Degradation of Polymers

Degradation of Polymers

 

the breakdown of macromolecules owing to heat, oxygen, moisture, light, penetrating radiation, mechanical stresses, biological agencies (for example, by the action of microorganisms), and other factors. Depending on the agent, the following forms of polymer degradation are distinguished: thermal, thermal oxidative, photochemical, hydrolytic, and radiation, among others. Usually several types of degradation processes take place simultaneously in a polymer; for example, making a polymer into a product, it undergoes thermal, thermal oxidation, and mechanical forms of degradation.

The degradation leads to a decrease in the polymer’s weight, and its structure and physical and chemical properties alter, that is, it ages and often becomes unsuitable for practical use. However, polymer degradation is not always undesirable. Thus, for example, the process is used in the mechanical synthesis of various block and graft copolymers, in the plasticization of rubber, and in the production of valuable low-molecular-weight substances (for example, glucose) from natural polymers. The study of degradation makes it possible to work out the scientific foundations and practical methods of stabilizing polymers.

V. S. PAPKOV

References in periodicals archive ?
On the other hand, degradation of polymers was investigated by TGA where Tg and Mn, Mw values were obtained from DSC curves and GPC, respectively.
We attempted to differentiate between mechanical and thermal factors affecting degradation of polymers and distinguish the relative importance of the two mechanisms.
Composites of inorganic particles with polymers is an interesting research subject because of the important potential applications in photocatalytic degradation of polymers, the production of controlled release products such as pesticides and drugs, and in the fields of adhesives, textiles, optics, and electronics.
These additives can be used to prevent degradation of polymers during the manufacturing process, protect against environmental impact, or enhance physical properties like heat or light resistance of the polymer.
He was a Postdoctoral Fellow at Glasgow University, 1970-1972, studying thermal degradation of polymers.
21) Although detailed mechanism for chemical degradation of PU in the UVO cleaner needs further study, it is reasonable to conclude that in the UVO-cleaner condition, ZnO nanoparticles reduce the degradation of polymers (act as a pholostabilizer), while in the SPHERE exposure condition, they accelerate the photodegradation of polymers (act as a photocatalyst).
Chemical/physical degradation of polymers and rebounding of coatings are the major phenomena affecting the durability of anticorrosion protection.
Nonstaining, nondiscoloring Wingstay phenolic antioxidants provide long-term protection against aging and degradation of polymers.
These benefits are achieved without sacrificing the quality of the process, resulting in less degradation of polymers, pigments, and/or additives, notes Ampacet.
on Advances in the Stabilization and Controlled Degradation of Polymers, Zurich, Switzerland, June, 1983.
His industry and academic career spans more than 30 years in the fields of polymers, and his research interests include characterization, flame retardancy, thermodynamics and degradation of polymers, pyrolysis, and adhesives.