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Preparation Oraganozinc Compounds Bearing Styrene Moiety for One-pot Synthesis of Polystyrene-Polyolefin- Polystyrene Multi-Block Copolymers
- Alternative Title
- Preparation Oraganozinc Compounds Bearing Styrene Moiety for One-pot Synthesis of Polystyrene-Polyolefin- Polystyrene Multi-Block Copolymers
- Author(s)
- 김청솔
- Alternative Author(s)
- Kim Chungsol
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2018-02
- Language
- kor
- Keyword
- Blockcopolymer; Polyolefin; Thermoplastic elastomer
- Alternative Abstract
- 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
- Fulltext
- Appears in Collections:
- Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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