과산화물 매개 알킬-알킬 커플링 반응을 이용한 ABA- 유형 올레핀 트리 블록 공중합체의 합성
- 주제(키워드) Coordinative chain transfer polymerization , Olefin triblock copolymer , Alkyl-Alkyl coupling reaction , Elastomer , Peroxide
- 발행기관 아주대학교
- 지도교수 이분열
- 발행년도 2019
- 학위수여년월 2019. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000028369
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
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
more목차
1. Introduction 1
2. Results and Discussion 3
2.1 Alkyl-alkyl coupling reaction of dialkylzinc 3
2.2 Preparation of PE-b-poly(ethylene-co-propylene)-b-PE 8
2.3 Characterization of PE-b-poly(ethylene-co-propylene)-b-PE 12
2.4 Preparation of iPP-b-poly(ethylene-co-propylene)-b-iPP 13
3. Conclusions 14
4. Experimental Section 15
4.1 General remarks 15
4.2 Synthesis of (Oct)2Zn 15
4.3 Reaction between (Oct)2Zn and lauroyl peroxide 16
4.4 PE-b-poly(ethylene-co-propylene)-b-PE (entry 4 in Table 1) 16
5. Acknowledgements 17
6. Reference 18
7. Supporting information 26
