亚氯酸钠碱性氧化制备纤维素纳米纤丝的研究

以高温自水解处理后的漂白硫酸盐针叶木浆为原料,采用亚氯酸钠(NaClO2)碱性氧化结合高压均质处理制备纤维素纳米纤丝(CNF)。探讨了氧化时间、NaClO2用量、氧化温度、浆浓对氧化后浆料Zeta电位和NaClO2消耗情况等的影响。结果表明,NaClO2氧化后浆料的Zeta电位显著降低,适宜的氧化条件为:氧化时间6 h,NaClO2用量8%,氧化温度95℃,浆浓10%,该氧化条件下浆料的Zeta电位为-37. 6 mV,较氧化前降低了43%。将上述氧化后的浆料进行高压均质处理,得到CNF产品,对其进行了形态尺寸、黏度、Zeta电位和热失重等分析。结果表明,最优氧化条件下得到的纸浆在80 MPa下均质70次,得到尺寸分布良好的CNF产品,其直径主要分布在20~60 nm之间,长径比大于100,CNF胶体的Zeta电位为-42. 3 mV,具有良好的稳定性。

Preparation of Cellulose Nanofibril by Alkaline Oxidation Process with NaClO2

Int he present work,a combined methodi nvolving oxidation and high-pressure homogenization was usedt ot reatt he autohydrolyzed BKP(bleached softwood kraft pulp)for preparing cellulose nanofibril(CNF). Under alkaline condition,NaClO2 was used as an oxidantt o decreaset hez eta potential andt he DP oft he pulp. The oxidationt ime,temperature,NaClO2 dosage,as well ast he pulp consistency were optimized,the zeta potential oft he oxidized pulp,andt he consumption of NaClO2 were determined. The results showedt hatt he zeta potential oft he oxidized pulp was obviously decreased,andt he optimum conditions of oxidation were asf ollows:pulp consistency 10%,NaClO2 dosage 8%,oxidationt ime 6 h,and oxidationt emperature 95℃. Undert hat optimized conditions,the zeta potential oft he oxidized pulp was-37. 6 mV,with a decrease of 43% compairingt ot he autohydorlyzed pulp. The oxidized pulp wast reated using high-pressure homogenizationt o obtain CNF,andt he dimension,viscosity,TG as well ast he zeta potential oft he CNF were analyzed. Ther esults showed thatt he CNF with a good size distribution was prepared whent he oxidized pulp was homogenized under 80 MPaf or 70 t imes. The diameter distribution oft he CNF was mainlyi nt her ange of 20-60 nm,andi tsl ength-to-diameter ratio was over 100. The zeta potential oft he CNF wasa sl owa s-42. 3 mV,indicatingt hatt he CNF hada g ood dispersions tabilityi na queous medium.