Synthesis And Characterization Of Poly(perfluorocyclobutyl Aryl Ether)s Containing Phthalazinone Moieties

Due to the existence of fluorine atoms,fluoropolymers have many excellent properties,such as good heat resistance,strong solvent resistance,low dielectric constant and good gas permeability.Perfluorocyclobutyl poly(aryl ether)is a semi-fluorinated fluoropolymer,which was invented by Babb et al in 1993.The existence of the random erect perfluorobutyl structure in the polymer has improved the solubility and melting property of the polymer,which makes the polymer have excellent processability and have a great advantage in the industrial production.In addition,perfluorocyclobutyl aryl ether polymers also have many excellent properties,including good optical transparency,high heat resistance,high oxidation resistance,excellent chemical stability and so on.They can be used in aerospace,information engineering,construction industry and food environmental protection and other fields.In this paper,by using 4-(4-hydroxyphenyl)-2,3-phthalazin-1-ketone(DHPZ)as the raw material,through the fluoroalkylation and elimination reaction,a new type of intermediate(DTD)and trifluorovinyl monomer(TFVE-DTD)were obtained.The structural analysis of intermediate and monomer was carried out.The results showed that the relative molecular mass was the same as expected.The results of IR and NMR showed that the structure was consistent with the expected structure,which proved that the intermediate DTD and the monomer TFVE-DTD were successfully synthesized.By using TFVE-DTD as monomer,the homopolymerization was carried out.A series of polymer PFCB-D were obtained by changing the reaction temperature,reaction time and other reaction conditions.The structural characterization and performance test of polymer PFCB-D were carried out.The results of IR and NMR showed that the structure was consistent with the expected structure.The results of TGA and DSC test showed that the decomposition temperatures for 5% weight loss of PFCB-D increased and the glass transition temperature of PFCB increased with the increase of reaction time or reaction temperature.As the existence of phthalazin,the thermal decomposition temperature and the glass transition temperature were higher.The polymer PFCB-D had good solubility in such common solvents as N,N-Dimethylacetamide(DMAc),Dimethyl sulfoxide(DMSO),chloroform and acetone,but they were insoluble in water and methanol.By using TFVE-DTD and 4,4’-bis(trifluorovinyloxy)biphenyl(TFVE-DTB)as monomers,the copolymerization was carried out.Polymer structure and properties were investigated by changing polymerization time.A series of copolymers PFCB-B-D were synthesized by changing monomer ratio.The copolymer PFCB-B-D was characterized by structural characterization and performance test.The results of IR and NMR showed that the structure was consistent with the expected structure.The molecular weight and its distribution of PFCB-B-D were tested by GPC,showing that the molecular weight was above 9700 and the molecular weight distribution was narrow.TGA test results revealed that the decomposition temperatures for 5% weight loss of PFCB-B-D were all higher than 400℃,and the pyrolysis temperature increased with the increasing monomer TFVE-DTB.It could be known from the DSC curves that the glass transition temperature of PFCB-B-D was higher than 150℃,and the glass transition temperature of PFCB-B-D also increased with the increasing proportion of the monomer TFVE-DTD.Solubility test represented that polymer PFCB-B-D had good solubility in such common solvents as DMAc,DMSO,chloroform and acetone,but they were insoluble in water and methanol.