一种氟化含吡啶和氧化三苯膦结构聚酰胺的合成与表征

Synthesis and Characterization of Fluorinated Polyamide Bearing Pyridine and Triphenylphosphine Oxide Moieties

以4-三氟甲基苯甲醛和4-硝基苯乙酮为主要原料,设计经两步反应合成了一种含吡啶结构和三氟甲基侧基的芳香二胺———4-(4-三氟甲基苯基)-2,6-二(4-氨基苯基)吡啶,并将其与二(4-氯甲酰苯基)苯基氧化膦进行低温溶液缩聚制备了一种氟化含吡啶和氧化三苯膦结构的聚芳酰胺。采用FT-IR、DSC、TG及WAXD等方法对其进行了分析表征。结果显示,该聚芳酰胺的特性黏度为0.98 dL/g,具有非晶态结构及良好的透光率(截断波长为329 nm),其玻璃化转变温度(Tg)为291℃,在氮气氛中10%的热失重温度为540℃,800℃时的残炭率为64%。聚合物易溶于N,N-二甲基乙酰胺、N-甲基吡咯烷酮、间甲酚、吡啶和四氢呋喃等有机溶剂,并可浇注得到韧性好且透明的薄膜,其拉伸强度为86 MPa,拉伸模量为2.0 GPa,断裂伸长率为10%。同时,该聚合物的体积电阻、表面电阻和介电常数分别为8.62×1015Ψ·cm、9.85×1014Ψ和3.48(100 Hz),呈现出良好的电绝缘性能。

An aromatic diamine with a pyridine unit and a trifluoromethyl pendant, 4-(4-trifluoromethylphenyl)-2,6-bis(4-aminophenyl)pyridine, was successfully synthesized via modified Chichibabin reaction of 4-trifluoromethylbenzaldehyde and 4-nitroacetophenone,followed by catalytic hydrogenation using hydrazine hydrate and Pd/ C catalyst in refluxing ethanol, which was employed to prepare fluorinated polyamide bearing pyridine and triphenylphosphine oxide moieties with bis(4-chloroformylphenyl)phenyl phosphine oxide through low temperature polycondensation. The resulted polyamide was characterized by FT-IR, DSC, TGA and WAXD, etc. The polyamide with inherent viscosity of 0.98 dL/g is amorphous and exhibits a high transparency with the ultraviolet-visible absorption cut-off wavelength of 329 nm. The glass transition temperature(Tg)is 291℃, decomposition temperature(Td)at 10% mass loss is 540℃ and char yield is 64% at 800℃ in N2. This polyamide can be readily soluble in organic solvents such as N, N-dimethylacetamide(DMAc), N, N-methyl-2-pyrrolidone, m-cresol, pyridine and tetrahydrofuran. Transparent, flexible, and tough film of the polymer cast from DMAc solution exhibits tensile strength of 86 MPa, elongation at break of 10%, tensile modulus of 2.0 GPa. This polyamide indicates excellent electrical resistance properties,such as the volume resistivity of 8.62× 1015Ψ·cm,surface resistivity of 9.85× 1014Ψ and dielectric constant of 3.48(100 Hz).