Views: 3 Author: Site Editor Publish Time: 2023-04-07 Origin: Site
A polymer is a substance or material consisting of very large molecules called macromolecules, consisting of many repeating subunits.Due to their wide range of properties,synthetic and natural polymers play important and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are critical to biological structure and function.Polymers, whether natural or synthetic, are formed by the aggregation of many small molecules called monomers.Thus, their large molecular mass produces unique physical properties relative to small molecule compounds, including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals.The word "polymer" is derived from the Greek πολύς (polus, meaning "many") and μέρος (meros, meaning "part").The term was coined by Jöns Jacob Berzelius in 1833, but its definition differs from the modern IUPAC definition.The modern concept of polymers as covalently bonded macromolecular structures was proposed by Hermann Staudinger in 1920, and he spent the next decade seeking experimental evidence for this hypothesis.
Polymers are studied in the fields of polymer science (including polymer chemistry and polymer physics), biophysics, and materials science and engineering.Historically, products resulting from the linking of repeating units by covalent chemical bonds have been the primary focus of polymer science.An emerging and important field is now focused on supramolecular polymers formed by noncovalent linkages.Polyisoprene for latex is an example of a natural polymer and polystyrene for Styrofoam is an example of a synthetic polymer.In a biological context, essentially all biomacromolecules that is, proteins (polyamides), nucleic acids (polynucleotides), and polysaccharides—are pure polymers, or consist of mostly polymer components.
Polyglutamic acid (PGA) is a polymer of the amino acid glutamic acid (GA). Gamma PGA (poly-gamma-glutamic acid, γ-PGA) a form in which the peptide bond is located between the amino group of GA and the carboxyl group at the end of the side chain of GA is the main component of the Japanese food natto.Gamma PGA is fermented by bacteria form.Gamma PGA has a wide range of potential uses ranging from food, pharmaceuticals and cosmeceuticals  to water treatment.Another isomer, poly-alpha-glutamic acid, is used as a drug delivery system in cancer therapy and is being investigated for its use in the treatment of type 1 diabetes and its potential use in the production of AIDS vaccines.
Heavy metal removal
G-PGA is covalently incorporated into microfiltration membranes by attaching to the membrane pore surface, exhibiting ultrahigh heavy metal adsorption capacity.With a suitable low-pressure ultrafiltration technique, it was found that G-PGA could bind and effectively remove 99.8% of lead ions in water.