This is the first report on the derivation and structures of cellulose nanocrystals from grape skins. Pure cellulose was isolated from chardonnay grape skins at a 16.4% yield by a process involving organic extraction, acid and base dissolutions, and basic and acidic oxidation. The as-extracted cellulose was 54.9% crystalline and microfibrillar. Acid hydrolysis (64-65% H 2SO4 45 °C, 30 min) of grape skin cellulose produced the more crystalline (64.3%) cellulose nanocrystals (CNCs) that appeared mostly as spherical nanoparticles with diameters ranging from 10 to 100 nm and a mean diameter of 48.1 (±14.6) nm as observed by TEM. AFM further disclosed the spherical nanoparticles actually consist of a nano-rod core (seed) surrounded by numerous tiny cellulose fragments as the shell. Interestingly, the spherical core-shell nanoparticles resemble the shape of grape bundles, the starting biomass, may be assembled via interfacial hydrogen bonds.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry