Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Investigation of a fine-grain MgCl2-supported Ziegler catalyst by stopped-flow propene polymerization: Model for the formation of active sites induced by catalyst fragmentation during polymerization (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 3207-3214 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A fine-grain catalyst, as a model of catalyst fragmentation in the course of polymerization, was prepared by grinding an original MgCl2-supported Ziegler catalyst. In order to clarify the nature of the active sites generated after catalyst fragmentation, the kinetic parameters for propene polymerization with both catalysts were estimated using the stopped-flow method. The active sites concentration of the fine-grain catalyst was higher than that of the original MgCl2-supported catalyst, indicating that the grinding treatment induced the formation of new active sites. However, the propagation rate constant and stereoregularity of polypropene remained unaffected. This is an indication that the nature of the active sites formed after the grinding treatment was the same as that of active sites on the original MgCl2-supported catalyst.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021981018
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Kinetic investigation of the active-sites precursors on MgCl2-supported Ziegler catalyst through interaction with a Lewis base (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 55-59 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The initial polymerization stage of propene with a MgCl2-supported Ziegler catalyst after the pre-treatment with a Lewis base was examined as a study of the stereospecificity of the active sites precursors. A drastic depressing effect on the catalyst activity occurs, accompanied by an increase in stereospecificity, by the direct interaction of cyclohexylmethyldimethoxysilane (CMDMS) with the catalyst before the polymerization. The kinetic study of the polymerization indicated that the active sites concentration ([C*]) decreases drastically by the catalyst pre-treatment with CMDMS. On the other hand, the increase of propagation rate constant (kp) is relatively small and corresponds to the moderate increase of the mmmm pentad fraction. This is an indication that the interaction of the Lewis base with the active sites precursors prevents formation of the active sites and that inhibition occurs preferentially at the aspecific precursor.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...