Cellulosic materials, and in particular cellulose nanocrystals (CNCs), show significant promise in many applications where synthetic polymer components are traditionally used. To improve their compatibility, stability, and dispersibility however, surface-modification is often required. Methods to tune CNC properties via surface modification already exist but generally require the use of harsh chemicals, multistep or complex chemistries, as well as tedious purification procedures. We present here a surface modification technique that makes it possible to tune CNC properties through the precipitation of cellulose phosphate oligosaccharides during their isolation or post-production. Oligosaccharides are small chain sugars formed as by-products during the production of CNCs. Within a specific range of degree of polymerization, oligosaccharides are selectively soluble in highly acidic environments but precipitate in more neutral conditions. Leveraging this selective solubility, we have modified anionic sulfated CNCs extracted using sulfuric acid hydrolysis as well as uncharged CNCs produced using both vapour and liquid hydrochloric acid hydrolyses. Following the same straightforward protocol, we show that the precipitation of externally prepared oligosaccharides can be used to improve the redispersibility of dry CNCs, decrease their water binding ability, control their rheological profile, and enhance their colloidal stability. We have also expanded this procedure to precipitate oligosaccharide block copolymers to the CNC surfaces and increased the range of obtainable CNC properties in this way. The nature of this modification method allows it to be easily implemented in CNC manufacturing facilities, without alterations to existing production lines and as such, provides a simple and green alternative for expanded CNC functionality and applications.

Improving cellulose nanocrystal performance via a sugar precipitation modification route

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

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