Synthesis And Characterization Of Aromatic Polyamides Bearing Xanthene Cardo Groups Or Triphenylamine Groups

In this dissertation, the recent progress on the study of polyamides containingcardo and triphenylamine groups was investigated. This paper was mainly composedof two parts as follow.1.9,9-bis(3-methyl-4-hydroxylphenyl)xanthene was successfully prepared fromxanthone and o-cresol, and then followed by the nucleophilic aromatic halogendisplacement reaction with4-fluorobenzonitrile.9,9-bis[(3-methyl-4-carboxyphenoxy)phenyl]xanthene was lastly synthesized after the alkaline hydrolysisreaction of9,9-bis[(3-methyl-4-cyanophenoxy)phenyl]xanthene. The yield was80%. A series of polyamides with xanthene units and methyl groups weresynthesized from the dicarboxylic acid and various diamines by means of thephosphorylation polycondensation technique describled by Yamazaki. Thepolyamides displayed inherent viscosities ranging from0.39to0.80dL/g. Allpolyamides could be soluble in many polar organic solvents at room temperaturesuch as N, N′-dimethylacetamide (DMAc), N, N′-dimethylformamide (DMF),N-methyl-2-pyrrolidinone (NMP), dimethylsulfoxide (DMSO), and even could besoluble in less polar solvents at room temperature or heating conditions such asTHF and pyridine. Flexible and tough polyamide films were prepared from DMAcsolvent, which exhibited good transmittance and low dielectric constants (100KHz,2.19–3.11). The results showed that the polyamides have relatively highglass transition temperature in the range of260–286°C. The range ofdecomposition temperature at10%weight loss was from373°C to383°C. Thecarbonized residue of the polymers was more than54%at800°C in nitrogenatmosphere. All polymers were amorphous and their films exhibited tensilestrengths of64–91MPa, elongations at break of5–8%, and tensile modulus of1.55–2.14GPa. 2. N, N-Bis(4-caboxyphenyl)-3-trifluoromethyl phenylamine were prepared by thesubstitution reaction of m-trifluoromethyl aniline with4-fluorobenzonitrile,followed by the alkaline hydrolysis reaction in60%yield. Five different kinds ofpolyamides containing trifluoromethy and triphenylamine units were directlyprepared from the polycondensation reaction of N,N-bis(4-caboxyphenyl)-3-trifluoromethylphenylamine with five various diaminesrespectively. The prepared polyamides showed inherent viscosities ranging from0.63to1.29dL/g. The resulting polyamides were characterized by TGA. Theresults showed that the range of decomposition temperature at5%and10%weight loss were from458°C to462°C and from489°C to504°C respectively.The carbonized residue of the polymers was more than59%at800°C in nitrogenatmosphere. These polymer films had tensile strengths ranging from60to76MPa,elongations at break from9to21%, and initial moduli from1.21to1.54GPa.Transparent, flexible and tough films of these polymers had high transparency at400nm with an ultraviolet-visible absorption cut-off wavelength about at the216nm. Besides, these polyamides exhibited low dielectric constants ranging from2.49to2.96(100kHz), and the polymer films show the characterization ofelectrochromism in the process of circulation current-voltage.