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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1243-1249 
    ISSN: 0887-624X
    Keywords: semirigid copolyurethanes ; biphenyl unit ; fluorine-containing diols ; alkylene diphenyl dicarbamates ; melt polycondensation ; nematic phase ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New semirigid thermotropic liquid crystalline (LC) copolyurethanes 4 and 5 made up of biphenyl units and partially fluorinated aliphatic chains in the backbones were synthesized by melt polycondensation of a mixture of a dioxydihexanol of biphenyl 1 and two fluorine-containing diols 2a,b taken in definite feed mole ratios with alkylene diphenyl dicarbamates 3a-i having various lengths of aliphatic chains. The assigned structures of copolyurethanes 4 and 5 were identified by FTIR, 1H- and 13C-NMR spectra, and elemental analyses. The thermal and mesogenic properties were evaluated by differential scanning calorimetry (DSC), thermal mechanical analyses (TMA), polarizing microscopy, and temperature-changeable X-ray analyses, whose measurements indicated that the copolymers 4 and 5 form thermotropic nematic phases and have glass transition steps around room temperature. It is suggested that the incorporation of partially fluorinated aliphatic chains into the backbones has no drastic effect on the LC formation in the semirigid copolyurethanes 4 and 5. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1243-1249, 1998
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2727-2734 
    ISSN: 0887-624X
    Keywords: molecular imprinting ; adsorption ; surface template polymerization ; bifunctional monomer ; ion exchange resin ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interfacial activity and the molecular structure of functional monomers are critical factors that determine the success of synthesizing metal-imprinted polymers by surface template polymerization. From this point of view, first we prepared three distinct novel bifunctional organophosphorus monomers that are interspaced, in each case, by an alkyl spacer having a specific length. Each monomer carries two phosphonic acid groups and two aromatic groups in its molecular structures. Further, by using the synthesized bifunctional monomers, we prepared highly selective Zn(II)-imprinted polymers by the surface template polymerization initiated from a water-in-oil emulsion. To evaluate the template effect, we conducted diagnostic adsorption studies on Zn(II)-imprinted and unimprinted polymers with zinc ions. A high interfacial activity was found to be required for the functional monomers to create the predominant template effect. It became clear that Zn(II)-imprinted polymers having bifuctional monomers with 12-length alkyl chains (1,12-dodecanediol-O, O′-diphenyl phosphonic acid: DDDPA) yielded the best results. Moreover, analysis results of adsorption behavior supported a high-performance of the Zn(II)-imprinted polymers with DDDPA. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2727-2734, 1998
    Additional Material: 6 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 39 (1996), S. 465-470 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 4 Ill.
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  • 4
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dissociation rate constant kd related to the homolytic cleavage of the C—ON bond formed between a polystyrene (PS) and 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) is determined by adopting the gel permeation chromatography peak-resolution method to the styrene polymerization with a PS-TEMPO adduct as a probe and the radical initiator tert-butyl hydroperoxide. The result was given by the Arrhenius equation, kd = A exp(-E/(RT)) with A = 3.0 × 1013 s-1 and E = 124 kJ · mol-1.
    Additional Material: 6 Ill.
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  • 5
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dissociation rate constant kd of the PS-TEMPO adduct, where PS is polystyrene and TEMPO is 2,2,6,6-tetramethylpiperidin-1-oxyl, was determined by the gel permeation chromatographic tracing of the evolution of polydispersities at an early stage of styrene polymerization with a model PS-TEMPO adduct as initiator. The results agree with those obtained by the direct method in Part 1.
