Search

This book provides expert coverage of the current state of the art in the application of nanotechnologies to cellulose research. It offers a comprehensive collection of topics including nanocellulose isolation, assembly into hierarchical structures, and advanced emerging applications. During the past decades, research in nanocellulose has advanced quickly, driven by the urgent needs for sustainability and the availability of advanced nanotechniques. Although cellulose has been investigated and used for thousands of years, the recent advances in nanotechnology have transformed our view of this natural substance. Cellulose, when present in the highly crystalline nanoscale form, can demonstrate interesting mechanical, optical, and fluidic properties that can be manipulated in designing materials with novel applications.This book contains 12 chapters. Chapter 1 focuses primarily on the fundamentals of nanocellulose, including general aspects on its structure, isolation, and characterization. Chapters 2-4 summarize the recent progress on assembly of nanocellulose into the macroscopic scale using state-of-the-art techniques. Chapters 5-13 cover the most advanced applications of nanocellulose in emerging areas, including superstrong materials, light management, electronics, energy storage, printed battery, water treatment, nanogenerator, and biomedicine. The book will appeal to upper undergraduate and graduate students through practicing researchers as a comprehensive reference on the subject of nanocellulose and its use in various fields.

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.

This book provides an overview of the advances on nanostructured celullose from different obtaining forms: natural plants and bacterial microorganisms. It gives the reader an introduction of cellulose focusing in nanosize particles, its potential applications and future perspectives. The potential use of cellulose in the biomedical field is highlighted.