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  • 1
    Electronic Resource
    Electronic Resource
    Polypropylene/elastomer/poly(styrene-co-acrylonitrile) blends: Manifestation of the critical volume fraction of SAN in dynamic mechanical, tensile and impact properties (2000)
    Springer
    Journal of polymer research 7 (2000), S. 7-14 
    Details
    ISSN: 1572-8935
    Keywords: Polymer blends ; Critical volume fraction ; Predictive models ; Mechanical properties
    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: Abstract The effect of the critical volume fraction vcr of poly(styrene-co-acrylonitrile) (SAN) on the mechanical properties of its blends with rubber-toughened polypropylene (RTPP) containing about 12% grafted ethylene-propylene copolymer was studied. To encompass a wide spectrum of mechanical properties, blend components were selected which are characterized with rather different viscoelastic, tensile and ultimate properties. The SAN volume fraction in blends covers the interval 0∼0.30; concentration dependencies of measured mechanical properties indicate vcr = 0.13. Experimental data on storage modulus Eb′, loss modulus Eb″, tensile modulus Eb, yield Syb and tensile Sub strength are in plausible accord with their simultaneous prediction based on a predictive scheme which operates with a two-parameter equivalent box model and the data on the phase continuity of components obtained from modified equations of the percolation theory. Strain at break, tensile energy to break and total impact energy of blends show a conspicuous drop in the interval 0∼15 % of SAN where SAN forms a discontinuous component; further growth of the SAN fraction accounts for a reduction of the blend ultimate properties to the values typical of brittle polymers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0098-8
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  • 2
    Electronic Resource
    Electronic Resource
    Positron Lifetime Study of Polycarbonate/Poly(Styrene-co-Acrylonitrile) Blends (2001)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 363-365 (Apr. 2001), p. 340-342 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/05/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.363-365.340.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and hydrolytic stability of model poly(ester urethane ureas) (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 228 (1995), S. 201-219 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Hydrolyse von Poly(ester-urethan-harnstoffen) (PURUs) wurde untersucht. Es handelt sich dabei um einen komplexen Vorgang, der die Analyse der Beziehung zwischen der Zusammensetzung der PURUs und ihrer Hydrolysebeständigkeit erschwert. Es wurde gefunden, daß die Hydrolysebeständigkeit mit Zunahme (i) der Polyol-Acidität, (ii) des Estergruppen-Gehaltes, (iii) der Beweglichkeit der Hauptketten und (iv) deren Hydrophilie abnimmt; die Molmasse des Polyols scheint keinen merklichen Einfluß darauf zu haben. Der negative Einfluß von Ethergruppen (obwohl hydrolysebeständiger als Estergruppen) ist möglicherweise auf eine Zunahme der Hauptkettenbeweglichkeit und den dadurch leichteren Zugang von Wassermolekülen zu Estergruppen zurückzuführen. Der positive Effekt von aromatischen Ringen in Polyolen kann einer erhöhten Steifigkeit der Hauptkette als auch einer ansteigenden Hydrolysebeständig-keit benachbarter Estergruppen durch Resonanzeffekte zugeschrieben werden. Insgesamt kann angenommen werden, daß die beschriebenen Effekte sich überlagern und gleichzeitig die resultierende Hydrolysebeständigkeit vorherbestimmen. Es sollte daher möglich sein, qualitative Vorhersagen bezüglich der Hydrolysebeständigkeit in Abhängigkeit von der Zusammensetzung der PURUs zu treffen.
    Notes: Hydrolysis of poly(ester urethane ureas) (PURUs) is a complex phenomenon which impedes the analysis of the relationships between their composition and hydrolytic stability. Hydrolytic stability of PURUs decreases due to rising (i) polyol acidity, (ii) content of ester groups, (iii) flexibility and (iv) hydrophilicity of the backbones; molar mass of polyols does not seem to have any appreciable effect on it. Negative influence of ether groups (which have better hydrolytic stability than ester groups) is probably linked to the increase in the backbone flexibility and, consequently, to easier access of water molecules to ester groups. Positive effect of aromatic rings in polyols can be ascribed to enhanced rigidity of the backbones as well as to increased hydrolytic stability of adjacent ester groups due to the resonance effect. It can be presumed that the mentioned effects will superpose and simultaneously predestine the resulting hydrolytic resistance. Considering the observed tendencies, it is possible to qualitatively predict the trends how the hydrolytic stability will respond to changes in PURUs composition.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052280116
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  • 4
    Electronic Resource
    Electronic Resource
    Hydrolytic stability and mechanical properties of poly(ester urethanes) (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 220 (1994), S. 49-60 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß der Hydrolysedauer bei 70°C auf die Molmasse und die mechanischen Eigenschaften handelsüblicher Polyesterurethane (Estane 54600, 54610 und 54650) wurde untersucht. Die Kinetik der Hydrolyse läßt sich als Reaktion erster Ordnung mit einer mittleren Induktionsperiode von etwa 7 Tagen beschreiben. Die resultierende Molmassenabnahme verursacht eine signifikante Verschlechterung der Eigenschaften, insbesondere der Bruchdehnung und der Zugarbeit bis zum Bruch, während die elastischen Eigenschaften weit weniger beeinträchtigt wurden. Eine quantitative Beziehung zwischen der relativen Änderung der Zugfestigkeit und der Molmasse wird vorgeschlagen. Die in der Reihenfolge 54650 〉 54600 〉 54610 abnehmende Hydrolysebeständigkeit der Estane läßt sich mit Unterschieden in deren chemischer Zusammensetzung erklären.
