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  • 1
    Electronic Resource
    Electronic Resource
    Selective permeation of CO2 and O2 by membrane of poly(maleic acid-co-styrene)-poly(ethylene glycol) interpolymer complexes (1988)
    Springer
    Polymer bulletin 20 (1988), S. 521-524 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Contrary to most polymer membranes, the membrane composed of poly(maleic acid-co-styrene)-poly(ethylene glycol)(PMS-PEG) complexes gives separation factor for CO2 to O2 smaller than 1. While the unit molar ratio reaches 1, the separation factor for CO2 to O2 exhibits a minium. The temperature dependence of CO2 permeability is larger than O2 permeability, i.e. the permeation activation energy of CO2 (16 kcal/mol) is larger than that of O2 (3 kcal/mol). The separation factor for CO2 to O2 increases with increasing temperature. A tentative explanation is proposed for the results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263666
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  • 2
    Electronic Resource
    Electronic Resource
    Radical polymerization and graft polymerization with ceric ion and 3-phenylmethyl-2,4-pentanedione system (1994)
    Springer
    Polymer bulletin 32 (1994), S. 581-588 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Radical polymerization of acrylamide (AAM) initiated with ceric ion 1, 3-diketone compound, i.e. 3-phenylmethyl-2,4-pentanedione system and grafting acrylamide polymerization onto macromolecules having 1,3-diketone pendant groups using ceric ion as an initiator have been studied. The initiation mechanism was proposed on the basis of EPR and kinetics studies. The formation of grafted copolymer was revealed by XPS spectra, FT-IR spectra and photomicrographs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973905
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  • 3
    Electronic Resource
    Electronic Resource
    Photopolymerization of N-substituted phenyl maleimide initiated with N,N-dimethyl-4-toluidine (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 643-650 
    Details
    ISSN: 0887-624X
    Keywords: photopolymerization of N-substituted phenyl maleimides ; N,N-dimethyl-4-Toluidine ; exciplex ; radical intermediate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several N-phenyl maleimides with different p-substituents have been synthesized from the maleic anhydride and relevant aromatic amine. In the presence of N,N-dimethyl-4-toluidine (DMT), the N-substituted phenyl maleimide (4-XPhMIs) could be polymerized under UV irradiation. It was observed that a new absorption appeared on the UV-Vis spectrum of the mixture solution of 4-XPhMI and DMT, which reveals the formation of charge-transfer complex in the ground state. It was found that the fluorescence of DMT was quenched by 4-XPhMI and the quenching constant of 4-XPhMI, obtained from the Stern-Volmer plot, increases with the electron-deficiency of ethylene double bond of 4-XPhMI. The dynamic quenching of the fluorescence of DMT by 4-XPhMI suggests the formation of exciplex in excited state between DMT and 4-XPhMI. The radicals formed in the systems have been detected by spin-trapping techniques and electron paramagnetic resonance (EPR) spectrometer. Based on all of these results, it has been proposed that the initiation process of the polymerization involves the formation of exciplex and the initial radicals were produced by proton-transfer in the exciplex from DMT to 4-XPhMI. © 1997 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of poly(1,4-dioxan-2-one-co-trimethylene carbonate) for application in drug delivery systems (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1301-1307 
    Details
    ISSN: 0887-624X
    Keywords: 1,4-dioxan-2-one ; trimethylene carbonate ; stannous octoate ; drug delivery system ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(1,4-dioxan-2-one-co-trimethylene carbonate), P(DON-co-TMC), copolymers with different compositions were synthesized by copolymerizations of 1,4-dioxan-2-one (DON) and trimethylene carbonate (TMC) at 120°C in the presence of Sn(Oct)2. Their structures and compositions were determined with FT-IR and 1H-NMR spectroscopies. The intrinsic viscosities of copolymers increased with the increase of the TMC fraction in feed. The DSC results of copolymers showed that the glass transition temperatures (Tgs) of copolymers are lower than those of homopolymers. Most copolymers are amorphous except for one with a high DON composition. The hydrophilicity of the copolymers is in proportion with the DON molar fraction in the copolymers. It was found that the Levonorgestrel (LNG) release rate is dependent of the composition and flexibility of polymer chains. The fastest one is the copolymer with nearly a equivalent fraction of DON to TMC. Among copolymers with other compositions, a higher DON fraction would be favorable to the release of LNG. All measurements demonstrate an almost constant release rate in the period of 1 month. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1301-1307, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of ABA-type block copolymer of poly(trimethylene carbonate) with poly(ethylene glycol): Bioerodible copolymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 695-702 
    Details
    ISSN: 0887-624X
