reduce postoperative complications caused by adhesion, and reduce operative mortality and disability rate.[3]
Lignin fibre
Lignin fiber is an organic fiber obtained by chemical treatment of natural wood, which is cotton like, white or grayish white in appearance.Through screening, splitting, high temperature treatment, bleaching, chemical treatment, neutralization and screening, fibers with different lengths and thicknesses are separated to meet the needs of different application materials.As the treatment temperature is above 250 ℃, it is a very chemically stable substance under normal conditions. It is not corroded by ordinary solvents, acids and alkalis. It has the good quality of non-toxic, tasteless, pollution-free and radioactive. It does not affect the environment and is harmless to human beings. It is a green environmental product, which is not possessed by other mineral fibers.The microstructure of the fiber is banded, uneven, porous, flat at the intersection, with good toughness, dispersibility and chemical stability, strong water absorption, and excellent thickening and crack resistance.[3]
Cellulose ether
Building grade cellulose ether is the general name of a series of products produced by the reaction of alkali cellulose and etherifying agent under certain conditions.Alkali cellulose is replaced by different etherifying agents to obtain different cellulose ethers.According to the ionization properties of substituents, cellulose ethers can be divided into ionic type (such as carboxymethyl cellulose) and non-ionic type (such as methyl cellulose).According to the type of substituent, cellulose ether can be divided into single ether (such as methyl cellulose) and mixed ether (such as hydroxypropyl methyl cellulose).According to different dissolubility, it can be divided into water solubility (such as hydroxyethyl cellulose) and organic solvent solubility (such as ethyl cellulose). Dry mixed mortar is mainly water soluble cellulose, and water soluble cellulose can be divided into instant type and delayed dissolution type after surface treatment.
The action mechanism of cellulose ether in mortar is as follows:
(1) After the cellulose ether in the mortar is dissolved in water, the effective and uniform distribution of the cementitious material in the system is ensured due to the surface activity. As a protective colloid, the cellulose ether "wraps" the solid particles and forms a lubricating film on its outer surface, which makes the mortar system more stable, and also improves the fluidity of the mortar in the mixing process and the smoothness of construction.
(2) Due to the molecular structure characteristics of cellulose ether solution, the water in mortar is not easy to lose, and gradually released over a long period of time, giving mortar good water retention and workability.[3]
Methyl cellulose
The refined cotton is treated with alkali, and the cellulose ether is prepared through a series of reactions with methane chloride as etherifying agent.Generally, the degree of substitution is 1.6~2.0, and the solubility varies with the degree of substitution.It belongs to non-ionic cellulose ether.
(1) Methylcellulose is soluble in cold water, but it is difficult to dissolve in hot water. Its aqueous solution is very stable in the range of pH=3-12.It has good compatibility with starch, guar gum and many surfactants.When the temperature reaches the gelation temperature, gelation will occur.
(2) The water retention of methyl cellulose depends on its addition amount, viscosity, particle fineness and dissolution rate.Generally, the water retention rate is high with large addition amount, small fineness and large viscosity.Among them, the addition amount has the greatest impact on the water retention rate, and the viscosity is not proportional to the water retention rate.The dissolution rate mainly depends on the surface modification degree and particle fineness of cellulose particles.Among the above cellulose ethers, methyl cellulose and hydroxypropyl methyl cellulose have higher water retention rates.
(3) The change of temperature will seriously affect the water retention rate of methyl cellulose.Generally, the higher the temperature, the worse the water retention.If the mortar temperature exceeds 40 ℃, the water retention property of methyl cellulose will become significantly worse, which will seriously affect the workability of mortar.
(4) Methylcellulose has obvious influence on the workability and adhesion of mortar.The "adhesiveness" here refers to the adhesive force felt by workers between the coating tool and the wall substrate, that is, the shear resistance of mortar.The adhesiveness is large, the shear resistance of mortar is large, and the force required by workers in the use process is also large, so the workability of mortar is poor.In cellulose ether products, the adhesion of methyl cellulose is at a medium level.[3]
Hydroxypropyl methyl cellulose
Hydroxypropyl methyl cellulose (HPMC) is a kind of cellulose whose yield and dosage are increasing rapidly.It is a non-ionic cellulose mixed ether made from refined cotton through a series of reactions with propylene oxide and methyl chloride as etherifying agents after alkalization treatment.The degree of substitution is generally 1.2~2.0.Their properties are different depending on the proportion of methoxy content and hydroxypropyl content.
