[Seminar] Liquids NMR toolbox for the analysis of topochemically modified cellulose, nanocellulose and cellulose with low degrees of substitution

Seminar

Title: Liquids NMR toolbox for the analysis of topochemically modified cellulose, nanocellulose and cellulose with low degrees of substitution

Speaker: Alistair W. T. King

Affiliation: Adjunct Professor in Organic Chemistry at the University of Helsinki

Host: Cristina Silva Pereira Lab

Abstract: 

Celluloses, which are chemically modified to low degrees, through heterogeneous or homogeneous processes are typically insoluble in most molecular solvents. An important example where this occurs is in the topochemical modification of nanocelluloses, to add functionality or aid in compatibilisation with different media, or for dispersion in different solvents. Therefore, most analytics for these materials are based on solid-state analyses (solid-state NMR, XPS, IR, elemental analysis etc..). Thus, there is need for a general liquids-NMR method for analysis of these celluloses. As such, I would like to present our recent results on the use of ionic liquid electrolytes for qualitative and quantitative analysis modified cellulosics. A PMMA-grafted cellulose nanocrystal is analysed as a difficult model to study. We make use of 1D and 2D NMR for assignment and quantification but also the relatively easy to implement translational diffusion-editing to allow for attenuation of the fast-diffusing species (ionic liquid signals) from the polymeric, thus, enhancing resolution of signals. Furthermore, the solubility of other biopolymers is also tested, including that of silkworm silk, allowing for wider application beyond cellulosics.

Short CV:

Alistair W. T. King is currently an Adjunct Professor in Organic Chemistry at the University of Helsinki. He works in the general areas of synthetic organic chemistry, physical organic chemistry, ionic liquids and biomass processing. However, his main area of expertise is in the design of direct-dissolution solvents, and conditions, for processing and analysis of cellulose. This work has led to the development of a new lyocell-type fibre-spinning process, termed as IONCELL-F (https://youtu.be/AGFDPyzN1C8), which is currently close to piloting. In addition, he has a keen interest in dispersion and modification of nanocellulose in novel solvents and his work heavily involves the use and development of NMR techniques for understanding cellulose chemistry and wood structure, in general.