Polyacrylamide gel is composed of acrylamide monomerBisacrylamideIs a cross-linking agentTetramethylethylenediamineCross linked polyacrylamide is polymerized by catalysis and free radical initiation (photoinitiation, chemical initiation, etc.).It is a chemically synthesized artificial gel whose trade name is Bio Gel P.Its bio gels of different specifications are indicated by numbers and symbols, such as Bio Gel P-4, etc. The numbers represent 1/1000 of the gel exclusion limit, that is, the exclusion limit is 4000 Da.[1]
It is a kind of synthetic gel, which is based on acrylamideMethylene bisacrylamideIt is cross-linked and made into granules by drying, crushing or processing. Various types ofGel: Set & Match。The more cross-linking agents, the smaller the pores.The commercial product of polyacrylamide gel is bio gel P (Bio Gel P), which is from the pw series of TSKGEL of Tosoh, Japan, and is suitable for the purification of proteins and polysaccharides.Namely, acrylamide and a small amount of cross-linking agent methylenebisacrylamideTEMEDAnd oxidizerAmmonium persulfateThe gel is formed by polymerization.
polyacrylamide gel(PolyacrylamideGel，abbreviationPAAG）Is used by the laboratory forgel electrophoresisMaterials.It is also used asBreast augmentationPlastic surgery Use, the advantage is that there is no need to open a knife, and it can be directly injectedbreastSo as to achieve the effect of breast augmentation.
According to the content of an orthopedic website, PAAG is "a kind of biological material with low toxicity to tissues and good biocompatibility", so it can achieve better breast augmentation effect.However, this product has not beenUS Food and Drug AdministrationTight test;On the other hand, orthopedic surgeons in Hong Kong point out that this material hascarcinogenicSo it should not be used again.
This kind of operation has had problems in Guangdong Province and Hong Kong.There are Hong Kong women who have inflamed and purulent breasts after surgery in Shanghai and need to take one sideMastectomy。In addition, plastic surgeons in Hong Kong also pointed out that some patients had undergone surgery in illegal beauty salons, and the gel along theLymph glandOr blood vessels travel to the chest or other parts of the body.Therefore, plastic surgery hospitals in Shenzhen have stopped this operation and replaced it with silicone implants for patients.However, in other parts of China, this kind of operation is still common.
PAM
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Polyacrylamide is called PAM for short. Its structural formula is [- CH2-CH (CONH2)] n -, and its molecular weight is 1 million to 5 million.Polyacrylamide mainly has two commercial forms, one is powder, the other is colloid, andPolyacrylamide emulsion(Shanghaisynthetic resinResearch Institute).SolubleIn cold water, very slow, highmolecular weightWhen the concentration of 20% polyacrylamide exceeds 10%, it will form a gelatinous structure.Increasing the temperature can slightly promote the dissolution, but the temperature should not exceed 50 ℃ to prevent molecular degradation.InsolubleIn organic solvents.It decomposes when the temperature exceeds 120 ℃. It is neutral and non-toxic.
be used asThickening agent、flocculant 、Drag reducing agentIt has the functions of gel, sedimentation and reinforcement.It should be stored in a cool, ventilated and dry warehouse, protected from moisture, light and heat. The storage time should not be too long.
2. Adhesion:It can play the role of adhesion through mechanical, physical and chemical actions.
3. Resistance reduction:PAM can effectively reduce theFrictional resistanceThe resistance can be reduced by 50-80% by adding a small amount of PAM to the water.
4. Thickening property: PAM has thickening effect under neutral and acid conditions. When the PH value is above 10, PAM is easy tohydrolysis。In case of semi reticular structure, thickening will be more obvious.
(1)FlocculationPrinciple: PAM is used forflocculationThe surface properties of the flocculated material, especiallyElectrokinetic potential, viscosityturbidityIt is related to the PH value of the suspension. The particle surface potential is the reason for the particle polymerization inhibition. Adding PAM with opposite surface charge can reduce the potential and agglomerate.
(2)Adsorption bridgingPAM molecular chain is fixed on the surface of different particles, forming a polymer bridge between the particles, so that the particles form aggregates and settle.
(3) Surface adsorption:Polar groupVarious adsorption of particles.
