자료유형  

 학위논문

Control Number  

0017161566

International Standard Book Number  

9798382762500

Dewey Decimal Classification Number  

660

Main Entry-Personal Name  

Wang, Tong.

Publication, Distribution, etc. (Imprint  

[S.l.] : Northwestern University., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

237 p.

General Note  

Source: Dissertations Abstracts International, Volume: 85-11, Section: B.

General Note  

Advisor: Torkelson, John M.

Dissertation Note  

Thesis (Ph.D.)--Northwestern University, 2024.

Summary, Etc.  

요약Interfaces play a pivotal role in dictating the properties of polymers, particularly at the polymer/air interface, where polymer dynamics undergo significant enhancement, leading to deviations from bulk responses in key properties like the glass transition temperature (Tg). Understanding and eliminating the nanoconfinement behavior, exemplified by the Tg-confinement effect observed in polystyrene thin films, have been a longstanding challenge in polymer physics. Considerable research efforts have been dedicated to elucidating and fine-tuning this phenomenon across various polymer films. Moreover, achieving tunability in the Tg-confinement effect is crucial for various applications, but existing techniques often require complex synthesis processes or the incorporation of small molecules. This dissertation introduces a novel method to eliminate the Tg-confinement effect in polystyrene and poly(4-methylstyrene) films by synthesizing random copolymers containing only 2-3 mol% of 2-ethylhexyl acrylate with styrene or 4-methylstyrene, which only requires simple free radical synthesis. It is demonstrated that bulk fragility and the fragility-confinement effect are dominant factors influencing the Tg-confinement effect, indicating that the low level of 2-ethylhexyl acrylate units can alter the chain packing efficiency, potentially via the interdigitation of 2-ethylhexyl groups.The healing of polymer/polymer interfaces is imperative for enhancing the self-healing capability and reprocessability of polymer materials. Most reported autonomous self-healing polymers require embedding specially designed functional groups or unique polymer chain arrangements, limiting their applicability. Addressing these challenges, this dissertation presents a new approach to achieving autonomous self-healing copolymer materials solely based on commodity monomers while offering a wider range of workable compositions. Additionally, traditional polymer network materials, due to their crosslinked structure, have been challenging to recycle or reprocess. Covalent adaptable network (CAN) materials, capable of being reprocessed or reshaped under specific stimuli while retaining strong mechanical properties, offer a solution. This dissertation introduces the first chain-growth CAN crosslinked by thionourethane linkages, demonstrating rapid reprocessability, full self-healing capability, and resistance to creep.Through comprehensive investigations and innovative approaches, this dissertation contributes to advancing our understanding and utilization of polymer interfaces and self-healing materials, offering promising avenues for enhancing the performance and sustainability of polymer materials in various applications.

Subject Added Entry-Topical Term  

Chemical engineering.

Subject Added Entry-Topical Term  

Materials science.

Subject Added Entry-Topical Term  

Polymer chemistry.

Index Term-Uncontrolled  

Confinement effect

Index Term-Uncontrolled  

Covalent adaptable network

Index Term-Uncontrolled  

Fragility

Index Term-Uncontrolled  

Glass transition

Index Term-Uncontrolled  

Polymer

Index Term-Uncontrolled  

Self-healing

Added Entry-Corporate Name  

Northwestern University Chemical and Biological Engineering

Host Item Entry  

Dissertations Abstracts International. 85-11B.

Electronic Location and Access  

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Control Number  

joongbu:658194