Block copolymers poly（endo-N-3,5-bis（trifluoromethyl）biphenyl-norbornene-pyrrolidine）-block-poly（exo-N-（cinnamoyloxyethyl）-7-oxanorborn-5-ene-2,3-dicarboximide）（endo-PTNP-b-exo-PCONBI） and poly（exo-N-3,5-bi...Block copolymers poly（endo-N-3,5-bis（trifluoromethyl）biphenyl-norbornene-pyrrolidine）-block-poly（exo-N-（cinnamoyloxyethyl）-7-oxanorborn-5-ene-2,3-dicarboximide）（endo-PTNP-b-exo-PCONBI） and poly（exo-N-3,5-bis（trifluoromethyl）biphenyl-norbornene-pyrrolidine）-block-poly（exo-N-（cinnamoyloxyethyl）-7-oxanorborn-5-ene-2,3-dicarboximide）（exo-PTNP-b-exo-PCONBI） were synthesized by ring-opening metathesis polymerization. The endo- or exoPTNP served as the high dielectric functional chain, and exo-PCONBI acted as the crosslinking segment. The endo-PTNPb-exo-PCONBI, in which endo-PTNP has a high content of trans double bond and adopts isotactic configuration, shows a dielectric constant（？） of 15.5, whereas exo-PTNP-b-exo-PCONBI, in which exo-PTNP has 67% trans double bonds and atactic microstructure, displays relatively low ？ of 7.1. The cinnamate groups in exo-PCONBI were crosslinked to form three-dimensional network by cycloaddition reaction under UV irradiation. Exposed to UV-light for 10 min, the cinnamate group in polymer films has a crosslinking conversion of 36%, as determined by UV-Vis absorption measurements. By photocrosslinking, the polymer film has an increased ？ of 16.6, a dielectric loss of 0.03, an elevated glass-transition temperature of 137 ？C, and an enhanced decomposition temperature of 405 ？C, compared to those of polymer films without irradiation.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21574041 and 21374030)Large Instruments Open Foundation of East China Normal University(No.20151006)
文摘Block copolymers poly（endo-N-3,5-bis（trifluoromethyl）biphenyl-norbornene-pyrrolidine）-block-poly（exo-N-（cinnamoyloxyethyl）-7-oxanorborn-5-ene-2,3-dicarboximide）（endo-PTNP-b-exo-PCONBI） and poly（exo-N-3,5-bis（trifluoromethyl）biphenyl-norbornene-pyrrolidine）-block-poly（exo-N-（cinnamoyloxyethyl）-7-oxanorborn-5-ene-2,3-dicarboximide）（exo-PTNP-b-exo-PCONBI） were synthesized by ring-opening metathesis polymerization. The endo- or exoPTNP served as the high dielectric functional chain, and exo-PCONBI acted as the crosslinking segment. The endo-PTNPb-exo-PCONBI, in which endo-PTNP has a high content of trans double bond and adopts isotactic configuration, shows a dielectric constant（？） of 15.5, whereas exo-PTNP-b-exo-PCONBI, in which exo-PTNP has 67% trans double bonds and atactic microstructure, displays relatively low ？ of 7.1. The cinnamate groups in exo-PCONBI were crosslinked to form three-dimensional network by cycloaddition reaction under UV irradiation. Exposed to UV-light for 10 min, the cinnamate group in polymer films has a crosslinking conversion of 36%, as determined by UV-Vis absorption measurements. By photocrosslinking, the polymer film has an increased ？ of 16.6, a dielectric loss of 0.03, an elevated glass-transition temperature of 137 ？C, and an enhanced decomposition temperature of 405 ？C, compared to those of polymer films without irradiation.
