Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


BZ phd dissertation.pdf (42.99 MB)

ETD Abstract Container

Abstract Header

Novel Dynamic Materials Tailored by Macromolecular Engineering

Zhang, Borui
http://orcid.org/0000-0003-2933-4285
http://rave.ohiolink.edu/etdc/view?acc_num=miami1564157701522666

Abstract Details

2019, Doctor of Philosophy, Miami University, Chemistry and Biochemistry.
Using dynamic chemistry to develop functional polymers is an emerging area in material science. This class of polymers possesses intrinsic reversibility owing to the covalent or noncovalent bonds within, therefore respond to external stimuli. In addition, combining dynamic interactions with polymers offers exciting dynamic features such as environmental adaptivity, malleability, self-healing, and shape memorizing properties. Noncovalent interactions, e.g., hydrogen bonds, metal-ligand coordination, host-guest interactions, ionomers or π-stacking, have been successfully built into polymers over the last decades. Researchers have also relied on dynamic covalent bonds, e.g., Diels-Alder adducts, disulfide exchange, imine bonds, or boronic ester bonds. However, the underlying kinetics of some covalent interactions have not been demonstrated explicitly. Besides, the dynamic nature of the crosslinkers introduces the potential for the material not only the weak toughness but also to creep or deform over time under load. Recently, a combination of dynamic and static crosslinkers on either the main polymer chains or side chains with different structures has been used to overcome these limitations and enhance the mechanical properties. Other than that, materials containing orthogonal dynamic chemistries enable the synthesis of intricate macromolecules which can respond to multiple stimuli to achieve the desired response. Our work mainly focuses on a deep understanding of the mechanism of the covalent interactions in terms of small molecule models to better manipulate them in the bulk polymers, making new dynamic materials, and exploring the impact of the macromolecular architectures on their properties. A mechanistic study of the thermally activated dynamic covalent chemistry of thiol-Michael adducts is the focus of Chapter two, using a model system of thiophenol/mercaptoethanol dynamic equilibrium with phenylvinylketone based Michael acceptors. Chapter three works on fabricating and characterizing the dynamers crosslinked by the thiol-Michael adduct. Chapters four and five concentrate on the dual-dynamic single network and interpenetrated networks using both free radical polymerization and RAFT polymerization. Relatively rapidly exchanging hydrogen-bonded and slowly exchanging Diels-Alder based cross-linkers are incorporated. It was found that the interpenetrated networks outperform the single networks. In addition, higher crosslink densities and longer chain length led to stronger materials that were less elastic. Chapter six moves to the nonequilibrium process but still takes advantages of the dynamic covalent bonds. We show that carbodiimides can be used to crosslink the polymer chains with pendant acid groups via the formation of anhydrides, giving transient crosslinked polymer networks. Multiple time-dependent gelation/decomposition cycles of the prepared water-soluble polymers were achieved.
Dominik Konkolewicz (Advisor)
Scott Hartley (Committee Chair)
Richard Taylor (Committee Member)
Gary Lorigan (Committee Member)
Jessica Sparks (Committee Member)
201 p.
Chemistry; Materials Science; Organic Chemistry; Physical Chemistry; Polymer Chemistry; Polymers
dynamic covalent and noncovalent chemistry; self-healing materials; Diels-Alder reactions; thiol-Micheal reactions; single network; interpenetrating network; transient crosslinked network; conventional free radical polymerization; RAFT polymerization

Recommended Citations

Citations

  • Zhang, B. (2019). Novel Dynamic Materials Tailored by Macromolecular Engineering [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1564157701522666

    APA Style (7th edition)

  • Zhang, Borui. Novel Dynamic Materials Tailored by Macromolecular Engineering. 2019. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1564157701522666.

    MLA Style (8th edition)

  • Zhang, Borui. "Novel Dynamic Materials Tailored by Macromolecular Engineering." Doctoral dissertation, Miami University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1564157701522666

    Chicago Manual of Style (17th edition)

miami1564157701522666
246
© 2019, some rights reserved.Creative Commons License Novel Dynamic Materials Tailored by Macromolecular Engineering by Borui Zhang is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Miami University and OhioLINK.