Polyacrylamide

Performance and Applications
　　Polyacrylamide(PAM)is a linear polymer,mainly available in dry powder and colloidal forms.
　　Based on its average molecular weight,it can be classified into three categories:low molecular weight(<1 million),medium molecular weight(2-4 million),and high molecular weight(>7 million).Based on its structure,it can be classified into nonionic,anionic,and cationic types.Anionic PAM is mostly a hydrolyzed form(HPAM).The main chain of PAM contains a large number of amide groups,exhibiting high chemical activity.It can be modified to produce many PAM derivatives,and the product is widely used in papermaking,mineral processing,oil extraction,metallurgy,building materials,and wastewater treatment industries.As a lubricant,suspending agent,clay stabilizer,oil displacement agent,fluid loss reducer,and thickener,PAM is widely used in drilling,acidizing,fracturing,water shut-off,cementing,and secondary and tertiary oil recovery,making it an extremely important oilfield chemical.
Characteristics
　　Flocculation property.PAM can flocculate suspended matter through charge neutralization;it also has adhesive properties,acting as a binder through physical and chemical processes;and it acts as a thickener,thickening under both neutral and acidic conditions.
Quality Indicators
　　Catonic polyacrylamide conforms to GB/T31246—2014 Technical Conditions and Test Methods for Cationic Polyacrylamide in Water Treatment Agents.
　　Anionic and nonionic polyacrylamide conform to GB/T17514-2017 Anionic and Nonionic Polyacrylamide in Water Treatment Agents.
Instructions for Use
　　The dosage of polyacrylamide is very small,generally 0.03-0.4 mg/L.Too little dosage results in poor treatment effect,while too much dosage can cause side effects.In practical applications,small-scale and pilot-scale tests should be conducted first,followed by full-scale testing.
Packaging,Transportation,and Storage
　　Polyacrylamide products are double-layered packaged,with each bag(drum)containing a net weight of 25 kg or 50 kg,or packaged according to customer requirements.During transportation,covered vehicles should be used to prevent rain and sun exposure.
　　Polyacrylamide products should be stored in a cool,well-ventilated,and dry warehouse,with a shelf life of two years.

Polyacrylamide is a linear polymer with unique chemical structure and physical properties,making it widely applicable in numerous fields.This article will elaborate on the working principle of polyacrylamide and explore its specific uses in different industries.

I.Working Principle of Polyacrylamide

　　1.Flocculation

　　When used as a flocculant,polyacrylamide's mechanism of action is mainly based on charge neutralization and adsorption bridging.In water treatment,suspended particles usually carry a charge on their surface,and the electrostatic repulsion between particles makes them difficult to aggregate and settle.The polar groups on the polyacrylamide molecular chain can adsorb onto the surface of suspended particles,neutralizing the charge on the particle surface and reducing the electrostatic repulsion between particles.Simultaneously,its long molecular chains can form bridges between multiple particles,causing them to aggregate into larger flocs,thereby accelerating the sedimentation process.For example,in wastewater treatment,after adding polyacrylamide,the fine suspended particles in the wastewater rapidly aggregate to form larger flocs,facilitating subsequent separation and treatment.

　　2.Thickening

　　Polyacrylamide has good thickening properties under neutral and acidic conditions.Its molecular chains intertwine in the solution,forming a network structure,increasing the viscosity of the solution.When the pH value is above 10,polyacrylamide readily hydrolyzes,forming a semi-network structure,resulting in a more pronounced thickening effect.In oil extraction,the thickening effect of polyacrylamide can increase the viscosity of injected water,improve the oil-water flow rate ratio,and thus enhance oil recovery.

　　3.Drag Reduction

　　Polyacrylamide effectively reduces the frictional resistance of fluids.Adding trace amounts of polyacrylamide to water can reduce the frictional resistance of the fluid by 50%-80%.This property has important applications in pipeline transportation and fluid transmission.For example,in oil pipeline transportation,adding polyacrylamide can reduce energy consumption and improve transportation efficiency.

　　4.Strengthening Effect

　　The polyacrylamide molecular chains bind the dispersed phase together through mechanical,physical,and chemical interactions,forming a network structure,thereby providing a strengthening effect.In the paper industry,polyacrylamide,as a paper strengthening agent,can improve the strength of paper,including both dry and wet strength.Its molecular chains interact with fibers and fillers to form a strong bond,allowing the paper to maintain good strength properties in both dry and wet conditions.

II.Applications of Polyacrylamide in Various Industries

　　(I)Water Treatment

　　*Raw Water Treatment:In raw water treatment processes such as waterworks,polyacrylamide is used in conjunction with activated carbon to coagulate and clarify suspended particles from daily life.Its flocculation effect enables fine impurities in water to quickly aggregate and settle,improving water quality.For example,in some large and medium-sized cities,when water supply is tight or water quality is poor,using polyacrylamide as a supplementary treatment agent can increase water purification capacity by more than 20%even without modifying the sedimentation tank.

