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  • 11
    Electronic Resource
    Electronic Resource
    Morphology influence on the permeation properties of styrene and polystyrene modified polyethylene membranes (1989)
    Springer
    Colloid & polymer science 267 (1989), S. 209-217 
    Details
    ISSN: 1435-1536
    Keywords: Modified polyethylene ; permeation properties ; light scattering ; internal order in spherulites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Influence of the structure of styrene and polystyrene modified PE membranes on their permeation properties is presented. It is demonstrated that the temperature of styrene treatment (N membranes) and the presence of polystyrene (P membranes) results in high differentiation of the permeation properties. SALS studies have shown the structural reorganization depending on modification extent and diffusion of the penetrant. It is also shown that the morphology of the dried films remains unchanged. This work proves that the appropriate modification of PE films results in membranes with controlled permeation behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410577
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  • 12
    Electronic Resource
    Electronic Resource
    Polyethylene-polystyrene gradient polymers III. Mechanical and rheo-optical studies of relaxation processes (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 490-497 
    Details
    ISSN: 1435-1536
    Keywords: Gradientpolymers ; low densitypolyethylene ; polystyrene contents ; intralamellarloss processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper the structure correlation of PE-PS gradient polymers, modified by styrene LDPE films with their mechanical and rheo-optical properties, is presented. The specific structural changes of both the investigated materials can be demonstrated by using dynamic mechanical deformation studies. The influence of the penetrant on LDPE crystalline and amorphous phase order is shown. Some interesting mechanical behaviour of the gradient polymers, depending on the polystyrene contents, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412502
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  • 13
    Electronic Resource
    Electronic Resource
    Oriented PP-PS composites obtained by polymerization of styrene inside oriented PP matrices. I. Dispersion of PS and the composites' orientation (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1405-1413 
    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: Dispersion of polystyrene (PS) and the molecular orientation of the polypropylene-polystyrene (PP-PS) composites acquired by the in situ polymerization of styrene in the oriented PP matrices were characterized by microscopic observations, birefringence measurements, and differential scanning calorimetry. It has been shown that applied processing of the “envelope” polymerization leads to obtaining oriented composites with large contents and the specific dispersion of PS. Some composites exhibit a substantial gradient of PS concentration and a gradient of molecular orientation, both strongly dependent on the initial structure of the oriented PP matrix. The modification of the PP structure taking place during processing does not disturb the orientation of the matrices deformed to the higher draw ratios. The structural changes of the oriented PP induced by processing are reflected in the shrinkage behavior and mechanical properties discussed in the second part of this paper. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490808
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  • 14
    Electronic Resource
    Electronic Resource
    Oriented PP-PS composites obtained by polymerization of styrene inside oriented PP matrices. II. Shrinkage behavior and mechanical properties (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 50 (1993), S. 637-644 
    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: Thermal shrinkage and the mechanical properties of oriented polypropylene-polystyrene (PP-PS) composites obtained by in situ polymerization of styrene in the oriented PP matrices were examined by the analysis of shrinkage stress curves and dynamic mechanical data. It has been shown that by changing the structure of the oriented matrices it is possible to control the properties of the obtained oriented composites. Some composites reveal an increased stability of the obtained oriented composites. Some composites reveal an increased stability of the molecular network at higher temperatures and the modulus of the material obtained from the matrix drawn at 90°C to the natural draw ratio is significantly increased. It is also shown that the differences between the untreated matrices and the PP component of the respective composites observed in the relaxation of the shrinkage stresses correspond very well with the differences seen in the mechanical loss in the frequency range of about 0.02 Hz. Such behavior suggests that similar molecular motions are involved both in the relaxation of shrinkage stresses and in this part of the mechanical loss. © 1993 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070500408
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  • 15
    Electronic Resource
    Electronic Resource
    Structure reorganization in isotactic polypropylene induced by styrene treatment (1991)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 42 (1991), S. 306-314 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Effekte einer Modifizierung von Polypropylen durch Einwirkung von flüssigem Styren werden mitgeteilt. Die strukturellen Änderungen in dem Polymer hängen von seiner Ausgangsstruktur und von der Transformation der smektischen Phase in die monokline Phase ab. Die durch die Quellprozesse induzierte Umstrukturierung wird analysiert und mit analogen Effekten verglichen, die früher an Polyethylen niedriger Dichte gefunden wurden.
