US 4,359,567 A · Thermooxidatively stable articulated p-benzobisoxazole and p-benzobisthiazole polymers

Abstract

Articulated p-benzobisoxazole and p-benzobisthiazole polymers which contain a limited number of 3,3'-biphenyl or 2,2'-bipyridyl segments are synthesized, with inherent viscosities as high as 14 dl/g being recorded. The 3,3'-biphenyl or 2,2'-bipyridyl segments in the p-benzobisoxazole and p-benzobisthiazole polymers impart flexibility to the polymers without adversely affecting the thermooxidative stability. While the resultant articulated polymers exhibit liquid crystalline behavior in methanesulfonic acid and form strong cast films from that solvent, they also exhibit thermooxidative stability comparable to other p-benzobisthiazole and p-benzobisoxazole polymers. The resultant films are useful for the fabrication of high strength laminates to be used in severe environment structural applications.

Claims6

Dependent claims

A thermooxidatively stable articulated polymer consisting essentially of recurring units having one of the following formulae:

##STR45## wherein Ar is a phenylene radical, Ar' is selected from the group consisting of biphenylene and bipyridylene radicals, and wherein the molar proportion of a ranges from about 0.80 to 0.97, b ranges from about 0.03 to 0.20, and the sum of a and b equals one.

Dependencies are inferred from the claim text.

Thermooxidatively stable articulated p-benzobisoxazole and p-benzobisthiazole polymers

Life of this patent

Thermooxidatively stable articulated p-benzobisoxazole and p-benzobisthiazole polymers

Life of this patent

Abstract

Claims6