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Inherent Viscosities (inherent + viscosity)
Selected AbstractsSynthesis and characterization of new soluble polyamides from an unsymmetrical diamine bearing a bulky triaryl pyridine pendent groupJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Mousa Ghaemy Abstract New unsymmetrical diamine monomer containing triaryl pyridine pendent group, 2,4-diaminophenyl [4-(2, 6-diphenyl-4-pyridyl) phenyl]ether, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-(2,6-diphenyl-4-pyridyl) phenol, followed by Pd/C-catalyzed hydrazine reduction. Five Polyamides (PA) were prepared by the phosphorylation polycondensation of different dicarboxylic diacids with the diamine. Inherent viscosities of PAs were in the range 0.51,0.59 g/dL indicating formation of medium molecular weight polymers. The weight and number average molecular weights of a PA, (PA-d), determined by GPC were 6944 g/mol and 17,369 g/mol, respectively. PAs exhibited glass-transition temperatures (Tg) in the range 140,235°C. These polymers, essentially amorphous, were soluble in polar aprotic solvents such as DMF, NMP, DMAc, DMSO, pyridine, m -cresol, and THF. The initial decomposition temperatures (Ti) of PAs, determined by TGA in air, were in the range 300,380°C indicating their good thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] New organosoluble polyimides with low dielectric constants derived from bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl] diphenylmethyleneMACROMOLECULAR SYMPOSIA, Issue 1 2003Der-Jang Liaw Abstract A new kink diamine with trifluoromethyl group on either side, bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl]diphenylmethane(BTFAPDM), was reacted with various aromatic dianhydrides to prepare polyimides via poly (amic acid) precursors followed by thermal or chemical imidization. Polyimides were prepared using 3,3,, 4,4,-biphenyltetracarboxylic dianhydride(1), 4,4,-oxydiphthalic anhydride(2), 3,3,,4,4,-benzophenonetetracarboxylic dianhydride (3), 4,4,-sulfonyldiphthalic anhydride(4), and 4,4,-hexafluoroisopropylidene-diphathalic anhydride(5). The fluoro-polyimides exhibited low dielectric constants between 2.46 and 2.98, light color, and excellent high solubility. They exhibited glass transition temperatures between 227 and 253°C, and possessed a coefficient of thermal expansion (CTE) of 60-88 ppm/°C. Polymers PI-2, PI-3, PI-4, PI-5 showed excellent solubility in the organic solvents: N -methyl-2-pyrrolidinone (NMP), N,N -dimethylacetamide (DMAc), N,N -dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridkie and tetrahydrofuran (THF). Inherent viscosity of the polyimides were found to range between 0.58 and 0.72 dLg-1. Thermogravimetric analysis of the polyimides revealed a high thermal stability decomposition temperature in excess of 500°C in nitrogen. Temperature at 10 % weight loss was found to be in the range 506-563°C and 498-557°C in nitrogen and air, respectively. The polyimide films had a tensile strength in the range 75-87 MPa; tensile modulus, 1.5-2.2 GPa; and elongation at break, 6-7%. [source] Synthesis and characterization of Schiff-base-containing polyimidesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Mousa Ghaemy Abstract Benzyl bisthiosemicarbazone and its complexes with nickel (NiLH4) and copper (CuLH4) were used as diamine monomers for the synthesis of new Schiff-base polyimides. The solution polycondensation of these monomers with the aromatic dianhydrides afforded metal-containing Schiff-base polyimides with inherent viscosities of 0.98,1.33 dL/g (measured in N -methyl-2-pyrrolidone at 25°C). The polyimides were generally soluble in a wide range of solvents such as N,N -dimethylformamide, N,N -dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, tetrachloroethane, hexamethylene phosphoramide, N -methyl-2-pyrrolidone, ethyl acetate, and pyridine at room temperature. The initial degradation temperatures of the resultant polyimides fell in the range of 220,350°C in nitrogen with char yields ranging from 36 to 64% at 700°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of new unsaturated polyesters containing cyclopentapyrazoline moiety in the main chainJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Ismail A. Alkskas Abstract 3-p -Hydroxyphenyl-6- p -hydroxybenzylidene cyclopentapyrazoline (III) and 3-vanillyl-7-vanillylidene cyclopentapyrazoline (IV) were used as new starting materials for preparing new unsaturated polyesters. The polyesters were prepared by reacting (III) or (IV) with adipoyl, sebacoyl, isophthaloyl, and terephthaloyl dichlorides utilizing the interfacial polycondensation technique. The polyester samples have been characterized by elemental and spectral analyses. The polyesters have inherent viscosities of 0.55,0.97 dL/g. All the polyesters are semicrystalline and most of them are partially soluble in most common organic solvents but freely soluble in concentrated sulfuric acid. Their glass transition temperatures (Tg) range from 103.34 to 208.81°C, and the temperatures of 10% weight loss as high as 190 to 260°C in air, indicating that these aromatic polyesters have high Tg and excellent thermal stability. Doping with iodine dramatically raised the conductivity and produced dark brown colored semiconductive polymers with a maximum conductivity in the order of 3.1 × 10,7 ,,1 cm,1. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Dehydration of benzene through fluorine containing aromatic polyamide membrane by pervaporationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008P. K. Gutch Abstract A series of soluble polyamides were synthesized by direct polycondensation of the 5- tert -butyl isophthalic acid with different diamines. Solution (20%) of the polymers in suitable solvents was used to cast the membranes. The membranes showed selectivity toward the benzene (Bz) in a mixture of Bz/water (H2O). Water affinity of the membrane was found to be lower than that of Bz. The polyamide incorporating hexafluoro isopropylidene moiety was promising for the dehydaration of Bz and breaking of Bz/H2O azeotrope. The polymers exhibited inherent viscosities, ranging from 0.40 to 0.92 dL/g and 10% weight loss in synthetic air up to 474°C. Glass transition temperature measured by DSC and DMA reached up to 258°C. The membranes were pale yellow in appearance having tensile strength up to 85 MPa, modulus of elasticity up to 2.6 GPa, and elongation at break up to 9.5%, depending upon the exact repeating unit structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and properties of novel organosoluble aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkagesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Shou-Ri Sheng Abstract Several novel aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages with inherent viscosities of 0.62,0.65 dL/g were prepared from 2-methyldiphenylether and 3-methyldiphenylether with 4,4,-bis(4-chloroformylphenoxy)diphenylsulfone and 4,4,-bis (3-chloroformylphenoxy)diphenylsulfone by electrophilic Friedel,Crafts acylation in the presence of N,N -dimethylformamide with anhydrous AlCl3 as a catalyst in 1,2-dichloroethane. These polymers, having weight-average molecular weights in the range of 57,000,71,000, were all amorphous and showed high glass-transition temperatures ranging from 160.5 to 167°C, excellent thermal stability at temperatures over 450°C in air or nitrogen, high char yields of 52,57% in nitrogen, and good solubility in CHCl3 and polar solvents such as N,N -dimethylformamide, dimethyl sulfoxide, and N -methyl-2-pyrrolidone at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 84.6,90.4 MPa, Young's moduli of 2.33,2.71 GPa, and elongations at break of 26.1,27.4%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] A phosphorus-containing thermotropic liquid crystalline copolyester with low mesophase temperature and high flame retardanceJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2008Cheng-Shou Zhao Abstract A novel phosphorus-containing thermotropic liquid crystalline copolyester with flexible spacers (P-TLCP-FS) was synthesized by melt transesterification from p -acetoxybenzoic acid (p -ABA), terephthalic acid (TPA), ethylene glycol, and acetylated 2-(6-oxid-6H-dibenz(c,e) (1,2) oxaphosphorin 6-yl) 1,4-benzenediol (AODOPB). The chemical structure and properties of the obtained P-TLCP-FS were characterized by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), inherent viscosity measurements, differential scanning calorimetry (DSC), thermogravimetry (TGA), polarizing light microscopy (PLM), and X-ray diffraction (XRD) analysis. P-TLCP-FS had inherent viscosities of 0.92,1.12 dL/g and exhibited low and wide mesophase temperatures, ranging from 185 to 330 °C, which can match with the processing temperatures of most conventional polymers and high flame retardancy with a limiting oxygen index value of 70% and UL-94 V-0 rating. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5752,5759, 2008 [source] Synthesis, photoluminescence, and electrochromic properties of wholly aromatic polyamides bearing naphthylamine chromophoresJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2006Guey-Sheng Liou Abstract A series of novel polyamides with pendent naphthylamine units having inherent viscosities of 0.15,1.02 dL/g were prepared via direct phosphorylation polycondensation from various diamines and a naphthylamine-based aromatic dicarboxylic acid, 1-[N,N -di(4-carboxyphenyl)amino]naphthalene. These amorphous polyamides were readily soluble in various organic solvents and could be cast into transparent and tough films. The aromatic polyamides had useful levels of thermal stability associated with high glass-transition temperatures (268,355 °C), 10% weight loss temperatures in excess of 480 °C, and char yields at 800 °C in nitrogen higher than 60%. These polymers showed maximum ultraviolet,visible absorption at 350,358 nm and exhibited fluorescence emission maxima around 435,458 nm in N -methyl-2-pyrrolidinone solutions with fluorescence quantum yields ranging from 0.4 to 15.0%. The hole-transporting and electrochromic properties were examined with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium tin oxide coated glass substrate exhibited one oxidative redox couple around 1.08,1.16 V (oxidation onset potential) versus Ag/AgCl in an acetonitrile solution and revealed good stability of the electrochromic