Polyarylates

Polyarylates

 

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.

REFERENCES

See References under .

P. M. VALETSKII

References in periodicals archive ?
Polyacetylenes, polyaniline, polyarylene ethers, polyarylates, polycarbonates, polyetherimides, polyethylene oxide, polyimides, polyphenylene oxides, polypyrroles, polysulfones, and amino groups such as polyethyleneimine blends, polymethacrylates are examples of polymeric membranes used for C[O.sub.2] separation [17, 216-218].
Robeson, "Polyarylates," in Engineering Thermoplastics: Properties and Applications, J.M.
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.
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.
First observed by Shih in 1991 while rubber-toughening polyarylates, phase inversion refers to a process in which the lower-viscosity minor component softens more rapidly than the higher-viscosity major component and initially forms the matrix (5).
Polyarylates containing phenyl phosphine oxide groups can be synthesized from cheap materials, are remarkably fire resistant, and can be made into high-performance systems or complexed with metals for high-performance adhesives.
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.
patent (28) and part of a chapter of a book (29) dealt with blends of poly(aryl ether ketones) and polyarylates. It was claimed that PEEK/PAr blends had, at most compositions, both notched Izod and tensile impact strengths significantly higher than those of either of the unblended constituents.
Potential applications of blends of PEI with polyarylates or carbonate-containing polymers have also been disclosed in several patents (9, 10).
Notable combinations include blends of PEEK with polyetherimides, polyimides, and polyarylates. In each case, the approach is to blend PEEK with an amorphous, high [T.sub.g] thermoplastic.