Synthesis And Dielectric Energy Storage Properties Of Polymers Bearing Terpyridyl Group

Dielectric materials have a wide range of applications in daily life,and play an important role in the fields of electronics,electrical,and film capacitors.Polymer dielectric materials have the advantages of high breakdown strength,low dielectric loss,and easy processing.However,the lower dielectric constant and energy storage density limits its application in the dielectric field.Therefore,it is necessary to improve the dielectric constant and energy storage density of polymer dielectric materials.In this paper,a series of polymers bearing terpyridine and metal ions were prepared by ring-opening metathesis polymerization（ROMP）,and their dielectric and energy storage properties were studied.The monofunctional norbornene dicarboximide monomers TPNDI-Ru and TPNDI-Cr containing metal ion coordinated terpyridine side groups,and the dodecyl norbornene dicarboximide monomer DNDI were synthesized.Polymers with different feed or block ratios were prepared by ROMP and their structural characterizations were carried out.The dielectric properties of the polymers were explored by adjusting the type and proportion of metal ions,and they exhibited excellent dielectric properties due to the strong electronic polarization and interface polarization of the metal ions.The results showed that the copolymer(PTNP₂₀₀-co-PNDI₁₀₀)-b-PTPNDI₂₀-Ru had a high dielectric constant（37）,low dielectric loss（<0.02）,and high energy storage density(5.4J·cm^-3).The bifunctional norbornene dicarboximide monomer DTPNDI-Ru containing metal ions coordinated with terpyridine side groups was synthesized.The cyclic and cyclic-linear polymers were prepared by ROMP,and the structure was characterized.The dielectric properties of the polymer were studied by adjusting the content of metal ions and the structure of polymers.The research results showed that the cyclic-linear polymer has better dielectric properties due to its well-assembled nano-structure in selective solvents.The dielectric constant of the copolymer PBNP₁₀-b-(PTNP₂₀₀)₂-b-(PDTPNDI₁₀-Ru)-b-(PTNP₂₀₀)₂ reached high value of 33,the dielectric loss was lowered to 0.02,and the energy storage density was up to 3.94J·cm^-3at 240MV·m^-1.Compared with single-stranded polymers,double-stranded polymers showed better dielectric properties under the same electric field strength.