Nanofibrillated cellulose from Alfa, Eucalyptus and Pine fibres: Preparation, characteristics and reinforcing potential

Cellulose fibres from Alfa (Alfa tenassissima), Eucalyptus and Pine pulp were fibrillated into nanosized fibrils using the homogenization process. To facilitate the fibrillation process, fibres were previously oxidised under neutral conditions to bring the carboxyl content up to 500 μmol/g. Comparison of light transmission and viscosity measurements of the ensuing gels showed that Eucalyptus and Pine fibres were more easily-fibrillated, with a yield in nanosized fibrils exceeding 90% after several passes at 600 bar, than Alfa fibres, which exhibit higher resistance to the fibrillation process. This difference in behaviour was ascribed to the higher crystallinity degree of the Alfa fibres. The morphology of the nanofibrillated cellulose (NFC) from the different fibres using FE-SEM observation revealed nanosized fibrils with widths from 5 to 20 nm, roughly the same for the three types. The reinforcing potential of the ensuing three nanofibrillated cellulose was investigated using dynamic mechanical analysis (DMA) from measurements carried out on nanocomposite films prepared by casting a mixture of NFC suspension and a commercial latex of poly(styrene-co-butyl acrylate).