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In recent times, cellulosic materials are witnessing strong interest from both industry and academia for their ability to progress in high-value products with green stamp. Besides the renewability and biodegradability appeal, exceptional properties such as mechanical strength together with toughness are pursued. In the present work, wood fibre networks from eucalyptus Kraft pulp fibres and cellulose nanofibres are combined to produce nanostructured composite networks with outstanding mechanical behaviour. For this purpose, xyloglucan (XG) polymer is adsorbed on cellulose nanofibres (CNF) forming core-shell CNF fibrils in hydrocolloidal suspension which is used to dramatically strengthen wood fibre networks. TEMPO-CNF at two different oxidation levels were coated with XG. The exceptional Young’s modulus and tensile strength found for fibre networks with only 10 wt% CNF was attributed to the fibre-fibre bond strength with better homogeneous stress distribution at the micro/nano scale. The production, mechanical characterization and structure analysis of such bionanocomposites is here presented.

Biobased polymers such as starch and hemicelluloses from wood are of interest for packaging applications, but suffer from limitations in performance under moist conditions. Xyloglucan from industrial tamarind seed waste offers potential, but its Tg is too high for thermal processing applications. Regioselective modification is therefore performed using an approach involving periodate oxidation followed by reduction. The resulting polymer structures are characterized using MALDI-TOF-MS, size-exclusion chromatography, FTIR and carbohydrate analysis. Films are cast from water and characterized by thermogravimetry, dynamic mechanical thermal analysis, dynamic water vapor sorption, oxygen transmission and tensile tests. Property changes are interpreted from structural changes. These new polymers show much superior performance to current petroleum-based polymers in industrial use. Furthermore, this regioselective modification can be carefully controlled, and results in a new type of cellulose derivatives with preserved cellulose backbone without the need for harmful solvents.