Yes, polyacrylamide (PAM) can be used in cosmetics, but you need to pay attention to its specific functions and safety specifications. The following is the key information of the comprehensive search results:

1. The role of polyacrylamide in cosmetics

• Moisturizing and film-forming: Polyacrylamide can absorb moisture, increase the water content of the stratum corneum, form a protective film, and reduce skin moisture loss.
• Antistatic: It reduces static electricity generated by friction through hygroscopicity and improves the feel of product use, especially in hair care and skin care products.
• Stable formula: As a binder and stabilizer, it helps other ingredients to be evenly dispersed and extend the shelf life of cosmetics.
• Absorption cleaning: It can absorb oil and dirt on the surface of the skin and assist the efficacy of cleaning products.

2. Safety and potential risks

• Acrylamide monomer residue problem: Polyacrylamide itself is highly stable, but acrylamide monomer (neurotoxin and potential carcinogen) may remain during the production process. International standards strictly limit its residual amount (such as the EU requires that the residual amount of acrylamide in cosmetics is ≤0.1mg/kg).
• Skin irritation: Some people may be sensitive to polyacrylamide, and long-term use of high-concentration products may cause dry skin or allergic reactions.
• Usage suggestions: Choose a regular brand to ensure that the product meets safety standards.

3. Avoid direct contact with damaged skin or mucous membranes.

If redness, swelling, itching, etc. occur after use, stop using it immediately and consult a doctor.

III. Typical application scenarios

Skin care products: such as lotions and creams as thickeners and moisturizers.

Hair care products: used for anti-static and smooth hair.

Cleaning products: assist in absorbing oil and improving cleaning effects.

Polyacrylamide has multiple functions in cosmetics, but the purity of raw materials and production processes must be strictly controlled to reduce the risk of acrylamide residues. Consumers should pay attention to the product ingredient list and safety certification, and reasonably choose and use related products.

The main raw materials and synthesis-related components of anionic polyacrylamide (APAM) are as follows:

1. Main monomer raw materials

Acrylamide (AM): As a basic monomer, it forms a polyacrylamide skeleton through polymerization reaction. Acrylamide is usually prepared by catalytic hydrolysis of acrylonitrile.

Acrylic acid (AA) or sodium acrylate: used to introduce anionic groups (such as carboxylic acid groups) through copolymerization or hydrolysis reaction. For example, in the copolymerization method, acrylamide is directly mixed with acrylic acid/sodium for reaction, while in the hydrolysis method, carboxyl groups are generated by reacting polyacrylamide with alkali (such as NaOH).

2. Auxiliary raw materials

• Initiator: An oxidation-reduction system such as potassium persulfate is used to start free radical polymerization.
• Alkaline substances: Such as sodium hydroxide, which is used to catalyze the conversion of amide groups into carboxylic acid groups in the hydrolysis process.
• Other additives: May include stabilizers (to prevent the polymerization process from being too fast), solubilizers (to improve solubility), etc.

3. Synthesis method

Copolymerization method: Directly mix acrylamide and acrylic acid/sodium monomers for copolymerization to generate anionic polyacrylamide in one step.

Homopolymerization followed by hydrolysis: first synthesize polyacrylamide homopolymer, and then introduce anionic groups by alkaline hydrolysis.

4. Influence of raw material selection

Raw material purity directly affects the molecular weight and solubility of the product. For example, impurities will reduce the efficiency of the polymerization reaction.

The monomer ratio (such as n(AM)/n(AA)) affects the charge density and application performance of the final product.

5. Related derivative raw materials

If other processes (such as inverse emulsion polymerization or precipitation polymerization) are used, solvents (such as white oil) and emulsifiers may be involved.

If you need specific raw material ratios or process optimization details, please refer to the synthesis case literature.

Pall rings and Intalox saddles are both types of random packing used in industrial processes to enhance mass transfer in packed columns. However, they differ in design, performance characteristics, and specific applications. Here’s a detailed comparison:

Design:

1. Pall Rings:

   Shape: Cylindrical with an open structure and internal struts.

   • Surface Area: Provides a high surface area due to the internal and external geometry.
   • Material: Made from metal, plastic, or ceramic.