    Notes: The effects of modification of polypropylene by liquid styrene are reported. The structural changes in the polymer are related to its initial structure and the processes of transformation of the smectic phase into the monoclinic one. The structure reorganization induced by the swelling processes is analyzed and compared with analogous effects reported earlier for low density polyethylene.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1991.010420705
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  • 16
    Electronic Resource
    Electronic Resource
    Influence of the initial polyethylene structure on the modification with styrene and polystyrene (1989)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 40 (1989), S. 575-581 
    Details
    ISSN: 0323-7648
    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 ursprünglichen Struktur von Polyethylen auf die Effekte einer Modifizierung mit Styren und Polystyren wird untersucht. Es wird gezeigt, daß die Auswirkung der Modifizierung wesentlich durch die Nature der kristallinen und amorphen Phasen des Polyethylens bestimmt wird. Die in die Polyethylenmatrix eingebaute Polystyrenphase verändert die mechanischen Eigenschaften des Polymers in Abhängigkeit von der ursprünglichen amorphen Phase des Polyethylens. Die wesentlichen Unterschiede zwischen der Temperung des Polyethylens niedriger Dichte und seiner in dieser Untersuchung durchgeführten Modifizierung werden herausgestellt.
    Notes: The influence of the initial polyethylene structure on the effects of modification with styrene and polystyrene is investigated. It is shown that the effectivity of modification is basically governed by the nature of the crystalline and amorphous phases in polyethylene. The polystyrene phase included into the polyethylene matrix changes its mechanical properties in dependence on the origin of the amorphous phase of the polyethylene. The main differences between annealing of low density polyethylene and the modification presented in this work are pointed out.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1989.010400906
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  • 17
    Electronic Resource
    Electronic Resource
    The processing and structure of composites of isotactic polypropylene and atactic polystyrene with a high dispersion of the polystyrene component (1991)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 42 (1991), S. 485-492 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Heterogene Polymersysteme aus Polypropylen und Polystyren mit unterschiedlicher Morphologie wurden durch UV-initiierte Polymerisation von flüssigem Styren in der Polypropylenmatrix mit kontrollierter molekularer und übermolekularer Struktur erhalten. Der Einfluß der Bechandlung mit Styren und dessen Polymerisation auf die kristalline Struktur der Polypropylenmatrix wurde ermittelt, und die Korrelation zwischen der Ausgangsstruktur des Polypropylens und der Dispersion der Polystyrenkomponente wird aufgezeigt.
    Notes: Heterogenic polymeric systems of polypropylene and polystyrene with different morphology have been obtained by UV initiated polymerization of liquid styrene within polypropylene matrices of controlled molecular and supermolecular structure. The influence of styrene treatment and its polymerization in situ on the crystalline structure of the polypropylene matrix is determined, and the correlation between the initial structure of the matrix and the dispersion of the polystyrene component is shown.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1991.010421002
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  • 18
    Electronic Resource
    Electronic Resource
    Influence of thermal treatment on the crystalline and supermolecular structure of isotactic polypropylene (1986)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 37 (1986), S. 726-733 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß verschiedener thermischer Vorbehandlungen auf die kristalline Ordnung sowie auf die übermolekulare Struktur von isotaktischem Polypropylen wird beschrieben. Die Strukturen von zwei Arten von Proben werden untersucht. Die Proben wurden bei gleicher Temperatur kristallisiert, aber einerseits direkt aus der Schmelze hergestellt und im anderen Fall aus dem Glaszustand, der durch Abschrecken der Schmelze auf -100°C erhalten wurde. Die innere Struktur beider Probenarten wurde mit folgenden Methoden charakterisiert: Weit- und Kleinwinkelröntgenstreuung, Kleinwinkellichtstreuung, Differential-Scanning-Calorimetrie, IR-Absorptionsspektrometrie und optische Mikroskopie. Es wurde gezeigt, daß die bei beiden Probenarten angewendeten verschiedenen Präparationsprozesse nahezu äquivalente kristalline Zustände, aber sehr unterschiedliche morphologische Strukturen ergeben.
