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  • 1985-1989  (48)
  • 1970-1974  (33)
  • General Chemistry  (48)
  • Polymer and Materials Science  (33)
  • 1
    Electronic Resource
    Electronic Resource
    The effect of diblock and homopolymer impurities on the morphology of triblock polymers (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 2079-2089 
    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: Commercial triblock polymers (Kratons) consisting of polystyrene and a polydiene were characterized via gel permeation chromatography and small-angle x-ray scattering in order to determine the amount of free polystyrene and diblock material and to clarify the effect of these polymeric impurities on the morphology of solvent-cast samples. Gel permeation chromatography measurements revealed the Kratons to consist of 80-85% triblock, 15-20% diblock, and trace amounts of free polystyrene. Pure triblocks, impurity-doped pure triblocks, the Kratons, and a postpolymerically degraded Kraton were examined with regard to the effect of polymeric impurities on morphology. Small amounts (〈5%) of free polystyrene induce a regularization of the glassy domains, while increased amounts of this homopolymer apparently lead to diffuse phase boundaries. The presence of diblock polymer results in a loss of macrolattice details, indicating the presence of less ordered and more diffuse glassy domains.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160819
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of crosslink density and internetwork grafting on the transparency of polyurethane/polystyrene interpenetrating polymer networks (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 1467-1473 
    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: Because of their incompatibility and the different refractive indices of the homopolymer components, polyurethane/polystyrene interpenetrating polymer networks are turbid by nature. Different parameters likely to enhance their transparency are examined: the crosslink density of each network and the level of internetwork grafting. The results prove that the latter factor is the most effective, as in some cases, very clear and transparent samples are obtained. Correspondingly, preliminary investigations of the dynamic mechanical properties show an inward shift of the glass transition temperatures for such systems. It is concluded that parameters able to cause a higher degree of phase dispersion can yield transparent materials.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360616
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  • 3
    Electronic Resource
    Electronic Resource
    Estimation of molecular weight error for concentration uncertainties in the intrinsic viscosity determination (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 2435-2438 
    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
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160923
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  • 4
    Electronic Resource
    Electronic Resource
    Silicone rubber temporomandibular joint (TMJ) meniscal replacements: Postimplant histopathologic and material evaluation (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 475-484 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Medical grade silicone rubber has long been considered a suitable meniscal replacement, but there has been increasing concern about migration of this material into adjacent tissues. The objectives of this study were to determine the definitive composition of tissue-incorporated material which is presumed by light microscopy to be silicone and to identify long term histopathologic sequelae of meniscal replacements. Adult female patients underwent meniscectomy and replacement with silicone rubber (Silastic) implants. After 12 to 18 months, recurrence of symptoms in 8% of these cases led to implant removal with excision of peri-implant fibrous pseudo-capsules. Excised tissues, including one preauricular lymph node and implants were submitted for light microscopy, SEM, and energy dispersive x-ray microanalysis (EDX) for the identification of elemental composition, critical surface tension measurement, and internal reflection infrared spectroscopy. EDX revealed prominent peaks for silicon in both pseudocapsular and nodal tissues. Morphologic findings surrounding the long-term implants included foreign body reaction, synovitis, dystrophic calcification, fibrocartilaginous metaplasia, hyalinization, and scarring. Particulate silicone debris induced a pathologic response in the tissues and migrated to nodes. These findings suggest that periodic evaluation be performed over the life of such implants to rule out breakdown under function. These findings should intensify the search for improvements or replacements for silicone rubber as an interpositional material in the temporomandibular joint.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820220604
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  • 5
    Electronic Resource
    Electronic Resource
    Zur Bildung und Konzentration der aktiven Spezies löslicher Ziegler-Natta-Katalysatoren (1970)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 12 (1970), S. 175-183 
    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: The rate of polymerisation of ethylene by the soluble ZIEGLER-NATTA-catalyst (C5H5)2Ti(C2H5)Cl/Al(C2H5)Cl2 was investigated in toluene as solvent. From the dependence of the initial rate of the polymerisation follows, that the primary complex, formed by the catalyst components, is not the active species of this system. The obtained dependences rather suggest, that the active species is to be viewed as an equilibrium product and the location of this equilibrium is determined by the ratio of the catalyst compounds in that manner, that only at high Al/Ti-ratios the charged Ti(IV)-compound is equal to the initial concentration of the active species. The existence of such an equilibrium is also suggested by the increase of the rate, occuring at lower Al/Ti-ratios, when polymer is falling out. The desactivation of propagating chains is of complex nature. Considerable desactivation of the active species by the aluminiumorganic compound is obtained.
