Cellulose nanosheets formed by mild additivefree ball milling
Ball milling. One gram of cellulose was milled in a planetary ball mill (Pulverisette 7, Fritsch, Germany), using 45 mL zirconia pot with 7 zirconia balls of 15 mm diameter. It took 5 min for rest after every 20 min of operation to release the heat. Milling time was 1 h, 2 h, 4 h, 8 h, 12 h, 24 h at 150 rpm. Characterization