Types and properties of polyacrylamide

2021-11-01 21:56:42

Polyacrylamide (PAM) is a water-soluble linear polymer made of acrylamide monomer. The chemical properties of monomer acrylamide is very active, and a series of chemical reactions can be carried out in the double bond and amide group, using different processes, into different functional groups, can get different charge products: anionic, cationic, non-ionic, amphoteric polyacrylamide. The average molecular weight of PAM from thousands to tens of millions of more than a number of functional groups along the bond molecule, can be mostly ionized in water, belonging to the polymer electrolyte. It can be divided into anionic type (such as --COOH,--SO3H,--OSO3H, etc.) cationic type (such as --NH3OH,--NH2OH, -ConH3OH) and non-ionic type according to the characteristics of its separable groups. Product appearance is white powder, soluble in water, almost insoluble in benzene, ether, ester, acetone and other general organic solvents, its aqueous solution almost transparent viscous liquid, is a non-hazardous, non-toxic, non-corrosive, solid PAM has hygroscopic, hygroscopic with the increase of ionic degree and increase, PAM thermal stability; It has good stability when heated to 100℃, but it is easy to decompose the produced nitrogen when it is above 150℃, and it is insoluble in water due to imination between molecules. Density (g) mL 23℃1.302. When the vitrification humidity is 153℃, PAM exhibits non-Newtonian fluidity under stress.

Use the feature

1) flocculation: PAM can make suspended substances through electric neutralization, bridging adsorption, flocculation.

2) bonding: through mechanical, physical and chemical effects, the bonding effect.

3) resistance reduction: PAM can effectively reduce the frictional resistance of fluid, adding trace PAM in water can reduce the resistance by 50-80%.

4) thickening: PAM has thickening effect under neutral and acid conditions, and PAM is easy to hydrolysis when PH value is above 10. Thickening will be more pronounced with a semi-reticular structure.

Introduction to the principle of PAM

1) flocculation principle: PAM is used for flocculation, and the surface properties of the species to be flocculated, especially the electrokinetic potential, viscosity, turbidity and the PH value of the suspension, the electrokinetic potential on the surface of the particles, is the reason for particle resistance to polymerization, adding PAM with opposite surface charge, can reduce the electrokinetic potential and condense.

2) adsorption bridge: PAM molecular chain is fixed on the surface of different particles, the formation of polymer bridge between the particles, so that the particles form aggregates and settlement.

3) surface adsorption: various adsorption of polar group particles on PAM molecules.

4) Strengthening effect: PAM molecular chain and dispersed phase through a variety of mechanical, physical, chemical and other effects, the dispersed phase implicated together, forming a network, so as to enhance the effect.

Anionic polyacrylamide

[Product Application]

1, mainly used as flocculant: for suspended particles, coarse, high concentration, particles with positive charge, water PH value is neutral or alkaline sewage, due to anionic polyacrylamide molecular chain contains a certain amount of polar base can absorb suspended solid particles in water, so that the formation of large flocculant bridging between particles. Therefore, it accelerates the sedimentation of particles in suspension, accelerates the clarification of solution and promotes filtration. The product is widely used in chemical industry waste water, waste liquid treatment, municipal sewage treatment. Tap water industry, high turbidity water purification, sedimentation, coal washing, mineral processing, metallurgy, iron and steel industry, zinc, aluminum processing industry, electronic industry and other water treatment.

2, used in the petroleum industry, oil recovery, drilling mud, waste mud treatment, prevent water channelling, reduce friction, improve oil recovery, three oil recovery has been widely used.

3, used for textile sizing agent, slurry stable performance, less falling pulp, fabric breakage rate is low, clean cloth.

4, for the paper industry, (I) is to improve the retention rate of filler, pigment, etc. To reduce the loss of raw materials and environmental pollution; (2) is to improve the strength of paper (including dry strength and wet strength), in addition, the use of PAM can also improve the tear resistance and porosity of paper, to improve the visual and printing performance, but also used in food and tea wrapping paper.

5, other industries, food industry, used for sugar cane sugar, sugar beet sugar production sugar juice clarification and syrup phosphorus float extraction. Enzyme preparation fermented liquid flocculation clarifying industry, also used in feed protein recovery, stable quality, good performance, recovery of protein powder to chickens and raising the survival rate of weight gain, no adverse effects of egg production, synthetic resin coating, civil water plugging grouting materials, building materials industry, improve the quality of cement, construction adhesive, caulking repair and plugging agent, soil improvement, electroplating industry, printing and dyeing, etc.