    Notes: The effect of hydrolysis time at 70°C on molar mass and mechanical properties of commercial poly(ester urethanes), i.e., Estanes 54600, 54610, and 54650, was analyzed. Kinetics of hydrolysis is plausibly described in terms of a first-order reaction with an average induction period of about 7 days. The resulting reduction of molar mass brought about a significant decrease in ultimate properties, particularly in stress at break and tensile energy to break, while elastic properties were affected much less. A quantitative correlation between relative changes in tensile strength and molar mass was attempted. Hydrolysis resistance of Estanes decreasing in the succession 54650 〉 54600 〉 54610 was related to their chemical composition.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1994.052200105
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  • 5
    Electronic Resource
    Electronic Resource
    Blends of polycarbonate with poly(methyl methacrylate): Miscibility, phase continuity, and interfacial adhesion (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 886-893 
    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: Dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) concurrently show that polycarbonate (PC)/poly(methyl methacrylate) (PMMA) blends have a two-phase structure. The differences between the Tgs of parent polymers and the Tgs of conjugate phases, determined by both DMTA and DSC, indicate a limited miscibility of components and allow the approximate composition of conjugate phases to be calculated. The Flory-Huggins interaction parameter calculated by using these data assumes values about 0.035 ± 0.010. Phase inversion occurs in an interval close to the 50/50 composition, though the molar masses and melt viscosities of the polymers were rather different. Partial miscibility of components ensures interfacial adhesion capable of sustaining the stress transfer between phases up to fracture. Yield stress of the blends is very close to values foreseen by the rule of mixtures. A specific feature of the blends studied is that the addition of 10 to 20 vol% of PMMA to PC increases the strain at break and work to fracture, which are rather low for the PC used. The enhanced capability of the blends to absorb mechanical energy is probably linked to plastic deformation of the dispersed PMMA.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321308
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of low molecular weight compounds on the relaxation behavior of poly(2-hydroxyethyl methacrylate) in the glassy state and in the transition region from the glassy to the rubberlike state (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 11-22 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The method of free torsional vibrations was used to determine the temperature dependence of the storage and loss shear modulus of poly(2-hydroxyethyl methacrylate) samples swollen with ethylene glycol, formamide, n-propanol, and water. The measurements included the glassy region (starting with temperatures from -130 to -190°C) and the main (α) transition from the glassy to the rubberlike state. At a volume fraction of the low molecular weight compound vd 〉 0.2, the above systems exhibit, besides the α dispersion, only the secondary (βSW) dispersion, which is generally attributed to the relaxation motions of the hydroxyethyl groups of the side chains interacting with molecules of the diluent. If no separation of the diluent in a second phase occurs at the measurement temperatures, the temperatures of both dispersions decrease with increasing vd and approach the glass transition temperature of the low molecular weight compound. The concentration dependences of the dispersion temperatures were described by an equation derived elsewhere for the concentration dependence of the glass transition temperature. The results indicate that molecules of the diluent contribute significantly to the intensity of the βSW transition and simultaneously affect its limiting temperatures (for vd = 1 and vd = 0). Specific differences among the systems described above appear only at those temperatures where same of the low molecular weight compound separates into a crystalline or glassy phase.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100102
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  • 7
    Electronic Resource
    Electronic Resource
    Miscible blends of polycarbonate with polyurethane elastomers (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 209 (1993), S. 119-130 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aus aliphatischen Polycarbonatdiolen und/oder Polypropylenglykolen hergestellte Polyurethan-Elastomere bilden mit Polycarbonaten mischbare Blends und verbessern so möglicherweise deren Widerstandsfähigkeit gegen die Bildung mikroskopischer Risse und deren Wachstum. Die Herstellung von Blends aus Polycarbonaten mit bis zu 20 Gew.-% der synthetisierten Polyurethan-Elastomeren erfolgte durch Filmgießen aus Lösung bzw. durch mechanisches Mischen in der Schmelze und anschließendes Spritzgießen. Bei Filmen aus Lösungen mit 10- 20 Gew.-% Polyurethan-Elastomerem wurde in einigen Fallen Phasenseparation beobachtet; diese Filme wurden gewöhnlich durch nachfolgendes Tempern einphasig. Unter den untersuchten Polyurethan-Elastomeren erwiesen sich die Produkte aus Toluylendiisocyanat und Mischungen aus Polycarbonatdiolen und Polypropylenglykolen als effektive Polycarbonatmodifikatoren, so daß sie auch bei den durch Spritzgießen hergestellten Blends eingesetzt wurden.
