Abstract

Polymer matrix composites (PMCs) utilize thermoset resins in large part because of their low starting molecular weights which allow for good reinforcement infiltration prior to curing. Formed networks owe much of their mechanical properties to covalent crosslinks tethering molecules within the matrix. Traditional covalent bonds are irreversible and thus damaged composites are either repaired or replaced. For the former, traditional repair techniques remain costly and time consuming. Dynamic covalent bonds represent a potential alternative to traditional covalent bonds. These unique chemical groups can be tailored to engender thermoset-like characteristics at use-temperatures and thermoplastic-like behavior at elevated temperatures thus enabling self-healing. In this work a thermally mendable self-healing PMC matrix material is proposed enabled by the use of hindered urea bonds. In this investigation traditional crosslinked networks containing hindered urea bonds (HUBs) with varying levels of aromatic content have been synthesized. Optimization of synthetic processes presented in this research has allowed for the formation of materials with varied material properties such as Tg, toughness and tensile strength. These polymers have been used to investigate the restoration of mechanical properties when exposed to thermal stimulus promoting accelerated self-healing. It is envisioned that advanced polymeric matrix materials have numerous practical applications including but not limited to composite structures and military vehicles alongside commercial applications as self-healing polymers.

Library of Congress Subject Headings

Polymeric composites--Materials; Polymeric composites--Mechanical properties; Self-healing materials

Publication Date

6-7-2018

Document Type

Thesis

Student Type

Graduate

Degree Name

Manufacturing and Mechanical Systems Integration (MS)

Department, Program, or Center

Manufacturing and Mechanical Engineering Technology (CET)

Advisor

Christopher Lewis

Advisor/Committee Member

Mark Olles

Advisor/Committee Member

Elizabeth M. Dell

Campus

RIT – Main Campus

Plan Codes

MMSI-MS

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