    Additional Material: 5 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 16 (1995), S. 139-146 
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Novel semi-rigid fluorocarbon-containing coplycarbonates composed of biphenyl moiety and rigid rod-like hexafluoropentane chain were prepared by melt polycondensation of 6,6′-(biphenyl-4,4′-diyldioxy)dihexanol (1) and 2,2,3,3,4,4-hexafluoro-1,5-pentanediol (2) with alkylene diphenyl dicarbonates 3 of various aliphatic lengths (m = 6, 8, 10 and 12). The structures of the copolymers 4 were confirmed by FT-IR, 1H and 13C NMR spectra and elemental analyses. The thermal and liquid-crystalline (LC) properties were examined by differential scanning calorimetry (DSC), polarizing microscopy and temperature-changeable X-ray analyses. These measurements indicated that the copolymers show well-defined thermotropic nematic textures and have block-like sequences. It is suggested that the introduction of the hexafluoropentane chain into the main chain gives more stable LC phases.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1451-1457 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Gas chromatography was employed to quasi-continuously determine the amount of carbon dioxide that evolved from carbonate apatite specimens during sintering. Assuming that the carbonate in the specimens decomposed to carbon dioxide on a mole-for-mole basis, the determination of the carbon dioxide evolved allowed for the determination of the amount of carbonate that remained in the specimens during different stages of sintering. Previously, this measurement could be carried out only after sintering was completed. Comparison of data obtained from specimens compacted isostatically at 600 MPa for sintering with powder specimens indicated that the amount of carbonate remaining in the sintered apatite mass strongly depended on heating rates, heating temperatures, and holding-time intervals. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 8
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Block copolymers consisting of poly(γ-benzyl L-glutamate) and poly(ethylene oxide) as the hydrophobic and hydrophilic components, respectively were prepared. Cell attachment onto the surfaces of block copolymers fabricated either as well-defined ordered Langmuir-Blodgett (LB) films or solvent cast microphase-separated structures was studied. On ordered LB surfaces, adherent fibroblasts were larger than on the microphase-separated cast surfaces within 15 min. The difference in cell adhesion between LB films and cast surfaces increased with increasing PEO contents in block copolymer. Adherent cells increased with an increase in surface pressure of LB films in any polymer. Phase-contrast microphotographs of adherent cells showed rapid and extensive morphologic changes associated with the LB surface as compared to cast film surfaces. The number of cells grown on the LB surface is greater than that on the cast film. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1557-1565 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: N-p-Vinylbenzyl-O-β-D-galactopyranosyl-(1,4)-D-gluconamide (PVLA) has been used as an asialoglycoprotein model polymer. Rat hepatocytes expressing asialoglycoprotein receptors are capable of binding to hydrophobic plastic dishes coated with PVLA. PVLA, water-soluble polystyrene derivatives bearing galactose residues preferentially adsorb to plastic plates made of polystyrene rather than those of poly(methyl methacrylate). Hence, we modified chitosan beads with linear chains composed of a long alkyl or phenyl moiety to study the effect of structural variations of adsorbed PVLA, and investigated the extent of hepatocyte attachment to the hydrophobic beads coated with PVLA. The attachment was independent of the amount of immobilized PVLA; rather, it was dependent on the hydrophobicity of the beads with PVLA. To simplify the surface of the hydrophobic beads with PVLA, galactopyranoses were covalently linked to chitosan beads via hydrophobic spacer arms, and hepatocyte attachment was compared among the prepared beads. The beads with spacer arms containing phenylalanine and a phthalic moiety showed increased hepatocyte attachment, which was elicited by galactose residues on the beads. These results suggest that rotational restriction or stiffness and hydrophobicity due to the phenyl moiety are essential to enhance the specificity of terminal galactose in PVLA. This analysis contributes to the design and optimization of an artificial ligand for cellular receptors recognizing surgar moieties. © 1995 John Wiley & Sons, Inc.
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  • 10
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: It has been proposed that the essential requirement for artificial materials to bond to living bone is the formation of bone-like apatite on their surfaces in the body. Recent studies have shown that titanium hydrogel and silica gel induce apatite formation on their surface in a simulated body fluid. In this study, the influence of titanium oxide and titanium silicate on the bonding of titanium alloys to bone was studied. Rectangular implants (15 × 10 × 2.2 mm) of titanium, Ti-6Al-4V, Ti-6Al-2Nb-Ta, Ti-6Al-4V coated with TiO2, and Ti-6Al-4V coated with Ti5Si3 were implanted into the tibial metaphyses of mature rabbits. At 8 and 24 weeks after implantation, the tibiae containing the implants were dissected out and subjected to a detaching testing. The failure load for titanium, Ti-6Al-4V, Ti-6Al-2Nb-Ta, Ti-6Al-4V coated with TiO2, and Ti-6Al-4V coated with Ti5Si3 were, respectively, 0.68 ± 0.48, 0.22 ± 0.46, 0.67 ± 0.59, 2.18 ± 0.71 and 2.03 ± 0.41 kgf at 8 weeks, and 2.7 ± 0.91, 2.58 ± 1.29, 2.38 ± 0.41, 3.79 ± 1.7, and 2.79 ± 0.87 kgf at 24 weeks after implantation. Histological examination by Giemsa surface staining, CMR, and SEM-EPMA revealed the coated titanium alloy implants directly bonded to bone tissue during early implantation. A Ca-P layer was observed at the interface of the coated implants and the bone. The results of this study indicated that TiO2 and Ti5Si3 can enhance the early bonding of titanium alloys to bone by inducing a Ca-P layer (chemical apatite) on the surface of titanium alloys. It also is suggested that the direct bone contact occurs in relation to the calcium and phosphorus adsorption onto the surface of the titanium passive layer formed during long-term implantation. © 1996 John Wiley & Sons, Inc.
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