(农药-纤维素)酯类缓释剂的合成及水解性能的研究

以纤维素和羧甲基纤维素作为载体,将带有羧基的2,4-二氯苯氧乙酸和带有羟基的五氯酚等农药分别与它们相结合。制备了分子链上键合有农药的高聚物。进而通过水解试验其释放农药的性能。结果表明:农药在纤维素链上的替代度可以通过控制反应条件加以调节,所制备的键合有农药的高聚物可以自行水解而缓慢地释放出农药,并随水解时间的延长,释放速度逐渐减慢。     

稻草制取多羟基化合物的探讨

本文探讨将农业废料稻草纤维素水解、发酵,制多羟基化合物的原理及方法。     

棉纤维素/N-甲基吗啉-N-氧化物—水合物(NMMO·H_2O)溶液的流变性能

利用Instron3211型毛细管流变仪和Instron3325型流变力学谱仪研究了棉纤维素/N-甲基吗啉-N-氧化物一水合物(NMMO·H_2O)溶液流变性能,讨论了剪切速率、温度和溶液中的纤维素的质量分数对棉纤维素/NMMO·H_2O溶液流变性能的影响,计算了不同质量分数溶液的粘流活化能。     

In vitro and in vivo investigation of bacterial cellulose dressing containing uniform silver sulfadiazine nanoparticles for burn wound healing

Silver sulfadiazine(SSD) particles in homogeneous dispersion state were prepared by an ultrasonic method and then nano- and microparticles were separated using centrifugation. SSD particles with narrow size distribution were impregnated with bacterial cellulose(BC) to produce BC–SSD composite membrane used as burn wound dressing. A scanning electron microscope(SEM) was used to examine the surface morphology of BC–SSD membranes. The incorporation of SSD in BC–SSD was confirmed by X-ray diffraction(XRD). Antimicrobial tests in vitro indicated that BC–SSD showed excellent antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The effects of BC–SSD on burn wound healing were assessed by rat models. The comparative study confirmed that the wound treated with BC–SSD showed high healing rate. The bacteria count in BC–SSD group was far less than control group. Histological analysis showed that epithelialization progressed better in wound treated with BC–SSD. These values demonstrated that the BC–SSD composite membrane could be a promising wound dressing for burn.     

球形纤维素吸附特性的研究(英)

对两种商业用球形胶质纤维素和它的低孔隙的胶质改性物的吸附特性进行了研究．得到了他们的孔隙率、排斥分离尺寸和描述微粒分配平衡系数的模型．特别是,发现他们中的一种的微粒分配平衡系数可用简单的RandomPlane模型来描述．     

Cellulose nanocrystals as green fillers to improve crystallization and hydrophilic property of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

The green nanocomposites of poly(3-hydroxybutyrate-co-3-hyd roxyvalerate) (PHBV) with various cellulose nanocrystals (CNCs) contents were prepared by solution casting method. Th e effects of CNCs on the crystallization behavior, spherulitic morphology, crystal structure and hydrophilic property of PHBV were studied by differential scanning calorimeter (DSC), polarized optical microscope (POM), wide-angle X-ray diffraction (WAXD) and static water contact angle measurement. It is found that the CNCs act as an effective nucleation agent for crystallization of PHBV, inducing an increase in the melt crystallization tempera ture of the nanocomposites. A study of the non-isothermal crystallizatio n kinetics further illustrated that overall crystallization rate of PHBV in the nanocomposites was faster than that of neat PHBV, but exhibited a decrease in the crystallinity and the spherulite size of PHBV. Furthermore, the contact angle decreased from 60.1° for neat PHBV to 32.5° for the nanocomposites with 10% CNCs (mass fraction).     

纤维素衍生物的制备与应用前景展望

介绍了近年来报导的具有代表性的几种纤维素衍生物的制备和用途，综述了采用化学修饰方法，对纤维素进行化学变性的研究进展。     

纤维素月桂酸酯的制备及其结构和性能表征

在均相体系下,以微晶纤维素为原料,以月桂酰氯为酯化试剂,吡啶为催化脱酸剂制备纤维素月桂酸酯,研究了酯化试剂用量、反应温度、反应时间对纤维素月桂酸酯取代度和得率的影响,确定了合成纤维素月桂酸酯的适宜条件为：酰氯用量16 mol（基于纤维素上羟基摩尔数）,反应温度100 ℃,反应时间10 h,此时纤维素月桂酸酯的得率为3108 %,取代度达248。采用红外光谱和核磁共振氢谱对纤维素月桂酸酯的结构进行了表征,证明了纤维素已发生酯化反应。接触角实验结果表明,所得纤维素月桂酸酯的接触角随取代度增加而增加,取代度>16时产物具有极强的疏水性。     

用羟乙基纤维素(HEC)改善短碳纤维的分散性

实验采用HEC作为分散剂,采用旋转搅拌方式在其水溶液中对短碳纤维进行分散.对HEC的质量浓度、搅拌速度及搅拌时间对短碳纤维分散率的影响进行了研究,通过SEM表征了短碳纤维在分散前后的镀铜效果.结果表明:短碳纤维经HEC分散后,分散性明显改善.HEC在水中的浓度要适中,过高或过低,短碳纤维的分散效果不显著;搅拌速度的提升和分散时间的延长会提高短碳纤维的分散率.当HEC质量浓度为1.5 g/L,搅拌速度为800 r/min,搅拌时间为30 min时,短碳纤维的分散率达到98%.分散处理过的短碳纤维镀铜层更加完整均匀,无黑心现象.     

气相色谱法测定醋酸纤维滤棒中的三醋酸甘油酯

以异丙醇为萃取剂,正十七烷为内标,采用气相色谱法测定了醋酸纤维滤棒中的三醋酸甘油酯含量.该法的相对标准偏差(RSD)为1.74%,平均回收率为98.83%,适用于醋酸纤维滤棒中三醋酸甘油酯的快速分析.