Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Ph.D. Thesis.pdf (6.99 MB)

ETD Abstract Container

Abstract Header

Epoxy Functional Materials

Yuan, Dian
http://rave.ohiolink.edu/etdc/view?acc_num=case1568810282832668

Abstract Details

2020, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
Thermoset epoxies with crosslinked molecular architecture are highly desirable engineering materials because they are dimensionally stable, and have good mechanical properties. Therefore, they have been widely applied in aerospace and automotive, construction, and electrical industries. However, epoxies are rigid and brittle, they lose much of their performances when damaged, thus limiting their life-time. Endowing epoxy with self-healing functionality can help them to restore their physical properties upon damage, therefore saves the labor and materials required for replacement. A self-healing epoxy coating system is obtained by blending epoxy with thermoplastic polyurethane (TPU) prepolymers. TPU prepolymers are capable to melt and flow to rebound the crack in the coating. These coatings show remarkable transparency and fast healing performance. To obtain a stiff but self-healable epoxy, we design a water-responsive self-healing system with reversible and permanent covalent networks by crosslinking polypropylene glycol with boroxine and epoxy. This system can change modulus from stiff thermoset to soft rubber upon water stimulus, enabling potential applications of either direct or transfer printing for micro/nano-fabrication. Moreover, by incorporating conductive nanofillers, it becomes feasible to fabricate versatile strain/stress sensors. This system also shows strong adhesion to metal; using conductive fillers in the system enables the use of epoxy-boroxine crosslinked systems for fabricating self-healable electrically conductive adhesives. To eliminate the overuse of fossil fuels and the environmental issues caused by using petroleum-based epoxy, a bio-based epoxy (diglycidyl ether of diphenolate esters,DGEDP) is used to replace the petroleum derived epoxy in the system incorporating thermoplastic polyurethane prepolymers. A rational design strategy to control the morphology of such a self-healing coating to balance its mechanical properties and self-healing performance is discussed. To reduce the impact of existing epoxy waste on the environment, we report a facile and effective strategy to recycle the epoxy waste and to convert it into high-performance conductive composites by incorporating conductive fillers. These recycled epoxy composites can be reprocessed up to three times and exhibit very low percolation threshold and high electrical conductivity at low filler loading. The good mechanical and electrical properties enable potential applications for these recycled epoxy composites for strain sensing and EMI shielding.
Ica Manas-Zloczower (Committee Chair)
Gary Wnek (Committee Member)
David Schiraldi (Committee Member)
Donald Feke (Committee Member)
Polymers

Recommended Citations

Citations

  • Yuan, D. (2020). Epoxy Functional Materials [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1568810282832668

    APA Style (7th edition)

  • Yuan, Dian. Epoxy Functional Materials. 2020. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1568810282832668.

    MLA Style (8th edition)

  • Yuan, Dian. "Epoxy Functional Materials." Doctoral dissertation, Case Western Reserve University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1568810282832668

    Chicago Manual of Style (17th edition)

case1568810282832668
218
© , all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.