α-Chitin Nanocrystals Prepared from Shrimp Shells and Their Specific Surface Area Measurement

Alpha-chitin was isolated from shrimp shells. The chitin was subjected to extensive treatments of acid hydrolysis and mechanical disruption to yield nanocrystals. The goal of this article is to characterize alpha-chitin nanocrystals produced from shrimp shells in regard to crystallite properties and the specific surface area of the chitin nanoparticles. X-ray diffraction data indicate an increase in chitin crystallinity after hydrolysis, as less-ordered chitin domains are digested. Line broadening data were used to measure crystallite size and particle size in the hydrolyzed chitin nanocrystals. Dye adsorption with Congo red was used to measure the specific surface area of the particles, indicating values near 350 m2/g. This value was supported with calculations derived from X-ray crystallite size measurements. Particle surface area measurements were compared with similarly prepared cellulose nanocrystals.