Synthesis And Characterization Of Aromatic Plyazomethines、Polyimides And Polyamides Based On 9,9-bis(4-aminophenyl) Xanthene

The article first introduced the research progress of polyazomethines,polyimides and polyamides.The specific work can be divided into the following four parts:1.Xanthone,thionyl chloride and aniline as the main raw materials,a high yield(85%)of 9,9-bis(4-aminophenyl)xanthene(mp=267.8-269.2 ~oC)was obtained in a one-pot two-step process,as well as the 9,9-bis[(4-aminophenoxy)phenyl]xanthene currently synthesized in the laboratory,these two amines by nucleophilic addition reactions with terephthalaldehyde,Isophthalaldehyde and 1,4,-bis(4-formylphenoxyp-henyl)benzene were used to prepare six novel polymethines containing xanthenes,with high glass transition temperature(Tg=251.2-277.3 ~oC),excellent heat resistance(Td=382.3-443.7 ~oC),the solublility in some organic solvents at room temperature is well,such as N-methylpyrrolidone,N,N-dimethylformamide,N,N-dimethylacetamide;Most of the polymers in this series are amorphous.2.The second part uses the same type of diamine monomer and four kinds of anhydride respectively:pyromellitic dianhydride,biphenyl tetracarboxylic dianhydride,4,4’,-terephthalic dioxyphthalic anhydride and 3,3’,4,4’-benzophenone tetracarboxylic dianhydride was synthesized by two-step obtained four novel polyimides.First,diamine and dianhydride are gradually polycondensed in a low-temperature environment to obtain a polyacyl acid,and the final product polyimide is obtained through physical imidization(thermal imidization).The infrared contrast diagram before and after imidization shows that the imidization is complete.The obtained PI film was used to characterize its mechanical properties,thermal properties and optical properties.The polymer has a high glass transition temperature(Tg=308.3-348.2 ~oC)and excellent heat resistance(Td=470.1-510.6 ~oC).The optical properties of the transparent polymer film were measured by UV-visible spectroscopy.All data of the mechanical properties were averaged three times from the stress-strain curve.The polymer weakness is that poorly solubility and needs further study in this regard.3.Diamines with terephthaloyl dichloride,isophthaloyl dichloride,4,4,-biphenyl dichloride,1,3-bis(4-chloroformylphenoxy)benzene,2,2-diamine[4-(4-Chloroylphenox y)phenyl]hexafluoromethane was reacted to obtain five novel polyamides.The series of polymers exhibited high glass transition temperatures(Tg=248.3-367.3 ~oC),excellent heat resistance(Td=382.5-440.3 ~oC),the solublility in some organic solvents at room temperature is well,such as N-methylpyrrolidone,N,N-dimethylformamide,N,N-dimethylacetamide and dimethyl sulfoxide,slightly soluble in chloroform.The XRD curves of all polymers showed a similar shape of the wide dispersion peak,indicating that the series of polymers with low crystallinity,amorphous structure.4.9,9-bis(4-aminophenyl)xanthene and trimellitic anhydride as the main raw materials,glacial acetic acid as the solvent,a new monomer diacidic was obtained at a high yield(69%),Five new polyimide-amide were obtained by phosphonating polycondensation with five different diamines.This series of polymers has poor solubility and needs further improvement.The thermal decomposition temperature is not high,and it may be that the activity of the acid in the polycondensation process is not high,failing to reach the desired degree of polymerization.A broadly dispersed peak with similar shapes appears in all polymer curves,indicating that the polymers of this series have low crystallinity and are amorphous structures.