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.

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Cellulose and chitin nanoparticles were isolated from bagasse, and shrimp shells, respectively. The nanoparticles were characterized by optical, electron, and atomic force microscopy, solid-state NMR spectroscopy, and X-ray powder diffraction methods. The nanoparticles were then topochemically modified with maleate ester groups in the case of cellulose, and medium-to long-chain aliphatic esters in the case of chitin. The derivatized nanoparticles were further characterized with spectroscopic techniques and subsequently melt processed with elastomeric thermoplastics to create nanocomposites having a significant improvement in the mechanical properties relative to the neat thermoplastics. IntroductionSince the start of the 20th century, polymeric materials have begun replacing conventional materials such as wood and metals in a diverse array of industries. Today, polymers have a ubiquitous presence in our society. They are often mixed with fillers or fibers as a versatile route to fabricating advanced materials with improved thermal and mechanical properties, to form what are called polymer composites. Typically, polymer composites have greater mechanical strength and stiffness than any of their individual components, and are used in a variety of applications. Historically, polymer composites consisted of synthetic thermoset resins reinforced with inorganic filler materials like glass fiber. TheThe Nanoscience and Technology of Renewable Biomaterials Edited