(1) Hydroxypropyl methyl cellulose is easily soluble in cold water, but it is difficult to dissolve in hot water.However, its gelation temperature in hot water is significantly higher than that of methyl cellulose.Compared with methyl cellulose, the solubility in cold water is also greatly improved.
(2) The viscosity of hydroxypropyl methyl cellulose is related to its molecular weight, and the higher the molecular weight, the higher the viscosity.The temperature will also affect its viscosity. When the temperature rises, the viscosity decreases.But the effect of high temperature on its viscosity is lower than that of methyl cellulose.The solution is stable at room temperature.
(3) The water retention of HPMC depends on its addition amount, viscosity, etc. Its water retention rate is higher than that of methyl cellulose at the same addition amount.
(4) Hydroxypropyl methyl cellulose is stable to acids and bases, and its aqueous solution is very stable in the range of pH=2~12.Caustic soda and lime water have little effect on its performance, but alkali can accelerate its dissolution rate and improve the viscosity pin.Hydroxypropyl methyl cellulose is stable to common salts, but when the concentration of salt solution is high, the viscosity of hydroxypropyl methyl cellulose solution tends to increase.
(5) Hydroxypropyl methyl cellulose can be mixed with water-soluble polymer compounds to form a uniform solution with higher viscosity.Such as polyvinyl alcohol, starch ether, vegetable gum, etc.
(6) Hydroxypropyl methyl cellulose has better enzyme resistance than methyl cellulose, and the possibility of enzymatic degradation of its solution is lower than that of methyl cellulose.
(7) The adhesion of hydroxypropyl methyl cellulose to mortar construction is higher than that of methyl cellulose.[3]
Hydroxyethyl cellulose
The refined cotton is prepared by reacting with ethylene oxide as etherifying agent in the presence of acetone after alkali treatment.Its degree of substitution is generally 1.5~2.0.It has strong hydrophilicity and is easy to absorb moisture.
(1) Hydroxyethyl cellulose is soluble in cold water, but difficult to dissolve in hot water.The solution is stable at high temperature and does not have gelation.It can be used for a long time under the medium and high temperature of mortar, but its water retention is lower than that of methyl cellulose.
(2) Hydroxyethyl cellulose is stable to common acids and bases. Alkali can accelerate its dissolution and slightly increase its viscosity. Its dispersibility in water is slightly worse than that of methyl cellulose and hydroxypropyl methyl cellulose.
(3) Hydroxyethyl cellulose has good performance for anti sag of mortar, but it has a long retarding time for cement.
(4) The performance of hydroxyethyl cellulose produced by some domestic enterprises is significantly lower than that of methyl cellulose due to its high water content and ash content.[3]
Carboxymethyl cellulose
The ionic cellulose ether is prepared from natural fibers (cotton, etc.) by alkali treatment, sodium monochloroacetate as etherifying agent, and a series of reaction treatments.Its degree of substitution is generally 0.4~1.4, and its performance is greatly affected by the degree of substitution.
(1) Carboxymethyl cellulose is hygroscopic, and it will contain more water when stored under general conditions.
(2) The carboxymethyl cellulose aqueous solution will not produce gel, and the viscosity will decrease with the increase of temperature. When the temperature exceeds 50 ℃, the viscosity is irreversible.
(3) Its stability is greatly affected by pH.Generally, it can be used in gypsum based mortar, but not in cement based mortar.In high alkalinity, viscosity will be lost.
(4) Its water retention is far lower than that of methyl cellulose.It has retarding effect on gypsum based mortar and reduces its strength.However, the price of carboxymethyl cellulose is significantly lower than that of methyl cellulose.[3]
