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Advancing Selective Post-Polymerization C-H Functionalization of Semicrystalline Polyolefins
Advancing Selective Post-Polymerization C-H Functionalization of Semicrystalline Polyolefins
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202104728
- ISBN
- 9798291554975
- DDC
- 547
- 서명/저자
- Advancing Selective Post-Polymerization C-H Functionalization of Semicrystalline Polyolefins
- 발행사항
- [Sl] : The University of North Carolina at Chapel Hill, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 277 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 87-02, Section: B.
- 주기사항
- Advisor: Leibfarth, Frank A.;Alexanian, Erik J.
- 학위논문주기
- Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 2025.
- 초록/해제
- 요약The development of selective polyolefin C-H functionalization methodologies facilitates the elucidation of structure-property relationships in semicrystalline polyolefins. We find that site selective hydrogen atom transfer using N-tBu amidyl radicals can dictate the regioselectivity of C-H functionalization, circumventing polymer chain scission events that would compromise the mechanical properties of the resultant polymer. Coupling this selectivity with remarkably general thiosulfonate radical traps, we transfer functional groups that crosslink polymer chains through ionic and dynamic covalent bonds. These materials display multi length-scale phase separation that contributes to their high toughness during use, yet have the potential to be reprocessed through dynamic bond exchange. The translation of this approach to mixed polyolefin waste streams-which exhibit poor mechanical properties because of polymer phase separation and brittle interfaces between the phases- affords tough blends that offer synergistic properties of the blend constituents. A mechanistic study supports the key role of covalent crosslinking particularly between, but also within phases. Despite the benefits of the aforementioned C-H functionalization approaches, random functionalization along the polymer backbone limits the crystallinity of the resultant polymers, and accordingly the stiffness and strength (i.e. Young's modulus and stress at yield) of the material. We develop an alternative approach wherein the polymer is reacted in a semicrystalline gel state to sterically protect crystalline domains while affording functionalization in the solvent swelled amorphous domains, providing blocky functionalized polymers that exhibit greater crystallinity fraction, melt temperature, stiffness, and strength in comparison to randomly functionalized analogues.
- 일반주제명
- Polymer chemistry
- 일반주제명
- Organic chemistry
- 일반주제명
- Materials science
- 키워드
- Polymers
- 키워드
- Crystallinity
- 키워드
- Regioselectivity
- 기타저자
- The University of North Carolina at Chapel Hill Chemistry
- 기본자료저록
- Dissertations Abstracts International. 87-02B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■006m o d
■007cr#unu||||||||
■020 ▼a9798291554975
■035 ▼a(MiAaPQ)AAI32122692
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a547
■1001 ▼aNeidhart, Eliza Katherine.
■24510▼aAdvancing Selective Post-Polymerization C-H Functionalization of Semicrystalline Polyolefins
■260 ▼a[Sl]▼bThe University of North Carolina at Chapel Hill▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a277 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 87-02, Section: B.
■500 ▼aAdvisor: Leibfarth, Frank A.;Alexanian, Erik J.
■5021 ▼aThesis (Ph.D.)--The University of North Carolina at Chapel Hill, 2025.
■520 ▼aThe development of selective polyolefin C-H functionalization methodologies facilitates the elucidation of structure-property relationships in semicrystalline polyolefins. We find that site selective hydrogen atom transfer using N-tBu amidyl radicals can dictate the regioselectivity of C-H functionalization, circumventing polymer chain scission events that would compromise the mechanical properties of the resultant polymer. Coupling this selectivity with remarkably general thiosulfonate radical traps, we transfer functional groups that crosslink polymer chains through ionic and dynamic covalent bonds. These materials display multi length-scale phase separation that contributes to their high toughness during use, yet have the potential to be reprocessed through dynamic bond exchange. The translation of this approach to mixed polyolefin waste streams-which exhibit poor mechanical properties because of polymer phase separation and brittle interfaces between the phases- affords tough blends that offer synergistic properties of the blend constituents. A mechanistic study supports the key role of covalent crosslinking particularly between, but also within phases. Despite the benefits of the aforementioned C-H functionalization approaches, random functionalization along the polymer backbone limits the crystallinity of the resultant polymers, and accordingly the stiffness and strength (i.e. Young's modulus and stress at yield) of the material. We develop an alternative approach wherein the polymer is reacted in a semicrystalline gel state to sterically protect crystalline domains while affording functionalization in the solvent swelled amorphous domains, providing blocky functionalized polymers that exhibit greater crystallinity fraction, melt temperature, stiffness, and strength in comparison to randomly functionalized analogues.
■590 ▼aSchool code: 0153.
■650 4▼aPolymer chemistry
■650 4▼aOrganic chemistry
■650 4▼aMaterials science
■653 ▼aSemicrystalline polyolefins
■653 ▼aPolymers
■653 ▼aCrystallinity
■653 ▼aRegioselectivity
■653 ▼aCrosslink polymer chains
■690 ▼a0495
■690 ▼a0490
■690 ▼a0794
■71020▼aThe University of North Carolina at Chapel Hill▼bChemistry.
■7730 ▼tDissertations Abstracts International▼g87-02B.
■790 ▼a0153
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17358625▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
