Festkörper-NMR- und DNP-Untersuchungen an anorganisch-organischen Funktionsmaterialien / Timmy Schäfer.

Format:

Book

Author/Creator:

Schäfer, Timmy, author.

Language:

German

Subjects (All):

Cellulose.

Physical Description:

1 online resource (179 pages)

Edition:

First edition.

Place of Publication:

Göttingen : Cuvillier Verlag, [2021]

Summary:

This thesis focusses on the application of solid state nuclear magnetic resonance (ssNMR) and dynamic nuclear polarization (DNP) to characterize functional materials. DNP enables to increase the sensitivity of ssNMR by several orders of magnitude which next to the measurements of 13C nuclei, allows measurements of 15N nuclei even in natural abundance. Therefore, ssNMR combined with DNP is used as a valuable tool for analyzing the chemical structure of inorganic-organic functional materials containing less surface functionalization or low specific surface areas and low sensitive nuclei. This approach is used to characterize a variety of materials including chemically modified cellulose, core-shell particle systems as well as thermosets. In the first part of this thesis, materials based on cellulose are investigated using DNP enhanced 13C CP MAS to identify surface near functional groups. In addition, the binding of certain nitrogen containing functional groups is verified by DNP enhanced 15N CP MAS experiments on samples containing15N in natural abundance. The second part of this work deals with the characterization of core-shell particle systems. Since these organic particles were functionalized with a silicon containing shell, 29Si CP MAS measurements, partially combined with DNP, are used in addition to 13C CP MAS measurements to examine the 29Si nuclei directly. Thus, it becomes feasible to characterize the cross-linking in the shell of core-shell particles with different alkoxysilane shells. Finally, this approach enables to characterize the binding of an allylhydidopolycarbosilane (SMP-10) to the core particles at a molecular level. In the third part, ssNMR techniques are applied on cross-linked epoxy resins (thermosets) to identify their structure and chemical composition. The chemical components of the cross-linked network system are determined directly by using 13C CP MAS NMR. In addition to the basic components (resin and hardener) the analyses are also extended to phosphorus-containing flame retardants, which are characterized by 31P CP MAS NMR. Finally, the database created from these measurements is applied to commercially available systems to demonstrate their applicability for industrial purposes.

Contents:

Intro

Danksagung

Abstract

Inhaltsverzeichnis

1. Einleitung

2. Kernresonanzspektroskopie (NMR)

2.1. Grundprinzip der Magnetresonanzspektroskopie

2.2. Relaxation

2.3. Die chemische Verschiebung

2.4. Festkörper-Magnetresonanzspektroskopie

2.5. Drehung im "magischen Winkel"

2.6. Das Einzelimpulsexperiment

2.7. Dipolare Entkopplung

2.8. Das Kreuzpolarisationsexperiment

3. Dynamische Kernpolarisation (DNP)

3.1. DNP-Transfer-Mechanismen

3.2. Biradikale

4. Cellulose und funktionalisierte Papiermaterialien

4.1. Vorkommen und Gewinnung von Cellulose

4.2. Kristalline Formen von Cellulose

4.3. Anwendungen funktionalisierter Cellulose

4.4. Untersuchungen an Cellulosesystemen

5. Kolloidale Kristalle

5.1. Sphärische Polymer-Kolloide

5.2. Suspensionspolymerisation

5.3. Dispersionspolymerisation

5.4. Emulsionspolymerisation

6. Epoxidharze

6.1. Synthese von DGEBA

6.2. Mechanismus der Aminhärtung

7. Flammschutz von Kunststoffen

7.1. Verbrennungsprozesse von Kunststoffen

7.2. Wirkungsweise von Flammschutzmitteln

7.3. Phosphorhaltige Flammschutzmittel

7.4. Flammtest nach UL-94

8. Material und Methoden

8.1. Durchführung von DNP-Experimenten

8.2. Geräteaufbau der DNP in Darmstadt

8.3. Messparameter der DNP-Experimente

8.4. Messparameter der ssNMR-Experimente

8.5. Signalzuordnung der beobachteten NMR Signale

8.6. Probenpräparation für DNP-Untersuchungen an Hydroxypropylcellulose

8.7. DNP-Untersuchungen von Calcofluor White an Celluloseträgermaterial

8.8. ssNMR-Untersuchungen an Kern-Schale-Polymer hybrid Nanopartikeln

8.9. DNP- und ssNMR-Untersuchungen an pre-keramischen Kern-Schale-Partikeln

8.10. DNP- und ssNMR-Untersuchungen an vernetzten Epoxidharzen

8.11. Durchführung des UL-94-Tests

9. Ergebnisse und Diskussion.

9.1. Hydroxypropylcellulose und dessen Reaktionsprodukte

9.2. Interaktion von Calcofluor White mit einem Celluloseträgermaterial

9.3. Kern-Schale Partikel

9.4. Epoxidharz-Analytik

10. Zusammenfassung/Ausblick

10.1. Charakterisierung von funktionellen Cellulosematerialien

10.2. Charakterisierung von Kern-Schale-Partikeln

10.3. Charakterisierung von duroplastischen Epoxidharzen

11. Anhang

A) Abbildungsverzeichnis

B) Tabellenverzeichnis

C) Abkürzungsverzeichnis

D) Zusätzliche Spektren

12. Literaturverzeichnis

Liste der Veröffentlichungen.

Notes:

Description based on publisher supplied metadata and other sources.

Description based on print version record.

ISBN:

9783736964082

3736964080

OCLC:

1246581556