The Influence of the Internal Donors in the Heterogenous Olefin Polymerization Catalyst on the Molecular Structure of Linear Low Density Polyethylene

불균일계 올레핀 중합촉매내 내부전자공여체가 선형 저밀도폴리에틸렌 분자구조에 미치는 영향

  • Ko, Young Soo (Department of Chemical Engineering, Kongju National University)
  • Received : 2007.06.03
  • Accepted : 2007.06.12
  • Published : 2007.08.31

Abstract

The effect of internal donor(ID) in the heterogeneous Ziegler-Natta catalyst on the ethylene-1-butene copolymerization and the molecular structure of the resulting copolymer was investigated. $SiO_2$-supported $TiCl_4$ catalysts having ID/Ti molar ratio of 0.5 were prepared with ethyaluminium dichloride, magnesium alkyl, 2-ethyl-1-hexanol and $TiCl_4$. Three different IDs were employed such as ethylbenzoate(EB), diisobuylphthalate(DIBP) and dioctylphthalate(DOP). ID-added catalyst showed a larger fraction of Ti(+3) compared to that of no ID-added catalyst. The EB-added catalyst showed the highest activity in copolymerization. Xylene soluble value decreased by more than 50 % with ID-added catalysts compared to that of no ID-added catalyst. Crystaf analysis showed the chemical compositional distribution of PE copolymer was improved in the case of DIBP-added catalyst significantly. It could be explained that the presence of ID could make more even active sites and block the non-stereospecific active sites.

불균일계 중합촉매내 내부전자공여체(ID)의 존재 유무와 종류가 에틸렌과 1-부텐 간의 공중합에서 얻어지는 공중합물에 미치는 영향에 대하여 살펴보았다. 실리카 담지 $TiCl_4$ 촉매를 실리카 담지체에 ethylaluminium dichloride, magnesium alkyl, 2-ethyl-1-hexanol, $TiCl_4$와 여러 종류의 ID 등을 이용하여 제조하였으며 이 때 ID와 Ti의 몰비를 0.5로 고정하였다. ID는 ethylbenzoate(EB), diisobuylphthalate(DIBP), dioctylphthalate(DOP)을 사용하였다. ID가 촉매 내에 존재하는 경우 Ti(+3)의 함량비가 증가하였다. 공중합 활성은 EB를 $TiCl_4$ 반응 후에 투입한 촉매가 가장 높았으며 그 외의 ID가 존재하는 촉매는 활성이 감소하는 현상을 보였다. Xylene soluble(XS) 측정값은 ID가 존재하는 모든 중합촉매가 ID가 없는 경우 보다 50% 이상 감소하였으며 Crystaf 분석 결과 DIBP가 존재하는 촉매가 상대적으로 균일한 화학조성분포를 보였다. 이는 ID가 분균일한 촉매활성점을 보다 균일하게 만드는 역할에서 기인한 것으로 보이며 입체규칙성을 갖는 활성점을 만들거나 비입체규칙성 활성점을 blocking하는 역할 때문인 것으로 설명할 수 있다.

