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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.
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) 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, which which endo-PTNP has a high content of trans double bond and accommodating isotactic configuration, shows a dielectric constant (?) Of 15.5, an ex 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.