NaOH溶液预处理结合超声制备微纤化纤维素的研究
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摘要
应用Na OH溶液与超声处理进行微纤化纤维素的制备研究。粒径分析表明,Na OH溶液造成纤维素有限溶胀和溶解,后续超声处理后的纤维素粒径指标D_([4,3])和D_([3,2])明显减小。电镜观察发现,超声空化作用促使纤维素微纤束直径和长度减小;经过化学预处理(10%Na OH,70℃,1h)和超声作用,比单一超声处理时纤维素微纤束直径尺寸缩减更加明显。电镜观察结果说明Na OH溶液预处理造成纤维素溶胀和解离,而超声空化强化了纤维素微纤束的剥离与分解。单一超声处理(200 W,15 min)不改变纤维素的结晶度和热稳定性。10%Na OH溶液预处理(70℃,1 h)和超声处理(200 W,15 min)后,纤维素的结晶度下降,但热稳定性几乎不发生变化。
Preparation of microfibrillated cellulose by using ultrasonication combined with NaOH solution pretreatments is presented. The particle sizes of the cellulose samples before and after treatment were analyzed. It was showed that limited swelling and dissolution of cellulose were induced by NaOH solution, and particle size indices D[4,3] and D[3,2] of cellulose were decreased obviously combing with ultrasonic treatment. SEM images showed that the diameter and length of cellulose microfibril bundles reduced by the ultrasonic cavitation, and the diameter of cellulose microfibril bundles decreased more significantly after NaOH pretreatment(10% NaOH, 70℃,1 h) and ultrasonication. The SEM results illustrated that pretreatment with NaOH solution could cause swelling and dissociation of cellulose, while ultrasonic cavitation enhanced the removal and separation of cellulose microfibrils. It was not altered in crystallinity and thermos stability of cellulose after ultrasonication(200 W,15 min). Combined with the use of ultrasonic treatment(200 W, 15 min) and 10%NaOH pretreatment, the crystallinity of cellulose decreased and its thermal stability was hardly changed.
Preparation of microfibrillated cellulose by using ultrasonication combined with NaOH solution pretreatments is presented. The particle sizes of the cellulose samples before and after treatment were analyzed. It was showed that limited swelling and dissolution of cellulose were induced by NaOH solution, and particle size indices D[4,3] and D[3,2] of cellulose were decreased obviously combing with ultrasonic treatment. SEM images showed that the diameter and length of cellulose microfibril bundles reduced by the ultrasonic cavitation, and the diameter of cellulose microfibril bundles decreased more significantly after NaOH pretreatment(10% NaOH, 70℃,1 h) and ultrasonication. The SEM results illustrated that pretreatment with NaOH solution could cause swelling and dissociation of cellulose, while ultrasonic cavitation enhanced the removal and separation of cellulose microfibrils. It was not altered in crystallinity and thermos stability of cellulose after ultrasonication(200 W,15 min). Combined with the use of ultrasonic treatment(200 W, 15 min) and 10%NaOH pretreatment, the crystallinity of cellulose decreased and its thermal stability was hardly changed.
引文
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[16]Dinand E,Vignon M,Chanzy H,et al.Mercerization of primary wall cellulose and its implication for the conversion of celluloseⅠ→celluloseⅡ[J].Cellulose,2002,9(1):7-18.
[2]Spence K L,Venditti R A,Rojas O J,et al.Water vapor barrier properties of coated and filled microfibrillated cellulose composite films[J].BioResources,2011,6(4):4370-4388.
[3]Chakraborty A,Sain M,Kortschot M.Cellulose microfibrils:A novel method of preparation using high shear refining and cryocrushing[J].Holzforschung,2005,59(1):102-107.
[4]Taniguchi T,Okamura K.New films produced from microfibrillated natural fibres[J].Polymer International,1998,47:291-294.
[5]Iwamoto S,nakagaito A N,Yano H.Nano-fibrillation of pulp fibers for the processing of transparent nanocomposites[J].Applied Physics A-Materials Science&Processing,2007,89(2):461-466.
[6]Chen W S,Yu H P,Liu Y X,et al.Individualization of cellulose nanofibers from wood using high-intensity ultrasonication combined with chemical pretreatments[J].Carbohydrate Polymers,2011,83(4):1804-1811.
[7]Chen W S,Yu H P,Liu Y X,et al.Isolation and characterization of cellulose nanofibers from four plant cellulose fibers using a chemical-ultrasonic process[J].Cellulose,2011,18(4):433-442.
[8]P??kk?M,Ankerfors M,Kosonen H,et al.Enzymatic hydrolysis combined with mechanical shearing and high-pressure homogenization for nanoscale cellulose fibrils and strong gels[J].Biomacromolecules,2007,8(6):1934-1941.
[9]Henriksson G,Nutt A,Henriksson H,et al.Endoglucanase 28(Cell 12A),a new Phanerochaete chrysosporium cellulose[J].European Journal of Biochemistry,1999,259(1):88-95.
[10]Janardhnan S,Sain M M.Isolation of cellulose microfibrils-an enzymatic approach[J].Bioresources,2007,1(2):176-188.
[11]Habibi Y,Lucia L A,Rojas O J.Cellulose nanocrystals:Chemistry,self-assembly and applications[J].Chemical Reviews,2010,110(6):3479-3500.
[12]项秀东,万小芳,李友明,等.超声处理对制备竹浆微纤化纤维素的影响[J].中国造纸,2015,34(2):9-13.
[13]段玲,于伟东.黄麻微纤化纤维素的制备及特征分析[J].应用化工,2015,44(11):2014-2017.
[14]张俊华,宋海农,林鹿.高压均质化处理对微纤化纤维素性质的影响[J].纤维素科学与技术,2009,17(3):7-11.
[15]郭婷,裴莹,郑学晶.预处理对高压均质法制备微纤化纤维素结构与性能的影响[J].功能材料2016,47(1):1049-1052.
[16]Dinand E,Vignon M,Chanzy H,et al.Mercerization of primary wall cellulose and its implication for the conversion of celluloseⅠ→celluloseⅡ[J].Cellulose,2002,9(1):7-18.