characteristics, with a color change from colorless to green at applied potentials ranging from 0 to 1.6 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6094,6102, 2006 [source] Synthesis and characterization of new polyamides based on DiphenylaminoisosorbideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2005Asmaa A. Caouthar Abstract New aromatic polyamides were synthesized by the microwave-assisted polycondensation of an optically active isosorbide-derived diamine with different diacyl chlorides in the presence of a small amount of N -methylpyrrolidinone. Polymers with inherent viscosities between 0.22 and 0.73 dL/g were obtained corresponding to molecular weights up to 140,000 g/mol. With interfacial polymerization or the Higashi method, lower molecular weight polymers were obtained with inherent viscosities in the range of 0.04,0.36 dL/g. Differential scanning calorimetry measurements clearly demonstrated the high thermal stability of these polymers (mp = 180,300 °C) and the absence of decomposition. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6480,6491, 2005 [source] Synthesis and properties of novel soluble polyamides having ether linkages and laterally attached p -terphenyl unitsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2004Sheng-Huei Hsiao Abstract A new ether-bridged aromatic dicarboxylic acid, 2,,5,-bis(4-carboxyphenoxy)- p -terphenyl (3), was synthesized by the aromatic fluoro-displacement reaction of p -fluorobenzonitrile with 2,,5,-dihydroxy- p -terphenyl in the presence of potassium carbonate, followed by alkaline hydrolysis. A set of new aromatic polyamides containing ether and laterally attached p -terphenyl units was synthesized by the direct phosphorylation polycondensation of diacid 3 with various aromatic diamines. The polymers were produced with high yields and moderately high inherent viscosities (0.44,0.79 dL/g). The polyamides derived from 3 and rigid diamines, such as p -phenylenediamine and benzidine, and a structurally analogous diamine, 2,,5,-bis(4-aminophenoxy)- p -terphenyl, were semicrystalline and insoluble in organic solvents. The other polyamides were amorphous and organosoluble and could afford flexible and tough films via solution casting. These films exhibited good mechanical properties, with tensile strengths of 91,108 MPa, elongations to break of 6,17%, and initial moduli of 1.95,2.43 GPa. These polyamides showed glass-transition temperatures between 193 and 252 °C. Most of the polymers did not show significant weight loss before 450 °C, as revealed by thermogravimetric analysis in nitrogen or in air. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4056,4062, 2004 [source] Polyesterification of aromatic dicarboxylic acids and bisphenols with tosyl chloride/dimethylformamide/pyridine promoted by the improvement of the difficult solubility of the activated diacids with lithium chlorideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2004Fukuji Higashi Abstract The solution polyesterification of dicarboxylic acids in pyridine, the activated intermediates of which were difficult to dissolve in tosyl chloride/dimethylformamide/pyridine, was investigated in the presence of lithium chloride. The solubility of the activated dicarboxylic acids was largely improved by the presence of the salt, and the polycondensation with bisphenols was greatly facilitated. The salt was more effectively added to a pyridine solution of dicarboxylic acids than to the activated dicarboxylic acids in pyridine. The favorable additive effect on the improved solubility was attributed to a lowered degree of association of the activated dicarboxylic acids, which led to distributions of the resulting oligomers from bisphenols at an earlier stage closer to the theoretical ones and yielded better polycondensation results. The reaction, which proceeded through favorable distributions of the co-oligomers, produced copolymers of higher inherent viscosities and slightly block sequence distributions determined by NMR. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2725,2733, 2004 [source] Synthesis and properties of novel polyimides derived from 2,2,,3,3,-benzophenonetetracarboxylic dianhydrideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2004Xing-Zhong Fang Abstract A new synthetic route to 2,2,,3,3,-BTDA (where BTDA is benzophenonetetracarboxylic dianhydride), an isomer of 2,3,,3,,4,-BTDA and 3,3,,4,4,-BTDA, is described. Single-crystal X-ray diffraction analysis of 2,2,,3,3,-BTDA has shown that this dianhydride has a bent and noncoplanar structure. The polymerizations of 2,2,,3,3,-BTDA with 4,4,-oxydianiline (ODA) and 4,4,-bis(4-aminophenoxy)benzene (TPEQ) have been investigated with a conventional two-step process. A trend of cyclic oligomers forming in the reaction of 2,2,,3,3,-BTDA and ODA has been found and characterized with IR, NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and elemental analyses. Films based on 2,2,,3,3,-BTDA/TPEQ can only be obtained from corresponding polyimide (PI) solutions prepared by chemical imidization because those from their polyamic acids by thermal imidization are brittle. PIs from 2,2,,3,3,-BTDA have lower inherent viscosities and worse thermal