高耐热可溶性含氟含吡啶环聚芳酰胺的制备及性能研究

Preparation and Properties of High Heat-resistant Soluble Fluorinated and Containing Pyridine Ring Aromatic Polyamides

以4-三氟甲硫基苯甲醛和4-硝基苯乙酮为原料,设计合成一种新型二胺单体—4-(4-三氟甲硫基苯基)-2,6-双(4-胺基苯基)吡啶(FTPAP),通过傅里叶红外光谱(FTIR)、核磁共振(NMR)和质谱(MS)等对二胺单体进行结构表征.将FTPAP分别与1,4-萘二甲酸(NDA)、4,4-二苯醚二甲酸(CPBA)、对苯二甲酸(PTA)通过Yamazaki膦酰化法制备一系列含吡啶环及大侧基三氟甲硫基苯基非共平面结构新型可溶性聚酰胺(PA).采用FTIR,~1H-NMR等对PA进行结构表征.凝胶渗透色谱(GPC)数据显示PA具有较高的分子量和低的分散系数,相对分子量在9.30×10~4~1.26×10~5之间,分散系数范围为1.12~1.33.结果表明:PA具有优异的溶解性能,在室温条件下可以溶解在N-甲基-2-吡咯烷酮(NMP)、二甲基亚砜(DMSO)、N,N-二甲基甲酰胺(DMF)等高沸点有机溶剂中,甚至在加热条件下能部分溶解于低沸点四氢呋喃(THF)、氯仿(CHCl_3)溶剂中.PA呈现出优异的热稳定性和光学性能,聚合物玻璃化转变温度(T_g)在285~325°C之间;在氮气氛围中5%和10%热失重时的温度范围分别为396~435°C和430~490°C,且残炭率都在70%以上;聚合物截止波长(λ_(cutoff))范围为369~384 nm,80%透过率(λ_(80%))的波长范围为440~478 nm;广角X射线图谱表明聚合物为无定型结构.此外,PA薄膜具有良好的力学性能,其拉伸强度43.2~95.0 MPa,杨氏模量0.90~1.39 GPa,断裂伸长率3.3%~8.8%.

A novel diamine monomer 4-（4-trifluoromethylthiophenyl）-2,6-bis（4-aminophenyl）pyridine （FTPAP） was synthesized from 4-trifluoromethylthiobenzaldehyde and 4-nitroacetophenone by two-step reaction, and its structure was characterized via Fourier transform infrared spectroscopy （FTIR）, nuclear magnetic resonance （NMR） and mass spectrometry （MS）. A series of novel soluble fluorinated aromatic polyamides （PA） containing pyridine ring, bulky group trifluoromethylthiophenyl and non-coplanar structure were prepared by Yamazaki phosphorylating condensation with aromatic dicarboxylic acids, such as terephthalic acid （NDA）, 4-（4- carboxyphenoxy）benzoic acid （CPBA） and terephthalic acid （PTA）. The structure of PA was characterized by FTIR and 1H-NMR. Gel permeation chromatography （GPC） data showed that PA has a relatively higher molecular weight and a lower dispersion coefficient, and the weight-average molecular weight and molecular weight distribution of PA were in the range of 9.30 × 10^4 - 1.26 × 10^5 and 1.12 - 1.33, respectively. Obviously, PA presenting excellent solubility was not only dissolved in high boiling organic solvents, such as N-methyl-2- pyrrolidone （NMP）, dimethylsulfoxide （DMSO）, N,N-dimethylformamide （DMF）, at room temperature, but also partially dissolved in low boiling solvents, such as tetrahydrofuran （THF） and chloroform （CHC13） under heating. Furthermore, they also showed excellent thermal properties with the glass transition temperature （Tg） in the range of 285 - 325℃ under nitrogen atmosphere, T5%, and T10% weight loss temperature in the range of 396 - 435 ℃ and 430 - 490℃ under nitrogen atmosphere respectively, and all with a char yield above 70%. Moreover, they also showed excellent optical properties with the cutoff wavelength ranges of 369 - 384 nm, the wavelengths of 80% transmittance above 440 nm. The result of WAXD indicated that all the polymers exhibited amorphous structure. In addition, PA films also presented good mechanical properties with the tensile strength ranged from 43.2 - 95.0 MPa, Young＇s modulus from 0.90 - 1.39 GPa, and the elongation at break from 3.3% - 8.8%.