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  • 1
    Electronic Resource
    Electronic Resource
    Diels-Alder and ene reactions of 4-substituted 1,2,4-triazoline-3,5-diones and some substituted styrenes (1985)
    s.l. : American Chemical Society
    The @journal of organic chemistry 50 (1985), S. 4378-4381 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00222a036
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Control of hard segment size in polyurethane formation (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1767-1772 
    Details
    ISSN: 0887-624X
    Keywords: polyurethane ; hard segment ; reaction conditions ; aliphatic diisocyanate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In general, segmented polyurethane elastomers are prepared by reacting an isocyanate-capped polyol prepolymer with a short-chain diol chain extender, yielding an elastomer with hard segments of uniform size. However, the hard segment size will not be uniform if the polyurethane polymer is prepared by forming the hard segment first, followed by soft segment formation. Because the mechanical properties of polyurethane elastomers depend on the relative ratio of the hard to soft segments as well as the effectiveness of the hard segment as a physical crosslinker, the control of the size distribution of the hard segment is a key factor in designing polyurethane elastomers. It was found that reaction conditions can affect the size distribution of hard segments derived from an aliphatic diisocyanate with differential reactivity between the two isocyanate groups. Lower reaction temperatures and simultaneous mixing of all reactants gave the preferred size distribution of hard segments. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331103
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of α,ω-bis(4-hydroxybutyl) polydimethylsiloxanes (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1773-1782 
    Details
    ISSN: 0887-624X
    Keywords: hydroxy-terminated polysiloxane ; synthesis ; characterization ; molecular weight determination ; stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α,ω-Bis(4-hydroxybutyl) polydimethylsiloxane (molecular weight 1500 to 4500) can be pre-pared with well-controlled molecular weight through the reaction of 1,3-bis(4-hydroxybu-tyl)tetramethyl disiloxane and dimethoxydimethyl silane or diethoxydimethyl silane in the presence of a stoichiometric amount of water and hydrochloric acid. The molecular weight of these hydroxybutyl-terminated polysiloxanes can be determined fairly consistently by a titration method. These polysiloxanes are stable toward cyclization. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331104
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  • 4
    Electronic Resource
    Electronic Resource
    Syntheses and characterization of UV-curable polysiloxane-based polyurethane prepolymers (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1783-1793 
    Details
    ISSN: 0887-624X
    Keywords: polyurethane prepolymer ; hard segment ; gel permeation chromatography ; structure ; structure-property relationship ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: UV-curable polyurethane prepolymers were prepared from the following components: iso-phorone diisocyanate, hydroxybutyl-terminated polysiloxane, and 2-hydroxyethyl meth-acrylate with diethylene glycol or neopentyl glycol added as an optional chain extender. These prepolymers, with hard segments of different structures, were characterized by high resolution NMR, FTIR, and gel permeation chromatography. Model oligomers were prepared to confirm the structures of the prepolymers. The structure-property relationship of cured prepolymers were determined. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331105
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  • 5
    Electronic Resource
    Electronic Resource
    A novel crosslinker for UV copolymerization of N-vinyl pyrrolidone and methacrylates to give hydrogels (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1039-1046 
    Details
    ISSN: 0887-624X
    Keywords: crosslinker ; copolymerization ; hydrogel ; HEMAVC ; shelf-life ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methacryloxyethyl vinyl carbonate, a novel crosslinker containing a vinyl carbonate and a methacrylate group which is capable of copolymerizing N-vinyl pyrrolidone and methacrylates, was prepared. With this crosslinker, N-vinyl pyrrolidone (NVP) and methacrylates can copolymerize efficiently under strictly UV conditions. It was found that this crosslinker was able to give hydrogels with higher water content, higher tear strength, and lower modulus, compared to a traditional dimethacrylate crosslinker. In addition, hydrogel lenses fabricated by UV curing of formulations using this crosslinker were found to be superior to those fabricated with established process in terms of optical quality. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1039-1046, 1997
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Synthesis and structure-property relationships of UV-curable urethane prepolymers with hard-soft-hard blocks (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 2039-2044 
    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: UV-curable urethane prepolymers derived from diisocyanates, rigid diols, and polypropylene glycols of different molecular weights and end-capped with 2-hydroxylethyl methacrylate were prepared by stepwise addition reactions. These prepolymers have the common structure, HEMA-hard segment-soft segment-hard segment-HEMA. As the weight ratio of soft segment to hard segment and thus the rigidity varied, the cured films from these prepolymers exhibited a wide range of mechanical and other key properties such as oxygen permeability.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420731
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  • 7
    Electronic Resource
    Electronic Resource
    Graft copolymers of nylon 6 and polyphenylene oxide: Syntheses and their role in compatibilizing nylon 6/polyphenylene oxide blends (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1289-1296 
    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: Poly(2,6-dimethyl-p-phenylene) oxides (PPO) grafted with nylon 6 were prepared by first quantitatively brominating the PPO, followed by reacting the brominated products with nylon 6 of different molecular weights. The molecular weights of PPOs were kept intact during bromination. These graft copolymers with well-defined structures were used as compatibilizers for nylon 6/PPO blends. Some compatibilization phenomena were observed, as indicated by the mechanical properties of the blends. The best compatibilization was achieved when the graft copolymer is most block-copolymer-like. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070540910
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  • 8
    Electronic Resource
    Electronic Resource
    The role of bulky polysiloxanylalkyl methacrylates in polyurethane-polysiloxane hydrogels (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1193-1199 
    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: Silicone hydrogels based on polyurethane-polysiloxane prepolymer and hydrophilic monomers such as N,N-dimethylacrylamide, although possessing high oxygen permeability and satisfactory tear strength, are too stiff to be targeted for applications such as contact lenses. However, with the inclusion of bulky polysiloxanylalkyl methacrylates, such as methacryloxypropyl tris(trimethylsiloxy)silane (TRIS), to replace part of the polyurethane prepolymer, the hydrogels obtained not only maintained high oxygen permeability, but also had a lower modulus and improved tear strength. These changes in properties are all favorable for applications such as oxygen-permeable hydrogel lenses. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 9
    Electronic Resource
    Electronic Resource
    Control of properties in silicone hydrogels by using a pair of hydrophilic monomers (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 2051-2058 
    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: Silicone hydrogels have been under intensive investigation for use in the biomedical field, especially as contact lenses. When silicone hydrogels were prepared using a combination of N-vinyl pyrrolidone and N,N-dimethyl acrylamide as the hydrophilic monomers, it was found that the surface wettability of these hydrogels can be improved with the mechanical properties and that water contents are in the acceptable range for certain applications, such as contact lenses. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 10
    Electronic Resource
    Electronic Resource
    Novel polyurethane hydrogels for biomedical applications (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 3173-3179 
    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: Polyurethane hydrogels derived from UV-curable urethane prepolymer and hydrophilic monomers were prepared and their properties were evaluated. The urethane prepolymer used in this study contained well-defined hard segments centered with a polyether-based soft segment and end-capped with methacrylate groups. The hydrophilic monomers studied were 2-hydroxyethyl methacrylate (HEMA), N-vinyl pyrrolidone, and glycerol methacrylate. Methacryloxypropyl tris (trimethysiloxy) silane (TRIS) was also used in some cases to modify properties. All composition were UV-cured and formed hydrogels after hydration. The oxygen permeabilities of the hydrogels decreased as the water contents increased and increased as the TRIS content was increased. The tear strengths and moduli decreased as the water contents of the hydrogels increased. Most compositions studied have higher oxygen permeability and tear strength than poly(HEMA) because of the presence of urethane prepolymer in the composition.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070421210
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