Improving the flexibility of bamboo mechanical pulp fibers for production of high soft tissue handsheets

Softness is generally seen as one of the most important consumer attributes that can determine the quality of tissue papers. Herein, a green integrated technology, i.e., ultrasonication combined with subsequent cellulase treatment, was developed to improve the flexibility of bamboo CTMP fibers and the softness of obtained handsheets fabricated with treated bamboo CTMP. Ultrasonication can effectively open up the fiber structure by destroying its crystalline structure and expose the fiber surface, which can greatly facilitate the efficiency of cellulase treatment for improved fiber flexibility. It was found that the crystallinity of bamboo pulp decreased from 56.7%-36.2% after ultrasonication (800 W, 40 min) and cellulase (0.3 EGU/g) treatments. Single bamboo fiber flexibility was increased from 2.5 x 2.5 x 10(14) /N.m(2) to 26 x 10(14) /N.m(2) after ultrasonication pretreatment (50 min). The softness and other physical properties of prepared tissue handsheets were also enhanced compared with that of the control and a commercial tissue sample.