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  • 1
    Electronic Resource
    Electronic Resource
    Preparation of highly active supported catalysts for producing polypropylene with less content of chloride (1981)
    Springer
    Polymer bulletin 4 (1981), S. 39-44 
    Details
    ISSN: 1436-2449
    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: Summary Highly active supported catalysts for propylene polymerization have been prepared by treating the complexes of TiCl3· 3C5H5N and MgCl2·(THF) with AlEt2Cl in the presence of MgO, Mg(OH) 2 x or SiO2. Polypropylene with less content or chloride was produced over these catalysts combined with AlEt3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01045238
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of (s)-(+)-ethyl-2-phenylbutanoate and poly(ethylene terephthalate) on the polymerization of propylene and 3-methyl-1-pentene over TiCl3-AlET3 (1980)
    Springer
    Polymer bulletin 3 (1980), S. 179-184 
    Details
    ISSN: 1436-2449
    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: Summary (s)-(+)-Ethyl-2-phenylbutanoate was synthesized and polymerizations of propylene and racemic 3-methyl-1-pentene were conducted over TiCl3-AlEt3 combined with the compound. The addition of the compound caused a significant increase in the isotacticity of polypropylene as well as a substantial decrease in the activity. However, stereoelective polymerization of racemic 3-methyl-1-pentene didn't take place at all. Propylene polymerization was also carried out over TiCl3-AlEt3 by using poly(ethylene terephthalate) in place of the compound. The results obtained have led to the conclusion that these additives act mainly as reagents to reduce the concentration of AlEt3 by the formation of the complexes between AlEt3 and these additives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254170
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  • 3
    Electronic Resource
    Electronic Resource
    Blood-contacting properties of polypropylene surfaces (1998)
    Springer
    Journal of artificial organs 1 (1998), S. 4-9 
    Details
    ISSN: 1619-0904
    Keywords: Polypropylene ; Blood-contacting properties ; Crystalline-amorphous microstructure ; Protein ; Platelets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Blood-contacting properties of polypropylene varied with changes in crystalline-amorphous microstructure such as the crystallinity and the degree of orientation. The results from our evaluation of surface adhesiveness using polymeric glue and water structure which was sorbed into the surfaces indicate that variations in the microstructure may cause differences in macromolecular entanglement with the glue and hydrophobic interaction at the surfaces. Therefore, the prevention of these interactions may help to attain better blood-contacting properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01340445
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  • 4
    Electronic Resource
    Electronic Resource
    Tensile and flexural behavior of polypropene sheets with different crystallinities of surface layer (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 253 (1997), S. 201-210 
    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 Zug- und Biegemoduli von preßgeformten Polypropen-Probekörpern mit unterschiedlichen Oberflächenkristallinitäten wurden basierend auf der Annahme eines Schicht-Verbund-Modells untersucht. Es zeigte sich, daß die Spannungs-Dehnungs-Kurven der Zugversuche und die Werte der Biegeablenkung im wesentlichen von der Oberfächenkristallinität abhängen, jedoch erwiesen sich die Bruchspannungen als von der Oberflächenkristallinität unabhängig. Es wird angenommen, daß das beobachtete Zug- und Biegeverhalten der Proben auf der Grundlage eines Schicht-Verbund-Modells, bei dem eine massive, starre Platte zwischen zwei weichen Schichten eingebettet ist, charakterisiert werden kann.
    Notes: The tensile and flexural moduli of the compression-molded sheets of polypropene with different surface layer crystallinity were investigated based on a layered composite model. It was found that the tensile stress-strain curve and flexural deflection depended largely on the surface layer crystallinity, but the ultimate strain-at-break values were independent of the surface layer crystallinity. It is suggested that the tensile and flexural behavior can be characterized using a layered composite model in which a bulk plate was sandwiched between two surface layers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052530116
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  • 5
    Electronic Resource
    Electronic Resource
    Polymerization of propylene with γ-Al2O3- or SiO2-supported titanium tetrachloride catalyst (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 657-669 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The preparation of γ-Al2O3- and SiO2-supported titanium tetrachloride catalysts for the polymerization of propylene is described. The ESR spectra of these products, measured at -196°C, display broad signals with g-values of 1,942 and 1,952 in the cases of γ-Al2O3 and SiO2, respectively, which are assignable to Ti(III) species. The concentration of the Ti(III) species depends strongly upon the conditions of treatment. With these products as catalysts the polymerization of propylene takes place at 40 -75°C in the absence of any activator. The polymerization activity significantly depends upon the conditions of catalyst treatment, but it is approximately proportional to the concentration of the Ti(III) species. The molecular weight and the isotacticity of the resulting polymer remain almost unchanged. These results lead to the conclusion that Ti(III) is the active species in these catalysts.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1980.021810311
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  • 6
    Electronic Resource
    Electronic Resource
