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Title:Hindered urea bond for the design of dynamic materials
Author(s):Ying, Hanze
Director of Research:Cheng, Jianjun
Doctoral Committee Chair(s):Cheng, Jianjun
Doctoral Committee Member(s):Braun, Paul; Sottos, Nancy; Kilian, Kristopher; Moore, Jeffrey
Department / Program:Materials Science & Engineerng
Discipline:Materials Science & Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Dynamic covalent chemistry
Hindered urea bond (HUB)
Dynamic polymers
Self-healing
Hydrolyzable
Malleable thermoset
Abstract:Dynamic covalent bonds (DCBs) featuring reversible bonding/debonding properties have found various applications in dynamic materials designs such as self-healing, malleable, shape-memory or environmentally-adaptive materials. However, most DCBs developed so far require either catalyst or harsh environments to facilitate bond reversion and involve special building blocks for synthesis. Here we seek to develop a novel platform for dynamic materials design using a new type of DCB – hindered urea bond (HUB). Differing from normal urea bond, HUB bears bulky substituents on one of the nitrogen atom, which distorts the atomic co-planarity, weakens the bonding stability, and allows reversible dissociation of HUB to isocyanate and hindered amine. The dynamic properties of HUB enables the design of self-healing polymeric elastomers/malleable thermosets through bond exchange and hydrolyzable polymers through quenching of dissociative intermediate – isocyanate. HUB shows many advantages in dynamic materials designs compared with other DCB systems in terms of simplicity, dynamicity, tunability and cost.
Issue Date:2017-01-04
Type:Thesis
URI:http://hdl.handle.net/2142/97648
Rights Information:Copyright 2016 Hanze Ying
Date Available in IDEALS:2017-08-10
Date Deposited:2017-05


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