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  • 1
    Electronic Resource
    Electronic Resource
    Chiroptical and photochromic properties of stereoregular copolymers of 4-methacryloxyethylenoxyazobenzene with (-)-menthyl methacrylate (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 3 (1991), S. 292-298 
    Details
    ISSN: 0899-0042
    Keywords: photochromic polymers ; chiral polymers ; stereoregular polymers ; 4-methacryloxyethylenoxyazobenzene ; (-)-menthyl methacrylate ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolymers of the photochromic monomer 4-methacryloxyethylenoxyazobenzene with the optically active comonomer (-)-menthyl methacrylate, having different stereoregularity, were investigated in order to obtain a better understanding of the relationship between microstructure and photochromism in synthetic macromolecules. No appreciable effect was observed by copolymer composition, sequence distribution, and microtacticity on the photoinduced trans → cis isomerization of the azobenzene side chains. This last, however, is reflected in changes of the chiroptical properties, type and entity of the photoinduced variation being dependent on chain structure. The long spacer separating the azo chromophore from the main chain limits the extent of chiroptical properties dependence on irradiation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530030413
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    FT-IR microspectroscopy study of blends of ester functionalized ethylene-propylene copolymer with (vinylidene fluoride-hexafluoropropene) elastomer (1992)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 75-79 
    Details
    ISSN: 1042-7147
    Keywords: FT - IR microspectroscopy ; Polymer blends ; Phase separation ; Intermolecular interactions ; 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
    Notes: An ethylene - propylene (EPR) copolymer functionalized with (1,2-dicarboethoxy)ethyl groups has been blended with a vinylidene fluoride - hexafluropropene elastomer (NML). The existence of intermolecular interactions involving mainly the carbonyl groups of the side chains of the functionalized copolymer and the methylene hydrogens of the fluoroelastomer through hydrogen bonding was shown by means of FT - IR spectroscopy. The structure and composition of some microdomains in the mixture was examined by means of FT - IR microspectroscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1992.220030205
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of photochromic polymers by stereospecific copolymerization of trans-4-(2-methacryloxyethyloxy)azobenzene and (-)-menthyl methacrylate (1991)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 2 (1991), S. 3-14 
    Details
    ISSN: 1042-7147
    Keywords: Photochromic polymers ; Optically active polymers and copolymers ; Stereoregular polymers and copolymers ; 4-(2-Methacryloxyethyloxy)azobenzene ; (-)-Menthyl methacrylate ; 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
    Notes: The synthesis is reported of a new photochromic monomer, trans-4-(2-methacryloxyethyloxy) azobenzene (MEAB), where the azobenzene chromophore is separated from the ester group by an ethylenoxy spacer arm. Comparative experiments show that trans-4-methacryloxyazobenzene (MAB), having the azobenzene group directly attached to the ester functionality, does not homopolymerize or copolymerize with (-)-menthyl methacrylate (MnMA) in the presence of different anionic initiators, whereas isotactic homopolymers and copolymers of MEAB can be obtained: the microstructure is described with reference to analogous atactic macromolecules.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1991.220020101
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  • 4
    Electronic Resource
    Electronic Resource
    Photoresponsive polypeptides: Photochromism and conformation of poly (L-glutamic acid) containing spiropyran units (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1505-1517 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spirobenzopyran units were bound to the side chains of poly (L-glutamic acid) and partially methylated poly(L-glutamate)s. The modified polymers were found to exhibit “reverse photochromism” in hexafluoro-2-propanol (HFP), so the samples kept in the dark were characterized by an intense absorption band in the visible range of the spectrum, which was completely erased upon exposure to sunlight or irradiation at 500-550 nm.The CD spectra showed that the macromolecules adopted a random coil conformation in the dark, whereas the bleached solutions after exposure to light displayed the typical CD pattern of the α-helix. The back reaction in the dark was accompanied by the progressive decrease of the helix content and recovery of the original disordered conformation. The photoinduced conformational changes resulted in large and reversible viscosity variations.When spiropyran side chains were converted to “spiropyran salts” of trifluoroacetic acid, the system was still photochromic, but the macromolecules were disordered both in the dark and light conditions. However, when appropriate amounts of methanol were added as a cosolvent to the HFP solutions, the system responded to light, giving reversible variations of the α-helix content. Irradiation at appropriate solvent compositions allowed modulation of the extent of the photoresponse. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360331003
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    Paper (German National Licenses)
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