Details

Autor(en) / Beteiligte

• Jiang, Feng
• Hsieh, You-Lo

Titel

Chemically and mechanically isolated nanocellulose and their self-assembled structures

Ist Teil von

• Carbohydrate polymers, 2013-06, Vol.95 (1), p.32-40

Ort / Verlag

Kidlington: Elsevier Ltd

Erscheinungsjahr

2013

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• ► Cellulose nanocrystals and nanofibrils isolated from rice straw yielded up to 20%. ► Isolation by acid hydrolysis, blending and TEMPO oxidation was compared. ► Nanocellulose showed distinctly different sizes and surfaces. ► Nanocellulose had cellulose Iβ crystalline structure with crystallinity up to 91%. ► Nanocellulose self assembled into 153–440nm fibers upon rapid freezing and drying. Cellulose nanocrystals (CNCs) and nanofibrils (CNFs) have been isolated from pure rice straw cellulose via sulfuric acid hydrolysis, mechanical blending and TEMPO-mediated oxidation to 16.9%, 12% and 19.7% yields, respectively. Sulfuric acid hydrolysis produced highly crystalline (up to 90.7% CrI) rod-like (3.96–6.74nm wide, 116.6–166nm long) CNCs with similarly negative surface charges (−67 to −57mV) and sulfate contents but decreasing yields and dimensions with longer hydrolysis time. Mechanical defibrillated CNFs were 82.5% crystalline and bimodally distributed in sizes (2.7nm wide and 100–200nm long; 8.5nm wide and micrometers long). TEMPO mediated oxidation liberated the most uniform, finest (1.7nm) and micrometer long, but least crystalline (64.4% CrI) CNFs. These nanocellulose self-assembled into submicron (153–440nm wide) fibers of highly crystalline (up to 90.9% CrI) cellulose Iβ structure upon rapid freezing (−196°C) and freeze-drying. The self-assembling behaviors were analyzed based on nanocellulose dimensions, specific surfaces and surface chemistries.