    Notes: Es wurde die Geschwindigkeit der Polyreaktion von äthylen mit dem löslichen ZIEGLER-NATTA-Katalysator (C5H5)2Ti(C2H5)Cl/Al(C2H5)Cl2 in Toluol als Lösungsmittel untersucht. Aus der Abhängigkeit der Anfangsgeschwindigkeit der Polyreaktion von der Aluminiumalkylkonzentration ergibt sich, daß der aus den Katalysatorkomponenten sich bildende Primärkomplex nicht die aktive Spezies dieses Systems ist. Vielmehr sprechen die ermittelten Abhängigkeiten dafür, daß die aktive Spezies als Gleichgewichtsprodukt anzusehen ist und die Gleichgewichtslage vom Verhältnis der Katalysatorkomponenten bestimmt wird, derart, daß erst bei sehr hohen Verhältnissen Al/Ti die insgesamt eingesetzte Titan(IV)-Verbindung momemtan als aktive Spezies vorliegt. Für das Vorliegen eines solchen Gleichgewichtes spricht auch der für kleine Verhältnisse Al/Ti stets zu beobachtende Geschwindigkeitsanstieg nach dem Ausfallen des Polymeren. Die Desaktivierung der wachsenden Ketten ist komplexer Natur. Es zeigt sich, daß das Aluminiumorganyl in starkem Maße an der Desaktivierung der aktiven Spezies beteiligt ist.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1970.050120114
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  • 6
    Electronic Resource
    Electronic Resource
    Über eine anomale Teilchenbildungsphase bei der Emulsionspolymerisation von SBRHerrn Prof. Dr. Heinrich Hellmann zum 60. Geburtstag gewidmet (1974)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 39 (1974), S. 167-174 
    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: In the course of emulsion polymerization of SBR the rate of polymerization during the stage of particle formation is running through a significant maximum, if initiation takes place with a redox-system, consisting of the partially oil-, partially water-soluble components pinenehydroperoxide, ethylenediamine-tetraacetic acid, ferrous sulfate and rongolite. This anomaly is discussed by means of a reaction scheme, which, among other steps, postulates radical formation directly in the micelles themselves.
    Notes: Bei der Emulsionspolymerisation von SBR durchläuft die Polymerisationsgeschwindigkeit während der Teilchenbidungsphase ein ausgeprägtes Maximum, wenn als Initiator das aus den teils öl-, teils wasserlöslichen Komponenten Pinanhydroperoxid, Äthylendiamintetraessigsäure, Eisensulfat und Rongalit bestehende Redoxsystem eingesetzt wird. Diese Anomalie wird an Hand eines Reaktionsschemas diskutiert, das u. a. von einer Radikalbildung unmittelbar in den Mizellen ausgeht.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1974.050390114
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  • 7
    Electronic Resource
    Electronic Resource
    Zur nachkondensation von polyamiden im teilkristallinen zustandHerrn Prof. Dr. H. HELLMANN zum 60. Geburtstag gewidmet (1973)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 34 (1973), S. 165-175 
    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: The molecular weight of polyamides can be changed by postcondensation in the solid state. The equilibrium molecular weight distribution in the partially crystalline polyamide can be calculated using reasonable assumptions. Under equal post-condensation conditions the calculation yields a higher molecular weight average for the partially crystalline material as compared with the amorphous one, while the type of the distribution function (SCHULZ-FLORY) remains nearly unchanged.
    Notes: Das Molekulargewicht von Polyamiden kann durch Nachondensation im festen Zustand verändert werden. Unter naheliegenden Annahmen läßt sich die Molekulargewichtsverteilung berechnen, die sich dabei im teilkristallinen Polyamid als Gleichgewichtszustand einstellt. Bei sonst gleichen Bedingungen ergibt sich ein höheres mittleres Molekulargewicht als in völlig amorphem Material, während sich der Typ der Verteilung (SCHULZ-FLORY) praktisch nicht ändert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1973.050340111
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  • 8
    Electronic Resource
    Electronic Resource
    [η]-M-Beziehung von PolyoctenamerenHerrn Prof. Dr. Heinrich Hellmann zum 60. Geburtstag gewidmet (1974)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 37 (1974), S. 97-103 
    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: Solution properties of polyoctenamers were studied. A relation [η]-M in toluene at 25°C was elucidated. The kθ-value derived from this relation agrees quite well with similar data of polybutadiene, polypentenamer and polyethylene. No evidence was found for the existence of cyclic structures in polyoctenamers.
