Record number :
Title of article :
A new class of aromatic polybenzoxazoles containing ortho-phenylenedioxy groups
Author/Authors :
Sheng-Huei Hsiao، نويسنده , , Ya-Huei Huang، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2004
Pages :
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Abstract :
A series of poly(o-hydroxy amide)s having both ether and ortho-catenated phenylene unit in the main chain were synthesized via the low-temperature solution polycondensation of 4,4′-(1,2-phenylenedioxy)dibenzoyl chloride and 4,4′-(4-tert-butyl-1,2-phenylenedioxy)dibenzoyl chloride with three bis(o-aminophenol)s including 4,4′-diamino-3,3′-dihydroxybiphenyl, 3,3′-diamino-4,4′-dihydroxybiphenyl, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. The poly(o-hydroxy amide)s exhibited inherent viscosities in the range of 0.23–0.96 dl/g. Most of the poly(o-hydroxy amide)s were soluble in polar organic solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP) and could afford flexible and tough films by solution casting. Subsequent thermal cyclodehydration of the poly(o-hydroxy amide)s afforded polybenzoxazoles. However, the polybenzoxazoles were organic-insoluble except for those with the hexafluoroisopropylidene group. The polybenzoxazoles exhibited glass-transition temperatures (Tg) in the range of 200–232 °C by DSC and softening temperatures (Ts) of 250–256 °C by thermomechanical analysis. Thermogravimetric analyses indicated that most polybenzoxazoles were stable up to 500 °C in air or nitrogen. The 10% weight loss temperatures were recorded in the ranges of 546–606 °C in air and 574–631 °C in nitrogen.
Keywords :
Polybenzoxazoles , Ortho-phenylenedioxy , Thermal Properties , Structure–property relations , Poly(o-hydroxy amide)s
Journal title :
European Polymer Journal(EPJ)
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