      

     Intalox Saddles:

   •  

     • Shape: Saddle-shaped with a contoured surface and open structure.
     • Surface Area: Offers a large surface area due to the saddle shape.
     • Material: Typically made from ceramic, plastic, or metal.

    

Performance Characteristics:

1. Pall Rings:

   • Efficiency: High mass transfer efficiency due to excellent gas-liquid contact.
   • Pressure Drop: Low pressure drop, making them energy-efficient.
   • Capacity: High capacity for gas and liquid flow.
   • Mixing: Promotes turbulent flow, enhancing mixing and mass transfer.

2. Intalox Saddles:

   • Efficiency: High mass transfer efficiency with good gas-liquid distribution.
   • Pressure Drop: Very low pressure drop, even lower than pall rings.
   • Capacity: High capacity, often higher than pall rings.
   • Mixing: Provides uniform liquid distribution and good mixing.

Applications:

1. Pall Rings:

   • Suitable for a wide range of applications, including distillation, absorption, and stripping.
   • Often used in processes requiring high efficiency and low pressure drop.

2. Intalox Saddles:

   • Ideal for applications requiring very low pressure drop and high capacity.
   • Commonly used in distillation, absorption, and other mass transfer operations, especially in processes where minimizing energy consumption is critical.

Advantages:

1. Pall Rings:

   • Robust design with high durability.
   • Versatile and suitable for various industries and processes.

2. Intalox Saddles:

   • Excellent liquid distribution and low pressure drop.
   • High capacity and efficiency, making them suitable for large-scale operations.

Summary:

While both pall rings and Intalox saddles are effective in enhancing mass transfer, the choice between them depends on specific process requirements. Pall rings are known for their robustness and versatility, while Intalox saddles are preferred for their superior liquid distribution and extremely low pressure drop. Selecting the appropriate packing can optimize process efficiency and reduce operational costs.

Support Plate:

1. Design:

   • Flat or slightly curved plates with openings (holes, slots, or grids) to allow the passage of gas and liquid.
   • Typically made from metal, plastic, or composite materials.

2. Function:

   • Primary Role: To provide a stable base for the packing material and distribute the weight evenly.
   • Flow Distribution: Ensures uniform distribution of gas and liquid across the packing bed.
   • Drainage: Allows liquid to drain effectively while preventing excessive hold-up or flooding.

3. Applications:

   • Used in both random and structured packing systems.
   • Suitable for a wide range of industries, including chemical, petrochemical, and environmental.

4. Advantages:

   • Simple and robust design.
   • Provides excellent support and drainage capabilities.

Hump Support:

1. Design:

   • Curved or arched plates with a "hump" shape, often with openings for gas and liquid flow.
   • Made from materials such as metal or plastic.

2. Function:

   • Primary Role: To support the packing material while minimizing pressure drop and improving liquid distribution.
   • Enhanced Drainage: The hump shape facilitates better liquid drainage and reduces the risk of liquid pooling.
   • Gas Flow Optimization: The design allows for smoother gas flow, reducing resistance and energy consumption.

3. Applications:

   • Commonly used in columns with high liquid flow rates or where minimizing pressure drop is critical.
   • Ideal for applications involving random packing.

4. Advantages:

   • Improved liquid and gas distribution compared to flat support plates.
   • Lower pressure drop, leading to energy savings.
   • Reduces the risk of flooding and channeling.

Key Differences:

1. Design:

   • Support plates are typically flat or slightly curved, while hump supports have a distinct arched or hump-like shape.

2. Pressure Drop:

   • Hump supports are designed to minimize pressure drop more effectively than flat support plates.

3. Liquid Drainage:

   • Hump supports offer better liquid drainage due to their arched design, reducing the risk of liquid hold-up.

4. Application Specificity:

   • Support plates are more versatile and widely used, while hump supports are often chosen for specific applications requiring optimized flow and drainage.

Comparison Summary:

The process of processing mud into a body with a certain shape is called forming. The formed body has a denser and uniform structure and a certain strength.

