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Architecture of Polyolefin and Polyester Chains with Zinc Ions
- Author(s)
- 이현주
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2023-02
- Language
- eng
- Keyword
- activation; biodegradability; co-catalyst; polyester; polyolefin
- Alternative Abstract
- This paper covers synthesis of polyolefin and polyester. The synthesis method we developed aims to manufacture high value-added products by architecture the chains of polymers with zinc ions. <br>Chapter 1 reviews background information of polyolefin and polyester, concept of coordinative chain transfer copolymerization (CCTP), and biodegradability issue. <br>Chapter 2 shows that synthesis of long-chain branched polymers has been great interest in the polyolefin industry. In this study, a method to produce long-chain branches (LCBs) in CCTcoP is suggested. A dialkylzinc compound bearing vinyl groups ((9-decenyl)2Zn) is prepared. It functions not only as a chain transfer agent but also as a comonomer for CCTcoP to generate LCBs. The generation of LCBs is confirmed by gel permeation chromatography studies and rheological data analysis. The formation of LCBs by connecting the two growing polyolefin chains can facilitate the generation of polymers with molecular weights higher than that expected. Significant shear thinning behavior is observed due to the presence of LCBs. Ethylene/1-octene copolymers can be readily prepared to exhibit nearly the same shear thinning behavior as commercial-grade of low-density polyethylene, which is known to contain large amounts of LCBs. <br>Chapter 3 indicates that homogeneous olefin polymerization catalysts are activated in situ with a co-catalyst ([PhN(Me)2-H]+[B(C6F5)4]− or [Ph3C]+[B(C6F5)4]−) in bulk polymerization media. These co-catalysts are insoluble in hydrocarbon solvents and require excess co-catalyst (>3 eq.). Feeding the activated species as a solution in an aliphatic hydrocarbon solvent may be advantageous over the in situ activation method. In this study, highly pure and soluble ammonium tetrakis(pentafluorophenyl)borates ([Me(C18H37)2N-H]+[B(C6F5)4]− and [(C18H37)2NH2]+[B(C6F5)4]−) containing neither water nor Cl− salt impurities were prepared easily via the acid–base reaction of [PhN(Me)2-H]+[B(C6F5)4]− and the corresponding amine. Using the prepared ammonium salts, the activation reactions of commercial-process-relevant metallocene (rac-[ethylenebis(tetrahydroindenyl)]Zr(Me)2, [Ph2C(Cp)(3,6-tBu2Flu)]Hf(Me)2, [Ph2C(Cp)(2,7-tBu2Flu)]Hf(Me)2) and half-metallocene complexes ([(η5-Me4C5)Si(Me)2(κ-NtBu)]Ti(Me)2, [(η5-Me4C5)(C9H9(κ-N))]Ti(Me)2, and [(η5-Me3C7H1S)(C10H11(κ-N))]Ti(Me)2) were monitored in C6D12 with 1H NMR spectroscopy. Stable [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4]− species were cleanly generated from -[ethylenebis(tetrahydroindenyl)]Zr(Me)2, [Ph2C(Cp)(3,6-tBu2Flu)]Hf(Me)2, and [Ph2C(Cp)(2,7-tBu2Flu)]Hf(Me)2, while the species types generated from [(η5-Me4C5)Si(Me)2(κ-NtBu)]Ti(Me)2, [(η5-Me4C5)(C9H9(κ-N))]Ti(Me)2, and [(η5-Me3C7H1S)(C10H11(κ-N))]Ti(Me)2 were unstable for subsequent transformation to other species (presumably, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4]−-type species). [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4]−-type species were also prepared from [(η5-Me4C5)Si(Me)2(κ-NtBu)]TiCl(Me) and [(η5-Me4C5)(C9H9(κ-N))]TiCl(Me), which were newly prepared in this study. The prepared [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4]−-, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4]−-, and [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4]−-type species, which are soluble and stable in aliphatic hydrocarbon solvents, were highly active in ethylene/1-octene copolymerization carried out in aliphatic hydrocarbon solvents. <br>Chapter 4 describes that synthetic biodegradable polyesters have recently been rejected or banned for environmentally friendly applications because they tend to biodegrade slowly under ambient natural conditions. In this study, we demonstrate the preparation of polyesters exhibiting enhanced biodegradability generated through a combination of old controversial macromolecules and aggregate theories. H3PO4-catalyzed diacid/diol polycondensation afforded polyester chains with chain-end −CH2OP(O)(OH)2 and inner-chain (−CH2O)2P(O)(OH) groups, which were subsequently treated with M(2-ethylhexanoate)2 (M = Zn, Mg, Mn, and Ca) to form ionic aggregates of polyesters. The prepared ionic aggregates of polyesters, which were constructed with fertilizer ingredients (such as M2+ and phosphate), exhibit much faster biodegradation than the conventional polyesters under controlled soil conditions at 25 °C, while displaying comparable or excellent rheological and mechanical properties.
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- Graduate School of Ajou University > Department of Molecular Science and Technology > 4. Theses(Ph.D)
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