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Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition. Polymers and particularly plastics are subject to degradation at all stages of their product life cycle , including during their initial processing, use, disposal into the environment and recycling. [ 1 ]
Enzyme-based microbial biodegradation can occur under two conditions: aerobic and anaerobic. Plastics are typically made up of hydrophobic polymers, so the first step of biodegradation under both conditions involves the breakdown of the polymer by the enzyme into smaller constituents such as oligomers, dimers, and monomers. [6]
That is, the polymer is unstable in a water based environment. This is the prevailing mechanism for the polymers degradation. This occurs in two stages. 1. Water penetrates the bulk of the device, attacking the chemical bonds in the amorphous phase and converting long polymer chains into shorter water-soluble fragments.
Plastic degradation in marine bacteria describes when certain pelagic bacteria break down polymers and use them as a primary source of carbon for energy. Polymers such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) are incredibly useful for their durability and relatively low cost of production, however it is their persistence and difficulty to be properly ...
The breakdown of these polymers depend on a variety of factors including the polymer and also, the environment the polymer is in. Polymer properties that influence degradation are bond type, solubility, and copolymers among others. [2] The surrounding environment of the polymer is just as important as the polymer structure itself.
Purine degradation takes place mainly in the liver of humans and requires an assortment of enzymes to degrade purines to uric acid. First, the nucleotide will lose its phosphate through 5'-nucleotidase. The nucleoside, adenosine, is then deaminated and hydrolyzed to form hypoxanthine via adenosine deaminase and nucleosidase respectively.
The biocompatibility of this polymer is generally determined by the products that it degrades into, as well as the rate of degradation into degradation products. The way that PLGA degrades is by means of an enzyme known as esterase , which forms lactic acid and glycolic acid.
Specific materials and their applications include polymer-protein and polymer-drug conjugates, mediation of enzyme activity, molecular recognition processes and polymeric micelles which can deliver a drug to a specific site in the body. [19] RAFT has also been used to graft polymer chains onto polymeric surfaces, for example, polymeric ...