1. Molding method

The commonly used molding methods for producing refractory brick products are as follows:

(1) Grouting molding

The mud is injected into the plaster mold, and the plaster mold absorbs the moisture in the mud and accumulates on the surface of the plaster mold to form a mud film with less water. The longer the time, the thicker the accumulated mud film. The time for placing the plaster mold after grouting is mainly determined based on the required thickness of the product. When the required thickness of the green body is reached, the excess mud in the plaster mold is poured out and left for a certain period of time. After the green body has a certain strength, it is demoulded, dried and repaired. The moisture content of the mud used for grouting molding is generally 35 to 45%. This method is mainly used to produce thin-walled hollow products, such as thermowells, high-temperature furnace tubes and crucibles.

(2) Plastic molding

Plastic molding (also called extrusion molding) generally refers to the method of making clay materials in a plastic state with a water content of 16 to 25%. The molding method of making the plastic mud materials pass through the die holes with force is called extrusion molding. A continuous spiral mud extruder or blade mixer is usually used in conjunction with a hydraulic press to mix, compact and shape the mud. This molding method is suitable for processing plastic mud materials into strips and tubes with uniform cross-sections.

(3) Machine pressing molding

Machine press molding is also called semi-dry molding, which refers to the method of preparing a green body from mud with a moisture content of about 2 to 7%. Generally, various brick presses, tamping machines, and vibration machines are used for molding. Compared with plastic molding, the green body has the advantages of high density, high strength, small drying and firing shrinkage, and easy control of product size. Semi-dry molding is a commonly used molding method.

(4) Casting and molding

This is a method in which materials are melted at high temperatures and then directly cast into products. Currently it is mainly used to produce advanced refractory materials such as fused corundum, mullite and zirconium corundum.

Other molding methods for refractory materials include hot press molding and hot press injection molding. At present, refractory products are mainly formed by machine pressing. The following focuses on machine press molding.

2. Machine pressing molding

(1) Suppression process

The pressing process of ordinary machine-pressed bricks is essentially a process in which the particles in the mud material are densely packed and the air is discharged to form a dense body. Usually expressed by pressure-shrinkage curve. As can be seen from Figure 3-7, the pressing process is carried out in several stages. In the first stage, the mud particles move under pressure to form a green body. Its characteristic is that the mud material has a large compression amount, and the compression amount increases almost in proportion to the pressure; when the green body is compressed to a certain extent, it enters the second stage of the pressing process. At this stage, the molding pressure has increased to the extent that the particles in the clay material can undergo brittle and elastic deformation. Therefore, during the pressing, the particles in the clay material are compressed and deformed and the edges of the polygonal particles are pressed away, thus causing the inside of the green body to become brittle and elastic. The contact surface between particles increases and the frictional resistance increases. Therefore, the pressing characteristics at this stage show a jump-like compression change, that is, a step-shaped change curve; when pressing enters the third stage, the molding pressure has exceeded the critical pressure, and even if the pressure increases again, the green body will almost no longer is compressed.

It is not desirable to carry out all three stages in refractory production. Because when the bricks are formed, it is required that the particles are not crushed but only move densely and eliminate air. Therefore, the actual pressing process of bricks is generally carried out in the first stage.

The above-mentioned pressing characteristics of the bricks indicate that the greater the natural packing density of the mud, the smaller the friction between particles, the greater the compression of the mud when subjected to unit pressure, and the higher the volume density of the bricks. Therefore, adding some organic activators to the mud material can increase the mobility of the particles in the mud material and reduce the friction between the mud material and the mold wall, which can improve the compactness of the dysenindustrial bricks.

(2) Layer density phenomenon

The phenomenon that the density of the brick after molding gradually changes along the direction of pressure is called layer density. Bricks that are unidirectionally pressurized from above are generally dense at the top and sparse at the bottom. If they are at the same level, they are dense in the middle and sparse at the outside. The reasons for different density levels on the same brick are mainly due to the friction between particles in the mud material (called internal friction) and the friction between the mud material and the mold wall during the pressing process (called external friction). . When the bricks are pressed, the upper material layer is pressed first, and the pressure is transmitted down layer by layer in the direction of pressure. During the transmission process, part of the pressure is consumed in overcoming internal and external friction, so the pressure decreases. This causes inhomogeneity, the farther away the brick is from the pressure surface along the pressure direction, the lower the density, that is, as shown in Figure 3-8, D1>D2>D3.

