Syudy On The Synthesis Of Symmetric Ether Diamine Of Polyimide Monomer

Polyimide?PI?is a polymeric material which shows a high performance,due to its excellent thermal and chemical,mechanical and electrical properties,PI has a wide range of application in high-tech fields such as aerospace,electrical and electronics,precision machinery.To meet the application needs of different situations,modified polyimide materials have become the focus of researches and attention.Polyimide is polymerized by dianhydride monomer and diamine monomer.The synthesis and exploration of diamine plays an important role in the modification of polyimide,also,introduction of flexible groups such as ether linkages and aliphatic chains,functional atom such as sulfur and fluorine in diamine monomer,has become an important means to improve the solubility of the polyimide.The process for synthesis of symmetrical aromatic diamine monomer containing ether linkages was investigated.The process for synthesis of symmetrical diamine monomer containing aliphatic ether chain was studied.1,2-bis?p-aminophenoxy?ethane was prepared by condensation reaction and catalytic reduction reaction from p-chloronitrobenzene and the diols.The effects of the molar ratio of the materials,the amount of potassium carbonate,reaction time,reaction pressure and catalyst on the yield were studied.The optimum reaction conditions were obtained as follows:the amount of potassium carbonate 115mmol,the molar ratio of raw materials 2.5:1,reaction temperature 130¹42?,reaction time 24 h.The reduction reaction pressure 0.6 MPa,the amount of catalyst 0.30 g,reaction temperature70?.The total yield of 1,2-bis?p-aminophenoxy?ethane was 74.1%under these conditions.The optimum reaction conditions were also applied in the synthesis of other fluorinated aliphatic chain ether diamine monomer with yields in the range of 44.2%⁸0.1%.All the products were characterized by¹H-NMR and ¹³C-NMR.The process for synthesis of biaryl symmetrical ether diamine monomer was studied.1,4-bis?2-trifluoromethyl-4-aminophenoxy?-benzene was prepared by Williamson reaction and catalytic reduction from quinol and 2-chloro-5-nitro-benzotrifluoride.The effects of the molar ratio of the materials,the amount of potassium carbonate,reaction time,reaction pressure and catalyst on the yield were studied.The optimum reaction conditions were obtained as follows:the amount of potassium carbonate 105mmol,the molar ratio of raw materials 1:2.1,reaction temperature 128¹39?,reaction time 5.5 h.The reduction reaction pressure 0.6 MPa,the amount of catalyst 0.37 g,reaction temperature 70?.The total yield of 1,4-bis?2-trifluoromethyl-4-aminophenoxy?-benzene was 80.5%under these conditions.The optimum reaction conditions were also applied in the synthesis of other11 biaryl symmetrical ether diamine monomer with yields in the range of77.0%⁸2.9%.All the products were characterized by¹H-NMR.