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Volume 64, Issue 12
Displaying 1-13 of 13 articles from this issue
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Comprehensive Papers
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Masayo SAKATA, Masami TODOKORO, Masashi KUNITAKE2007 Volume 64 Issue 12 Pages 821-829
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSTo remove endotoxin (lipopolysaccharide; LPS) from a protein solution used as drugs, various aminated cellulose beads were prepared by immobilization of diaminoalkanes, polyethyleneimime or poly(ε-lysine) onto cellulose beads (Cellufine). The LPS adsorption capacity of the aminated Cellufine depended strongly on the bead pore size (molecular mass exclusion; Mlim) but not necessarily on their amino-group content. The larger the Mlim of the beads, the larger was the LPS adsorption capacity. As a result, when the adsorption of LPS was measured by a column method at pH 7.0, μ=0.17, only poly(ε-lysine)-immobilized Cellufine (pore sizes Mlim 5×104) selectively removed LPS from a bovine serum albumin (BSA) solution contaminated with LPS: the residual concentration of LPS in the BSA solotion was <0.1 EU/mL (<10 pg/mL), and the recovery of the BSA was 98%.
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Yoshifumi SAKAGUCHI, Kozaburo TAMURA2007 Volume 64 Issue 12 Pages 830-848
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSLiquid sulfur undergoes a polymerization transition from S8 rings to a mixture of S8 rings and polymeric chains at Tp=159°C. Recently, we have found that such a transition can be induced below Tp through laser illumination and that there are three photo-excited structural stages, which are controlled by the laser intensity; (1) an intermediate product between a S8 ring and a polymer, produced by weak laser illumination, (2) a polymer, produced by medium laser illumination, and (3) ordered macromolecules, produced by strong laser illumination. In this paper, we report the details of these photo-structural changes and discuss the origin of these changes based on the electronic nature of a sulfuric chain which posses lone-pair electrons.
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Akiko OKAMOTO, Tadahiro HORIGUCHI, Ryosuke MITSUI, Noriyuki YONEZAWA2007 Volume 64 Issue 12 Pages 849-862
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSSyntheses of wholly aromatic polyketones bearing trifluoromethyl side groups by electrophilic aromatic aroylation polymerization have been performed with the aid of molecular design of acyl-acceptant and acyl-donor monomers, retro synthetic analyses and practical optimization of monomer syntheses, and optimization of polycondensation system based on the choice of acidic mediator. The wholly aromatic polyketones having biphenylylenedicarbonyl moieties substituted with one or two trifluoromethyl groups in the main chain were synthesized by stepwise constructions of the corresponding dicarboxylic acid equivalent monomers by electrophilic aromatic substitutions and/or aromatic couplings followed by phosphorus (V) oxide-methanesulfonic acid-mediated regioselective electrophilic aromatic aroylation polymerizations. The sequence of the wholly aromatic polyketone bearing an unsymmetrical biphenylylenedicarbonyl moiety was constructed by suitable arrangement of CF3 and methoxy groups on the monomers realizing satisfactory regioselectivity. The acyl-acceptant monomers bearing CF3 groups were designed and synthesized by introduction of CF3-bearing aryl moiety on the 2,2′-dioxybiphenylylene unit, which successfully gave wholly aromatic polyketones by trifluoromethanesulfonic acid-mediated electrophilic aromatic aroylation polymerization.
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Takahiro INATSUGI, Mitsuo MATSUDA, Mathias DESTARAC2007 Volume 64 Issue 12 Pages 863-882
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSBackground and Recent developments and of Macromolecular Design by Interchange of Xanthate (MADIX) are reviewed. MADIX is a useful method for control/living radical polymerization(C/LRP). The effect of the activation Z′ group and leaving R group of the xanthate, Z′O-(C=S)SR is investigated. Optimal control of molar mass and polydispersities of MADIX derived polymers can be achieved by selecting suitable structures. The MADIX process allows the ab initio emulsion polymerization which is not easy for other C/LRP methods. Nano composite particles of block copolymer are also prepared by seed emulsion polymerization. Oxidation, reduction and ionic cleavage are easily implemented to remove the xanthate end group after polymerization. MADIX is a powerful tool for the design of tailor made polymers such as block copolymers, polymer brushes, star-like polymers, microgels, etc. These polymers can be used as rheology modifiers, polymer emulsifiers, stabilizers for organic-inorganic nano-composites and for surface modifications.
