Study On Synthesis And Properties Of Novel Polyimides Containing Pyridine With High Heat-resistant

Polyimide(PI)is a type of macromolecular high performance polymer with an imide ring in its main chain.It is widely used in mechanical transportation,military aerospace,Separation membrane,osmotic membrane and other high-end technology,due to their excellent mechanical properties,high heat resistance and corrosivity.However,However,the traditional polyimide material due to its insoluble non-melting,processing difficulties and defects,so that its application is further limited.To meet the development needs of some special filed,overcome some disadvantages of polyimide materials,we introduced to the polymer backbone of pyridine heterocyclic ring,pyrrolyl,morpholinyl and diethylamino and other structures,so that the solubility,hydrophobic performance has greatly improved.Work from the following aspects.1?Synthesis of intermediate 4-4'-nitrophenoxyacetophenone(NPAP)by using4-hydroxyacetophenone and 1-chloro-4-nitrobenzene as raw materials and potassium carbonate as catalyst,Then,NPAP and(4'-4"-nitroxyphenoxybenzene)was successfully obtained from ammonium acetate4-(4-(pyrrolidin-1-yl)phenyl)-2,6-bis(4-(4-nitrophenoxy)phenyl)pyridine(PPNPP)and then reduced by Pd/C to give the diamine monomer4-(4-(pyrrolidin-1-yl)phenyl)-2,6-bis(4-(4-aminophenoxy)phenyl)pyridine(PPAPP),and finally the five dianhydride monomers were prepared by “two-step” solution polymerization,and the main chain containing pyridine ring,ether bond and pyrrolyne polyimide material was successfully prepared and characterized by its performance The results show that the new polyimide material has good solubility,heat stability and high hydrophobic properties.2? The reaction of 4-4-nitrophenoxyacetophenone(NPAP)with 4-morpholine benzaldehyde under ammonium acetate as catalyst gave4-(4-(2,6-bis(4-(4-nitrophenoxy)phenyl)pyridyl)phenyl)morpholine(NOPPM),which is further reduced by Pd/C to4-(4-(2,6-bis(4-(4-aminophenoxy)phenyl)pyridyl)phenyl)morpholine(AOPPM),and then AOPPM with five aromatic dianhydride by “two-step” to get a new type of polyimide.The structure and properties of the determination,the results show excellent thermal stability,better hydrophobic properties.3 ?(4-diethylaminophenyl)-2,6-bis(4-aminophenyl)pyridine(APAP)was obtained by two-step reaction using 4-Diethylaminobenzaldehyde,4'-Nitroacetophenone as raw materials,and then polymerized APAP with a series of dianhydride monomer to prepare polyimide material,and its structure and properties were tested and characterized.The results show that the obtained polyimide has excellent thermal stability and good hydrophobic properties.