EFFECTS OF EXTERNAL DONOR ON ACTIVE CENTRE DISTRIBUTION OF SUPPORTED ZIEGLER-NATTA CATALYST
Zhiqiang, F; Sacchi, MC; Locatelli, P
| HERO ID | 1313032 |
|---|---|
| In Press | No |
| Year | 1997 |
| Title | EFFECTS OF EXTERNAL DONOR ON ACTIVE CENTRE DISTRIBUTION OF SUPPORTED ZIEGLER-NATTA CATALYST |
| Authors | Zhiqiang, F; Sacchi, MC; Locatelli, P |
| Journal | Chinese Journal of Polymer Science |
| Abstract | The composition distribution (CD) and microisotacticity distribution (ID) of propene/1-hexene copolymer synthesised by MgCl2/DIBP/TiCl4 (DIBP:diisobutyl phthalate) are determined by fractionating the copolymers according to crystallinity and characterising the fractions by 13C NMR. The effects of two alkoxysilane donors, triethoxyphenylsilane (PTES) and dimethoxydi-tert-butylsilane (TBMS), on CD and ID of the copolymers are compared. Three main parts in the CD diagram of each copolymer are distinguished, which are correlated to active centre distribution (ACD) based on three groups of different active centres. By studying the changes in 1-hexene content, microisotacticity and reactivity ratio product of three typical fractions, the effects of external donor on ACD are better elucidated. It is found that TBMS shows much stronger effects on ACD than PTES. In the former system, most fractions are produced on active centres with relatively lower r1r2, higher reactivity to 1-hexene, and higher stereospecificity as compared to the system without external donor. It is concluded that the observed very extensive changes in ACD mainly result from the formation of new types of active centres, possibly by co-ordination of external donor to certain positions on the catalyst. 16 refs. |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | POLYMERISATION CATALYSTS; PLASTIC; THERMOPLASTIC; ZIEGLER CATALYST; TABLES; ISOTACTIC POLYMERIZATION; ITALY; GRAPH; HEXENE COPOLYMER; POLYMERIZATION; ELECTRON DONOR; EUROPEAN COMMUNITY; ZIEGLER-NATTA CATALYST; STEREOSPECIFICITY; STEREOSPECIFIC; POLYMERISATION; ISOTACTIC POLYMERISATION; CATALYST; DATA; INSTITUTION; POLYMERIZATION CATALYST; PROPYLENE COPOLYMER; PROPENE COPOLYMER; TECHNICAL; POLYMERISATION CATALYST; EUROPEAN UNION; CHINA; WESTERN EUROPE |