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Hiroki SHIMIZU, Takahiko MATSUSHITA, Shin-Ichiro NISHIMURA2007 Volume 64 Issue 12 Pages 883-896
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSMicrowave irradiation has been used in chemical reactions as an efficient heating tool for two decades. We have found that microwaves also contribute other factors while studying three carbohydrate-related syntheses. 1) With microwave irradiation under Lewis acid conditions, methyl glycosides could behave as glycosyl donors. 2) Microwaves were able to accelerate oligopeptide synthesis, fourteen times more effectively than conventional methods. Using this method, we have successfully synthesized a focused oligopeptide library, and this focused library has been applied in biological research to reveal a cancer epitope. 3) Finally, microwave irradiation has been used at low temperatures in Lewis X oligosaccharide synthesis. Galactosylation of 4-OH in a fucosyl glucosamine acceptor has proceeded in high yield without producing byproducts, e.g., cleavage of the fucosyl bond or nucleophilic rearrangement of methylthio group.
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Junji SAITO, Nobuo KAWAHARA, Shingo MATSUO, Hideyuki KANEKO, Tomoaki M ...2007 Volume 64 Issue 12 Pages 897-906
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSPolyolefin/non-polyolefin hybrid materials, named polyolefin hybrids, have been synthesized. These were block, graft and star polymers that consisted of both polyolefin and non-polyolefin segments. The properties of these hybrids were examined. Various polyolefin hybrids were prepared by using three kinds of methods: (1) PO Macroinitiator, (2) PO Macromonomer, and (3) Reactive PO using functionalized polyolefins formed with metallocene catalyst systems as starting materials. Polyolefin hybrids exhibited micro phase separation between polyolefin and non-polyolefin segments at nm level. Among them, PE-b-PMMA, PP-g-PS, and PMMA-g-EPR were found to work as excellent compatibilizers of polyolefin and non-polyolefin blend polymers. In addition, surface coated PP sheets with poly(2-hidroxyethylmethacrylated) were successfully synthesized as new polyolefin materials.
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Naomi AJIOKA, Akihiro YOKOYAMA, Tsutomu YOKOZAWA2007 Volume 64 Issue 12 Pages 907-921
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSThis article covers the synthesis and self-assembly of several polymer architectures containing condensation polymers with low polydispersities by chain-growth condensation polymerization utilizing substituent effects. Well-defined AB, ABA, BAB, ABC type block copolymers, star polymers, star block copolymers and miktoarm star copolymers containing aromatic polyamide or aromatic polyether as a segment were synthesized by 1) sequential addition of monomers, 2) a polymer coupling reaction, 3) a macroinitiator method with modification of polymer end group, and 4) macroinitiator method with an orthogonal initiator. Furthermore, the polymers self-assembled in a unique way.
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Original Papers
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Yoshihiko SHIMADA, Shin-ichi YUSA, Tohei YAMAMOTO, Yotaro MORISHIMA2007 Volume 64 Issue 12 Pages 922-928
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSWell-defined poly(N-isopropylacrylamide)-block-poly(acrylic acid) (PNIPAM-b-PAA) was prepared via reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization. The “living” polymerization was evidenced by the fact that the molecular weight increased linearly with monomer conversion while the molecular weight distribution (Mw/Mn) remained reasonably narrow independent of the conversion. The thermo- and pH-responsive association behavior of the diblock copolymer was investigated by 1H NMR, transmittance (%T), and fluorescence probe techniques. The diblock copolymer indicated a cloud point (Tcp) in 0.1 M NaCl aqueous solutions. The Tcp value strongly depends on the solution pH because of an interaction between the pendent carboxyl group of the PAA block and the amide group of the PNIPAM block at pH<5. Above the Tcp, the 1H NMR peak intensity of the PNIPAM block and the %T value decreased. 8-Anilino-1-naphthalenesulfonic acid, an ammonium salt hydrate (ANS), a fluorescence probe, was confirmed to be incorporated into the hydrophobic domain formed from the polymer association above Tcp.
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Moriyuki SATO, Atsushi NAKASHIMA, Isao YAMAGUCHI2007 Volume 64 Issue 12 Pages 929-936
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSNew structure-controlled A2+B3 type hyperbranched (HB) polymers containing a phenylstilbene analogue (PEPT) of 1,3,4-thiadiazole as mesogen in the interiors were prepared by solution polycondensation from dioxydiundecanol derivative of PEPT (A2) and trimesic acid trimethyl ester (B3) at various feed molar ratios (A2/B3) and their liquid crystalline (LC) and optical properties were examined. The structure of polymers changed depending on the feed molar ratios. Their number-average molecular weights increased after acetylation of terminal OH groups of the polymers. The HB polymer prepared with a feed molar ratio of A2/B3=3/2 had the maximum molecular weight. All HB polymers are soluble in organic solvents and formed enantiotropic smectic LC phases above their glass transition temperatures. The UV-vis and photoluminescent (PL) spectra of polymers displayed absorption and emission maxima in the blue region, but the fluorescence intensities were extremely weak. The properties of HB polymers were also compared with those of the corresponding linear polymers.
