HNO3/H3PO4-NANO2 mediated oxidation of cellulose -: preparation and characterization of bioabsorbable oxidized celluloses in high yields and with different levels of oxidation
HNO3/H3PO4-NANO2 mediated oxidation of cellulose -: preparation and characterization of bioabsorbable oxidized celluloses in high yields and with different levels of oxidation
复制标题
DOI：
10.1016/s0144-8617(01)00290-9
复制
发表时间：
2002-06-01
影响因子：
11.2
通讯作者：
Yang, TR
中科院分区：
文献类型：
--
作者：
Kumar, V;Yang, TR
研究了纤维素与HNO_3/H_3PO_4-NaNO_2（2：1：1.4，v/v/%w）的混合物在室温下反应不同时间间隔以制备氧化纤维素（OC），其是一种生物相容性和生物可吸收的聚合物。结果表明，随着反应时间的增加，OC的羧基含量增加，对应于约8.0，13.4，17.4和18.4%的羧基含量后12，24，36，和48小时，分别。OC的产率在75 - 81%之间。在反应中使用不同比例的HNO 3和H3 PO 4（11：1、4：1、2：1、1：1、1：2和1：4; v/v）对OC产物的羧基含量和产率没有显著影响。所生产的所有产品均为低结晶度（27-35%）纤维材料。纤维长度随反应时间的延长而减小。球磨24小时后，纤维的长度进一步减小，产物转化为由小纤维和聚集的非纤维颗粒组成的细粉末。在12、24和48小时的反应持续时间后产生的OC产物的聚合度（DP）分别为81、63和53。球磨24小时后，相应值分别变为57、51和46。然而，在球磨之后没有注意到产物的结晶度的显著变化。TGA结果显示OC产物的热稳定性低于纤维素。随着羧基含量的增加，降解温度降低。总之，结果表明，低结晶度OC产品可以成功地制备在高产率和不同水平的羧基含量从纤维素通过处理与HNO 3/H3 PO 4-NaNO 2的混合物。(C)2002爱思唯尔科技有限公司版权所有。
The reaction of cellulose with a mixture of HNO3/H3PO4-NaNO2 (2:1:1.4, v/v/%w) at room temperature for different time intervals has been investigated to produce oxidized cellulose (OC), a biocompatible and bioresorbable polymer. The results revealed an increase in carboxyl content of OC with increasing reaction time, corresponding to about 8.0, 13.4, 17.4 and 18.4% carboxyl content after 12, 24, 36, and 48 h, respectively. The yield of OC ranged between 75 and 81%. The use of different ratios of HNO3 and H3PO4, (11:1, 4:1, 2:1, 1:1, 1:2, and 1:4; v/v), in the reaction had no significant effect on the carboxyl content and yield of the OC products. All products, as produced, were low crystallinity (27-35%) fibrous materials. The length of fibers decreased with increasing reaction time. After ball milling for 24 h, the length of fibers further decreased and products converted into a fine powder consisting of small fibers and aggregated non-fibrous particles. The degrees of polymerization (DP) of the OC products produced after 12, 24, and 48 h of reaction duration were 81, 63, and 53, respectively. After ball milling for 24 h, the corresponding values changed to 57, 51 and 46. However, no significant change in the crystallinity of the products was noted after ball milling. The TGA results showed the OC products to be less thermally stable than cellulose. The degradation temperature appears to decrease with increasing carboxyl content. In conclusion, the results show that the low crystallinity OC products can be successfully prepared in high yields and with different levels of carboxyl content from cellulose by treatment with a mixture of HNO3/H3PO4-NaNO2. (C) 2002 Elsevier Science Ltd. All rights reserved.