Autonomous materials for active erosion resistance in low-Earth orbit

Chang, Kelly M.

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https://hdl.handle.net/2142/122208 Copy

Description

Title

Autonomous materials for active erosion resistance in low-Earth orbit

Author(s)

Chang, Kelly M.

Issue Date

2023-10-20

Director of Research (if dissertation) or Advisor (if thesis)

Sottos, Nancy R

Doctoral Committee Chair(s)

Sottos, Nancy R

Committee Member(s)

• Chasiotis, Ioannis
• Evans, Chris M.
• Krogstad, Jessica A.
• Baur, Jeffery W.

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• self-healing
• polydicyclopentadiene
• low Earth orbit
• atomic oxygen erosion
• transverse microcracks
• microcapsules

Abstract

This dissertation presents a comprehensive investigation on enhancing the performance and durability of aerospace-grade polymer matrix composites (PMCs) through autonomous repair mechanisms. The research comprises of four interconnected projects that collectively advance the understanding and application of self-healing strategies and self-passivation mechanisms. Chapter 1 is a literature review on microcapsule based self-healing strategies and the standard protocols for characterizing their success. The review establishes the context for the significance of the scientific contributions described in the first project (Chapter 2). In Chapter 2, a microcapsule based self-healing approach was tailored to address transverse microcracking in high-Tg carbon fiber reinforced polymers, achieving a noteworthy self healing efficiency of 57% for isolated crack events evaluated by digital image correlation. Shifting focus to the harsh conditions of low Earth orbit (LEO) environment, Chapter 3 describes the primary environmental hazards (i.e., erosion by atomic oxygen (AO) and high-velocity impact by orbital debris) and several potential strategies for improving the AO-erosion resistance of polymers. The subsequent project (Chapter 4) examined the AO erosion resistance of an impact-resistant polymer, polydicyclopentadiene (pDCPD), under true LEO conditions, revealing that the addition of silica nanoparticles reduced AO erosion rates significantly. Additionally, hypervelocity impact tests demonstrated that AO erosion-induced surface changes had minimal impact on impact crater volume. The investigation continued with a systematic exploration of active mechanisms for improving AO-erosion resistance (Chapter 5), demonstrating that microcapsule-based self-healing was not effective and leading to a new focus on developing a novel pDCPD-based copolymer with norbornene-functionalized PDMS for self-passivation triggered by exposure to AO (Chapter 6). This material exhibited efficient self-passivation at low loadings of PDMS and completely mitigating AO-induced mass loss at moderate loadings. In all, net-p(DCPD-co-PDMS) represents a promising avenue for combining exceptional impact resistance with the self-protecting behavior of PDMS in LEO environments. This thesis contributes valuable insights and methodologies for advancing the durability and longevity of PMCs in challenging space conditions.

Graduation Semester

2023-12

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/122208

Copyright and License Information

Copyright 2023 Kelly M. Chang

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