| Due to its excellent optical properties,fluorinated polyimides have been widely used in optoelectronic fields such as flexible displays.Nowadays,the demand for fluorinated polyimides in the optoelectronic field is increasing.In this paper,several synthetic methods of fluorinated polyimide diamine monomers were studied,and fluorinated polyimides were prepared by using these diamines and commercially available dianhydride monomers.Section one studies the synthesis of 4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(oxy))di-aniline,a diamine monomer.First,using pentafluorobenzoic acid and pentafluorobromobenz-ene as starting materials,synthesis of decafluorobiphenyl by copper-catalyzed decarboxylation coupling was carried out.The catalyst dosage,raw material ratio,solvent,reaction temperature and time were screened to determine the optimal reaction conditions for the synthesis of decafluorobiphenyl.Then,4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(oxy))dianiline was synthesized by C-O coupling with decafluorobiphenyl and 4-aminophenol.The optimal reaction conditions for this reaction were determined.In this part,4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(oxy))dianiline was synthesized by a facile and atom-economical method using cheap and readily available pentafluorobenzoic acid as starting material.Second two studies 4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(oxy))bis(2,6-dimethyla-niline)and 4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(sul))dianiline and preparation of fluorinated polyimide.Using decafluorobiphenyl,3,5-dimethyl-4-aminophenol and4-aminothiophenol as starting materials,these two fluorinated polyimides were synthesized by nucleophilic substitution reaction without metal catalysis.Using these three substances synthesized above as fluorinated polyimide diamine monomers,we prepared fluorinated polyimide with the commercially available dianhydride monomer,pyromellitic dianhydride.The thermogravimetric analysis of 4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(oxy))dianilin-e and 4,4’-((perfluoro-[1,1’-biphenyl]-4,4’-diyl)bis(oxy))bis(2,6-dimethylaniline)was carried out,and the two fluorinated polyimides all had quite good thermal stability. |
