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Purification of Tadpole-Shaped Polystyrene Precursor and Investigation of Silyl Hydride-Functionalized Polybutadiene

Kippenbrock, Grant
http://orcid.org/0000-0002-2301-518X
http://rave.ohiolink.edu/etdc/view?acc_num=akron1586863602288104

Abstract Details

2020, Master of Science, University of Akron, Polymer Science.
Polymers with nonlinear architecture such as cyclic or star architectures can have properties including crystallinity, glass transition temperature, and melt-flow dynamics that are strikingly different than those of their linear analogues. In the past two decades, there has been increased interest in the intriguing topology of tadpole-shaped chains due to the presence of both linear and cyclic parts in a single molecule. Systematic study of tadpole-shaped polymers has been limited by the availability of molecules of high purity and well-defined structure. However, Zhang et al.1,2 developed an efficient method for the synthesis of well-defined, tadpole-shaped polystyrene (TPS) with a single atom junction point. It was discovered that unwanted linear material possessing vinyl end groups, namely α-4-pentenylpolystyrene, was present in low concentrations with the tadpole-shaped polystyrene precursor, the asymmetric, three-arm, star. In order to ensure a well-defined tadpole product, a new method of purification was investigated using hydrosilation chemistry coupled with silica gel column chromatography. Using hydrosilation chemistry, trichlorosilane, trimethoxysilane, and triethoxysilane were reacted with the vinyl groups of the contaminant as a purification procedure. While the method requires optimization, the resulting polar functional groups enabled the functionalized contaminant to be separated using silica gel column chromatography. It has been proposed that cyclic or looped structures have to be formed during polybutadiene syntheses due to the presence of in-chain, reactive vinyl groups. A broad molecular weight distribution is produced during the emulsion polymerization of styrene-butadiene rubber (SBR), as a result of branching from chain transfer and intermolecular reactions. In order to investigate whether a backbiting reaction occurs during propagation reactions for polybutadiene, alkyllithium-initiated polybutadiene, end-functionalized with chlorodimethylsilane, was used to produce silyl hydride-functionalized polybutadiene. This model system had a narrow molecular weight distribution, a well-defined microstructure, and was reacted in the presence of Karstedt’s catalyst to determine the ratio of intermolecular to intramolecular reaction during the hydrosilation reaction. Reaction in the presence of allylamine was also performed to determine if reaction with the functionalizing agent competes appreciably with the hydrosilation of the vinyl groups. The results showed no indication of reaction with allylamine, and the dominant factor affecting the course of the reaction was the concentration of the polymer in solution. The degree of intramolecular to intermolecular reaction was quantified using gel permeation chromatography (GPC) peak areas. This ratio varied from 1.0:0.3 to 1.0:0.01 as concentration of polymer decreased from 0.27 mM to 0.017mM.
Mark Foster (Advisor)
Roderic Quirk (Advisor)
135 p.
Polymers

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Citations

  • Kippenbrock, G. (2020). Purification of Tadpole-Shaped Polystyrene Precursor and Investigation of Silyl Hydride-Functionalized Polybutadiene [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1586863602288104

    APA Style (7th edition)

  • Kippenbrock, Grant. Purification of Tadpole-Shaped Polystyrene Precursor and Investigation of Silyl Hydride-Functionalized Polybutadiene. 2020. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1586863602288104.

    MLA Style (8th edition)

  • Kippenbrock, Grant. "Purification of Tadpole-Shaped Polystyrene Precursor and Investigation of Silyl Hydride-Functionalized Polybutadiene." Master's thesis, University of Akron, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1586863602288104

    Chicago Manual of Style (17th edition)

akron1586863602288104
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This open access ETD is published by University of Akron and OhioLINK.