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과산화물 매개 알킬-알킬 커플링 반응을 이용한 ABA- 유형 올레핀 트리 블록 공중합체의 합성
- Alternative Title
- KIM SUNG DONG
- Author(s)
- 김성동
- Alternative Author(s)
- KIM SUNG DONG
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2019-02
- Language
- kor
- Alternative Abstract
- Synthesis and applications of block copolymers are a main theme in polymer chemistry. Especially, polyolefin (PO)-based block copolymers are of immense research interest in both academia and industry with a huge industrial impact in some cases. Multistep strategies (e.g., hydrogenation followed by the controlled ring-opening metathesis polymerization (ROMP) or the controlled anionic polymerization) have been developed for the synthesis of PO-based block copolymers, but single step methods with direct use of common olefin monomers are practically more desirable. One of the direct methods is growing a PO-chain upon a living initiator by sequential addition or stepwise variation of the feed ratio of the two olefin monomers. Another commercially useful tool is the so-called "coordinative chain transfer polymerization (CCTP)" which involves the use of a single transition metal-based catalyst (e.g., 1 in Scheme 1) and a chain transfer agent (CTA, e.g., Et2Zn) in excess (e.g., [Zn]/[Hf] > 100). Once the alkyl exchange reaction between CTA and the catalyst is reversibly fast with minimal beta-elimination process, the consequence is uniform PO-chain growth from CTAs. In CCTP, the number of PO-chains generated per transition metal is advantageously high (e.g., [PO-chains]/[Hf] > 200) in comparison with that in the aforementioned living initiator based method where [PO-chains]/[Hf] = 1. The CCTP technique is actively used for precise design as well as end group functionalization of PO-chains. For example, diblock copolymers composed of high density polyethylene (HDPE) and very low density polyethylene (VLDPE) blocks were successfully prepared by sequential feed of ethylene and ethylene/1-octene mixed monomers in CCTP. Recently we also disclosed the preparation of poly(ethylene-co-1-octene)-b-polystyrene (PS) diblock copolymers by sequentially performing CCTP and anionic styrene polymerization in one pot
- Fulltext
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- Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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