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Poly(ethenyl‐1,3,4‐oxadiazole‐2,5‐diyl‐1,4‐phenylene). Electrical properties and phase transition studies
Author(s) -
Varma I. K.,
Geetha C. K.
Publication year - 1976
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1976.070200711
Subject(s) - sulfuric acid , glass transition , phenylene , materials science , polymer chemistry , copolymer , amorphous solid , dielectric , atmospheric temperature range , ternary operation , transition temperature , solubility , phase diagram , oxadiazole , phase transition , polymer , phase (matter) , analytical chemistry (journal) , chemistry , organic chemistry , thermodynamics , composite material , physics , superconductivity , optoelectronics , quantum mechanics , computer science , metallurgy , programming language
The phase diagrams of the ternary system poly(ethenyl‐1,3,4‐oxadiazole‐2,5‐diyl‐1,4 phenylene), sulfuric acid, and water indicated that the increase of the ethenyl residue in the copolymers increased the solubility in the acid. The critical point of separation in sulfuric acid was determined, and it decreased from 74% to 60.5% as the ethenyl ratio of copolymers was increased. The electrical properties in the temperature range of 0–90°C at a fixed frequency of 1592 Hz were also investigated. The tan δ values increased with increase in temperature and passed through a maximum. The temperature of this maximum varied with the nature of the copolymer. The observed increase in the dielectric constant with temperature may be due to increased segmental motion in the amorphous region of the polymers.