Dielectric and thermal behaviors of fluorine-containing dianhydride-modified polybenzoxazine: A molecular design flexibility

Abstract

Fluorine-containing copolybenzoxazines were successfully prepared by reacting bisphenol-AF/aniline-based benzoxazine resin (BAF-a) with 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) in N,N-dimethylacetamide solvent. The dielectric and thermal properties as well as flexibility of the resulting copolymer films were investigated. The incorporation of fluorine groups into polybenzoxazine was found to substantially decrease the dielectric constant of the resulting copolybenzoxazine to as low as 2.6. The formation of ester linkages between the hydroxyl groups in the poly(BAF-a) and the carbonyl groups in the 6FDA resulted in substantially enhanced flexibility of the copolybenzoxazines. Moreover, the copolymers showed superior degradation temperature and significant improvement in char yield, up to 464 °C and 56%, respectively. The glass-transition temperature of the copolybenzoxazines was increased with increasing dianhydride content and exhibited a maximum value of 290 °C at 2.5/1 mole ratio of poly(BAF-a) to 6FDA. Therefore, the fluorine-containing dianhydride-modified polybenzoxazines are appropriate for applications as polymeric films for coatings and as a good electrical insulation material with high thermal resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45204. © 2017 Wiley Periodicals, Inc.