New Technology for Preparations of Metallocene Catalysts and Applications in the Preparations of Isotactic Polystyrene-based Stereoregular Diblock Copolymers
| Autor: | Wu, Chia-Yu, 吳家瑜 |
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| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Isotactic polystyrene (iPS) was typically prepared by conducting the isospecific polymerization of styrene in the presence of heterogeneous Ziegler-Natta catalyst. Because of the heterogeneous and non-living polymerization nature of Ziegler-Natta catalyst, preparations of end-functionalized iPS and iPS-based block copolymer are very difficult. In this research, we demonstrate that isotactic polystyrene-based diblock copolymer can be prepared via postpolymerization of end-functionalized iPS using the end-functionalized iPS as the macroinitiator. In our synthetic route, allyl group end-capped iPS can be generated by conducting the isospecific polymerization of styrene in the presence of dialkylmagnesium (chain transfer agent) and allyl bromide (chain capping agent) using the isospecific [(IndCMe2Ind)Y(1,3-(SiMe3)2C3H3)] complex as the catalyst. After converting the allyl end group into hydroxyl group, the resulting hydroxyl-capped iPS can then be used as the macroinitiator to undergo the ring opening polymerization of L-lactide so as to provide iPS-b-PLLA with high yield. The resulting the iPS-b-PLLA diblock copolymer was found to have a well-defined chemical structure with uniform molecular chain length and can be used in the self-assembly studies for displaying ordered nanomorphology as revealed by SAXS and TEM analyses. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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