一种主链含光敏基团聚酰亚胺的合成与表征

通过4,4′-二羟乙基查尔酮与1,2,4-苯三酸酐酰氯反应,得到了一种新型的主链含查尔酮的二酐单体,通过二酐和2,2-双(3(-氨基-4(-羟基苯基)六氟丙烷缩聚并高温亚胺化,得到了一种新型的主链含查尔酮,侧链含羟基的光敏聚酰亚胺,并通过1H-NMR、FTIR、GPC及热分析表征了得到的聚酰亚胺的结构和热性能.这种聚酰亚胺在极性溶剂中具有较好的溶解性,并具有较高的热稳定性,在紫外光照射下,能进行2+2]的环加成反应.

SYNTHESIS AND CHARACTERIZATION OF POLYIMIDE WITH MAIN-CHAIN PHOTOSENSITIVE GROUPS AND HYDROXYL SIDE-GROUPS

A polyimide containing main-chain chalcone groups and hydroxyl side-groups was synthesized.In the synthesis,1,3-dioxoisobenzofuran-5-carbonyl chloride was obtained by the reaction between 1,2,4-benzenetricarboxylic anhydride and SOCl_2.1,3-Bis(4-(2-hydroxyethyl) phenyl)prop-2-en-1-one was synthesized by the nucleophilic substitution reaction between 2-chloroethanol and 1,3-bis(4-hydroxyphenyl)-prop-2-en-1-one,which was synthesized from the Claisen-Schmidt condensation of 4-hydroxybenzaldehyde and 1-(4-hydroxyphenyl)ethanone.The new dianhydride monomer containing chalcone group was prepared by reactions between 1,3-dioxoisobenzofuran-5-carbonyl chloride and 1,3-bis(4-(2-hydroxyethyl)phenyl)prop-2-en-1-one.The polyimide was obtained by polycondensation of the dianhydride monomer with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and subsequent thermo imidization.The chemical structure and properties of the polyimide were characterized by 1H-NMR,FTIR,GPC and thermal analysis.The number average molecular weight(M_n) of the polyimide is 27310 with a polydispersity index of 1.55.The glass transition temperature(T_g) of the polyimide is 207℃ obtained from the DSC thermogram.The thermal degradation temperature(T_d) is 382℃ measured at the point with a weight lost of 2.5% from the thermogravimetric curve.The polymer shows good solubility in aprotic polar organic solvents such as DMF,DMAc and THF.The polyimide has an absorption maximum at 342 nm due to the chalcone group.Upon the UV light irradiation,the polyimide can undergo sensitive photocycloaddition reaction.After UV light irradiation with the dose of 20 J/cm2,the absorbance band at 342 nm disappears completely,and the film is insoluble in DMF.The polyimide synthesized in this work can be expected for applications as photoimagable materials and others.