• Macromolecular Research
• /
• v.17 no.11
• /
• pp.912-918
• /
• 2009

An optically active diacid containing the L-histidine moiety was prepared by reacting pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydride) 1 with L-histidine 2 in acetic acid, and was polymerized with several aromatic diamines 5a-g to obtain a new series of optically active poly(amide-imide)s (PAIs) using two different methods, such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,N-dimethylformamide (DMF) system as a condensation agent. The resulting new polymers 6a-g with inherent viscosity was obtained in good yield. The polymers were readily soluble in polar organic solvents, such as N,N-dimethyacetamide (DMAc), N,N-dimethyformamide (DMF), and dimethyl sulfoxide (DMSO). The obtained polymers were characterized by FTIR, specific rotation, elemental analysis as well as $^1$H-NMR spectroscopy and gel permeation chromatography (GPC). The thermal stability of the resulting PAIs was evaluated with thermogravimetric analysis techniques under a nitrogen atmosphere.

• Macromolecular Research
• /
• v.17 no.11
• /
• pp.901-906
• /
• 2009

Several aromatic optically active polyamides (PA)s were synthesized from 5-(2-phthalimidiylpropanoylamino)isophthalic acid with various aromatic diamines via direct polycondensation with triphenyl phosphite and pyridine in the presence of calcium chloride and N-methyl-2-pyrrolidone under microwave irradiation and conventional heating conditions. Under the optimized conditions, the reaction mixture was irradiated for 2 min. with a 100% irradiation power (900 W). The resulting polymers were obtained in high yield and moderate inherent viscosity ranging from 0.35 to 0.60 dL/g. All synthesized polymers showed excellent solubility in amide-type solvents. Thermogravimetric analysis revealed a 10% weight loss temperature and char yield at $600^{\circ}C$ in a nitrogen atmosphere of > $350^{\circ}C$ and > 58%, respectively, which suggests that the resulting PAs have good thermal stability.

• Macromolecular Research
• /
• v.12 no.3
• /
• pp.258-262
• /
• 2004

We have developed facile and rapid polycondensation reactions of N-trimellitylimido-L-leucine diacid chloride 1 with eight different derivatives of hydantoin compounds 2a-h, in the presence of a small amount of a polar organic medium, such as Ο-cresol, by using a domestic microwave oven. The polycondensation reactions proceeded rapidly-they were complete within 7-9 min-to produce a series of novel optically active poly(amide-imide)s (3a-h) in high yield with inherent viscosities of 0.33-0.51 dL/g. We characterized the resulting poly(amide-imide)s by elemental analysis, thermal gravimetric analysis (DSC, TGA, and DTG), and FTIR spectroscopy, and by measuring their viscosities, specific rotations, and solubilities. All of the polymers were soluble at room temperature in polar solvents such as N ,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, and N-methyl-2-pyrrolidone.

• Bulletin of the Korean Chemical Society
• /
• v.10 no.2
• /
• pp.172-177
• /
• 1989

Stereoselective solvolyses of optically active activated esters in the aggregate system of optically active polymeric surfactants containing imidazole and benzene moieties were performed. The catalyst polymers employed were copolymers of N-methacryloyl-L-histidine methyl ester (MHis) with N,N-dimethyl-N-hexadecyl-N-[10-(p-methacryloylo xyphenoxycarbonyl)-decyl]ammonium bromide(DEMAB). In the solvolyses of N-carbobenzoxy-D- and L-phenylalanine p-nitrophenyl esters (D-NBP and L-NBP) by polymeric catalysts, copoly(MHis-DEMAB) exhibited not only increased catalytic activity but also enhanced enantioselectivity as the mole ${\%}$ of surfactant monomers in the copolymers increased. The polymeric catalysts showed noticeable enantioselective solvolyses toward D- and L-NBP of the substrates employed. As the reaction temperature was lowered for the solvolyses of D- and L-NBP with the catalyst polymer containing 3.5 mole ${\%}$ of MHis, the increased reaction rate and enhanced enantioselectivity were observed. The coaggregative systems of the polymer and monomeric surfactants were also investigated. In the case of coaggregate system consisted of 70 mole ${\%}$ of cetyldimethylethylammonium bromide with polymeric catalyst showed maximum enantioselective catalysis, viz., $k_{cat}(L)/k_{cat}(D)$ = 2.85. The catalyst polymers in the sonicated solvolytic solutions were confirmed to form large aggregate structure by electron microscopic observation.