    A study on the states of ethyl benzoate and TiCl4 in MgCl2-supported high-yield catalysts (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1477-1487 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The states of ethyl benzoate (EB) and TiCl4 in the primary types of MgCl2-supported catalysts were studied by thermogravimetry/differential thermal analysis (TG-DTA) in combination with other methods. The results obtained by all experiments indicate that TiCl4 and EB in the MgCl2-supported high-yield catalysts interact only with MgCl2, leaving no vacant sites on TiCl4.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880622
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  • 7
    Electronic Resource
    Electronic Resource
    A convenient method for the preparation of a highyl active MgCl2-supported TiCl3 catalyst for the polymerization of propylene (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2439-2443 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A highly dispersed MgCl2-supported TiCl3 catalyst was conveniently prepared by treating the complex of TiCl3 · 3 C5H5N with AlEt2Cl in the presence of MgCl2. The catalyst combined with AlEt3 showed a very high activity for the polymerization of propylene, and gave a polymer with considerably high isotacticity. The catalyst displayed a sharp ESR signal with a g-value of 1,94, which is identical with that of the ground H-grade TiCl3.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820907
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  • 8
    Electronic Resource
    Electronic Resource
    Analytical and kinetic approaches for the basic type of MgCl2-supported high yield catalysts (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 2035-2048 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal analysis in combination with infrared spectroscopy was applied to investigate the states of ethylbenzoate (EB) and TiCl4 in the simple type of the MgCl2-supported high-yield catalysts. A further attempt was made to evaluate kinetic parameters in the initial stage of propylene polymerization (〈 1s) by a stopped flow method. The catalysts employed in the present study were prepared by co-grinding MgCl2 and TiCl4 · EB complex. Thermal analysis and infrared spectroscopy showed that TiCl4 · EB complex decomposes during co-grinding process. It was also indicated that EB, thus produced, has strong interaction with MgCl2. This was consistent with observations made by infrared spectroscopy. It was deduced that EB and TiCl4 are supported at separate sites of MgCl2 in the co-ground catalyst. Kinetic parameters including rate constants of propagation (kp) and transfer (ktr), and concentration of polymerization centers ([C*]) were determined. The values of kp and ktr remained almost constant throughout the range of co-grinding time, but [C*] increased with time of co-grinding. No significant changes in the value of ktr were observed. Accordingly, the improvement of catalyst activity was attributed to an increase in [C*] rather than kp. These results lead to the conclusion that the complex decomposes during the co-grinding to yield EB and TiCl4 which interact only with MgCl2.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1990.080280802
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  • 9
    Electronic Resource
    Electronic Resource
    Determination of titanium distribution on the catalyst surface of industrial supported Ziegler catalysts by means of scanning auger electron microscopy (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 2709-2715 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Scanning Auger electron microscopy (SAM), which is one of the best surface analytical methods, was applied to achieve basic understandings of the surface distribution of titanium species on supported Ziegler catalysts. Three different types of supported Ziegler catalysts were prepared by grinding MgCl2 with TiCl4 (Cat-A), by grinding MgCl2 with ethyl benzoate (EB) followed by the reaction with TiCl4 (Cat-B), and by reacting TiCl4 with a mixture of Mg(OEt)2 and dibutyl phthalate (DBP) (Cat-C). The SAM analysis revealed that the titanium species were scattered over the surface of Cat-A, while the distribution of the titanium species was rather even on the surface of Cat-B. In the case of Cat-C, the titanium species were found to exist evenly on the surface, and all particles of the catalyst showed a similar tendency. Hence, the influence of the preparation method of the catalyst on the distribution of the titanium species is clearly observed by SAM. Models of the catalyst particles obtained by different preparation methods were proposed on the basis of the results.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of surface crystallinity on dynamic mechanical properties of compression-molded polypropene sheets (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 243 (1996), S. 87-98 
    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 dynamisch-mechanischen Eigenschaften von preßgeformten Polypropen-Probekörpern mit gleicher Massekristallinität aber unterschiedlicher Oberflächenkristallinität, wurden untersucht. Die Temperatur der α-Relaxation sinkt mit abnehmender Oberflächenkristallinität. Eine zwischen den Temperaturen der α- und β-Relaxation auftretende Schulter wird der Oberflächenschicht zugeschrieben. Das Takayanagi-Modell wurde auf die experimentellen Ergebnisse angewendet und deutet auf die unterschiedliche Kontinuität der amorphen Phase zwischen der Oberflächenschicht und der Masse hin.
    Notes: Dynamic mechanical properties are measured for a series of compression-molded polypropene sheets having the same bulk crystallinity but different surface crystallinity. The temperature of the α-dispersion was shifted to lower temperatures with lowering the surface crystallinities of the sheets. A shoulder peak, which is ascribed to the surface layer, appeared between the α- and β-dispersion for the sheets. In addition, the application of the Takayanagi model to the experimental results suggests the difference in the continuity of the amorphous phase between the surface layer and the bulk.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1996.052430108
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