Home About us Contact
|
Home About us Contact | ||
|
|
||
Direct Polycondensation (direct + polycondensation)
Selected AbstractsDehydration 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 characterization of amphiphilic biodegradable poly(glutamic acid- co -lactic acid- co -glycolic acid) by direct polycondensationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Dedai Lu Abstract Poly(glutamic acid- co -lactic acid- co -glycolic acid) (PGLG), an amphiphilic biodegradable copolymer, was synthesized by simply heating a mixture of L -glutamic acid (Glu), DL -lactic acid, and glycolic acid with the present of stannous chloride. The unique branched architecture comprising of glutarimide unit, polyester unit, and polyamide unit was confirmed by NMR spectrum. The PGLG was soluble in many organic solvents and aqueous solution of sodium hydroxide (pH , 9.0). The thermal properties were evaluated using thermogravimetric analysis and differential scanning calorimetry. Molecular weights were determined by 1H NMR end-group analysis and GPC, respectively, and the results indicated that the higher Glu content resulted in a decrease of the molecular weight. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and characterization of aromatic polyamides containing alkylphthalimido pendent groupsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2002E. Ferrero Abstract A series of polyisophthalamides containing pendent phthalimido groups and flexible side spacers were prepared from four novel diacids and three commercial aromatic diamines. These polyamides were prepared in high yields and with high molecular weights by direct polycondensation with triphenyl phosphite and pyridine as condensing agents. The weight-average and number-average molecular weights, measured by gel permeation chromatography, were 70,000,137,000 and 47,000,86,000 g/mol, respectively. The novel polyamides were amorphous and readily soluble and showed glass-transition temperatures of 150,240 °C, as measured by differential scanning calorimetry. Thermogravimetric analysis showed that the 10% weight-loss temperatures in nitrogen were 355,430 °C, a significant improvement in thermal stability having been observed with the increase in the side-chain length. A theoretical quantum mechanical study was successfully carried out to explain these results. Flexible and tough films, cast from polymer solutions, showed tensile strengths of 50,125 MPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3711,3724, 2002 [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] New poly ether ether ketones containing phosphorus for membrane preparationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010Francesco Trotta Abstract In this study is reported the synthetic procedure and the characterisation of novel phosphorus containing polyether ether ketone (PEEK-P). The new polymer was synthesized via direct polycondensation of 2,2-bis(3-diethylphosphono-4-hydroxyphenyl)-propane and 4,4,-difluorobenzophenone according to well known general procedure and was extensively characterized by using infrared spectroscopy (FT-IR), thermogravimetric analyses (TGA), viscosity measurements and ,H-NMR analysis. The obtained polymer is soluble in some organic solvents and the solution of phosphonated polymer could be used to obtain membranes by using the phase inversion technique. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||