    Keywords: ABA-type block copolymers ; ring-opening polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ABA-type block copolymers of poly(trimethylene carbonate) with poly(ethylene glycol) (Mn 6820), PTMC-b-PEG-b-PTMC, were synthesized by the ring-opening polymerization of 1,3-dioxan-2-one (trimethylene carbonate) in the presence of poly-(ethylene glycol) with stannous octoate catalyst, and the copolymers with various compositions were obtained. The PTMC-b-PEG-b-PTMC copolymers were characterized with Fourier transform infrared and nuclear magnetic resonance spectroscopies. The intrinsic viscosities of resulting copolymers increased with the increase of 1,3-dioxan-2-one content in feed while the molar ratio of monomer over catalyst kept constant. It has been observed that the glass transition temperature (Tg) of the PTMC segments in copolymers, recorded from differential scanning calorimetry, was dependent on the composition of copolymers. The melting temperature (Tm) of PEG blocks in copolymer was lower than that of PEG polymer, and then disappeared as the length of PTMC blocks increased. The results of dynamic contact angle measurement clearly revealed that the hydrophilicity of resulting copolymers increased greatly with the increase of PEG content in copolymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 695-702, 1998
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation and properties of poly(styrene-co-maleic anhydride)/silica hybrid materials by the in situ sol-gel process (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1607-1613 
    Details
    ISSN: 0887-624X
    Keywords: sol-gel ; hybrid material ; poly(styrene-co-maleic anhydride) ; tetraethoxysilane ; (3-aminopropyl)triethoxysilane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(styrene-co-maleic anhydride)/silica hybrid material has been successfully prepared from styrene-maleic anhydride copolymer and tetraethoxysilane (TEOS) in the presence of a coupling agent (3-aminopropyl)triethoxysilane (APTES) by an in situ sol-gel process. It was observed that the gel time of sol-gel solution was dramatically influenced by the amount of APTES. The hybrid material exhibits optical transparency almost as good as both silica gel and the copolymer. The covalent bonds between organic and inorganic phases were introduced by the aminolysis reaction of the amino group with maleic anhydride units of copolymer to form a copolymer bearing trimethoxysilyl groups, which undergo hydrolytic polycondensation with TEOS. The differential scanning calorimetry (DSC) showed that the glass transition temperature of the hybrid materials increases with increasing of SiO2 composition. Photographs of scanning electron microscopy (SEM) and atomic force microscopy (AFM) inferred that the size of the inorganic particles in the hybrid materials was less than 20 nm. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1607-1613, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    On the kinetics and initiation mechanism of acrylamide polymerization using the ceric ion/acetoacetanilide system as initiator (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 823-831 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is found that acetoacetanilide (system. name: N-phenyl-3-oxobutanamide) possesses a very high reactivity towards ceric ions, Ce4+, in initiating the polymerization of vinyl monomers. In the presence of acetoacetanilide, the rate of the acrylamide polymerization is larger by a factor of 30 than the rate of initiating by ceric ions alone. The reaction orders were 0,58, 0,75 and 1,2 with respect to acetoacetanilide, ceric ion and acrylamide concentration, respectively. The activation energy of the acrylamide polymerization initiated by ceric ion/acetoacetanilide is only 12,9 kJ/mol. According to the IR spectrum, fragments of acetoacetanilide are present in the polymer produced by the ceric ion redox initiator comprising acetoacetanilide. The C-centered and N-centered primary radicals generated via redox reaction of ceric ion and acetoacetanilide were detected by spin trapping and electron paramagnetic resonance. An initiation mechanism of the ceric ion/acetoacetanilide initiated polymerization is proposed on the basis of experimental results.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950301
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  • 8
    Electronic Resource
    Electronic Resource
    Gas transport in lanthanide-polymer membranes (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 40 (1990), S. 891-897 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Permeation properties of O2, N2, and CO2 were investigated by using copolymer membranes having the pyridine-lanthanids complexed group. The membranes of poly(4-vinylpyridine-co-n-butylmethacrylate) and its complexes with lanthanide were prepared. Complexation with lanthanide can be used to tailoring selectivity of CO2/O2. The CO2 permeability for lanthanide-polymer, which is oppsite to most polymers. the upstream pressure dependent of grass in lanthanide-polymer varies with temperature. A tentative explanation is given for the results according to the free colume model.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070400522
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  • 9
    Electronic Resource
    Electronic Resource
    Gas permeation in poly[(butyl methacrylate)-co-(4-vinylpyridine)] membrane containing transition metal ions (1989)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 10 (1989), S. 145-147 
    Details
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1989.030100306
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  • 10
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    Asymmetric Formal Synthesis of (−)-Cephalotaxine via Palladium-Catalyzed Enantioselective Tsuji Allylation (2018)
    American Chemical Society (ACS)
    Details
    Publication Date: 2018-02-06
    Description: Organic Letters DOI: 10.1021/acs.orglett.7b04008
    Print ISSN: 1523-7060
    Electronic ISSN: 1523-7052
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society (ACS)
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