Synthesis And Characterization Of Sulfonated Fluorinated Heterocyclic Polyaryl Ethers

In recent years,the booming fields of 5G communications,clean energy and information engineering have continued to place new demands on material properties,making it of great research value to develop high performance polymeric materials that can be applied to specific fields.The development of polytetrafluoroethylene（PTFE）has brought fluoropolymers to the attention of researchers for their high chemical and thermal stability.Since then,fluoropolymers have been greatly developed and various types of fluoropolymers have been developed.Fluorinated polyarylenes are high-performance polymers that use C-F bonds to partially replace the C-H bonds in polyarylenes.The introduction of strong polar fluorine atoms gives fluorinated polyarylenes excellent thermal stability,chemical stability and high mechanical strength,making them an important material in the field of automotive,aerospace,biomedical and therefore of great interest to researchers.In this paper,4-（4-hydroxyphenyl）-2,3-diazanonaphthalenone（DHPZ）and 4,4’-bis（trifluorovinyloxy）biphenyl（TFVE-DTB）were used as raw materials to synthesise fluoroethyl ether heteronaphthalene biphenyl polyaryl ether（PPFEE）by stepwise polymerisation reaction,and PPFEE was modified by sulphonation to prepare sulphonated fluoroethyl ether heteronaphthalene biphenyl polyaryl ether（SPPFEE）.The polymer structure and properties were tabulated.)The structure and properties of the polymers were characterised.The PPFEE had a characteristic viscosity of 1.03 d L/g,a glass transition temperature of 189°C and a 5%thermal weight loss temperature(T_d5)of 358°C,with excellent thermal properties;the ion exchange capacity of the SPPFEE ranged from 0.75-1.62 mmol/g and the Td5 was above252°C;the PPFEE and SPPFEE were soluble in solvents such as dimethyl sulfoxide（DMSO）,N-methylpyrrolidone（NMP）and N,N-dimethylformamide（DMF）.To further improve the thermal stability of the sulphonated polymers,a new trifluorovinyl aryl ether monomer（TFVE-DTD）was prepared by fluoroalkylation and elimination reaction of DHPZ,followed by polymerisation with TFVE-DTB to prepare a series of perfluorocyclobutyl heteronaphthalene biphenyl polyaryl ethers（PFCB-B-Ds）,and PFCB-B-Ds was modified by sulphonation to produce sulphonated perfluorocyclobutyl heteronaphthalene PFCB-B-Ds was modified by sulfonation to produce sulfonated perfluorocyclobutylated naphthalene heterobiphenyl polyaryl ether（SPFCB-B-Ds）.The structure and properties of the polymers were characterized,and the number average molecular weight of PFCB-B-Ds was higher than 7500 Da,and the PDI was around 1.4.The glass transition temperature is higher than 162°C and the 5%thermal decomposition temperature in nitrogen atmosphere is higher than 343°C,with excellent thermal properties,it shows good solubility in chloroform（CHCl₃）,N-methylpyrrolidone（NMP）,N,N-dimethylformamide（DMF）,tetrahydrofuran（THF）,dimethyl sulfoxide（DMSO）and dichloromethane（CH₂Cl₂）.The 5%thermal weight loss temperature of SPFCB-B-Ds was above 282°C in a nitrogen atmosphere,have better thermal stability than SPFEE,and still have good solubility in NMP,DMF,DMSO,THF,insoluble in CH₂Cl₂ and partially soluble in CHCl₃.