    Notes: Lösungseigenschaften von Polyoctenameren wurden untersucht. Eine Viskositäts-Molekulargewichts-Beziehung in Toluol bei 25°C wurde ermittelt. Der daraus abgeleitete kθ-Wert stimmt mit den für Polybutadien, und Polyäthylen bekannten Werten überein. Ein Hinweis auf die Existenz von ringförmigen Makromolekülen konnte nicht gefunden werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1974.050370108
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  • 9
    Electronic Resource
    Electronic Resource
    Polymere mit dem Zentralatom eines Makrocyclus in der Hauptkette, 1. Polykondensationsreaktionen mit Phthalocyaninsilicium- und Hemiporphyrazingermanium-Verbindungen (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 715-728 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Dihydroxy(phthalocyanino)silicon (1b) and dihydroxy(hemiporphyrazino)germanium (2b) react with different monovalent alcohols to afford low-molecular bisalkoxy derivatives (4 and 5), and with thiophenol the phenylthio derivatives 11a and 11b, resp. With bivalent alcohols and phenols polymers of the structure 6 and 7 or 8a, b, 9a, b, and 10a, b, resp. are obtained.Dichloro(phthalocyanino)silicon (1a) and dichloro(hemiporphyrazino)germanium (2a) react also with phenol, resp. hydroquinone, to give low-molecular and polymeric phenoxy derivatives. The reaction of 1b and 2b with mono- and dibasic carboxylic acids leads to the corresponding esters.The IR-spectra of the prepared compounds are discussed. Thermogravimetric and semiconductive measurements (σ298K ≈ 10-7 to 10-16Ω-1cm-1) are described.
    Notes: Dihydroxyphthalocyaninsilicium (1b) und Dihydroxyhemiporphyrazingermanium (2b) werden mit verschiedenen einwertigen Alkoholen zu den niedermolekularen Bisalkoxy-Derivaten (4 bzw. 5) und mit Thiophenol zu den Phenylthio-Derivaten (11a und 11b) umgesetzt. Mit zweiwertigen Alkoholen und Phenolen köml;nnen Polymere der Struktur 6 und 7 bzw. 8a, b, 9a, b und 10a, b erhalten werden. Dichlorphthalocyaninsilicium (1a) und Dichlorhemiporphyrazingermanium (2a) reagieren mit Phenol bzw. mit Hydrochinon ebenfalls zu niedermolekularen und polymeren Phenoxy-Derivaten. Die Umsetzung von 1b und 2b mit einund zweibasischen Carbonsäuren führt zu den entsprechenden Estern.Die IR-Spektren der dargestellten Verbindungen werden diskutiert. Thermogravimetrische und Halbleitermessungen (σ298K ≈ 10-7 bis 10-16Ω-1cm-1) werden beschrieben.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021750302
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  • 10
    Electronic Resource
    Electronic Resource
    Morphologie der segmentierten polyetheresteramide auf der basis von polyamid 12 und oligotetrahydrofuranHerrn Prof. H.-J. Cantow zum 65. Geburtstag gewidmetVorgetragen anläßlich des Makromolekularen Kolloquiums in Freiburg, 1986. (1988)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 2053-2065 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyetheresteramides (PEEA) on the basis of polyamide 12 and oligotetrahydrofuran (OTHF) may be referred to as intrinsically plasticized and intrinsically impact strength toughened thermoplastic elastomers. This is due to their special 4-phase morphology consisting of two pure crystalline and two mixed amorphous phases, which was completely analysed by various TEM preparation techniques. PEEA containing more than 50% PA 12 hard segments exhibit a space filling dendritic superstructure of lamellar crystallized hard segments. In the range of 50 - 30% PA 12, the dendrites become more and more isolated, and below 30% PA 12 only single lamellae can be observed. The matrix in all PEEA is an amorphous, PA 12-rich mixed phase (“OTHF-plasticized PA 12”) located between the hard segment lamellae. An amorphous OTHF-rich mixed phase is very finely dispersed in PEEA and acts as an intrinsically impact strength toughening modifier. Lamellar crystallized soft segments could be imaged by TEM in this dispersed phase, but only in PEEA products with a higher molecular OTHF and at sufficient low temperatures.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1988.021890908
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