One-pot Synthesis of Polystyrene-Polyolefin-Polystyrene Triblock Copolymer using Olefin and Styrene monomers
One-pot Synthesis of Polystyrene-Polyolefin-Polystyrene Triblock Copolymer using Olefin and Styrene monomers
- 주제(키워드) Blockcopolymer , Polyolefin , SEBS
- 발행기관 아주대학교
- 지도교수 이분열
- 발행년도 2018
- 학위수여년월 2018. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000026992
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Synthesis of polyolefin (PO)-based block copolymers is of immense research interest. In this work, we report a strategy for the construction of polystyrene (PS)-block-PO-block-PS, a useful thermoplastic elastomer, directly from olefin and styrene monomers. Multinuclear zinc species Et[Zn(CH2)6]aZnEt were prepared through successive additions of BH3 and Et2Zn to 1,5-hexadiene. Poly(ethylene-co-propylene) chains were biaxially grown from the −(CH2)6– units in Et[Zn(CH2)6]aZnEt via “coordinative chain transfer polymerization (CCTP)” using the pyridylaminohafnium catalyst. PS chains were subsequently grown in one pot from the generated polymeryl–Zn sites by subsequent introduction of the anionic initiator Me3SiCH2Li·(pmdeta) (pmdeta, pentamethyldiethylenetriamine) and styrene monomers. The fraction of the extracted PS homopolymer grown from the Me3SiCH2 sites was low (homo-PS (g)/total PS (g), 15–22%). The gel permeation chromatography (GPC) curves shifted evidently after styrene polymerization, and change in the molecular weight (ΔMn, 39–56 kDa) was approximately twice the homo-PS Mn (20–23 kDa), in accordance with attachment of the PS chains at both ends of the PO chains. Transmission electron microscopy analysis of the thin films showed segregation of the PS domains in the PO matrix to form spherical or wormlike rippled structures depending on the PS content. The prepared triblock copolymers exhibited elastomeric properties in the cyclic tensile test, similar to the commercial PS-block-poly(ethylene-co-1-butene)-block-PS.
more목차
1. Introduction 1
2. Results and Discussion 3
2.1 Synthesis of 1,5-hexanediylzinc species 3
2.2 CCTP studies 4
2.3 PS chain growth from dialkylzinc 9
2.4 Synthesis of PS-block-PO-block-PS 12
3. Conclusion 19
4. Experimental Section 20
4.1 General remarks 20
4.2 Synthesis and Characterization 20
5. References 25
Appendix 31
