Accession Number:

AD0608766

Title:

THERMAL DEGRADATION OF AN AROMATIC POLYPYROMELLITIMIDE IN AIR AND VACUUM. II. THE EFFECT OF IMPURITIES AND THE NATURE OF DEGRADATION PRODUCTS,

Descriptive Note:

Corporate Author:

JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB

Personal Author(s):

Report Date:

1964-05-01

Pagination or Media Count:

29.0

Abstract:

The effect of impurities on the thermal degradation of poly N,N-p,p-oxydiphenylene pyromellitimide du Ponts H-film is discussed. Purification of the polymer in dimethylformamide decreases the rates of degradation both in air and in vacuum, but only slightly reduces the activation energies. Infrared and mass spectrometric data suggest the participation of polypyromellitamic acid polyamide acid impurity in the degradation process by thermal cleavage of its carboxyl and hydrolytic scission of its amide groups. As far as the vacuum pyrolysis of the main polyimide chains is concerned, the activation energy of 74 kcalmole, bond dissociation energies, and elemental analysis of the residue remaining after pyrolysis suggest that the primary scission occurs at the imide bonds, most likely followed by a secondary cleavage resulting in the elimination of CO groups. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE