Modulation of the Nanostructural Characteristics of Cellulose Nanowhiskers via Sulfuric Acid Concentration

Abstract

CELLULOSE nanowhiskers (CNW) were synthesized from native cotton cellulose as per the acid hydrolysis methods. Thus Egyptian cotton slivers, after being purified, were subjected to three sulfuric acid concentrations, viz. 55%, 60% and 65% (w/w) at 60
 
0C for 60 min. The yield of CNW attains values of 65%, 57% and 50%, respectively. The amorphous regions along with thinner as well as shorter crystallites spreaded throughout the cellulose structure are digested by the acid leaving CNW suspension. The latter could be freeze-dried and CNW powder could be achieved. A thorough investigation pertaining to nanostructural characteristics of CNW was performed. These characteristics could be monitored using TEM for morphology, sizes and size distribution, XRD for degree of crystallinity and crystalline structure, FTIR spectra for following the changes in functionality and TGA for studying the sample weight loss as a function of temperature. Based on the results obtained CNW prepared using 60% w/w sulfuric acid are nominated as the best candidate within the range studied in the area of reinforcement by virtue of their salient features.