Characteristics and modeling of the fracture properties of polymer-silica microparticulate composites via macroscopic scratch tests

Bouche, Gregory Alexander

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https://hdl.handle.net/2142/88422 Copy

Description

Title

Characteristics and modeling of the fracture properties of polymer-silica microparticulate composites via macroscopic scratch tests

Author(s)

Bouche, Gregory Alexander

Issue Date

2015-04-28

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• multi-phase composite
• scratch test
• fracture toughness
• linear homogenization
• polymer-silica
• Mori Tanaka
• compressive strength
• scratch hardness
• macro scratch test device
• SUNLab Macroscopic Scratch Test Device
• micromechanics model
• spherical inclusions
• fracture energy
• Young's modulus
• linear elastic fracture mechanics
• glass bead
• paraffin wax
• coupling agent
• inclusion content

Abstract

The advantages of multi-phase materials are exploited in many industries, such as reinforced concrete in bridge construction, heterogeneous geological materials in petroleum engineering, advanced carbon fiber composites in aerospace engineering, and novel corrosion resistant coatings in the automotive industry. Although it is well known that the addition of inclusions can lead to improved multi-phase material properties, the characterization and prediction of these material properties is of current research interest. In this thesis, we evaluate the effect of spherical inclusion content on the material properties of polymer-silica microcomposites, both experimentally and theoretically. A wax mixture with spherical glass bead inclusions is developed as a model material. The hardness and fracture toughness of composites containing 0%, 5%, 10%, and 20% spherical glass bead inclusions by volume are analyzed using a built-in- house macroscopic scratch test device. The elastic modulus and compressive strength are obtained from a series of compression tests. Scanning electron microscopy is employed as an independent means to corroborate the morphology of the specimens. Several types of spherical glass beads with mean inclusion sizes of 20 μm and 200 μm are used in this study, and the effect of using a coating agent is investigated. We find that the compressive strength, elastic modulus, fracture toughness, and scratch hardness tend to increase with inclusion content. The composites containing coated glass beads exhibit superior properties in certain cases. Next, a rigorous linear elastic homogenization technique is derived to account for the observed change in elastic modulus and fracture toughness with inclusion content. The predictions developed are in strong agreement with the experimental data, creating a powerful tool for estimating the material properties of polymer-silica microcomposites. The generality of our theoretical framework makes it applicable to the study and prediction of elastic properties and fracture resistance in advanced composites.

Graduation Semester

2015-05

Type of Resource

text

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http://hdl.handle.net/2142/88422

Copyright and License Information

Copyright 2015 Gregory Bouche

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