Authors

Hayden Houck

Senior Project Advisor

Dr. Mike Larsen

Document Type

Project

Publication Date

Spring 2022

Keywords

Covalent Adaptable Networks, statistical copolymer, uncontrolled free radical copolymerization, Thermal Guanidine Metathesis, organic synthesis

Abstract

Covalent adaptable networks (CANs) are a newly emerging class of polymers that uniquely bridge the gap between traditional thermosets and thermoplastics. The distinguishing characteristic of these polymer networks is that they contain reversible crosslink bonds that allows these materials to be recycled. Two of the currently best-understood CAN systems include those based on Diels-Alder1 and transesterification2 reactions, both of which involve dissociative exchange mechanisms. Our group aimed to create a novel CAN system based on the thermal guanidine metathesis (TGM) reaction3 by using a guanidine functional group as a crosslinker. In order to create a guanidine-crosslinked network, our research took a postpolymerization modification approach wherein we synthesized a precursor polymer containing pendant reactive carbodiimide functionalities which, upon reaction with a multifunctional amine, are reversibly converted into guanidine crosslinks. The carbodiimide-containing polymer is synthesized using free-radical copolymerization with styrene and a carbodiimide (CDI)-containing monomer with a styrenic substituent. The CDI-containing monomer is synthesized via creation and subsequent dehydrosulfurization of a thiourea-based pre-monomer. This research presents a comprehensive overview of the process of creating a reliable, scalable, 4-step synthetic plan to create a covalent adaptable network which uses a dissociable guanidine functional group as a covalent crosslink.

Subjects - Topical (LCSH)

Organic compounds--Synthesis; Polymers; Carbodiimides; Guanidine

Genre/Form

essays

Type

Text

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

Language

English

Format

application/pdf

Included in

Chemistry Commons

Share

COinS