　　*Wastewater Treatment:Polyacrylamide plays an important role in wastewater treatment.It can be used for sludge dewatering,allowing concentrated sludge to undergo effective dewatering treatment before entering the filter press.After adding polyacrylamide,the sludge produces large flocs that do not stick to the filter cloth,do not disperse during filter press,produce a thicker sludge cake,have high dewatering efficiency,and the sludge cake moisture content can be reduced to below 80%.In addition,for industrial wastewater from breweries,monosodium glutamate(MSG)factories,alcohol factories,sugar factories,textile printing and dyeing factories,meat processing plants,and beverage factories,polyacrylamide can promote the rapid coagulation and sedimentation of suspended particles through charge neutralization and adsorption bridging,achieving separation and clarification,improving operational efficiency,and reducing operating costs.

　　Industrial Water Treatment:In industrial water treatment,polyacrylamide is mainly used as a formulation agent.It can be used in combination with other water treatment agents to regulate water quality,prevent equipment scaling and corrosion,and ensure the normal operation of industrial production.

      (II)Oil Extraction Field

　　Oil Displacement Agent:In tertiary oil recovery processes,polyacrylamide is widely used as an oil displacement agent.By increasing the viscosity of injected water,it improves crude oil flow and increases crude oil production.The use of polyacrylamide can increase the recovery rate by 5%-20%.Due to my country's special geological conditions,Daqing Oilfield and Shengli Oilfield have begun to widely adopt polymer flooding technology,achieving significant economic benefits.Drilling Mud Materials:Polyacrylamide has functions such as thickening,reducing filtration loss,and rheology regulation,and can be used in the preparation of drilling mud.It can increase the viscosity and shear strength of the mud,prevent wellbore collapse,and reduce accidents during drilling.Simultaneously,polyacrylamide can also reduce mud filtration loss and maintain wellbore stability.

        (III)Paper Industry

　　Retention Aids and Filtration Agents:As a retention aid,polyacrylamide can improve the retention rate of fillers,pigments,etc.,reducing raw material loss and environmental pollution.As a filtration agent,it can accelerate the paper dewatering process and improve production efficiency.During the papermaking process,polyacrylamide forms electrostatic bridges with fibers,inorganic salt ions,and other organic polymers,enhancing the physical strength of the paper and accelerating filtration.

　　Paper Strengthening Agents:Polyacrylamide can improve the strength of paper,including dry and wet strength.Furthermore,it can improve the tear resistance and porosity of paper,enhancing visual and printability.Nonionic polyacrylamide is mainly used to improve the filtration properties of pulp and increase the dry paper strength;anionic copolymers are mainly used as dry and wet strengthening agents and retention agents for paper;cationic copolymers are mainly used for papermaking wastewater treatment and filtration aids,and also have a good effect on improving the retention rate of fillers.

       (IV)Agricultural Field

　　Soil Conditioner:Polyacrylamide can be used as a soil conditioner to reduce soil erosion,improve soil water retention,and promote plant growth.In agriculture,the use of this material can reduce soil erosion by about 30%.It can improve soil structure,increase soil porosity,improve soil aeration and water retention,and provide a good environment for plant growth.

　　Water Retention Agent:Polyacrylamide has good water absorption and retention properties and can be used as a water retention agent in agricultural production.It can absorb and retain a large amount of water,providing a continuous water supply to plants during drought periods and improving their drought resistance.

        (IV)Agricultural Field

　　Gel Preparation:Polyacrylamide is used to prepare gels,which can be used for electrophoretic separation of biomolecules such as proteins and nucleic acids.Its stability and transparency make experimental results more accurate.At a certain critical temperature,the swelling property of polyacrylamide hydrogels in water undergoes a sharp change with small temperature variations,with volume changes reaching tens to hundreds of times.This property can be used in the concentration process of aqueous solutions,avoiding high temperatures,and is valuable for the extraction of some organic or biological substances.Controlled Drug Release:Polyacrylamide hydrogels can also be used for controlled drug release and enzyme encapsulation.By encapsulating drugs in polyacrylamide hydrogels,slow drug release can be achieved,improving efficacy and reducing side effects.

(VI)Other Fields

　　Textile and Dyeing Industry:As a sizing and finishing agent for fabric treatment,polyacrylamide can create a soft,wrinkle-resistant,and mildew-resistant protective layer.Its strong hygroscopic properties can reduce breakage during fine yarn spinning.As a post-treatment agent,polyacrylamide can prevent static electricity and provide flame retardancy in fabrics.When used as a dyeing and printing auxiliary agent,it can improve product adhesion and brightness,and can also be used as a non-silicone polymer stabilizer for bleaching.

　　Mining and Metallurgical Industry:In the mining process,the application of polyacrylamide flocculation can promote the settling of agglomerates,the clarification of liquids,and the dehydration of mud cakes,thereby improving production efficiency,reducing tailings loss and water consumption,lowering equipment investment and processing costs,and avoiding environmental pollution.Uranium ore extraction is one of the earliest and most important applications of polyacrylamide.Adding polyacrylamide during the concentration and filtration of the leachate from uranium ore using acid or sulfonate solutions is highly effective.

　　In the construction industry,polyacrylamide can increase the hardness of gypsum cement and accelerate the dehydration of asbestos cement.It can also be used as a protective coating for natural or synthetic leather and as a granulation aid for inorganic fertilizers.

　　Polyacrylamide,with its unique flocculating,thickening,drag-reducing,and reinforcing properties,has been widely used in various fields such as industry,agriculture,and medicine.With continuous technological advancements and increasing demand,the application prospects of polyacrylamide will be even broader.In the future,researchers will continue to explore new properties and applications of polyacrylamide,developing more efficient and environmentally friendly formulations.