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A study of physical properties of ODPA-p-PDA polyimide filmsPhysical properties were investigated of ODPA-p-PDA polyimide films, including their lower molecular weight versions with phthalimide endcaps. Free volume, determined by low energy positron annihilation in the test films, was the major parameter of interest since all other physical properties are ostensibly related to it. It affects the dielectric constant as well as the saturation moisture pickup of the test films. An empirical relation was developed between the free volume and molecular weight of the test films, comparable to the Mark-Houwink relation between the polymer solution viscosity and the molecular weight. Development of such a relation constitutes a unique achievement since it enables researchers to estimate the molecular weight of an intractable polymer in solid state for the first time.
Document ID
19900010821
Document Type
Technical Memorandum (TM)
Authors
Singh, Jag J. (NASA Langley Research Center Hampton, VA., United States)
Eftekhari, Abe (Analytical Services and Materials, Inc., Hampton VA., United States)
St.clair, Terry L. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 6, 2013
Publication Date
March 1, 1990
Subject Category
COMPOSITE MATERIALS
Report/Patent Number
NAS 1.15:102625
NASA-TM-102625
Funding Number(s)
PROJECT: RTOP 506-43-21-05
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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NameType 19900010821.pdf STI