The layer density phenomenon when pressing bricks is more obvious for bricks with large thickness and height, which is closely related to the degree of pressure decrease of pressing the above products.

In the production of refractory materials, in order to reduce or eliminate the layer density phenomenon produced during brick pressing, the following methods are usually adopted:

1) For products with large thickness and height, double-sided pressurization is generally used to shorten the pressure transmission distance and reduce the degree of pressure decline.

2) Improve the processing accuracy of the template and apply lubricating oil on the mold wall to reduce the friction between the mud and the mold wall.

3) Add some activators (such as pulp waste liquid, etc.) into the mud to reduce the friction in the mud during pressing.

4) Isostatic pressing is used, and multiple pressurization is used during the brick pressing operation.

Polyacrylamide conductive hydrogels are a type of smart material that combines the electrical conductivity of a conductive polymer with the unique properties of a hydrogel. These hydrogels have various applications, including bioelectronics, tissue engineering scaffolds, and sensors. Here's a general overview of the preparation and properties of polyacrylamide conductive hydrogels:

Preparation:

1. Synthesis of polyacrylamide (PAM): Polyacrylamide is often synthesized by free radical polymerization of acrylamide monomers. The reaction can be initiated using a chemical initiator or photochemical initiation.

2. Introduction of conductivity: To impart conductivity to the hydrogel, a conductive polymer, such as polypyrrole (PPy) or polyaniline (PANI), is often incorporated into the PAM matrix. This can be achieved through in-situ polymerization or by mixing pre-formed conductive polymer particles with the PAM solution.

3. Crosslinking: Crosslinkers are added to the PAM solution to form a three-dimensional network structure, giving the hydrogel its gel-like properties. Common crosslinkers include N,N'-methylenebisacrylamide (BIS) or poly(ethylene glycol) diacrylate (PEGDA). Crosslinking can be achieved by thermal, chemical, or photochemical methods.

4. Swelling and purification: The hydrogel is usually immersed in a solvent, such as water, to allow it to swell and remove any unreacted monomers or chemicals. The purification process is often repeated to ensure the removal of impurities.

Properties:

1. Electrical conductivity: The incorporation of a conductive polymer into the hydrogel matrix imparts electrical conductivity to the resulting material. This electrical conductivity allows for the transmission of electrical signals or the sensing of electrical stimuli.

2. Swelling behavior: Hydrogels have a high water content and can absorb large amounts of water or biological fluids. The swelling behavior of the polyacrylamide conductive hydrogel can be controlled by varying the crosslinking density, pH, temperature, or the addition of specific ions or molecules.

3. Mechanical properties: The mechanical properties of polyacrylamide conductive hydrogels can be tailored by adjusting the crosslinking density or incorporating reinforcing fillers or fibers. This allows for the development of hydrogels with specific elasticity, strength, and toughness suitable for various applications.

4. Biocompatibility: Polyacrylamide is generally considered biocompatible, and conductive hydrogels based on PAM have been extensively utilized in tissue engineering and biomedical applications. However, the biocompatibility of the hydrogel can be further enhanced by incorporating bioactive molecules or modifying the surface to promote cell adhesion and growth.

5. Stimuli-responsiveness: Hydrogels, including conductive ones, can exhibit stimuli-responsiveness when specific chemical or physical conditions change. For example, pH-sensitive hydrogels can undergo volume changes in response to changes in pH, while thermo-responsive hydrogels can change their properties with temperature variations.

Polyacrylamide conductive hydrogels offer a unique combination of electrical conductivity and hydrogel properties, making them versatile materials with a wide range of potential applications in various fields.

To perform a turbidity test on polyacrylamide, you can follow these general steps:

1. Prepare a polyacrylamide solution: Dissolve a known amount of polyacrylamide in a suitable solvent, such as water or a buffer solution, according to the desired concentration. Ensure that the polyacrylamide is completely dissolved before proceeding.

2. Set up a spectrophotometer: Calibrate the spectrophotometer at the appropriate wavelength (usually in the visible range) according to the instrument's instructions.

3. Fill cuvettes: Fill a cuvette or test tube with the prepared polyacrylamide solution. Fill another cuvette with the solvent used for dissolving the polyacrylamide (e.g., water or buffer solution) as a blank.

4. Measure the blank: Place the blank cuvette into the spectrophotometer and measure the absorbance of the blank solution using the calibrated wavelength. Note down the reading.

5. Measure the sample: Replace the blank cuvette with the cuvette containing the polyacrylamide solution. Measure the absorbance of the polyacrylamide solution using the same wavelength and note down the reading.

6. Calculate the turbidity: The turbidity of the polyacrylamide solution can be determined by comparing the absorbance of the sample to that of the blank. The higher the absorbance, the higher the turbidity. This can be calculated using the following formula:

   Turbidity = Absorbance_sample - Absorbance_blank

Keep in mind that the specific details and requirements of the turbidity test may vary depending on the intended purpose and the properties of the polyacrylamide being tested. It's always a good idea to consult any relevant protocols, standards, or specific procedures provided by regulatory bodies or scientific literature in your field.

Polyacrylamide, a synthetic polymer, has several applications in the cosmetic industry due to its unique properties. Some of the common applications of polyacrylamide in cosmetics include:

1. Thickening Agent: Polyacrylamide can act as a thickening agent in cosmetic formulations. It helps increase the viscosity of creams, lotions, and gels, providing a smooth and desirable texture to the products.

2. Stabilizer: It is used as a stabilizer in cosmetic emulsions, preventing the separation of oil and water phases. Polyacrylamide enhances the stability of emulsions such as creams, foundations, and moisturizers, ensuring a uniform distribution of ingredients.

3. Film-Forming Agent: Polyacrylamide is often utilized as a film-forming agent in cosmetics. It creates a thin film on the skin's surface, providing a protective barrier and assisting in improving the longevity of makeup, such as long-wear foundations, eyeliners, and mascaras.

4. Suspending Agent: It can be employed as a suspending agent to prevent the settling of solid particles in cosmetic formulations. Polyacrylamide helps maintain an even distribution of pigments, exfoliating particles, and other ingredients in products like scrubs, serums, and masks.

5. Texturizer: Polyacrylamide can modify the texture of cosmetic products. It imparts a silky, smooth, or gel-like texture to various formulations, enhancing the sensory experience for the users.

6. Hair Care Products: Polyacrylamide finds application in hair care products such as hair gels, mousses, and styling products. It provides hold, volume, and control to hairstyles, allowing for increased manageability and style retention.

It's important to note that the safety and efficacy of cosmetic ingredients, including polyacrylamide, are regulated by various authorities, and manufacturers must adhere to specific guidelines and standards to ensure consumer safety.

Polyacrylamide (PAM) is widely used in China, and its usage ratio changes dynamically according to industry demand and technological development. The following is a detailed analysis of the main application areas and their ratios, combined with the latest industry data and development trends:

I. Main application areas and ratios

1. Oilfield exploitation (about 81%)

• Application scenarios: As an oil displacement agent and drilling mud conditioner, it is used to improve crude oil recovery (tertiary oil recovery technology). Domestic Daqing, Shengli and other oil fields have significantly improved crude oil recovery by injecting PAM aqueous solution to improve the oil-water flow rate ratio.
• Technical features: High molecular weight PAM can increase oil displacement capacity and reduce mining costs, especially in low permeability reservoirs.

2. Water treatment (about 9%)

• Application scenarios: Mainly used for urban sewage treatment (sludge dehydration), industrial wastewater treatment (such as printing and dyeing, electroplating wastewater) and drinking water purification. As a high-efficiency flocculant, PAM can accelerate the sedimentation of suspended particles and reduce sludge volume.
• Growth trend: As environmental protection policies become stricter, the demand growth rate in the water treatment field is the fastest, and it is expected that the proportion will continue to increase in the future.

3. Papermaking (about 5%)

• Application scenarios: As a retention aid, filter aid and dry enhancer, it can improve paper strength, reduce fiber loss, and be used for papermaking wastewater treatment. Anionic PAM can improve filler retention and reduce production costs.
• Market potential: The domestic papermaking industry has a strong demand for PAM, especially in the production of high-end paper products.

