Study of Multi-Site Nature of Supported Ziegler-Natta Catalysts in Ethylene-Hexene-1 Copolymerization
Научная публикация
| Общая информация |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Оригинальная
|
| Конференция |
2nd International Conference on Polyolefin Characterization
14-17 сент. 2008
,
Valencia
|
| Журнал |
Macromolecular Symposia
ISSN: 1022-1360
, E-ISSN: 1521-3900
|
| Вых. Данные |
Год: 2009,
Том: 282,
Номер: 1,
Страницы: 157-166
Страниц
: 10
DOI:
10.1002/masy.200950816
|
| Ключевые слова |
Ethylene-hexene-1 copolymerization, Molecular weight distribution, Polyethylene (PE), Ziegler-Natta polymerization |
| Авторы |
Matsko Mikhail A.
1
,
Echevskaya Ludmila G.
1
,
Zakharov Vladimir A.
1
,
Nikolaeva Marina I.
1
,
Mikenas Tatyana B.
1
,
Vanina Marina P.
1
|
| Организации |
| 1 |
Институт катализа им. Г.К. Борескова СО РАН
|
|
Heterogeneity of active centers (AC) of titanium-magnesium catalysts (TMC) and vanadium-magnesium catalyst (VMC) in ethylene-hexene-1 copolymerization has been studied on the base of data of polymer molecular weight distribution (MWD) deconvolution technique and copolymer fractionation onto narrow fractions. It was found that 3 and 4 Flory components (groups of active centers) are required to describe experimental MWD curves of copolymers produced over TMC with different Ti content. In the case of VMC MWD of homopolymer and copolymer are characterized by set of 5 Flory components (5 groups of AC).
Different character of inter-relationship between MW and short chain branching (SCB) was found for ethylene-hexene-1 copolymers produced over different catalysts: heterogeneous type in the case of TMC and more uniform for copolymer prepared over VMC. The content of Ti affects on the slope of that profile in copolymers produced over TMC.
The results indicated that TMC and VMC are different greatly on the heterogeneity of active centers to the formation of polymers with different molecular weights and to formation of copolymers with different inter-relationship between MW and short chain branching. TMC produces polymers with more narrow MWD but it contains highly heterogeneous centers regarding comonomer reactivity ratios. VMC produces polymers with broad and bimodal MWD but it contains more homogeneous centers regarding comonomer reactivity ratios.