CHARACTERIZATION OF CELLULOSE NANOCRYSTALS SUSPENSIONS

MUCCI, VERÓNICA; ARANGUREN, MIRTA; BUFFA, JUAN MANUEL

Los Cocos

Simposio; Simposio Argentino de Polímeros; 2017

Cellulosenanocrystals (CNCs) are rod-like, highly crystalline particles, obtained fromcommercial microcrystalline cellulose by acid hydrolysis. Because of thehigh-aspect ratio and the high amount of hydroxyl groups in the surface, thoseparticles auto-assembly in different phases depending on the concentration. Itis well known that the ordering in the aqueous suspension modify itsrheological as well as light scattering behaviors, which depend mainly on thesize and shape of the domains formed. Inthis work, we present the rheological characterization as well as the staticlight scattering results of aqueous suspensions prepared with different CNCs concentrations.CNCs were also superficially modified by TEMPO-mediated oxidation, a greenprocedure to selectively oxidize the primary carbon of the glycosyl unit,changing the superficial charge of the particles, and therefore the domainsformed. Other approach to alter the ordering will be to use additives, such asNaCl or surfactants, modifying the environment of the nanocrystals and itsinteractions with each other when forming domains [1]. The work is devoted to the study of the phasediagram that investigate on the existence or coexistence of isotropic andanisotropic phases (nematic and quiral nematic). The light scattering resultswill be complemented by the rheological characterization of the suspensions, inorder to determine the size, shape, and number of domains in each suspensionand the predominant phase, and how those factors impact on the behavior of thesuspension during rotational rheometry essays [2].  Theauthors acknowledge the funding from CONICET (PIP 0866), ANPCyT (PICT 140732)and UNMdP (15/G430-ING436/15).