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Author ORCID Identifier

https://orcid.org/0000-0002-1854-9523

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2020

Month Degree Awarded

September

First Advisor

Alfred J. Crosby

Subject Categories

Physical Chemistry | Polymer and Organic Materials | Polymer Chemistry | Statistical, Nonlinear, and Soft Matter Physics

Abstract

A material is considered soft when its bulk modulus is significantly greater than its shear modulus. Rubbery polymers are a class of soft materials where resistance to extension is mainly entropic in nature. Polymeric soft solids differ from liquids due to the presence of a percolated network of strong bonds that resist deformation and flow on a given time scale. The incompressible nature, entropically driven elasticity, and molecular scale network structure of soft polymeric solids combine to impart unique mechanical behavior that often results in complex material responses to simple loading situations. An important example of this is cavitation in soft solids. Cavitation is the sudden, unstable expansion of a void within a liquid or solid due to the application of a negative hydrostatic stress. In soft solids, quantifying the damage imparted during cavitation is complicated by a balance between a large strain elastic expansion process and a complex fracture process. Understanding this damage is crucial to applications in materials characterization, the design of pressure sensitive adhesives, and damage of biological tissues. Previous work modeling the transition between these expansion processes has been limited to the continuum level where it is difficult to draw connections to damage on the molecular scale. The overarching goal of this thesis is to probe the cavitation to fracture transition and connect it to molecular scale network structure. In order to accomplish this goal, improvements to the experimental methods, materials structure, and molecular theory are developed in the first three chapters of this dissertation and are exploited in the fourth chapter to link cavitation and fracture to molecular scale structural damage.

DOI

https://doi.org/10.7275/18154481

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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