Keywords

References

  1. Ko, Y. S., Han, T. K., Sadatoshi, H. and Woo, S. I., 'Analysis of Microstructure of Ethylene–1-Hexene Copolymer Prepared over Thermally Pretreated $MgCl_2/THF/TiCl_4$ Bimetallic Catalyst,' J. Polym. Chem., Part A: Polym. Chem., 36(2), 291-300(1998) https://doi.org/10.1002/(SICI)1099-0518(19980130)36:2<291::AID-POLA12>3.0.CO;2-J
  2. Ko, Y. S., Han, T. K., Park, J. W. and Woo, S. I., 'Copolymerization of Ethylene–1-Hexene over a Thermally Pretreated $MgCl_2/THF/TiCl_4$ Bimetallic Catalyst,' J. Polym. Chem., Part A: Polym. Chem., 35(13), 2769-2776(1997) https://doi.org/10.1002/(SICI)1099-0518(19970930)35:13<2769::AID-POLA22>3.0.CO;2-8
  3. Perin, S. G. M., Severn, J. R., Koning, C. E. and Chadwick, J. C., 'Unusual Effect of Diethyle Zinc and Triisobutylaluminium in Ethylene/1-Hexene Copolymerisation using $MgCl_2$-Supported Ziegler-Natta Catalyst,' Macromol. Chem. Phys., 207(1), 50-56 (2006) https://doi.org/10.1002/macp.200500424
  4. Chu, K.-J., Soares, J. B. P., Penlidis, A. and Ihm, S.-K., 'The Influence of the Ti+3 species on the Microstructure of Etheylene/1-hexene Copolymers,' Macromol. Chem. Phys., 200(6), 1298-1305 (1999) https://doi.org/10.1002/(SICI)1521-3935(19990601)200:6<1298::AID-MACP1298>3.0.CO;2-H
  5. Kong, J., Fan, X., Xie, Y. and Qiao, W., 'Study on Molecular Chain Heterogeneity of Linear Low-Density Polyethylene by Cross-Fractionation of Temperature Rising Elution Fractionation and Successive Self-Nucleation/Annealing Thermal Fractionation,' J. Appl. Polym. Sci., 94(3), 1710-1715(2004) https://doi.org/10.1002/app.21084
  6. Kakugo, M., Miyatake, T. and Mizunuma, K., 'Chemical Composition Distribution of Ethylene-1-Hexene Copolymer Prepared with $TiCl_3-Al(C_2H_5)_2Cl$ Catalyst,' Macromolecules, 24(7), 1469-1472(1991) https://doi.org/10.1021/ma00007a006
  7. Kakugo, M., Miyatake, T., Mizunuma, K. and Kawai, Y., 'Characteristics of Ethylene-Propylene and Propylene-1-Butene copolymerization over $TiCl_3\;1/3AlCl_3-Al(C_2H_5)_2Cl$,' Macromolecules, 21(8), 2309-2313(1988) https://doi.org/10.1021/ma00186a002
  8. Soga, K., Uozumi, T. and Park, J. R., 'Effect of Catalyst Isospecificity on Olefin Copolymerization,' Makromol. Chem., 191(12), 2853-2864(1990) https://doi.org/10.1002/macp.1990.021911201
  9. Soga, K., Shiono, T. and Doi, Y., 'Effect of Ethyl Benzoate on the Copolymerization of Ethylene with Higher ${\alpha}-Olefins$ over $TiCl_4/MgCl_2$ Catalytic Systems,' Polym. Bull., 10(3-4), 168-174 (1983)
  10. Soga, K., Shiono, T. and Doi, Y., 'Effect of Ethyl Benzoate on the Copolymerization of Ethylene with Higher $\alpha$-Olefins over $TiCl_4/MgCl_2 $Catalytic Systems,' Polym. Bull., 10(3-4), 168-174 (1983)
  11. Ko, Y. S., 'Study on the Effect of EADC/Ti Molar Ratio on Ethylene-1-Butene Copolymerization Using Heterogeneous Polymerization Catalysts System,' Catalysis today, submitted(2007)
  12. Kissin, Y. V., Maribella, F. M. and Meverden, C. C., 'Multi-Center Nature of Heterogeneous Ziegler-Natta Catalysts: TREF Confirmation,' J. Polym. Sci., Part A: Polym. Chem., 43(19), 4351-4362(2005) https://doi.org/10.1002/pola.20875
  13. Thomas, G., Johanssen, S., Pesonen, K., Waldvogel, P. and Lindgren, D., 'Decrease in Activity caused by Hydrogen in Ziegler-Natta Ethene Polymerization,' Eur. Polym. J., 38(1), 121-132(2002) https://doi.org/10.1016/S0014-3057(01)00173-2
  14. Nowlin, T. E., Kissin, Y. V. and Wagner, K. P., 'High Activity Ziegler-Natta Catalysts for the Preparation of Ethylene Copolymers,' J. Polym. Sci. Part A.: Polym. Chem., 26(3), 755-764(1988) https://doi.org/10.1002/pola.1988.080260307
  15. Soares, J. B. P., Monrabal, B., Nieto, J. and Blanco, J., 'Crystallization Analysis Fractionation (CRYSTAF) of Poly(ethylene-co-1-octene) made with Single-Site-type Catalysts: A Mathematical Model for the Dependence of Composition Distribution on Molecular Weight,' Macromol. Chem. Phys., 199 (9), 1917-1926(1998) https://doi.org/10.1002/(SICI)1521-3935(19980901)199:9<1917::AID-MACP1917>3.0.CO;2-V
  16. Chien, J. C. W., Weber, S. and Hu, Y., 'Magnesium Chloride Supported High-mileage Catalysts for Olefin Polymerization. I. Chemical Composition and Oxidation States of Titanium,' J. Polym. Sci., Polym. Chem. Ed., 20(8), 2019-2032(1982) https://doi.org/10.1002/pol.1982.170200805