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  • 1
    Electronic Resource
    Electronic Resource
    Properties of polyisobutylene-polyurethane block copolymers: I. Macroglycols from ozonolysis of isobutylene-isoprene copolymer (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 337-349 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: The properties of a series of polyisobutylene (PIB) based polyurethanes were studied and compared to those reported in the literature for polyether, polyester, and polybutadiene-based polyurethanes. Good phase separation was reflected in the invariance of the soft segment Tn with increasing hard segment content. Increasing hard segment content resulted in larger domains, higher modulus and lower ultimate elongation. The modulus above the soft segment Tn was higher than that previously reported for polyurethanes of similar hard segment contant; improved phase separation and short contour lengths of the PIB chains were cited as possible causes of this behavior. Stress-strain data indicated a change from isolated to interconnected domain morphology with incerasing hard segment contant. Generally similar trends were seen for all types of urethanes. The overall properties of polybutadiene polyurethanes were closest to those of the polyisobutylene polyurethanes studied. The properties of both of these systems were suggested to suffer from significant synthesis problems in urethane formation due to the incompatibility of the nonpolar hydrocarbon soft segment and the polar diol chain extender. Preliminary environmental tests indicated that polyisobutylene based materials exhibit improved hydrolytic stability and reduced moisture permeability compared to polyether and polyester polyurethanes and greater oxidative stability compared to polybutadiene based materials.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760230608
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  • 2
    Electronic Resource
    Electronic Resource
    Properties of ultraviolet cured polydimethylsiloxane-urea acrylates (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 2115-2135 
    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: A series of polydimethylsiloxane-urea acrylate prepolymers was synthesized by reacting aminopropyl-terminated polydimethylsiloxane (ATPS) with isocyanatoethyl methacrylate (IEM). The oligomers were cured using ultraviolet radiation in the presence of different reactive diluents. Three systems were prepared with varying ATPS soft segment molecular weight. All of the samples were transparent. However, microphase separation was indicated by the observation of two glass transition temperatures attributed to separate ATPS and IEM/reactive diluent phases. Increasing ATPS molecular weight led to a lower rubbery phase transition temperature and a smaller rigid phase volume fraction. These effects were reflected in lower modulus and tensile strength at room temperature, and higher elongation at break. An increase in the reactive diluent content resulted in an increase in Young's modulus and the ultimate tensile strength of these materials. Increasing reactive diluent content caused the rubbery phase transition peak to decrease in magnitude without changing its position and shifted the hard segment transition to higher temperature. The tensile strengths and moduli of these materials were higher than those reported in the literature for other polydimethylsiloxane and urethane acrylate materials.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300527
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  • 3
    Electronic Resource
    Electronic Resource
    Properties of UV-curable polyurethane acrylates: Effect of reactive diluent (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 647-666 
    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: Several families of UV-cured polyurethane acrylates were synthesized, and the effects of reactive diluent type and content on their physical properties were investigated. Increasing reactive diluent content promoted the development of a second, high glass transition temperature phase in all the materials, thereby leading to increased strength and modulus. Changes in the extensibility of the samples upon addition of reactive diluent were inversely related to the effect of the diluent on the crosslink density. The effects of using different reactive diluents (di-, tri-, and tetraethylene glycol diacrylate and N-vinyl pyrrolidone) on the physical properties of the samples were attributed to differences in the softening point (Tg) of the homopolymer reactive diluents and the relative compatibility of the reactive diluents with the urethane acrylate segments.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300215
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and properties of polycyanoethylmethylsiloxane polyurea urethane elastomers: A study of segmental compatibility (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 315-337 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of polyurea urethane block polymers based on either aminopropyl-terminated polycyanoethylmethylsiloxane (PCEMS) soft segments or soft segment blends of PCEMS and polytetramethylene oxide (PTMO) were synthesized. The hard segments consisted of 4,4′-methylenediphenylene diisocyanate (MDI) chain-extended with 1,4-butanediol. The hard segment content varied from 11 to 36%, whereas the PTMO weight fraction in the soft segment blends varied from 0.1 to 0.9. The cyanoethyl side group concentration was also varied during the synthesis of the PCEMS oligomer. The morphology and properties of these polymers were studied by differential scanning calorimetry, infrared spectroscopy, dynamic mechanical and tensile testing, and small-angle x-ray scattering. These materials exhibited microphase separation of the hard and soft segments; however, attaching polar cyanoethyl side groups along the apolar siloxane chains promoted phase mixing in comparison with polydimethylsiloxane-based polyurethanes. The increased phase mixing is postulated to lead to improved interfacial adhesion and thus can account for the observed improvement in ultimate tensile properties compared with polydimethylsiloxane-based polyurethanes. Both hard segment content and cyanoethyl concentration are important factors governing the morphological and tensile properties of these polymers.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260209
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