University of Illinois Urbana-Champaign

Development and applications of acid degradable polymeric materials

Morado, Ephraim Gabriel

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https://hdl.handle.net/2142/117879

Description

Title
Development and applications of acid degradable polymeric materials
Author(s)
Morado, Ephraim Gabriel
Issue Date
2021-03-19
Director of Research (if dissertation) or Advisor (if thesis)
Zimmerman, Steven C
Doctoral Committee Chair(s)
Zimmerman, Steven C
Committee Member(s)
  • Moore, Jeffrey S
  • Chan, Jefferson
  • Braun, Paul V
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Polyurethane, Degradable, Acid, microcapsule, elastomers, adhesive, CATCH, CATCH cleavage, thermoset, crosslinked
Abstract
This dissertation is divided into two main projects the first section discusses a new mechanism for degrading polyurethanes called CyclizAtion-Triggered Chain (CATCH) cleavage. CATCH cleavage features a simple glycerol-based acyclic acetal unit as a kinetic and thermodynamic trap for chain shattering. Thus, transient oxocarbenium ion formation with an organic acid induces intramolecular cyclization to depolymerize a polyurethane (PU) backbone at room temperature in anhydrous or low moisture environments. With minimal chemical modification, the resulting degradation products can be repurposed into strong adhesives and combined with photochromic dyes to make smart coatings demonstrating the potential for PU repurposing. The CATCH cleavage strategy for low-energy input breakdown and subsequent upcycling may be generalizable to a broader range of synthetic polymers at their end-of-life waste streams. The CATCH cleavage was also utilized to develop acid and light degradable polyhydroxyurethane (PHU) microcapsules. The microcapsules are fabricated using interfacial polymerization with trimesoylchloride and a hydroxy acetal-bearing diamine that can undergo degradation in the absence of protic solvent. We demonstrate that by encapsulating a photoacid generator as a trigger, we can increase the internal local acid concentration and degrade these microcapsules using UV light (365 nm). The generation of high localized proton concentration inside the oil core is capable of degrading the microcapsule. Lastly, we switch gears from the CATCH cleavage and describe the 3-iodopropyl acetal moiety as a simple cleavable unit that undergoes acid-catalyzed hydrolysis to liberate HI (pKa ~ -10) and acrolein stoichiometrically. Integrating this unit into linear and network polymers gives a class of macromolecules that undergo a new mechanism of degradation with an acid amplified sigmoidal rate. This trigger-responsive self-amplified degradable polymer undergoes an accelerated rate of degradation and agent release.
Graduation Semester
2021-05
Type of Resource
Thesis
Copyright and License Information
Copyright 2021 Ephraim Gabriel Morado

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