Cationic polyacrylamide

Cationic polyacrylamide in acidic or alkaline media are positive, it is usually lower than anionic or non-ionic polyacrylamide molecular weight, its cleaning sewage performance is mainly through charge neutralization. The function of this kind of flocculant is mainly flocculating with a negative charge, with turbidity removal, decolorization function. In liquor factory, gourmet drinks factory, sugar factory, meat products factory, beverage factory, printing and dyeing factory wastewater treatment with cationic polyacrylamide than anionic polyacrylamide, non-ionic polyacrylamide or inorganic salt effect is several times or dozens of times higher, because this kind of wastewater is generally with negative charge. At present, water soluble azo initiator AIBA has been used to increase its molecular weight to more than ten million. Cationic polyacrylamide is suitable for high speed centrifuge, belt filter press, plate and frame filter press and other special sludge dewatering machinery, has the characteristics of fast flocculation, coarse flocculation, extrusion and shearing resistance, good agglomeration, easy to peel with the filter cloth and so on. So the dehydration rate is high, the filter cake liquid content is low, the dosage is small, can greatly reduce the user's use cost. It can also be used for hydrochloric acid, medium concentration of sulfuric acid and other liquids to separate and purify the suspended turbidity substances contained therein. Therefore, the product is widely used in sewage treatment plants, breweries, food factories, tanneries, paper mills, petrochemical plants, oil fields, metallurgy, chemical industry and cosmetics and other sludge dewatering treatment.

Three, non-ionic polyacrylamide

[Product Application]

1, mainly used as flocculant: because its molecular chain contains a certain amount of polar genes can absorb suspended solid particles in water, so that the formation of large flocculant between particles. It accelerates the sedimentation of particles in suspension, has very obvious effects of accelerating the clarification of solution, promoting filtration and so on. It is widely used in the treatment of chemical industrial wastewater, waste liquid, municipal sewage treatment. Especially when the sewage is acidic, using this product is the most suitable. It can be used with inorganic flocculants such as poly-iron and poly-aluminum.

2, used in the petroleum industry, oil recovery, drilling mud, waste mud treatment, prevent water channelling, reduce friction, improve oil recovery, three oil recovery has been widely used.

3, used for textile sizing agent, slurry stable performance, less falling pulp, fabric breakage rate is low, clean cloth.

4, for paper industry, one is to improve the retention rate of filler, pigment, etc. To reduce the loss of raw materials and environmental pollution; Two is to improve the strength of the paper (including dry strength and wet strength), in addition, the use of PAM can also improve the tear resistance and porosity of the paper, to improve the visual and printing performance, but also used in food and tea wrapping paper.

Four, amphoteric ion polyacrylamide

Product form: amphoteric ion polyacrylamide (ACPAM) appearance is white powder. Product features: amphoteric polyacrylamide because of the molecule containing cationic base and anionic base, it has the use of general cationic flocculant characteristics, showing more excellent performance. These flocculants can be used over a wide range of PH values, with higher water filtration, lower filter cake moisture content, and can also be used for strong acid leaching of ore or recovery of valuable metals from acidic catalysts containing metals.

Amphoteric ionic is not a mixture of anionic and cationic. If the use of cationic polyacrylamide and anionic polyacrylamide will react to produce precipitation. So amphoteric ion products are ideal. Main uses:

Oilfield profile control and water plugging agent, combined with crosslinking agent, stabilizer and coagulant, can produce high strength coagulant glue water plugging agent with important polymeric gel and resin gel. The gel time can be controlled to adapt to different geological conditions by blocking formation pores and fractures through adhesion and physical plugging and adjusting the proportion. All kinds of oil pollution, organic, inorganic, sewage, complex sewage treatment. In sewage systems with variable PH. Used for sludge dewatering. Used as auxiliary in paper making. Packaging and storage:

This product is non-toxic, pay attention to moistureproof, rain proof, avoid sun exposure. Storage life: 2 years,25kg paper bags (lined plastic bags and pasted kraft paper bags).