Preparation Oraganozinc Compounds Bearing Styrene Moiety for One-pot Synthesis of Polystyrene-Polyolefin- Polystyrene Multi-Block Copolymers
Preparation Oraganozinc Compounds Bearing Styrene Moiety for One-pot Synthesis of Polystyrene-Polyolefin- Polystyrene Multi-Block Copolymers
- 주제(키워드) Blockcopolymer , Polyolefin , Thermoplastic elastomer
- 발행기관 아주대학교
- 지도교수 이분열
- 발행년도 2018
- 학위수여년월 2018. 2
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000027119
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Triblock copolymers of polystyrene (PS) and a polyolefin (PO), e.g., PS-block-poly(ethylene-co-1-butene)-block-PS (SEBS), are attractive materials for use as thermoplastic elastomers and are produced commercially by a two-step process that involves the costly hydrogenation of PS-block-polybutadiene-block-PS. We herein report a one-pot strategy for attaching PS chains to both ends of PO chains to construct PS-block-PO-block-PS directly from olefin and styrene monomers. Dialkylzinc compound containing styrene moieties ((CH2=CHC6H4CH2CH2)2Zn) was prepared, from which poly(ethylene-co-propylene) chains were grown via “coordinative chain transfer polymerization” using the pyridylaminohafnium catalyst to afford di-end functional PO chains functionalized with styrene and Zn moieties. Subsequently, PS chains were attached at both ends of the PO chains by introduction of styrene monomers in addition to the anionic initiator Me3SiCH2Li·(pmdeta) (pmdeta = pentamethyldiethylenetriamine). We found that the fraction of the extracted PS homopolymer was low (~20 %) and that molecular weights were evidently increased after the styrene polymerization (ΔMn = 27–54 kDa). Transmission electron microscopy showed spherical and wormlike PS domains measuring several tens of nm segregated within the PO matrix. Optimal tensile properties were observed for the sample containing a propylene mole fraction of 0.25 and a styrene content of 33 %. Finally, in the cyclic tensile test, the prepared copolymers exhibited thermoplastic elastomeric properties with no breakage up over 10 cycles, which is comparable to the behavior of commercial-grade SEBS
more목차
1.Introduction
2. Experimental section
2.1 Preparation of (CH2=CHC6H4CH2CH2)2Zn
2.2 Typical Procedure for the Synthesis of Block
Copolymers
2.3 High-Temperature GPC Studies
2.4 Sample Preparation for Transmission Electron
Microscopy (TEM)
2.5 Tensile Tests
3. Results and Discussion
3.1 Strategy for the Preparation of PS-Block-PO-Block-PS
3.2 Synthesis of PS-Block-PO-Block-PS
3.3 Characterization of the Block Copolymers
4. Conclusion
5. Reference
6. Supporting Information
