Date of Award

Summer 8-22-2020

Level of Access

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Advisor

William Gramlich

Second Committee Member

Alice Bruce

Third Committee Member

Michael Kienzler

Abstract

Double network hydrogels were synthesized using two cellulose derivatives, carboxymethyl cellulose (CMC) and cellulose nanofibrils (CNF). CMC was functionalized to incorporate norbornene groups via amide linkages onto its backbone. These norbornene groups were later crosslinked using dithiol crosslinkers during hydrogel synthesis. CNF was also incorporated into these hydrogels via physical entrapment within the networks. In the final steps, UV radical initiators and irradiation were also used to form hydrogels. To better understand the structures and functions of these hydrogels, key properties such as swelling, moduli, and degradation were explored. Through this research, it was discovered that a critical number of effective crosslinks was required to form hydrogels. This revealed that certain hydrogel formulations were not viable. The addition of CNF produced hydrogels containing higher moduli and slower degradation rates. As the percentage of CNF varied, so did its function within the double networks. At lower percentages, CNF played a reinforcing role, while at higher percentages, interpenetrating networks (IPNs) were created. Ultimately, a high degree of control over hydrogel moduli and CNF composition was achieved.

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