    Notes: The influence of different thermal treatments on the crystalline order as well as on the supermolecular structure of isotactic polypropylene is described. The structures of two kinds of samples were investigated. The samples were crystallized at the same temperature but the first ones were prepared directly from the melt and the second ones from the glassy state, obtained by rapid quenching of the melt to -100°C. The internal structure of both kinds of samples was characterized using following techniques: wide- and small-angle X-ray diffraction, small-angle light scattering, differential scanning calorimetry, IR absorption spectrometry, optical microscopy. It has been shown that the different preparation processes used in case of both kinds of samples lead to almost equivalent crystalline states, but quite different structures on the supermolecular level.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1986.010371115
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  • 19
    Electronic Resource
    Electronic Resource
    Studies of α relaxation process in spherulitic and nonspherulitic samples of isotactic polypropylene with different molecular ordering (1987)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 38 (1987), S. 42-52 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: An zwei sphärolitischen beziehungsweise nicht-sphärolitischen Probenserien von isotaktischem Polypropylen wurden mechanische und rheo-optische Messungen in Abhängigkeit von der Frequenz bei konstanten Temperaturen durch geführt. Die Proben wiesen unterschiedliche Ordnung im molekularen Bereich auf. Die Strukturdifferenzierung hat einen Einfluß auf die Natur des α-Relaxationsprozesses. Bei Proben, die große Sphärolite enthalten, ist der α-Relaxationsprozeß hauptsächlich den Reinbungseffekten an den Grenzen der kristallinen Lamellen und einem Beitrag der intralamellaren Bereiche zuzuschreiben, der auf der eingeschränkten Reorientierung kristalliner Elemente in den sich orientierenden Lamellen beruht. Die Anwesenheit einer smektischen Phase und die Abnahme von Größe und Perfektion der Sphärolite bewirken eine Zunahme der Kristallitbeweglichkeit und folglich eine Zunahme des Beitrages der intralamellaren Bereiche zum α-Relaxationsprozeß. In aus dem Glaszustand kristallisierten nicht-sphärolitischen Proben wurden zwei Komponenten des α-Relaxationsprozesses gefunden. Die Tieftemperaturkomponente αa (unter 80°C) tritt bei niedrigen Frequenzen (〈 1 Hz) auf und wird hauptsächlich der Spannungsrelaxation der gespannten Moleküle in der nichtkristallinen Phase zugeschrieben sowie den Molekülsegmenten in der Oberflächenschicht der Kristallite. Die Hochtemperturkomponente α1 des α-Relaxationsprozesses tritt oberhalb von 80°C auf und hängt mit viskosen Gleitprozessen der kristallinen Elemente in der nicht-kristallinen Phase zusammen. Die Intensität dieses Prozessesnimmt mit Abnahme der Kristallitgröße zu. Die Anwesenheit einer smektischen Phase in der nicht-sphärolitischen Struktur erhöht den Anteil dieses Prozesses.
    Notes: Mechanical and rheo-optical data have been obtained as a function of frequency at constant temperatures for two series of spherulitic and nonspherulitic samples of isotactic polypropylene having different ordering on molecular level. It was found that the structure differentation influence on the nature of the α relaxation process. In the case of samples containing large spherulites, the α relaxation process is mainly attributed to the friction phenomena between boundaries of the crystalline lamellae and to a certain contribution arising from the intralamellar regions accompanied by restricted reorientation of crystalline elements within orienting lamellae. However, the presence of a smectic phase as well as the decrease of both the spherultie size and the structure perfection leads to enhancement of the mobility of crystallites, and consequently to an increase of the contribution from the intramellar regions to the α relaxation process. Two components of the α relaxation process were found for nonspherulitic samples, crystallized from the glassy state. The low-temperature component αa (below 80°C) appears at low frequencies (less than 1 Hz) and is mainly attributed to the stress relaxation of the fraction of the noncrystalline phase containing strained molecules and segments of molecules belonging to the specific (irregular) arrangement of the surface layer of the crystallites. The high-temperature component of the α relaxation process, αa, appears above 80°C and is connected with the viscous slip process of the crystalline elements within the noncrystalline phase. The internsity of this process increases with the decrease of crystallite size. The presence of the smectic phase in the nonspherulitic structure enhances the extent of that process.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1987.010380110
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