Synthesis And Characterization Of Polyarylether And Polyamide Containing Phenyl-s-triazine

Phenyl-s-triazine has a highly symmetrical flat rigid structure and shows good thermal stability and photoelectric property due to the strong charge transfer interactions between s-triazine and aromatic rings.Therefore,introducing phenyl-s-triazine into polymer chains is drawing much attention for their excellent thermal resistance,electronic properties,high tensile strengths and modulus at elevated temperatures.However,polymers containing phenyl-s-triazine generally have poor solubility and high softening temperature which limits the scope of application.In this paper,two types of phenyl-s-triazine monomer 2,4-bis(4-fluorophenyl)-6-phenyl-1,3,5-triazine(BFPT)and 2,4-bis(4-aminophenyl)-6-phenyl-1,3,5-triazine(BAPT)was successfully synthesized.The structure of the monomers was characterized by Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance spectroscopy(~1H NMR).BFPT was synthesized by using fluorobenzonitrile through two step method.To synthesize BAPT,p-nitrobenzonitrile hydrochloride was firstly synthesized using p-nitrobenzonitrile,then ring-closed with benzoyl chloride to give 2,4-di(4-nitrophenyl)-6-phenyl-1,3,5-triazine(BNPT),finally BAPT was successfully obtained by reducing nitro into amine groups by using Fe powder and hydrazine hydrate/Pd/C as reductant,respectively.The influences of reaction time and quantities of hydrazine hydrate and catalyst used on product yield were investigated.The results revealed that the highest yield of 90%was obtained with hydrazine hydrate/Pd/C as reductant.The optimum reaction conditions are mole ratio of BNPT:hydrazine hydrate is 20:1,the proportion of Pd/C is 8.5%,reaction time is 12h,reduction temperature is 65 ℃.A series of novel poly(arylene ether phenyl-s-triazine)s(PAEPTs)were successfully synthesized by direct solution polycondensation of 2,4-bis(4-fluorophenyl)-6-phenyl-1,3,5-triazine(BFPT)with 6-(4-hydroxyphenyl)pyridazin-3(2H)-one(HPZ)and 2,6-Dihydroxyanthraquinone(DHA)in different molar ratios.The synthesized PAEPTs shows good solubility and introducing HPZ groups could improve the solubility of in polar aprotic solvents such as NMP.The polymer structure was characterized using FT-IR,and the thermal properties were analyzed by differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA).The glass transition temperatures(T_g)of the copolymers were in the range of246-337℃.TGA results showed that the 5%mass-loss temperatures are between 440 and512℃,and the char yields at 900℃ are higher than 50%under the nitrogen atmosphere,which indicated that the PAEPTs have good high temperature resistance properties.A novel polyimide(PI)was successfully prepared from BAPT and pyromellitic dianhydride(PMDA)by two-step method.The structure of the PI was examined using FT-IR and elemental analysis.The thermal properties of polyimide were studied through TGA and DSC.The results showed that the polymers containing phenyl-s-triazine have high thermal stability with the 5%mass-loss temperature was 447℃,the char yeild was 47.8%at 800 ℃ in nitrogen atmosphere.The polymer could be dissolved in polar aprotic solvents such as NMP and DMF.The photoluminescent properties of polyimide were characterized by fluorescence spectrophotometer.The result showed that the polymer can emit blue fluorescence at the excitation wavelength of 350 nm,which might be used as blue fluorescent materials with potential application value.