含异丙基及三氟甲基可溶性聚酰胺的合成及性能研究

Synthesis and Properties of Soluble Polyamides Containing Isoproply Groups and Trifluoromethyl

以含异丙基和三氟甲基结构二胺单体3,3′-二异丙基-4,4′-二胺基苯基-4″-三氟甲基甲苯(PATFT)与萘-1,4-二甲酸、间苯二甲酸和4,4-二苯醚二甲酸3种二酸通过膦酰化反应制备一系列新型可溶性聚酰胺,其相对分子量在3.8×104~9.6×104之间.结果表明,该聚合物具有优异的溶解性能,常温不仅能溶解于N-甲基吡咯烷酮(NMP)、N,N-二甲基乙酰胺(DMAc)、N,N-二甲基甲酰胺(DMF)等高沸点有机溶剂,在加热条件下甚至能较好的溶解在四氢呋喃、氯仿、二氯甲烷等低沸点溶剂中;突出的光学性能,截止波长范围在322~350 nm,80%的透过率波长范围为378~403 nm;良好的热学性能,玻璃化转变温度(Tg)范围在213~220?C,氮气氛围下5%和10%热失重温度范围分别为453~458?C和470~482?C.聚合物薄膜具有优异的机械性能,拉伸强度、杨氏模量、断裂伸长率分别对应为68~97 MPa,1.9~2.9 GPa,14.8%~16.7%.广角X-射线图谱表明聚合物为无定形态结构.

A new diamine monomer, 3,3’-diisopropyl-4,4’-diaminodiphenyl-4＂-trifluoromethyltoluene（PATFT） was designed and synthesized, and its structure was confirmed by FTIR, NMR and mass spectrometry. A series of fluorinated aromatic polyamides were obtained by Yamazaki phosphorylating condensation method with aromatic dicarboxylic acids, such as terephthalic acid, isophthalic acid, and 4-（4-carboxyphenoxy）benzoic acid. All the obtained polyamides were studied with FTIR, NMR, GPC, TGA, DSC and WAXD. The chemical structure of the polymers was in good agreement with the proposed structures. The weight-average molecular weight of the polyamides were in the range of 3.8 × 104-9.6 × 104, with the molecular weight distribution varied from 3.2 to 3.7. These results indicate that the polymers were of high molecular weight with low polydispersity index, and they must be suitable toprepare flexible and tough films. The solubility of the polyamides was also tested, and the results showed that they possessed good solubility at room temperature in high-boiling organic solvents, such as N,N-dimethylacetamide（DMAc）, N,N-dimethylformamide（DMF）, N-methyl-2-pyrrolidone（NMP）, and dimethyl sulfoxide（DMSO）. Moreover, they could be dissolved in low-boiling solvents under heating, such as tetrahydrofuran（THF）, chloroform, methylene chloride and acetone. They also have outstanding thermal and thermo-oxidative stability with the glass transition temperature（Tg） in the range of 213-220 °C in nitrogen atmosphere, as well as T5% weight loss temperature range of 453-458 °C and that for T10% from 470 °C to 482 °C in nitrogen atmosphere. Furthermore, char yields of the polyamides at 800 °C was in the range from 55% to 66%. Obviously, these polymers exhibited excellent optical properties with the cutoff wavelength in the range of 322-350 nm, and 80% transmittance with the wavelengths of 403 nm or longer. The polyamide films showed outstanding mechanical property with tensile strength of 68-397 MPa, elongation at break of 14.8%-316.7%, and Young’s modulus of 1.9-32.9 GPa. The results of WAXD indicated that all the polymers were amorphous.