酶预处理结合研磨法对桉树纸浆纤维微/纳纤丝微观形貌的影响

Effect of cellulose hydrolysis and mechanical grinding on morphology of eucalyptus pulp micro/nano fibers

【目的】探究酶用量、酶解时间及研磨时间对制备的桉树纸浆纤维微/纳纤丝微观形貌及性能的影响。【方法】以桉树纸浆为原料,经不同的酶用量(20,40,60和80ECU/g)和酶解时间(2,4,6和8h)预处理后,用研磨法制备纤维素微/纳纤丝,利用扫描电镜、X射线衍射仪对制备的微/纳纤丝进行表征。【结果】在酶解时间为6h的条件下,当酶用量由20ECU/g增加至80ECU/g时,研磨制备的微/纳纤丝直径由143.89nm减小至52.21nm;在酶用量为60ECU/g的条件下,当酶解时间由2h增加至8h时,研磨制备的微/纳纤丝直径由131.23nm减小至43.73nm。酶处理后的纤维及研磨处理后的纤维均保持了天然纤维的Ⅰ型结构,结晶度分别比纸浆纤维(59.21%)提高11.68%和8.31%,所制备的微/纳纤丝的结晶度为67.52%。【结论】酶预处理可以有效降低微/纳纤丝的制备时间,减少能耗;随着酶用量及酶解时间的增加,微/纳纤丝直径逐渐减小;纤维素酶可降解纤维素部分非结晶区并使纤维润胀。

【Objective】The research studied the effects of enzyme dosage,hydrolysis time and grinding time on structural properties of micro/nano fibers.【Method】Eucalyptus pulp was chosen as starting materials and micro/nano fibers were isolated with cellulose hydrolysis and mechanical grinding.The effects of different enzyme dosages（20,40,60,and 80ECU/g）and hydrolysis times（2,4,6and 8h）were investigated.The properties of micro/nano fibers were characterized using scanning electron microscopy（SEM）and X-ray diffractometer（XRD）.【Result】The diameter of fibril decreased from 143.89 nm to 52.21 nm when the amount of enzyme increased from 20ECU/g to 80ECU/g under same hydrolysis times（6h）.When the amount of enzyme was 60ECU/g and the hydrolysis times increased from 2hto 8h,the diameter decreased from 131.23 nm to 43.73 nm.The micro/nano fiber with enzymatic and grinding processes maintained type I structure the crystallinities increased by 11.68% and 8.31% compared to pulp fibers（59.21%）.The crystallinity of obtained micro/nano fiber was 67.52%.【Conclusion】Enzyme pre-treatment could effec-tively reduce the preparation time and energy consumption.The micro/nano fiber diameter decreased with the increase of enzyme concentration and reaction time.The cellulose enzyme could decompose amorphous regions between the crystalline micro-fibrils and make fibers swell.