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Nanocellulose Crystals -a promising biomaterial- investigated with Small Angle Neutron Scattering

Lundi 7 septembre 2015 10:30 - Duree : 1 heure
Lieu : Science Building Seminar Room - ESRF - 71 avenue des Martyrs - Grenoble

Orateur : Martin UHLIG (Technical University, Berlin, Germany)

Cellulose is an abundant and versatile biomaterial. Many different interesting materials can be made from it, with Nanocellulose Crystals (NCC) being the most prominent one. Due to their high stiffness, high aspect ratio, water solubility and low cost NCCs are interesting for a lot of applications e.g. in nanocomposites [1]. The most commonly produced NCC is sulfuric acid hydrolyzed NCC-SO3H. The repulsive interaction of the sulfate groups on the surface stabilize NCC-SO3H in aqueous solution. However, salt addition can easily screen those repulsions and induce coagulation. Modifying the NCC, e.g. by carboxylation [2] (NCC-COOH) overcomes the problem of aggregation at low ion concentrations. This contribution focuses on the characterization of modified NCCs using Small Angle Neutron Scattering (SANS), Dynamic Light Scattering (DLS) and Transmission Electron Spectroscopy (TEM). DLS is used to investigate the increase in stability of modified NCC compared to unmodified one. SANS and TEM are used to investigate the change in shape and structure of modified NCCs. NCCs both with sulfate groups and carboxylic groups have been studied. Aqueous NCC dispersions were measured at various NCC and polymer concentrations and different polymer molecular weights. SANS data showed a structure peak at low q for (several) higher concentrated samples. Closer data analysis revealed a tendency of the rods to aggregate into 2D-stacks of several rods. The size parameters of these aggregates were extracted, using a 2-step fitting model.

References

[1] Y. Habibi et al., Chem. Rev. 110 (2011) 3479-3500

[2] M. Salajková et al., J. Mater. Chem. 22 (2012) 19798-19805

Contact : tellier@ill.fr

Discipline évènement : (Biologie / Chimie) - Discipline évènement : (Physique)
Entité organisatrice : (ILL)
Nature évènement : (Séminaire)
Evènement répétitif : (General ILL Seminar - College 9)
Site de l'évènement : Polygone scientifique

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