swelling

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swelling

an abnormal enlargement of a bodily structure or part, esp as the result of injury

Swelling

 

an increase in volume of solid bodies caused by their absorption of liquids or vapors from the environment. The capacity to swell is a characteristic property of bodies consisting of macromolecular compounds (polymers). Swelling is caused by diffusion processes, which are usually accompanied by solvation (the binding of a low-molecular-weight substance by a polymer).

A distinction is made between limited and unlimited swelling. In the first case the macromolecules are bonded fairly strongly, and swelling stops after having reached a certain limit. The swelled body retains its shape and a distinct boundary with the liquid phase. In the second case, mutual diffusion of the solvent and the polymer gradually leads to the disappearance of the interphase boundary between the swelling body and the liquid. Such swelling culminates in complete dissolution of the polymer. For example, limited swelling is exhibited by gel-like ion-exchange resins in water and by vulcanized rubber in benzene; unlimited swelling is exhibited by all polymers that are soluble in a particular solvent. In some cases, such as the gelatin-water system, limited swelling gives way to unlimited swelling with increasing temperature. Swelling is also a property of some minerals with a lamellar crystal lattice—for example, the montmorillonites. Upon swelling in water, such materials may undergo spontaneous dispersion, leading to the formation of highly disperse colloidal systems.

Swelling has wide use in industry and in everyday life. It frequently accompanies bonding of polymer materials, processing of polymers to produce various articles, production of rubber adhesives, and other processes, such as preparation of many foods and many natural processes (germination of seeds and spores).

REFERENCES

Tager, A. A. Fizikokhimiia polimerov. 2nd ed. Moscow, 1968. Page 314.
Voiutskii, S. S. Kurs kolloidnoi khimii. Moscow, 1964. Page 482.

L. A. SHITS

swelling

The volume increase caused by wetting, absorption of moisture, or chemical changes.
References in periodicals archive ?
Various thyroid swellings are studied for the history and clinical presentation.
Post-operative complications (pain and swelling) were assessed pre operatively and then on 3rd and 7th day post operatively using visual analogue scale and objective scale for swelling measurement using five anatomical points on face.
6 A rapidly growing swelling with a central crater filled with dead skin, and you may think it's skin cancer.
For all cases, regardless of the swelling media, the higher swellings were reached when the exposure time was 2 or 3 min.
Objective: To compare the specimen adequacy aspirated by various gauge (21 and 22) needles in external palpable swellings of lymph nodes, thyroid gland, salivary glands, breast and soft tissue.
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A 68-year old female, non-smoker was referred by her General Practitioner with a tender swelling in the left pre-auricular region.
Leukocytosis and neutrophilia were evident in horses due to swellings on the neck region before treatment.
Swellings was convicted along with Stephen Sorton, 17, who was jailed for at least 15 years, and Jordan Cunliffe, 16, jailed for a minimum of 12 years.
Swellings and fellow gang members Stephen Sorton, 17, and Jordan Cunliffe, 16, will be sentenced on February 11 at Chester Crown Court.
After the verdict it emerged that Swellings had been released from custody for an assault just hours before the attack.
One of the bail conditions, it has emerged, was that Swellings was to have kept out of Warrington.