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Preparation and Studies on the Structure and Properties of Novel Soluble and Functional Aromatic Polyamides

Author: LiPengHui
Tutor: LiGuang
School: Donghua University
Course: Materials Physics and Chemistry
Keywords: Polyaramid Solubility Trifluoromethyl Permittivity
CLC: O633.22
Type: Master's thesis
Year: 2010
Downloads: 71
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Abstract

Aromatic polyamide is an important class of high-performance polymers with excellent thermal stability, low dielectric and good flame resistance and other characteristics. Such aromatic polymer has been successfully applied in the aerospace, petrochemical, machinery, electronics and nuclear energy and other high-tech fields, and to many of the traditional products to achieve a replacement. However, such a high temperature polymer is typically a refractory insoluble, poor processing performance. To improve the solubility of the aromatic polyamide, given its functional is a challenging work to another application value. The papers from the design and synthesis of aromatic diamine monomer, the the step polycondensation Yamazaki Phosphorylamino Law five new series of soluble aromatic polyamide functional polymers. Successful trifluoromethyl, 2-methyl-cyclohexane, and an asymmetric structure were introduced into the molecular main chain of the polymer. Class polyaramid only in certain conventional solvent having excellent solubility and film-forming properties, and also exhibit excellent optical properties, dielectric properties and low water absorption. The main contents and results are as follows: (1) by the of homemade aromatic diamine monomer 3,5 - dimethyl-4 - (4 - amino -2 - (trifluoromethyl) phenoxy)-4'-amino benzoic ketone and four commercialization of an aromatic tetracarboxylic acid, the step Yamazaki Phosphorylamino of polycondensation, preparation of a series of molecular main chain containing trifluoromethyl and methyl, with asymmetric and non-coplanar structure of the new polyaramid (PEKA3a, -d). FT-IR and to 1H-NMR analysis confirmed the synthesis of polyarylene amide and the design of the polymer structure is completely consistent. Polyaramid The series intrinsic viscosity of 0.43 to 0.65 dL / g, having a relatively high molecular weight. They not only can be dissolved at room temperature N-methyl-2 - pyrrolidone, N, N-dimethyl acetamide, N, N-dimethyl formamide and other highly polar solvent, is also dissolved in a low boiling point in a solvent such as chloroform, tetrahydrofuran, methylene chloride, the solvent having good film-forming properties. DSC and TG analysis showed that such polymer has a glass transition temperature at 288 to 323 ° C, 10% thermal weight loss temperature of 431 ° C to 447 ° C. In addition, polyaramid, class Built film also has good dielectric properties and mechanical properties of: a dielectric constant at 1 MHz of less than 3; tensile strength and elongation were 78 to 98 MPa and 1.6 to 1.9%. 2, respectively, by two homemade aromatic diamine monomer containing para and ortho-bis-ether structure, preparing a series of molecular main chain structure containing a trifluoromethyl group and a bis-ether new polyaramid (PA1-PA3 and PA4- PA7). Its intrinsic viscosity of 0.55 to 0.78 dL / g. The series polyaramid exhibit excellent solubility properties: room temperature, not only can be dissolved in a strongly polar solvents, but also can be dissolved in a low boiling solvent, the solubility of up to 10 wt%. By the polymer film obtained is colorless and transparent, and cutoff wavelength in the 331 to 364 nm, 400 nm after having high transparency. In addition, the series of polyarylene ether amides exhibit good dielectric properties, the dielectric constant at 1MHz 2.43 ~ 2.93. In comparison, show better solubility and optical properties of fluorine-containing polyarylene amide structure based on the ortho-bis-ether. 3 use Willianmson reaction and then restore, design and synthesis of two new aromatic diamine cyclohexane structure by the diamine monomer with three commercialization acid monomers by polycondensation reaction prepared a new series containing fluorine-containing cyclohexane structure of the poly (aryl ether amide) (2a-2d and 4b-4d). With FT-IR, ~ 1H-NMR and elemental analysis confirmed the synthesis of a diamine monomer and the resulting polymer structure. DSC and TG analysis results show that the thermal properties of polymer: the glass temperature T_g between 202 to 246 ° C, 10% weight loss temperature of 330 ° C or more; solubility experiments showed that the type of polymer is dissolved excellent performance, nitrogen at room temperature capable of dissolving in an organic solvent such as N-methylpyrrolidone, dimethylacetamide, chloroform, wherein 2a-2d series having more excellent dissolution properties, solubility greater than 10 wt%, and the fast dissolving; polymer film UV - visible Absorption spectra: and such polyarylene amide cutoff wavelength at 335 to 357nm, the transmittance of 500 nm at most of 85%.

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CLC: > Mathematical sciences and chemical > Chemistry > Polymer chemistry ( polymer ) > Miscellaneous Chain Polymers > Nitrogen-containing polymer chain > Polyamide
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