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Synthesis, characterization and ESR study of the γ‐radiolysis of aromatic polyesters containing isomeric naphthalene links
Author(s) -
Hill David J T,
Choi BongKu,
Ahn HungKun,
Choi EJoon
Publication year - 1999
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199910)48:10<956::aid-pi254>3.0.co;2-n
Subject(s) - polyester , radiolysis , radical , thermogravimetric analysis , naphthalene , thermal stability , glass transition , polymer chemistry , polymer , materials science , chemistry , diol , nuclear chemistry , organic chemistry
Six polyesters were synthesized from 4,4′‐(hexafluoroisopropylidene)‐bis(benzoyl chloride) and 1,4‐, 1,5‐, 1,6‐, 2,3‐, 2,6‐ and 2,7‐naphthalene diol (ND) isomers. The structures of the polyesters were characterized by IR spectroscopy and the results were in good agreement with the expected structures. Inherent viscosities of tetrachloroethane, (TCE) solutions at 303 K ranged from 0.11 to 0.46 dl g −1 The glass transition temperatures were found to be in the range 425–494 K by DSC thermal analysis. Thermogravimetric analyses showed two‐stage weight losses and revealed the excellent thermal stability of the polymers. All the polyesters were irradiated in an AECL Gammacell 220 unit at a dose rate of approximately 6.7 kGy h −1 to doses in the range 0–15 kGy at 77 K and 300 K. The G values for radical formation in the polyesters were found to be in the range 0.41–0.81 at 77 K and 0.56–1.49 at 300 K. At 77 K up to 15% of the radicals formed on radiolysis were found to be anionic. Annealing experiments were carried out to identify the neutral radicals, which were assigned to phenyl, benzoyl and phenoxyl radicals. © 1999 Society of Chemical Industry