Fiber Morphology and Structure Changes with Ultrasonic Treatment in Bleaching Process

摘要

Tank model ultrasonic and probe model ultrasonic treatments on pulp fiber of Triploid Populus Tomentosa were studied. The fiber length and cellulose crystallinity were investigated, which were tested by fiber length and width tester and X-ray powder difrraction(XRD) respectively. The best bleaching results were achieved with 30 min tank model ultrasonic treatment at the temperature of 50 ° C. Pulp brightness improved as time was extended and temperature increased. Fiber length had no significant change after ultrasonic wave treatments, which indicated that cellulose supramolecular structures were not destroyed. With ultrasonic treatment, partial fibrillations were observed, S1 layer were damaged and S2 layer were exposed. Probe model ultrasonic treatment was more significant. Cellulose crystallinities firstly increased and then decreased as ultrasonic treatment time changed.