4. Mines (about 2%)

Application scenarios: used for mineral processing wastewater treatment, coal washing wastewater sedimentation and tailings concentration. PAM recovers useful mineral particles through flocculation to reduce resource waste.

5. Other fields (about 3%)

• Agriculture: as a soil water retainer and fertilizer slow-release agent, it improves crop drought resistance.
• Textile printing and dyeing: used for wastewater treatment and fabric finishing to reduce dye residues.
• Medicine and building materials: have specific applications in drug separation, gypsum reinforcement and other fields.

II. Industry development trend

The fastest growth in water treatment and papermaking: driven by environmental protection policies and industrial upgrades, it is expected that the proportion of water treatment will exceed 10%, and the annual growth rate of demand in the papermaking field will reach 8%.

Oilfield exploitation is still the core market: Although tertiary oil recovery technology is mature, the oil industry's reliance on PAM is difficult to replace in the short term and will still dominate in the future.

Emerging application expansion: Agricultural water retaining agents, highly absorbent materials and other sub-sectors are gradually emerging and may become future growth points.

Regional and enterprise distribution

• Production concentration: 53% of domestic PAM production capacity is concentrated in East China (such as Shandong and Jiangsu), and major companies include PetroChina Daqing Refining and Chemical, Beijing Hengju, etc.
• Technology upgrade: New processes such as microbial catalysis improve product purity and promote the localization of high-end PAM (such as ultra-high molecular weight type).

If you need more complete industry data or specific cases, you can further refer to other sources.

Preparation:

Instruments: Prepare a 721 spectrophotometer (or other spectrophotometers that meet the requirements), an electronic balance, a stoppered conical flask, a magnetic stirrer, a thermometer, a volumetric flask, etc.

Reagents:

• Polyacrylamide (HPAM) powder, determine its molecular weight, degree of hydrolysis and other parameters.
• Sodium hypochlorite (NaClO) solution: Use analytical grade sodium hypochlorite and prepare a sodium hypochlorite solution with a weight concentration of 1.31% with distilled water.
• Acetic acid (CH₃COOH) solution: Use analytical grade glacial acetic acid and prepare an acetic acid aqueous solution with a concentration of 5mol/L with distilled water.

Sample dissolution:

• Use an electronic balance to accurately weigh a certain mass (such as 1g) of polyacrylamide sample.
• Add the weighed sample to a stoppered conical flask containing an appropriate amount of distilled water (such as 100ml).
• Place the conical flask on a magnetic stirrer, set a certain speed (such as 200 rpm) for stirring, and use a thermometer to monitor the solution temperature. Record the time from the start of stirring to the complete dissolution of polyacrylamide, and observe whether the solution has lumps, turbidity, etc. during the dissolution process.

Turbidity test:

• Use a pipette to transfer a certain amount (such as 5ml) of dissolved polyacrylamide solution to a new clean volumetric flask.
• Add a certain amount (such as 2ml) of acetic acid solution to the volumetric flask to make the solution acidic.
• Then add a certain amount (such as 2ml) of prepared sodium hypochlorite solution. At this time, polyacrylamide reacts chemically with sodium hypochlorite in the acidic solution to generate insoluble chloramine, making the solution turbid.
• After shaking quickly, place the volumetric flask in an environment with a set temperature (depending on the experimental requirements, generally 18-25℃) to react for a certain time (such as 25min).
• After the reaction is completed, the solution is transferred to a cuvette and placed in a spectrophotometer to measure its absorbance at a specific wavelength (such as 472nm). The absorbance value can indirectly reflect the turbidity of the solution.

Result recording and analysis:

Record the absorbance value obtained for each measurement. If multiple sets of parallel experiments are performed, calculate the average value and deviation.

According to the pre-drawn standard curve of the relationship between turbidity value and polyacrylamide concentration (under the optimal test conditions, use polyacrylamide solutions of different known concentrations according to the above steps, with absorbance as the ordinate and concentration as the abscissa), the measured absorbance value is used to determine the concentration of polyacrylamide in the sample or evaluate the dissolution turbidity. If the turbidity of the dissolved solution is abnormal, the cause needs to be analyzed, such as whether the dissolution is insufficient, resulting in undissolved particles affecting the turbidity, or the reaction conditions are not well controlled, etc.