and mechanical properties than the corresponding 2,3,,3,,4,-BTDA- and 3,3,,4,4,-BTDA-based PIs. PIs from 2,2,,3,3,-BTDA and 2,3,,3,,4,-BTDA are amorphous, whereas those from 3,3,,4,4,-BTDA have some crystallinity, according to wide-angle X-ray diffraction. Furthermore, PIs from 2,2,,3,3,-BTDA have better solubility, higher glass-transition temperatures, and higher melt viscosity than those from 2,3,,3,,4,-BTDA and 3,3,,4,4,-BTDA. Model compounds have been prepared to explain the order of the glass-transition temperatures found in the isomeric PI series. The isomer effects on the PI properties are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2130,2144, 2004 [source] Synthesis and properties of fluorinated polyimides based on 1,4-bis(4-amino-2-trifluoromethylphenoxy)-2,5-di- tert -butylbenzene and various aromatic dianhydridesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2004Chin-Ping Yang Abstract A novel fluorinated diamine monomer, 1,4-bis(4-amino-2-trifluoromethylphenoxy)-2,5-di- tert -butylbenzene (2), was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 2,5-di- tert -butylhydroquinone in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Fluorinated polyimides (5a,5f) were synthesized from diamine 2 and various aromatic dianhydrides (3a,3f) via thermal or chemical imidization. These polymers had inherent viscosities of 0.77,1.01 dL/g. The 5 series polyimides were soluble in N -methyl-2-pyrrolidone, N,N -dimethylacetamide, and N,N -dimethylformamide and were even soluble in dioxane, tetrahydrofuran, and dichloromethane. 5(C) showed cutoff wavelengths between 363 and 404 nm and yellowness index (b*) values of 6.5,40.2. The polyimide films had tensile strengths of 93,114 MPa, elongations to break of 9,12%, and initial moduli of 1.7,2.1 GPa. The glass-transition temperatures were 255,288 °C. The temperatures of 10% weight loss were all above 460 °C in air or nitrogen atmospheres. In comparison with a nonfluorinated polyimide series based on 1,4-bis(4-aminophenoxy)-2,5-di- tert -butylbenzene, the 5 series showed better solubility and lower color intensity, dielectric constants, and moisture absorption. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2272,2284, 2004 [source] Synthesis and characterization of phthalazinone containing poly(arylene ether)s via a novel N,C coupling reactionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2003S. J. Wang Abstract High-molecular-weight poly(phthalazinone)s with very high glass-transition temperatures (Tg's) were synthesized via a novel N,C coupling reaction. New bisphthalazinone monomers (7a,e) were synthesized from 2-(4-chlorobenzoyl) phthalic acid in two steps. Poly(phthalazinone)s, having inherent viscosities in the range of 0.34,0.91 dL/g, were prepared by the reaction of the bis(phthalazinone) monomers with an activated aryl halide in a dipolar aprotic solvent in the presence of potassium carbonate. The poly(phthalazinone)s exhibited Tg's greater than 230 °C. polymer 8b synthesized from diphenyl biphenol and bis(4-flurophenyl) sulfone demonstrated the highest Tg of 297 °C. Thermal stabilities of the poly(phthalazinone)s were determined by thermogravimetric analysis. All the poly(phthalazinone)s showed a similar pattern of decomposition with no weight loss below 450 °C in nitrogen. The temperatures of 5% weight loss were observed to be about 500 °C. The poly(phthalazinone)s containing 4,4,-isopropylidenediphenol and 4,4,-(hexafluoroisopropylidene) diphenol and diphenyl ether linkage were soluble in chlorinated solvents such as chloroform. Other poly-(phthalazinone)s were soluble in dipolar aprotic solvents such as N,N,-dimethylacetamide. The soluble poly(phthalazinone)s can be cast as flexible films from solution. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2481,2490, 2003 [source] Effects of diamines and their fluorinated groups on the color lightness and preparation of organosoluble aromatic polyimides from 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-hexafluoropropaneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2003Chin-Ping Yang Abstract To investigate the position and amount of the CF3 group affecting the coloration of polyimides (PIs), we prepared 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane (2) with four CF3 groups with 2-chloro-5-nitrobenzotrifluoride and 2,2-bis(4-hydroxyphenol)hexafluoropropane. A series of soluble and light-colored fluorinated PIs (5) were synthesized from 2 and various aromatic dianhydrides (3a,3f). 5a,5f had inherent viscosities ranging from 0.80 to 1.19 dL/g and were soluble in amide polar solvents and even in less polar solvents. The glass-transition temperatures of 5 were 221,265 °C, and the 10% weight-loss temperatures were above 493 °C. Their films had cutoff wavelengths between 343 and 390 nm, b* values (a yellowness index) ranging from 5 to 41, dielectric constants of 2.68,3.01 (1 MHz), and moisture absorptions of 0.03,0.29 wt %. In a comparison of the PI series 6,8 based on 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]propane, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane, we found that the CF3 group close to the imide group was more effective in lowering the color; this means that CF3 of 5, 7, and 8f was more effective than that of 6c. The color intensity of the four PI series was lowered in the following order: 5 > 7 > 6 > 8. The PI 5f, synthesized from diamine 2 and 4,4,-hexafluoroisopropylidenediphthalic anhydride, had six CF3 groups in a repeated segment, so it exhibited the lightest color among the four series. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 922,938, 2003 [source] Synthesis and properties of organosoluble poly(amide imide imide)s based on tetraimide dicarboxylic acid condensed from 4,4,-(hexafluoroisopropylidene)diphthalic anhydride, 4,4,-oxydianiline, and trimellitic anhydride and various aromatic diaminesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2002Chin-Ping Yang Abstract A novel tetraimide dicarboxylic acid was synthesized with the ring-opening addition of 4,4,-(hexafluoroisopropylidene)diphthalic anhydride, 4,4,-oxydianiline, and trimellitic anhydride in a 1/2/2 molar ratio in N -methyl-2-pyrrolidone followed by azeotropic condensation to tetraimide dicarboxylic acid. A series of poly(amide imide imide)s (PAIIs) with inherent viscosities of 0.8,1.1 dL/g were prepared from tetraimide dicarboxylic acid with various aromatic diamines by direct polycondensation. Most of the PAIIs were readily soluble in a variety of amide polar solvents and even in less polar m -cresol and pyridine. Solvent-cast films had tensile strengths ranging from 99 to 106 MPa, elongations at break ranging from 8 to 13%, and initial moduli ranging from 2.0 to 2.3 GPa. The glass-transition temperatures of these PAIIs were recorded at 244,276 °C. They had 10% weight losses at temperatures above 520 °C in air or nitrogen atmospheres. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1092,1102, 2002 [source] Synthesis and Light-Emitting Properties of New Polyimides Containing Ethynylene Units in the Main ChainMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007Jun Ho Chi Abstract Two new polyimides (ODA-PI and HDA-PI) having 1,4-phenylenediethynylene unit and octyloxy groups were synthesized. Judging from inherent viscosities of their precursor PAAs (1.42 and 1.62 dL,·,g,1), the two PIs were very high in molecular weight. Casting and thermal imidization of PAAs results polyimides with good-quality films. They were stable up to 364,°C and showed no crystallites. UV-vis and PL spectra in NMP solutions of both PIs showed maxima at 442 and 501 nm, respectively, while PL spectra in ,10 µm thick films exhibited a maximum at 540 nm. CV indicates that two PIs were electrochemically active in redox region. The devices with construction of ITO/PEDOT/PIs/BAlq3/LiF/Al exhibited turn-on voltages of 6.5 V in ODA-PI and 7.5 V in HDA-PI and emitted a bright bluish-green light. ODA-PI and HDA-PI showed maximum luminescence of 256 and 316 cd,·,cm,2, respectively, at the same voltage of 12 V. [source] Synthesis and properties of new aromatic poly(ester-imide)s derived from 4- p -biphenyl-2,6-bis(4-trimellitimidophenyl) pyridine and various dihydroxy compoundsPOLYMER INTERNATIONAL, Issue 1 2007Hossein Behniafar Abstract A novel class of wholly aromatic poly(ester-imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32,0.49 dL g,1 was prepared by the diphenylchlorophosphate-activated direct polyesterification of the preformed imide-ring-containing diacid, 4- p -biphenyl-2,6-bis(4-trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6-bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and 1H NMR spectroscopy and elemental analysis. The ultraviolet ,max values of the poly(ester-imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m -cresol, as well as in polar organic solvents, such as N -methyl-2-pyrrolidone, N,N -dimethylacetamide, N,N -dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide-angle X-ray diffraction. The resulting poly(ester-imide)s showed nearly an amorphous nature, except poly(ester-imide) derived from 4,4,-dihydroxy biphenyl. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry thermograms were in the range 298,342 °C. The 10% weight loss temperatures (T10%) from thermogravimetric analysis curves were found to be in the range 433,471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry [source] Synthesis and properties of new aromatic polyimides based on 2,2,-dibromo-4,4,,5,5,-benzophenone tetracarboxylic dianhydridePOLYMER INTERNATIONAL, Issue 8 2004Ahmad Banihashemi Abstract New polyimides with enhanced thermal stability and high solubility were synthesized in common organic solvents from a new dianhydride, 2,2,-dibromo-4,4,,5,5,-benzophenone tetracarboxylic dianhydride (DBBTDA). DBBTDA was used as monomer to synthesize polyimides by using various aromatic diamines. The polymers were characterized by IR and NMR spectroscopy and elemental analysis. These polyimides had good inherent viscosities in N -methyl-2-pyrrolidinone (NMP) and also high solubility and excellent thermo-oxidative stability, with 5 % weight loss in the range 433 to 597 °C. Copyright © 2004 Society of Chemical Industry [source] Synthesis and characterization of novel aromatic poly(amide-imide)s derived from 2,2,-bis(4-trimellitimidophenoxy)biphenyl or 2,2,-bis(4-trimellitimidophenoxy)-1,1,-binaphthyl