Polystyrene Chain Growth Initiated from Dialkylzinc for Synthesis of Polyolefin-Polystyrene Block Copolymers
Polystyrene Chain Growth Initiated from Dialkylzinc for Synthesis of Polyolefin-Polystyrene Block Copolymers
- 주제(키워드) Polyolefin , polystyrene , block copolymer , coordinative chain transfer polymerization , initiator , organolithium , dialkylzinc
- 발행기관 아주대학교
- 지도교수 이분열
- 발행년도 2020
- 학위수여년월 2020. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000029920
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Polyolefins (POs) are the most abundant polymers; however, synthesis of PO-based block copolymers has only rarely been achieved. We aimed to synthesize various PO-based block copolymers by coordinative chain transfer polymerization (CCTP) followed by anionic polymerization in one-pot via conversion of the CCTP product (polyolefinyl)2Zn to polyolefinyl-Li. Addition of 2 equiv t-BuLi to (1-octyl)2Zn (a model compound of (polyolefinyl)2Zn) and selective removal or decomposition of (tBu)2Zn by evacuation or heating at 130 °C afforded 1-octyl-Li. Attempts to convert (polyolefinyl)2Zn to polyolefinyl-Li were unsuccessful. However, polystyrene (PS) chains were efficiently grown from (polyolefinyl)2Zn; the addition of styrene monomers after treatment with t-BuLi and pentamethyldiethylenetriamine (PMDTA) in the presence of residual olefin monomers afforded PO-block-PSs. Organolithium species that might be generated in the pot of t-BuLi, PMDTA, and olefin monomers, i.e., [Me2NCH2CH2N(Me)CH2CH2N(Me)CH2Li, Me2NCH2CH2N(Me)Li·(PMDTA), pentylallyl-Li(PMDTA)], as well as PhLi(PMDTA), were screened as initiators to grow PS chains from (1-hexyl)2Zn as well as from (polyolefinyl)2Zn. Pentylallyl-Li(PMDTA) was the best initiator. The Mn values increased substantially after the styrene polymerization with some generation of homo-PSs (2729%). The Mn values of the extracted homo-PS suggested that PS chains were grown mainly from polyolefinyl groups in [(polyolefinyl)2(pentylallyl)Zn][Li(PMDTA)]+ formed by pentylallyl-Li(PMDTA) acting onto (polyolefinyl)2Zn.
more목차
Abstract I
1. Introduction 3
2. Materials and Methods 4
2.1. Conversion of (1-octyl)2Zn to (1-octyl)Li 5
2.2. 1-Octene, n-BuLi, and PMDTA in methylcyclohexane . 5
2.3. Me2NCH2CH2N(Me)CH2CH2N(Me)CH2Li 5
2.4. Me2NCH2CH2N(Me)Li . 5
2.5. Pentylallyl-Li(PMDTA) . 5
2.6. PhLi(PMDTA) 6
2.7. PS chain growth from (1-hexyl)2Zn . 6
2.8. Synthesis of poly(ethylene-co-propylene)-b-PS 6
3. Results and Discussion 7
3.1. Converting dialkylzinc to alkyllithium . 7
3.2. Attempts to synthesize block copolymers 9
3.3. Initiators for PS chain growth from dialkylzinc 10
3.4. Synthesis of PO-block-PS 13
4. Conclusions 17
5. Acknowlegements 18
6. Reference . 18
7. Supporting information 24
