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Dissertation-Nethmi final edition.pdf (7.61 MB)

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Application of Photochemistry and Dynamic Chemistry in Designing Materials tuned through Macromolecular Architecture

De Alwis, Watuthanthrige Nethmi Thanurika
http://orcid.org/0000-0001-7058-2438
http://rave.ohiolink.edu/etdc/view?acc_num=miami1626694956739651

Abstract Details

2021, Doctor of Philosophy, Miami University, Chemistry and Biochemistry.
Polymer synthesis and modification have become one of the key research areas in recent industrial development. Dynamic chemistry and photochemistry are two different aspects that could benefit polymeric materials to improve their properties. Photochemistry allows polymerization and modifications of thermal-sensitive monomers to be carried out under mild reaction conditions. Photochemical modifications such as photo-labile cleavages often aid preventing side reactions in reactive monomers and protect the fidelity of the polymers. A novel photolabile monomer, 2-{[(benzyloxy)carbonyl]amino}ethyl 2-methylprop-2-enoate (ONBAMA) was synthesized and explored the deprotection under different wavelengths of light. It was found that ONBAMA yield well-controlled polymers and they can be used in post-polymer modifications upon UV irradiation. Often photochemical reactions are carried out using external light sources such as lasers, LEDs, and UV lights. However, the limited penetration efficacy and reaction vessel geometries can limit the efficiency of photopolymerization and light-mediated modifications. The introduction of an internal light generation is an effective way of overcoming these limitations. In the second chapter, a bi-phasic system was introduced employing the chemiluminescence reaction in the bottom phase and photo-induced polymerization in the top layer as a new concept for using internal light sources in polymerization. Phenyl vinyl ketone (PVK) is known as a photo-responsive molecule. Due to the presence of the acetophenone subgroup, PVK is known to undergo Norrish-type reactions. PVK is known to undergo the Norrish type I process under blue light to generate radicals to initiate polymerization and the Norrish type II process to degrade the poly(PVK). The fourth chapter focuses on using the photoinitiation and degradation of the PVK monomers in synthesizing block polymers and photodegradable thermoplastic elastomeric materials respectively. Dynamers or dynamic bonds often break and reform autonomously or as a repones to external stimuli. The introduction of these bonds in polymeric materials can offer dynamic properties such as self-healing, stress relaxation, malleability and creep resistance. Dynamic covalent bonds introduce creep resistance and dynamic nature in response to external stimuli. Instead, dynamic non-covalent bonds hold dynamic nature at ambient temperature. Both the dynamic bonds contain advantages and limitations as well. The combination of both bonds in an interpenetrating network benefits complementary properties from both bonds. However, it was found that not only the dynamic bonds, but the architectural features of polymers such as network type, composition, chain length, crosslink distribution, and crosslink density can regulate the properties of the dual dynamic interpenetrating networks.
Dominik Konkolewicz, Dr. (Advisor)
Scott Hartley, Dr. (Committee Chair)
Richard Taylor, Dr. (Committee Member)
Rick Page, Dr. (Committee Member)
Zhijiang Ye, Dr. (Committee Member)
213 p.
Organic Chemistry; Polymer Chemistry; Polymers
Chemiluminescence; Thermoplastic Elastomers; Dynamic Materials; Interpenetrating Networks

Recommended Citations

Citations

  • De Alwis, W. N. T. (2021). Application of Photochemistry and Dynamic Chemistry in Designing Materials tuned through Macromolecular Architecture [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1626694956739651

    APA Style (7th edition)

  • De Alwis, Watuthanthrige Nethmi. Application of Photochemistry and Dynamic Chemistry in Designing Materials tuned through Macromolecular Architecture . 2021. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1626694956739651.

    MLA Style (8th edition)

  • De Alwis, Watuthanthrige Nethmi. "Application of Photochemistry and Dynamic Chemistry in Designing Materials tuned through Macromolecular Architecture ." Doctoral dissertation, Miami University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1626694956739651

    Chicago Manual of Style (17th edition)

miami1626694956739651
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This open access ETD is published by Miami University and OhioLINK.