Microfibrillated cellulose with enhanced properties and methods of making the same

A method for re-dispersing dewatered, partially dried or essentially dried microfibrillated cellulose, the method comprising the steps of:

• (a) adding a quantity of a suitable dispersing liquid to a tank having at least a first and a second inlet and an outlet, wherein the tank further comprises a mixer and a pump attached to the outlet;
• (b) adding a quantity of dewatered, partially dried or essentially dried microfibrillated cellulose to the tank through the first inlet in sufficient quantity to yield a liquid composition of microfibrillated cellulose at a desired solids concentration of 0.5 to 5% fibre solids;
• (c) mixing the dispersing liquid and the dewatered, partially dried or essentially dried microfibrillated cellulose in the tank with the mixer to partially de-agglomerate and re-disperse the microfibrillated cellulose to form a flowable slurry;
• (d) pumping the flowable slurry with the pump to an inlet of a flow cell, wherein the flow cell comprises a recirculation loop and one or more sonication probe in series and at least a first and a second outlet, wherein the second outlet of the flow cell is connected to the second inlet of the tank, thereby providing for a continuous recirculation loop providing for the continuous application of ultrasonic energy to the slurry for a desired time period and/or total energy, wherein the flow cell comprises an adjustable valve at the second outlet to create back pressure of the recirculated slurry, further wherein the liquid composition comprising microfibrillated cellulose of step (c) is continuously recirculated through the recirculation loop at an operating pressure of 0 to 4 bar and at a temperature of 20° C. to 50° C.;
• (e) applying an ultrasonic energy input to the slurry of 200 to 10,000 kWh/t continuously by the sonication probe at a frequency range of 19 to 100 kHz and at an amplitude of up to 60%, up to 100% or up to 200% to the physical limitations of the sonicator used for 1 to 120 minutes;
• (f) collecting the re-dispersed suspension comprising microfibrillated cellulose with enhanced tensile strength and/or viscosity properties from the first outlet of the flow cell in a suitable holding vessel.