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Synthesis and Micelle Formation of Diblock Copolymers Containing of Polyisocyanates as a Rod SegmentSatoshi UCHIDA, Kotaro TANIMURA, Masataka MAKINO, Koji ISHIZU2007 Volume 64 Issue 12 Pages 937-942
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSPoly(isoprene-b-butyl isocyanate) diblock copolymer was synthesized through a combination of anionic and coordination polymerization techniques. Hydroxyl terminated polyisoprene was synthesized via anionic polymerization using ethylene oxide as an end capping reagent. The hydroxyl group was reacted with a titanium (IV) reagent to form a macroinitiator, with which butyl isocyanate was polymerized. The micelle formation of the rod-coil diblock polymer was investigated using dynamic light scattering (DLS), transmission electron microscopy, and atomic force microscopy. From the DLS measurements, we found that the size of micelles increased upon addition of n-heptane as a poor solvent. The aggregation of micelles was also observed by AFM.
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Keiji GOTO, Hironori UJINO, Takashi OKAI, Yasuhisa TSUKAHARA2007 Volume 64 Issue 12 Pages 943-948
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSIn this paper, we have investigated the living anionic polymerization of styrene with anions newly produced by lithiation in the initiator systems containing s-BuLi, a ligand and an aromatic compound. The ligands used were N,N,N′,N′-tetramethylethylenediamine (TMEDA), N,N,N′,N″,N″-pentamethyldiethylene-triamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylene-tetramine (HMTETA), and (-)-spartein (SP), and the aromatic compounds were toluene, 4-methylbiphenyl (4MB), 1-methylnaphthalene (1MN), and 9-methylanthracene (9MA). It was found that the initiation systems containing the combinations of toluene/TMEDA, toluene/SP, and 4MB/TMEDA gave polystyrene with very narrow molecular weight distribution (MWD), while that containing 9MA resulted in very broad MWD. Furthermore, the increase in the number of nitrogen atoms in the ligands influenced the MWD. Polymerizations with the initiator systems containing p-xylene, 4,4′-dimethylbiphenyl, and di-p-tolylmethane were also investigated.View full abstractDownload PDF (493K)
Notes
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Kazuhiro YAMABUKI, Suguru NAKAE, Yukio ISOBE, Kenjiro ONIMURA, Tsutomu ...2007 Volume 64 Issue 12 Pages 949-952
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSA new methacrylate monomer having a sec-amine, a triphenylmethyl group, and an internal olefin was synthesized. The polymer obtained by radical polymerization of the monomer was deprotected with trifluoroacetic acid, followed by washing with a saturated solution of NH4PF6 to afford the corresponding polymer having a sec-ammonium salt unit. The synthesis of side-chain-type polyrotaxane was carried out with the polymer and dibenzo-24-crown-8 ether in the presence of ruthenium carbene complex (Grubbs 1st catalyst). The resulting polymer was insoluble. The IR spectra suggested that the obtained polyrotaxane contained crosslinking structures.
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Kazunori SE, Teppei YAMAZAKI, Satoshi IRIE2007 Volume 64 Issue 12 Pages 953-956
Published: 2007
Released on J-STAGE: December 29, 2007
JOURNAL FREE ACCESSFrom a number fraction (nf) of the number of arms (f) for (PSt)f star polymers prepared via anionic living polymerization of polystyrene macromonomers (PStM), the distribution in number of arms, (f∼nf) has been determined. From a number fraction of polymer (Nf, i) having a degree of polymerization (i), each distribution in a degree of polymerization of (PSt)f, (i∼Nf, i) was first calculated using Nf, i=∑i=j+k (N(f-1), jN1, k) and (i∼N1, i) of the PStM, and then the distribution in a degree of polymerization of (PSt)<f>, (i∼N<f>, i)cal was calculated by N<f>, ical=∑fnfNf, i, where <f> is an average number of arms. By comparing the resultant (i∼N<f>, i)cal with (i∼N<f>, i)obs determined by GPC equipped with a low-angle laser light-scattering detector, each (f∼nf) of the five (PSt)f star polymers was determined. From the polymerization time dependence of the resultant (f∼nf) and polymerization conditions, a non-linear polymerization rate constant and its mechanism were discussed.View full abstractDownload PDF (372K)
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