Quantitative analysis of polymer-grafted cellulose nanocrystals using a ssNMR method on the basis of cross polarization reciprocity relation.

The quantitative analysis of surface modified CNCs is an essential issue for the research and development of the relating materials. Herein, an improved quantitative ssNMR method of rQCPZRC was employed for analyzing CNCs materials. Firstly, CNCs and three PMMA/CNCs mixtures were chosen to evaluate the performance of rQCPZRC method. It was demonstrated that rQCPZRC method is capable to quantify the carbon ratios of CNCs and the components contents of CNCs/PMMA mixtures, with percentage errors on the order of 4%. Furthermore, rQCPZRC method was employed determining the surface grafting proportion of three CNCs-g-PMMA samples. The measured results showed high precision with RSD of 2.1%. Moreover, the experimental time of rQCPZRC was 5.5 h for each sample, notably shorter than the traditional ssNMR method of 146-498 h. Thus, our work recommends rQCPZRC as a tool for quantitative analysis of CNCs and their relating materials.