• Journal of Pharmaceutical Investigation
• /
• v.18 no.2
• /
• pp.69-81
• /
• 1988

We studied on the synthesis of chloromethylated polystyrene as a precursor of optically active polymers for direct resolution of optical isomers. Changing the degree of crosslinking and the kind of crosslinking agents, several polystyrene resin matrices were synthesized. The matrices were chloromethylated with methylal and chlorosulfonic acid as chloromethylating agents. The effects of solvents of various dielectric constants on the chloromethylation were quantitavely examined. We also synthesized chloromethylated polystyrene of macroreticular type that retained large surface area and good physical stability. The differences between the macroreticular type and macroporous type were investigated.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.27-28
• /
• 2006

Chromatographic separation of enantiomers by high-performance liquidchromatography (HPLC) has considerably advanced in the past two, and many optically active polymers have been developed to be usedaschiral stationary phases (CSP). Among many CSPs, cellulose-andamylose-based CSPs are most attractive from the viewpoints of theirwide applicability and easy availability. The polysaccharides are readily modified to ester and carbamates. The derivatives have been used as CSPs after being coated on macroporus silica gel. Here, the CSPs based on phenylcarbamate derivatives of these two polysaccharides will be mainly discussed. The immobilization of the derivatives on silica gel will also be discussed.

• Macromolecular Research
• /
• v.17 no.10
• /
• pp.739-745
• /
• 2009

N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g were synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride 1 with two equimolars of Lalanine 2a, L-valine 2b, L-leucine 2c, L-isoleucine 2d, L-phenyl alanine 2e, L-2-aminobutyric acid 2f and L-histidine 2g in an acetic acid solution. Seven new poly(amide-imide)s PAIs 5a-g were synthesized through the direct polycondensation reaction of seven chiral N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g with bis(3-amino phenyl) phenyl phosphine oxide 4 by two different methods: direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$/pyridine (py), and direct polycondensation in a tosyl chloride (TsCl)/pyridine (py)/N,N-dimethylformamide (DMF) system. The polymerization reaction produced a series of flame-retardant and thermally stable poly(amide-imide)s 5a-g with high yield. The resulted polymers were fully characterized by FTIR, $^1H$ NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation and solubility tests. Data obtained by thermal analysis (TGA and DTG) revealed that the good thermal stability of these polymers. These polymers can be potentially utilized in flame retardant thermoplastic materials.

• Advances in nano research
• /
• v.14 no.2
• /
• pp.201-210
• /
• 2023

A ZnO/poly (amide-imide) hybrid nanocomposite film with different weight percentages of Zinc oxide (ZnO) nanoparticles is synthesized and characterized in this paper. A two-step reaction successfully synthesized a new kind of heteroaromatic diamine with bulky pendant groups. In order to produce 3, 5-dinitro-3, 3-bis (4-(4-Nitrophenoxy) phenyl) -2- benzofuran-1-one, 3, 3'-bis (4-hydroxyphenyl) benzofuran-1-one and 3'-bis (4-hydroxyphenyl) benzofuran-1-one were combined with 3'-bis (3-hydroxyphenyl) benzofuran-1-one. The obtained dinitro was then reduced by zinc dust and hydrochloric acid. The reaction of 4, 4^* carbonyl diphthalic anhydride with amino acid L-alanine in acetic acid leads to the production of very high yields of chiral diacid monomer. As a result of the direct polymerization of these monomers, new optically active polymers were formed (amide-imide). In order to synthesize poly (amide-imide)/ZnO nanocomposites with different weight percentages (2, 4, 6, 8, and 10%), PAI and ZnO nanoparticles were combined using ultrasonication SEM, Fourier transform infrared spectroscopy, X-ray diffraction and thermal gravimetry were used to characterize the PAI films.