(4) Enhancement: PAM molecular chain and dispersed phase connect the dispersed phase together through various mechanical, physical and chemical actions to form a network.
purpose
(1) ForSludge dewateringThe corresponding model of this product can be selected according to the nature of the sludge, which can effectively dewater the sludge before it enters the filter press. When dewatering, the floc will be large and non stickyFilter cloth, not dispersing and flowing during pressure filtrationMud cakeThick, high dewatering efficiency, mud cake moisture content below 80%.
(3) For the treatment of tap water with river water as the sourceflocculant , less consumption, good effect, low cost, especiallyinorganic flocculants It will become an efficient flocculant for waterworks in the Yangtze River, Yellow River and other basins.
(4) Reinforcing agent and other additives for paper making.Improve the retention rate of fillers and pigments, and the strength of paper.
(5) Used as oil field economic aid, such asclayAntiswelling agent, oilfieldacidificationUse thickener.
(6) For textileSizing agentStable size performance, less size dropping, low fabric end breakage rate and smooth cloth surface.
An electrophoretic procedure using polyacrylamide as a support matrix.Generally speaking, there are two types of polyacrylamide gel electrophoresisOne way electrophoresis: use complete protein orSodium lauryl sulfate(SDS) processed proteins are separated in parallel on the plate with gel (cylindrical rod gel used to be used in glass tube for electrophoresis, but few people use it now). (2)two-dimensional electrophoresis: First, the natural protein is used for separation, then the gel plate is treated with SDS, and the sample is separated in the second direction.Various proteins are separated for the first time, so the second separation isProtein subunit。The main advantages are: ⑴ The polymer is synthesized, so the repeatability is good; ⑵Good separation ability; ⑶By increasing or decreasing acrylamide monomer and crosslinking agent (N, N '-Methylene bisacrylamide）The pore size of the gel can be adjusted by the concentration ofSimple operation and short time; ⑸Stable chemical properties, good mechanical properties, and soft; (6)Electrophoresis can be carried out in acidic or alkaline buffer, and can be addedAmphoteric electrolyteconductIsoelectric pointElectrophoresis, available with electrolytesurface active agent (SDS) orNon electrolyteThe gel of surfactant (Np40, Tritonx-100, etc.) can be used for electrophoresis, and the combination of the two can also be usedtwo-dimensional electrophoresisAnd so on, with a wide range of use and increasing utilization value; (7)Due to the progress of dyeing technology, it can be quantified and can also detect extremely small spots（agaroseElectrophoresis).
denaturation
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Denatured polyacrylamide gel electrophoresis(PAGE) is separated according to the size of oligonucleotides, so the full length product can be separated from incomplete short molecules.During electrophoresis, at least 1mg syntheticoligonucleotides, after electrophoresisUV lampThe oligonucleotides with correct length were cut from the gel.Principle: protein or polypeptide combines with SDSThermal denaturationandDisulfide bondThe reduction of, to form a relatively consistent negative charge of the non folded derivatives, its swimming speed is mainly determined by the molecular weight.
Non denaturation
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Non denaturing polyacrylamide gel electrophoresis(Native PAGE) or called active electrophoresis means that when SDS andAlkyl alcoholetc.DenaturantThe polyacrylamide gel electrophoresis of active proteins is often used for enzyme identification, isoenzyme analysis and purification.The natural polyacrylamide gel electrophoresis without SDS can keep the natural shape and charge of biological macromolecules in the electrophoresis process, and their separation is based on theirElectrophoretic mobilityAnd gelatinousmolecular sieveTherefore, high resolution can be obtained, especially inElectrophoretic separationCan still maintain the biological macromolecules such as protein and enzymebiological activityIt is of great significance for the identification of biomacromolecules. The method is to carry out electrophoresis of two identical samples on the gel. After electrophoresis, the gel is cut into two halves. One half is used for active dyeing to identify a specific biomacromolecule, and the other half is used for dyeing all samples to analyze the types and contents of various biomacromolecules in the sample.
flocculant
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Polyacrylamide, referred to as PAM, is divided into cationic, anionic and non-ionic types. Its molecular weight ranges from 4 million to 20 million. Its appearance is white powder, which is easily soluble in water. It is easy to decompose when the temperature exceeds 120 ℃.Polyacrylamide is a syntheticPolymer flocculant, commonly known asWest Brown。It belongs to polyelectrolyte.It is leached by uranium hydrometallurgy plantpulpSolid liquid separation process (such as countercurrentDecantation-Washing process)flocculant The purpose is to improve the clarification, sedimentation andFiltration performance。
Properties: colorless or yellowish thick colloid.byWater soluble resin, soluble in water in any proportion.Only onGlacial acetic acid、Acrylic acid、glycol、FormamideIt can dissolve about 1% in a few solvents, such as glycerin and lactic acid, and is almost insoluble in organic solvents.It is easy to decompose when the temperature exceeds 120 ℃.
