degree between 0 00001 and 1 0 preferably 0 00001 and 0 4 the cationization is preferably performed by the introduction of at least one ammonium function most preferred a secondary tertiary or quaternary ammonium function or a mixture thereof into the derivative it is intended throughout the present description that the expression u201c mechanical comminution device u201d means any device which may be suitable for providing a nanocellulose a microfibrillated cellulose as set out above and said device may e g be a refiner a fluidizer a homogenizer or a microfluidizer according to a preferred embodiment of the first aspect of the present invention there is provided a method wherein said cellulose fibres cellulose material is present in the form of a pulp which may be chemical pulp mechanical pulp thermomechanical pulp or chemi thermo mechanical pulp cmp or ctmp said chemical pulp is preferably a sulphite pulp or a kraft pulp the pulp may consist of pulp from hardwood softwood or both types the pulp may e g contain a mixture of pine and spruce or a mixture of birch and spruce the chemical pulps that may be used in the present invention include all types of chemical wood based pulps such as bleached half bleached and unbleached sulphite kraft and soda pulps and mixtures of these the consistency of the pulp during manufacture of nanocellulose may be any consistency ranging from low consistency through medium consistency to high consistency the preferred concentration of amphoteric cellulose derivative is approximately 0 02 4 w w calculated on the dry weight of the fiber material a more preferred concentration is approximately 0 04 2 w w and the most preferred concentration of additive is approximately 0.