    Notes: Polyurethane elastomers based on aliphatic polycarbonate diols and/or polypropylene glycols form miscible blends with polycarbonate, thus potentially improving its resistance to microcrack initiation and growth. Up to 20 wt.-% of synthesized polyurethane elastomers were dissolved in polycarbonate via solution casting or melt mixing. Some phase separation was detected in films cast from solutions with 10 to 20 wt.-% of polyurethane elastomers; such blends usually turned into single-phase systems by subsequent thermal annealing. Among the tested polyurethane elastomers, the products based on toulene diisocyanate and mixtures of polycarbonate diols with polypropylene glycols were found to be effective modifiers for polycarbonate; therefore, they were also used in the blends prepared by melt mixing and processed by injection moulding.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052090111
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  • 8
    Electronic Resource
    Electronic Resource
    Dynamic mechanical behavior of chlorosubstituted derivatives of poly(ethyl methacrylate) and poly(ethyl acrylate) (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1565-1570 
    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 freely oscillating torsional pendulum was used in the investigation of the influence of trichloroethyl, tetrachloroethyl, trichloromethoxyethyl, and trichloroethoxyethyl side groups on the molecular mobility in the glassy state and on the glass transition temperature of poly(meth)acrylates. All the polymers under study, which may be used as fire retardants, exhibit a simple relaxation behavior. While the parameters of the low-temperature and secondary relaxation process in the glassy state are not noticeably affected by the substituents used, the glass transition temperature Tg, increases with rising polarity and volume of side chains. The increase is larger in the series of polyacrylates, so that differences in the softening temperatures of polymethacrylates and polyacrylates having the same side chains decrease considerably with growing substitution.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240617
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  • 9
    Electronic Resource
    Electronic Resource
    Mechanical properties of hydrophilic copolymers of 2-hydroxyethyl methacrylate with ethyl acrylate,n-butyl acrylate, and dodecyl methacrylate (1983)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 17 (1983), S. 757-767 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Copolymers were prepared of 2-hydroxyethyl methacrylate, which is strongly hydrophilic, with hydrophobic comonomers having a low glass transition temperature, i.e., ethyl acrylate, n-butyl acrylate, and dodecyl methacrylate. The glass transition temperature, Tα (1 Hz), of polymers in the dry state (xerogels) was determined by means of dynamic mechanical measurements. The dependence of Tα on composition in all the three series of copolymers was described in terms of a one-parameter equation. The equilibrium swelling of copolymers in water decreases more steeply than the weight fraction of 2-hydroxyethyl methacrylate. When swollen in water to equilibrium, all copolymers with ethyl acrylate or n-butyl acrylate are in the rubber-like state; their tensile modulus E assumes values in the range 0.17-0.50 MPa. While poly(2-hydroxyethyl methacrylate) has the modulus E = 0.39 MPa, the tensile strength σu = 0.32 MPa, and the strain-at-break ∊u = 1.81, for the weight fraction of the comonomer in the range 0.36 ≤ w2 ≤ 0.56 it is possible to achieve σu and ≤ u lying in the respective ranges 0.7-0.9 MPa and 5-7. Copolymers with the dodecyl methacrylate content w2 〈 0.2 or w2 〉 0.8 are rubberlike, and at 0.30 ≤ w2 ≤ 0.62 they become leathery; the latter have the modulus E and strength σu within the ranges 12-32 and 3-4 MPa, respectively. The stress-strain curves of these copolymers evidence yielding and orientation hardening which have been tentatively explained by the nonhomogeneous composition and structure of the copolymers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820170504
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  • 10
    Electronic Resource
    Electronic Resource
    Preparation and strength of poly(ethylene terephthalate) fiber bundles for model synthetic tendons (1984)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 18 (1984), S. 115-121 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Poly(ethylene terephthalate) fibers suited for model synthetic tendons were prepared on a pilot-plant scale by additional drawing (postdrawing) of commercial textile fibers texturized by false twist. The modified fibers have a tensile modulus of 7-9 GPa, a one-minute creep modulus of 5-6 GPa, tensile strength 0.55-0.63 GPa, and strain at break of 16-19%. It is essential for their application in synthetic tendons that plastic deformation was reduced to about 0.5%, which could be completely eliminated by subsequent mechanical conditioning of fibers. Since the strength of model tendons consisting of 20 vol % of fibers and of a hydrogel matrix is primarily determined by the strength of the fibers, some aspects of the theory of strength of fiber bundles are briefly recapitulated. The prediction is compared with earlier experimental results obtained for the synthetic tendons. Such an approach, taking into account the fiberstrength distribution in the bundle, predicts a strength of model tendons lower by 20-40% than does the rule of mixtures.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820180111
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