Accession Number : AD0828189

Title :   STUDIES OF THE BREAKDOWN MECHANISM OF POLYMERS. II. THE THERMAL DECOMPOSITION OF SOME AROMATIC POLYESTERS AND A POLYARYLENESULFONATE.

Descriptive Note : Technical rept. Sep 66-Feb 67,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH

Personal Author(s) : Ehlers, Gerhard F. L. ; Fisch, Kurt R. ; Powell, Wilbert R.

Report Date : JAN 1968

Pagination or Media Count : 44

Abstract : The decomposition of four aromatic polyesters and one polyarylsulfonate has been studied. The breakdown of the ester linkage in aromatic polyesters may already occur to an appreciable extent below 350 C. It seems to cleave preferentially between the carbonyl and the oxygen, but to some extent also between the oxygen and the benzene ring. Some phenolic monomer is regenerated, apparently due to the presence of water, and found in the sublimate. The corresponding carboxylic acid presumable undergoes decarboxylation. The sublimate did not contain any acidic component. Recombination of the remaining polymer free radicals results in crosslinked polyphenylene-polyphenylene-oxide structures. They, in turn, decompose with ring cleavage above 450 C, to form polymer carbon, carbon monoxide, hydrogen, and some methane. A polyester with a propylene linkage showed, as expected, early loss of methane. Pendant pentyloxy chains in two of the polymers are removed almost completely below 350 C with formation of alkanes and alkenes. Lack of oxygen in the fragments indicates that the main cleavage must occur between the ether oxygen and the aliphatic chain, or within the aliphatic chain. Above 350 C, the fluoroaliphatic chain in one of the polyesters decomposes.

Descriptors :   *POLYMERS), *POLYESTER PLASTICS), (*DEGRADATION, (*AROMATIC COMPOUNDS, (*SULFONATES, POLYMERS), MASS SPECTROSCOPY, SUBLIMATION, METHANE, RECOMBINATION REACTIONS, FREE RADICALS, CROSSLINKING(CHEMISTRY), ALIPHATIC COMPOUNDS, PYROLYSIS, QUINONES, INFRARED SPECTRA, SPECTROPHOTOMETERS, PHTHALIC ACIDS, PHENYL ETHER, FLUORIDES, CHLORIDES.

Subject Categories : Polymer Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE