Полиакриламид: свойства, применение и безопасность.

Polyacrylamide (abbreviated as PAM or pAAM) is a polymer with the formula ( CH2CHCONH2 ). It has a linear chain structure. PAM is highly water absorbent, forming a soft gel when hydrated. In 2008, an estimated 750,000,000 kg were produced, mainly for water treatment and the paper and mineral industries.

Polyacrylamide is a polyolefin. It can be viewed as polyethylene with amide substituents on alternating carbons. Unlike various nylons, polyacrylamide is not a polyamide because the amide groups are not in the polymer backbone. Owing to the presence of the amide (CONH2) groups, alternating carbon atoms in the backbone are stereogenic (colloquially: chiral). For this reason, polyacrylamide exists in atactic, syndiotactic, and isotactic forms, although this aspect is rarely discussed. The polymerization is initiated with radicals and is assumed to be stereorandom. The next major application by weight is additives for pulp processing and papermaking. About 30% of polyacrylamide is used in the oil and mineral industries.

The primary functions of polyacrylamide soil conditioners are to increase soil tilth, aeration, and porosity and reduce compaction, dustiness and water run off. Typical applications are 10 mg/L, which is still expensive for many applications. and of Raymond and Weintraub The technique is widely accepted today, and remains a common protocol in molecular biology labs. Acrylamide has other uses in molecular biology laboratories, including the use of linear polyacrylamide (LPA) as a carrier, which aids in the precipitation of small amounts of nucleic acids (DNA and RNA). Many laboratory supply companies sell LPA for this use. In addition, under certain conditions, it can be used to selectively precipitate only RNA species from a mixture of nucleic acids. This property makes polyacrylamide useful in the field of mechanobiology, as a number of cells respond to mechanical stimuli.

The polymer is also used to make Gro Beast toys, which expand when placed in water, such as the Test Tube Aliens. Similarly, the absorbent properties of one of its copolymers can be utilized as an additive in body powder. It has been used in Botox as a subdermal filler for aesthetic facial surgery (see Aquamid). It was also used in the synthesis of the first Boger fluid.

Considering the volume of polyacrylamide produced, these materials have been heavily scrutinized with regards to environmental and health impacts. Polyacrylamide is of low toxicity but its precursor acrylamide is a neurotoxin and carcinogen. Considerable effort is made to scavenge traces of acrylamide from the polymer intended for use near food. The single claim that polyacrylamide reverts to acrylamide has been widely challenged. Polyacrylamide is most commonly partially biodegraded by the action of amidases, producing ammonia and polyacrylates. Polyacrylates are hard to biodegrade, but some soil microbe cultures have been shown to do so in aerobic conditions.