Polyacrylamide (PAM for short) is a polymer with the molecular formula (-CH2CHCONH2-), which is made from the monomer acrylamide. It has a linear chain structure.PAM is highly absorbent and forms a soft gel when hydrated. The performance characteristics of polyacrylamide depend on its molecular weight, crosslink density and functional groups. The molecular weight of polyacrylamide determines its viscosity and gel strength. The crosslink density determines its mechanical strength and resistance to degradation. Functional groups can be used to modify the properties of polyacrylamide such as flocculation ability, water retention ability and biocompatibility. Polyacrylamides are mainly used in the water treatment, paper and mining industries.

Polyacrylamide is usually considered non-toxic. It is generally safe to use polyacrylamide properly. However, it is important to avoid ingesting or inhaling polyacrylamide and to follow the manufacturer's instructions for use.

Physical and Chemical Properties

Polyacrylamide is a polyolefin. It can be thought of as polyethylene with amide substituents on alternate carbon atoms. Unlike various nylons, polyacrylamide is not a polyamide because there is no amide group in the polymer backbone. The alternating carbon atoms in the backbone are stereospecific (commonly known as: chiral) due to the presence of amide (CONH2) groups. Thus, polyacrylamides are available in three forms: atactic, para- and homo-graphic, but there has been little discussion in this regard. Polymerization is initiated by free radicals and is assumed to be stereo-random.

Copolymers and modified polymers

Linear polyacrylamide is a water-soluble polymer. Other polar solvents include dimethyl sulfoxide and various alcohols. N,N-methylenebisacrylamide can be used for cross-linking. Some crosslinked materials are soluble but insoluble, i.e. they are hydrogels.

Partial hydrolysis occurs at elevated temperatures in aqueous media, converting some of the amide substituents to carboxylates. This hydrolysis makes the polymer particularly hydrophilic. Polymers derived from N,N-dimethylacrylamide are less susceptible to hydrolysis.

Acrylamide copolymers include acrylic acid copolymers.

Uses of Polyacrylamides

The main use of polyacrylamide is in water treatment. Other uses include: pulp processing and paper additives, petroleum and mineral industries.


One of the main uses of polyacrylamide is to flocculate solids in liquids. This process is used in water treatment as well as in processes such as paper and screen printing. Polyacrylamide can be supplied in powder or liquid form, with the liquid form being subdivided into solution and emulsion polymers.

Although these products are often referred to as "polyacrylamides", many of them are actually copolymers of acrylamide with one or more other substances such as acrylic acid or its salts. These copolymers have improved wettability and solubility.

The ionic form of polyacrylamide plays an important role in the drinking water treatment industry. Trivalent metal salts (such as ferric chloride and aluminum chloride) are bridged by the long polymer chains of polyacrylamide. This greatly increases the flocculation rate. In this way, water treatment plants are able to greatly improve the removal of total organic content (TOC) from raw water.

Fossil fuel industry

In the oil and gas industry, polyacrylamide derivatives (especially copolymers) can have a significant impact on production by increasing viscosity to enhance oil recovery. Low concentrations of polyacrylamide polymers can produce high viscosity aqueous solutions, the injection of which can improve the economics of conventional water injection. In another application, hydraulic fracturing can also reduce drag by injecting these solutions. These applications use large quantities of polymer solutions at concentrations of 30-3000 mg/liter.

Soil Amendment

The primary function of polyacrylamide soil amendments is to increase soil loaminess, aeration and porosity, and to reduce compaction, dust and water loss. Secondary functions are to increase plant vigor, color, appearance, rooting depth and seed germination while reducing water demand, disease, erosion and maintenance costs.

Some new research areas for polyacrylamide:

The use of polyacrylamides to remove contaminants from water and wastewater. For example, polyacrylamide has been used to remove heavy metals, pesticides and organic pollutants from water.

Use of polyacrylamide to create new materials with better properties. Examples include sensors to detect contaminants in water, actuators to control fluid flow, and scaffolds for tissue engineering.

Developing new ways to synthesize polyacrylamides that are more environmentally friendly. For example, researchers are developing ways to synthesize polyacrylamide from renewable resources such as corn starch.