polyesters of the general formula [—OAOOCA′CO—]n, produced by polycondensation of diacid chloride derivatives of dicarboxylic acids with dihydric phenols. In the above formula A is a phenol radical, most often 4,4’-dihydroxydiphenyl-2,2-propane, phenolphthalein, or 9,9-bis- (4-hydroxyphenyl)fluorene, and A’ is the dicarboxylic acid radical.

Polyarylates of aromatic dicarboxylic acids (mainly terephthalic and isophthalic acids) are of practical importance. These polyarylates, whose molecular weight is 100,000–160,000, have high softening points (200–360°C), good dielectric and mechanical properties, and high heat resistance (they begin to decompose only at about 300°C). They can withstand prolonged operation at 200°-280°c Polyarylates are also resistant to the action of fats, liquid fuels, and a number of organic solvents and dilute mineral acids, but they are not resistant to the action of alkalies, ammonia, and concentrated acids (for example, sulfuric and nitric acids). The highly crystalline polyarylate based on p- hydroxybenzoic acid, which is known by the trade name Ekonol (USA), is superior to polyimides in heat resistance (380°-400°C) and is similar to polyfluoroethylene resins in chemical resistance.

Polyarylates are processed by injection molding, extrusion, and compression molding; soluble polyarylates are processed from solutions in organic solvents. Polyarylates are used to make structural parts, films, fiber materials for the fine filtration of gases, and synthetic paper, mainly for electrical and radio engineering items.

The brands of polyarylates produced in the USSR are DV-101, F-l, and F-2.

A specific group of polyarlyates is the polycarbonates.


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References in periodicals archive ?
Miscible polyimide blends require polyester carbonates or polyarylates with at least 50 mole-% resorcinol-based aryl ester linkages.
Polyarylates are a family of polymers derived from the naturally occurring amino acid tyrosine (an "aryl" amino acid) and naturally occurring diacids, such as glutaric or adipic acid.
patent (28) and part of a chapter of a book (29) dealt with blends of poly(aryl ether ketones) and polyarylates.
Liquid-crystal polymers (LCPs) and polyarylates, representing separate, specialized segments of engineering TP polyesters, will not be reviewed in this article.
They used the thermoplastics such as polyetherimide, polyarylates, and polysulfone.
The inserts under investigation were created from polymers selected from a large combinatorial library of bioerodible polyarylates and polycarbonates, developed by the Rutgers University researchers and licensed to Lux Biosciences for ophthalmic use.
Potential applications of blends of PEI with polyarylates or carbonate-containing polymers have also been disclosed in several patents (9, 10).
Both polyarylates and polyestercarbonates belong within the amorphous polyester family (they're also related to polycarbonate), and are in the early stages of their life cycles.
TyRx was organized in 1998 to advance its core technology - a novel class of tyrosine-based biodegradable polymers, referred to as polyarylates.
The relaxation characteristics of the bisphenol-A polyarylates as a function of isophthalate content have been reported for both the glass-rubber and sub-glass relaxation regions (10).
Both of the licensed polymer families from Rutgers, known as polycarbonates and polyarylates, are derived from the amino acid tyrosine, a naturally occurring substance in the body and have been under extensive evaluation by others for various applications.
m] were useful indices of transesterification between PET or PBT and polyarylates.