Nanosized cellulose fibrils as stabilizers of emulsions

Cellulose fibres constitute an abundant, renewable and biodegradable raw material that can be manufactured by sustainable technology. Microfibrillar cellulose (MFC) is a novel nanosized material manufactured from cellulose fibres. Pure MFC will be prepar ed by disintegration of wood pulp. To obtain a more uniform size distribution of MFC is believed to be a crucial point in this respect. The MFC morphology will be characterized by AFM, SEM and TEM. Hydrophobized MFC wil be prepared, both in non-aqueous systems and in water. The degree of surface substitution will be determined by XPS and, possibly, NMR, using previously developed methodology. The structure of MFC layers formed at the oil/water interface will be investigated by SEM imaging of freeze-frac tured emulsions and measurements of surface energy and elasticity. Emulsion stability will be investigated. Particular attention will be paid to phase inversion from w/o to o/w as a function of oil:water ratio and MFC-hydrophobicity. Drop size distributi ons of the emulsions will be measured by microscopy, dynamic light scattering and/or NMR. Emulsion viscosity will be investigated as a function of oil/water ratio, concentration of MFC and MFC hydrophobicity. For concentrated emulsions, elastic and viscou s modules (G', G'') will be determined. The viscoelastic properties of layers of MFC at the o/w interface might also be investigated. The possibility of using MFC to stabilize water-in-diesel oil emulsion for fuel applications will be investigated. Also , the possiblity of using MFC as a multifunctional additive to paint will be investigated. Critical findings may be patented or kept unpublished for a limited time. A close contact with the mills associated in the project will be given high priority, and the project results will be made available for future industrial exploitation. Other results of the project will be published continuously throughout the project.