Recent developments in the area of ionic liquid electrolytes for cellulose or biomass dissolution has allowed for high-resolution 1H and 13C NMR on very high molecular weight cellulose. This should lead the way for the development of advanced liquid-state quantitative NMR methods for characterisation of nano-structured celluloses, before and after chemical modification. As such, we present the use of tetrabutylphosphonium acetate ([P4444][OAc]):DMSO-d6 electrolytes for 1 and 2D NMR characterisation of nanocelluloses. Special attention is put on poly(methylmethacrylate) (PMMA)-grafted CNCs, as a difficult to analyse model. CPMG T2 and diffusion filtered HSQC was shown to be effective in the discrimination between polymer graft and low molecular weight peaks, arising from the solvent system. Bulk ratios of MMA to AGU, graft lengths and thus graft densities were determined using a combination of quantitative 13C, quantitative HSQC and DOSY NMR analysis of grafts which had been cleaved off using different methods. The results showed that graft density was surprisingly low but molecular weight of grafted PMMA polymer was high. This is not apparent from any other methods of analysis of grafted CNCs.

Liquids NMR toolbox for the analysis of modified nanocelluloses

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.