An investigation of molecular structure of copolymers using positron annihilation spectroscopy
Year: 1985
Type: article
Abstract: Positron lifetime measurements were made in copolyimides synthesized from linear 4,4 prime-bis(3,4-dicarboxyphenoxy) diphenylsulfide dianhydride (BDSDA)/4,4 prime-diaminodiphenyl (ODA) and BDSDA/1,3-diaminobenzene (m-phenylene diamine) homopolymers. The probability of positronium formation as well as its subsequent lifetime are lower in the BDSDA/ODA/MPD (50-50) copolyimide, indicating the presence of a transition molecular architecture characterized by higher electron density and stronger bonds which permit both chemical as well as physical entry of water molecules into it. The presence of this transition region imparts unique physical and mechanical properties to the copolyimide.
Authors: J. J. Singh, T. L. St. Clair, W. H. Holt, W. Mock
Institution: Langley Research Center
Language: English
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W84697565