Preparation method
acrylonitrile Water is combined with copper catalyst to obtain acrylamide, and thenK2S2O8Under the action, it is polymerized into polyacrylamide.Copper aluminum alloy is made into catalyst after alkali treatment and washing, and loadedHydration reactorMedium, acrylonitrile raw material pumped toStorage tankRe insertMetering tankMedium,Ion exchangeThe treated pure water is sent into the metering tank, and then pumped into the hydration reactor through the raw material preheater in proportion to control 85-125 ℃Hydration reactionGenerate acrylamide aqueous solution, and the remaining acrylonitrileFlash towergocondenserThe recovered water flows into the water metering tank for recycling, while the acrylamide solution flows fromFlash tankFlow into storage tank and pump toElevated troughRemove the resin exchange column, enter the storage tank to prepare 7-8% monomer, and send it toPolymerizerThe finished product is made into colloidal polyacrylamide and packaged.
Polyacrylamide has a large amount ofLateral base- amide group.The chemical activity of amide group is very high, which can react with many compounds to produce many derivatives of polyacrylamide.The uniqueness of amide group lies in its ability to formhydrogen bondA strong hydrogen bond is formed in the compound of.
classification
Polyacrylamide is mainly sold in two forms, one is powder, the other is colloid.Colloid is not easy to transport and use, so powdered polyacrylamide is welcomed by users.lately.The emergence of polymer dispersion, called polyacrylamide latex, which is easily soluble in water, has attracted people's attention.Polyacrylamide index:relative molecular massThe size of is one of the main performance indicators to distinguish polyacrylamide.Polyacrylamide with high relative molecular weight is mainly used asflocculant Polyacrylamide with medium relative molecular weight is mainly used for paperDry strength agent, low relative molecular weight polyacrylamide is used asdispersant。
Development history
Polyacrylamide was first used by Moureau in 1883Acryloyl chlorideIt was produced by reacting with ammonia at low temperature, and was industrialized in 1955.The first widely usedUranium oreIndustry.Used to remove minor impurities from uranium brine solutionpolyacrylamide。Now, polyacrylamide has been widely used in papermaking, mineral processingTertiary oil recovery, sewage and drinking water treatment, building materials industry, food processing and other industries.China began to produce polyacrylamide in the 1960s, which is mainly used for purification and electrolysis of salt water.At that time, the production scale was very small.In recent years, due to the rapid development of China's petroleum industry, polyacrylamidePetroleum exploitationThe application field of drilling is more and more extensive.Its output has increased significantly, and it is sold in the form of colloid and powder.At the same time, it has also developedhydrolysisPolyacrylamide, methylene polyacrylamideSulfonated polyacrylamideAnd acrylamide and some other monomerscopolymer。These products have been widely used in oil production, water treatment, sugar productionCoal washing, mineral processing, paper making and other industrial sectors have received good results.With the continuous expansion of its application scope, new products and brand names of polyacrylamide are also emerging. It is expected that the production and application of polyacrylamide will achieve greater development.
Principles of use
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The use of polyacrylamide shall follow the following principles:
1. GranularPolyacrylamide flocculantIt cannot be directly added into the sewage.It must be dissolved in water before use to treat sewage with its aqueous solution.
2. The water for dissolving granular polymers should be clean (such as tap water), not sewage.Normal temperature water is enough, and heating is generally not required.The solution is slow when the water temperature is lower than 5 ℃.The increase of water temperature will accelerate the dissolution rate, but the polymer degradation will be accelerated when the temperature is above 40 ℃, which will affect the use effect.Generally, tap water is suitable for preparing polymer solutions.Water with strong acid, alkali and high salt content is not suitable for preparation.
3. The concentration of polymer solution is recommended to be 0.1% - 0.3%, that is, 0.1 g - 0.3 g of polymer powder is added to 1 liter of water.