and various aromatic diaminesPOLYMER INTERNATIONAL, Issue 7 2003Ahmad Banihashemi Abstract New aromatic diimide-dicarboxylic acids having kinked and cranked structures, 2,2,-bis(4-trimellitimidophenoxy)biphenyl (2a) and 2,2,-bis(4-trimellitimidophenoxy)-1,1,-binaphthyl (2b), were synthesized by the reaction of trimellitic anhydride with 2,2,-bis(4-aminophenoxy)biphenyl (1a) and 2,2,-bis(4-aminophenoxy)-1,1,-binaphthyl (1b), respectively. Compounds 2a and 2b were characterized by FT-IR and NMR spectroscopy and elemental analyses. Then, a series of novel aromatic poly(amide-imide)s were prepared by the phosphorylation polycondensation of the synthesized monomers with various aromatic diamines. Owing to structural similarity, and a comparison of the characterization data, a model compound was synthesized by the reaction of 2b with aniline. The resulting polymers with inherent viscosities of 0.58,0.97 dl g,1 were obtained in high yield. The polymers were fully characterized by FT-IR and NMR spectroscopy. The ultraviolet ,max values of the poly(amide-imide)s were also determined. The polymers were readily soluble in polar aprotic solvents. They exhibited excellent thermal stabilities and had 10% weight loss at temperatures above 500 °C under a nitrogen atmosphere. Copyright © 2003 Society of Chemical Industry [source] Microwave-assisted synthesis and characterization of heterocyclic, and optically active poly(amide-imide)s incorporating L -amino acidsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2008Abdol R. Hajipour Abstract N,N,-Pyromelliticdiimido-di- L -alanine (1), N,N,-pyromelliticdiimido-di- L -phenylalanine (2), and N,N,-pyromelliticdiimido-di- L -leucine (3) were prepared from the reaction of pyromellitic dianhydride with corresponding L -amino acids in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The microwave-assisted polycondensation of the corresponding diimide-diacyl chloride monomers (5,7) with 4-phenyl-2,6-bis(4-aminophenyl) pyridine (10) or 4-(p -methylthiophenyl)-2,6-bis(4-aminophenyl) pyridine (12) were carried out in a laboratory microwave oven. The resulting poly(amide-imide)s were obtained in quantitative yields, and they showed admirable inherent viscosities (0.12,0.55 dlg,1), were soluble in polar aprotic solvents, showed good thermal stability and high optical purity. The synthetic compounds were characterized by IR, MS, 1H NMR, and 13C NMR spectroscopy, elemental analysis, and specific rotation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Synthesis and properties of homopolyamide and copolyamides fibers based on 2,6-bis(p -aminophenyl)benzo[1,2-d;5,4- d,]bisoxazoleJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Xiangqun Chen Abstract A novel aromatic homopolyamide with benzobisoxazole units in the main chain was synthesized with 2,6-bis(p -aminophenyl)benzo[1,2- d;5,4- d,]bisoxazole and terephthaloyl chloride by low temperature solution polycondensation, the inherent viscosity of which was 1.98 dL/g. The diamine and p -phenylendiamine with terephthaloyl chloride were used to synthesize the copolyamides. The structures of homopolyamide and copolyamides were characterized by IR spectra, elemental analysis, and wide-angle X-ray diffraction. Wide-angle X-ray diffraction measurements showed that homopolyamide and copolyamides were predominantly crystallinity. The results of thermal analysis indicated that the thermal stabilities of the copolymer increased with an increase of the molar fraction of benzobisoxazole in the copolymers. The thermal stability of the copolyamides with decomposition temperatures (at 10% weight loss) above 570°C was better than that of poly(p -phenylene terephthalamide) (PPTA). Fibers of homopolyamide and copolyterephthalamides were spun from lyotropic liquid crystal dope in 100% H2SO4. When compared with PPTA fibers prepared under the same conditions, the tensile strengths of copolyamides fibers improved by 20,33% with tensile strengths of 1.81 GPa, tensile moduli of 76 GPa, and elongations at break of 3.8,4.1%, which indicated that copolyamides fibers had outstanding mechanical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and characterization of high molecular weight hexafluoroisopropylidene-containing polybenzimidazole for high-temperature polymer electrolyte membrane fuel cellsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2009Guoqing Qian Abstract A high molecular weight, thermally and chemical stable hexafluoroisopropylidene containing polybenzimidazole (6F-PBI) was synthesized from 3,3,-diaminobenzidine (TAB) and 2,2-bis(4-carboxyphenyl) hexafluoropropane (6F-diacid) using polyphosphoric acid (PPA) as both the polycondensation agent and the polymerization solvent. Investigation of polymerization conditions to achieve high molecular weight polymers was explored via stepwise temperature control, monomer concentration in PPA, and final polymerization temperature. The polymer characterization included inherent viscosity (I.V.) measurement and GPC as a determination of polymer molecular weight, thermal and chemical stability assessment via thermo gravimetric analysis and Fenton test, respectively. The resulting high molecular weight polymer showed excellent thermal and chemical stability. Phosphoric acid doped 6F-PBI membranes were prepared using the PPA process. The physiochemical properties of phosphoric acid doped membranes were characterized by measuring the phosphoric acid doping level, mechanical properties, and proton conductivity. These membranes showed higher phosphoric acid doping levels and higher proton conductivities than the membranes prepared by the conventional membrane fabrication processes. These membranes had sufficient mechanical properties to be easily fabricated into membrane electrode assemblies (MEA) and the prepared MEAs were tested in single cell fuel cells under various conditions, with a focus on the high temperature performance and fuel impurity tolerance. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4064,4073, 2009 [source] Synthesis and liquid crystalline properties of new amide-modified poly(1,4-cyclohexanedimethylene terephthalate),JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2006P. Deepa Abstract New series of cycloaliphatic poly(ester-amide)s, poly(1,4-cyclohexanedimethyleneterephthalate- co -1,3-cyclohexanedimethylene terephthalamide), were synthesized through solution polymerization route. The compositions of ester/amide units in the copolymers were varied from 0 to 100% by varying the amount of 1,4-cyclohexanedimethanol and 1,3-cyclohexanebis(methylamine) in the feed. The structures of the polymers were confirmed by NMR and FTIR, and the molecular weights were determined by inherent viscosity. The composition analysis by NMR reveals that the reactivity of the diamine toward the acid chlorides is lowered than that of diol, which results in the formation of more ester content in the poly (ester-amides). The thermal analysis indicate that the new poly(ester-amide)s having less than 10 mol % of amide linkages are thermotropic liquid crystalline from 200 to 250 °C and a thread like nematic phases are observed under the polarizing microscope. WXRD studies suggest that the liquid crystalline domains promote the nucleation process in the polyester chains and increases the percent crystallinity of the poly(ester-amide)s. The glass transition temperature of the copolymers initially increases with increase in amide units because of the presence of nematic phases and subsequently follows the Flory,Fox behavior. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 42,52, 2006 [source] Synthesis of soluble branched polyimides derived from an ABB, monomerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2004Kun-Li Wang Abstract A novel ABB, monomer, an isomeric mixture of 4-[4-(2,4-diaminophenoxy)phenoxy]phthalic acid 2-methyl ester, was successfully prepared. The direct polycondensation of the ABB, monomer was carried out to form polyamic acid monomethyl ester as a precursor with an inherent viscosity of 0.30 dL/g and a number-average molecular weight of 12,000. The degree of branching of the precursor, determined by 1H NMR, was 0.07. The low degree of branching was caused by the differences in the reactivities of the amino groups. The shape factor was calculated to be 0.72. End-modified reactions with acetyl chloride, benzoyl chloride, and phthalic anhydride were carried out. After the chemical imidization of the end-modified precursors, end-modified polyimides were successfully prepared. The end-modified polyimides were soluble in dimethyl sulfoxide, dimethylformamide (DMF), and N -methyl-2-pyrrolidinone. On the basis of thermogravimetry and differential scanning calorimetry measurements of the polyimides, the 5 wt % thermal loss temperatures were determined to be 400,520 °C, and the glass-transition temperatures were determined to be 200,258 °C. According to the X-ray diffraction measurements, the end-modified polyimides were amorphous. A strong but brittle film was prepared from an acetamide end-modified polyimide solution, via casting from a DMF solution, with a tensile strength of 46 MPa, an elongation at break of 4%, and a modulus of 1.3 GPa. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3200,3211, 2004 [source] Synthesis and characterization of poly(arylene ether)s derived from 4,4,-bishydroxybiphenyl and 4,4,-bishydroxyterphenylJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2002Arun Kashinath Salunke Abstract A series of poly(arylene ether)s were successfully prepared by aromatic, nucleophilic substitution reactions with various perfluoroalkyl-activated bisfluoromonomers with 4,4,-bishydroxybiphenyl and 4,4,-bishydroxyterphenyl. 4,4,-Bishydroxyterphenyl was synthesized through the Grignard coupling reaction of magnesium salt of 4-bromoanisole with dibromobenzene followed by demethylation with pyridine,hydrochloride. The products obtained by the displacement of fluorine atoms exhibited good inherent viscosity, up to 0.77 dL/g, and number-average molecular weights up to 69,300. These poly(arylene ether)s showed very good thermal stability, up to 548 °C for 5% weight loss according to thermogravimetric analysis under synthetic air, and high glass-transition temperatures, up to 259 °C according to differential scanning calorimetry, depending on the exact repeat unit structure. These polymers were soluble in a wide range of organic solvents, such as N -methylpyrrolidone, dimethylformamide, tetrahydrofuran, toluene, and CHCl3, and were insoluble in dimethyl sulfoxide and acetone. Thin films of these poly(arylene ether)s showed good transparency and exhibited tensile strengths up to 132 MPa, moduli up to 3.34 GPa, and elongations at break up to 84%, depending on their exact repeating unit structures. These values are comparable to those of high-performance thermoplastic materials such as poly(ether ether ketone) (PEEK) and Ultem poly(ether imide) (PEI). These poly(arylene ether)s exhibited low dielectric constants. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 55,69, 2002 [source] Local Viscosity of Si-O-C-N Nanoscale Amorphous Phases at Ceramic Grain BoundariesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2001Giuseppe Pezzotti Internal friction characterization has been used to quantitatively assess the viscosity characteristics of Si-O-C-N glasses segregated to nanometer-sized grain boundaries of polycrystalline Si3N4 and SiC ceramics. A relaxation peak of internal friction, which arises with rising temperature from the viscous sliding of glassy grain boundaries, was systematically collected and analyzed with respect to its shift upon changing the oscillation frequency. As a result of such an analysis, both activation energy for viscous grain-boundary flow and inherent viscosity of the intergranular glass film could be quantitatively evaluated. Two main features are shown: (i) the presence of N and/or C greatly affects the viscosity characteristics of SiO2 phases at Si3N4 and SiC grain boundaries; and (ii) the internal friction method has potential as a unique experimental tool for understanding the local properties of nanoscale amorphous phases in new ceramic materials. [source] Lyotropic Liquid Crystalline Polyamides Containing Aromatic, Heterocyclic Structures: Preparation and PropertiesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 17 2006Pengtao Liu Abstract Summary: A series of novel lyotropic liquid crystalline polyamides derived from 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-(aminophenoxyl)phenyl)]-phthalazinone (DHPZ-DA), p -phenylene diamine (PPD) and terephthaloyl dichloride (TPC) have been successfully synthesized by the low temperature solution polycondensation method. The copolymers obtained with inherent viscosity of ,1.21 to 3.29 dl,·,g,1, determined in NMP (1 wt.-% LiCl) or concentrated H2SO4 at 25,°C, were confirmed to be amorphous by WAXD and differential scanning calorimetry (DSC). Their solubility was improved by the introduction of non-coplanar, twisted phthalazinone moieties and ether linkages into the main chain with the result that they can be soluble in some polar solvents containing a small amount of LiCl. Their Tgs were all above 310,°C and 10% weight loss temperatures in nitrogen above 500,°C. Most of these polyamides can form an anisotropic phase in concentrated H2SO4, NMP (1 wt.-% LiCl) and DMAc (1 wt.-% LiCl) solutions, observed on a polarizing light microscope. Optical micrograph (×40) of polyamide P-4060 at 10 wt.-% in NMP/LiCl (1% w/v) solution at room temperature. [source] Nonstoichiometric polycondensation I. synthesis of polythioether from dibromomethane and 4,4,-thiobisbenzenethiolMACROMOLECULAR SYMPOSIA, Issue 1 2003Hirokazu Iimori Abstract High molecular weight poly(phenylene thioether) (3) was successfully obtained by the polycondensation of 4,4,-thiobisbenzenethiol (1) and dibromomethane (2) with a variety of feed ratios in the presence of 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) in 1-methyl-2-pyrrolidinone (NMP) at 75°C. The resulting polymer showed the maximum inherent viscosity (,inh) of 0.50 dL/g in 4 h when 1.5 equivalents excess of 2 was used. The model reaction using benzenethiol (4) and dichloromethane (5) in the presence of DBU in deuterated dimethylsulfoxide (DMSO- d6) at 25°C indicated that the rate of the second nucleophilic displacement reaction (k2) is 61 times faster than that of the first one (k1). The maximum of theoretical molecular weights calculated at various stoichiometric imbalance (S) under the condition of k2/k1 = 61 showed a good agreement with the experimental molecular weights at specific polymerization times. [source] Diacid architecture effect on the synthesis and microstructure of rigid-rod poly(benzobisthiazole)sPOLYMER INTERNATIONAL, Issue 12 2006Chien-Fan Chen Abstract Six poly(benzobisthiazole)s (PBTs) have been synthesized by the solution polycondensation of 2,5-diamino-1,4-benzenedithiol in poly(phosphoric acid) (PPA) with systematically varied diacids to demonstrate the diacid architecture effect of the aromatic heterocyclic rigid-rod polymers. The role of PPA is identified and the effects of phosphorus pentoxide and water on PBT during polycondensation are discussed. Polymer properties such as the inherent viscosity and decomposition temperature are correlated to the diacid chemistry. The effect of diacid architecture on the synthesis and microstructure of PBT is studied. The results are discussed in terms of resonance, symmetry, and solubilization of the diacids. Copyright © 2006 Society of Chemical Industry [source] | ||||||||||