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Internal Donors (internal + donor)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Influence of Internal Donors on the Performance and Structure of MgCl2 Supported Titanium Catalysts for Propylene Polymerization

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 1 2009
Gurmeet Singh
Abstract An insight on the influence of ethyl benzoate (EB) and diisobutyl phthalate (DIBP) as internal donors, differing in coordination nature on the structural aspects of MgCl2 matrix in high-performance MgCl2 -supported titanium catalysts was developed using FTIR spectroscopy and WAXD studies. The analysis of the >CO stretching IR band of internal donors showed their coordination to (104) and (110) lateral cuts of MgCl2 matrix. Transformation of magnesium ethoxide {Mg(OEt)2} to MgCl2 during catalyst preparation resulted in different MgCl2 phases, namely the , -form, , -form, and the disordered , -form, which were analyzed by WAXD studies. The results from WAXD showed the relative preference of , -form over , -form in case of DIBP-based catalysts, which might be due to interlayer bridging between adjacent layers due to the bidendate nature of DIBP. This can be one of the reasons for the high productivity of dialkyl-phthalate-based catalysts in comparison to ethyl-benzoate-based catalyst systems. [source]

Application of Fractionation Techniques to the Study of Olefin Polymerization Kinetics and Polymer Degradation

MACROMOLECULAR SYMPOSIA, Issue 1 2007
Hisayuki Nakatani
Abstract Summary: Temperature rising elution fractionation (TREF) has been regarded as a powerful technique for study of semicrystalline polymers. In this paper, two examples of unique applications of TREF were introduced. One was the study on the influence of extraction of internal donor on the variation of isospecific active sites of a MgCl2 - supported Ziegler catalyst, and the other was the estimation of the relationship between polymer micro-tacticity and degradation rate of isotactic polypropylene (iPP). The former example revealed the conversion from high to low isospecific site by the extraction of internal donors, whereas the latter showed a negative correlation between the level of isotacticity and the degradation rate. These results demonstrated that TREF was useful in these research applications. [source]

Influence of Internal Donors on the Performance and Structure of MgCl2 Supported Titanium Catalysts for Propylene Polymerization

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 1 2009
Gurmeet Singh
Abstract An insight on the influence of ethyl benzoate (EB) and diisobutyl phthalate (DIBP) as internal donors, differing in coordination nature on the structural aspects of MgCl2 matrix in high-performance MgCl2 -supported titanium catalysts was developed using FTIR spectroscopy and WAXD studies. The analysis of the >CO stretching IR band of internal donors showed their coordination to (104) and (110) lateral cuts of MgCl2 matrix. Transformation of magnesium ethoxide {Mg(OEt)2} to MgCl2 during catalyst preparation resulted in different MgCl2 phases, namely the , -form, , -form, and the disordered , -form, which were analyzed by WAXD studies. The results from WAXD showed the relative preference of , -form over , -form in case of DIBP-based catalysts, which might be due to interlayer bridging between adjacent layers due to the bidendate nature of DIBP. This can be one of the reasons for the high productivity of dialkyl-phthalate-based catalysts in comparison to ethyl-benzoate-based catalyst systems. [source]

Application of Fractionation Techniques to the Study of Olefin Polymerization Kinetics and Polymer Degradation

MACROMOLECULAR SYMPOSIA, Issue 1 2007
Hisayuki Nakatani
Abstract Summary: Temperature rising elution fractionation (TREF) has been regarded as a powerful technique for study of semicrystalline polymers. In this paper, two examples of unique applications of TREF were introduced. One was the study on the influence of extraction of internal donor on the variation of isospecific active sites of a MgCl2 - supported Ziegler catalyst, and the other was the estimation of the relationship between polymer micro-tacticity and degradation rate of isotactic polypropylene (iPP). The former example revealed the conversion from high to low isospecific site by the extraction of internal donors, whereas the latter showed a negative correlation between the level of isotacticity and the degradation rate. These results demonstrated that TREF was useful in these research applications. [source]