Polymeric sodium alginate interpenetrating network beads for the controlled release of chlorpyrifos

Novel polymeric sodium alginate (Na‐Alg) interpenetrating network (IPN) beads have been prepared by crosslinking Na‐Alg blend with gelatin (GE) or egg albumin (EA) using glutaraldehyde (GA) as the crosslinking agent. These beads were used for the controlled release of chlorpyrifos. The swelling experiments were performed in water at different temperatures, and these data were used to calculate the molecular mass (M_C) between crosslinks as well as diffusion coefficients. Diffusion coefficients calculated from desorption data were lower by about two orders of magnitude than those calculated from sorption results. Higher values of M_C were obtained for the gelatin‐based IPNs than the neat Na‐Alg and egg albumin‐based matrices. Size of the beads did not vary significantly either by the network or by increasing the exposure time to the crosslinking agent. The scanning electron microscopy (SEM) was used to understand the surface characteristics of the beads. Differential scanning calorimetry (DSC) indicated a molecular level dispersion of chlorpyrifos in the polymer matrix. The percentage entrapment efficiency showed a dependence on the type of network polymer as well as time of exposure to the crosslinking agent. The encapsulation efficiency decreased with an increase in time of exposure to the crosslinking agent. In vitro release experiments have been performed to follow the release kinetics of chlorpyrifos from the matrices. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 911–918, 2002     

复凝聚法制备农药微胶囊剂的研究

以壳聚糖和木质素磺酸钠为囊材,以三氟氯氰菊酯为囊芯,采用复凝聚法制备了微胶囊。考察了壳芯质量比、温度、搅拌速度、对包药率的影响,确定最佳工艺条件,并对其性能进行了研究。     

Wettability and surfactivity of sodium phosphate surfactants in strong alkali solutions

The wettability, surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate, sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied. A complex alkali resistant phosphate surfactant with good permeability was prepared. The wettability of surfactants was investigated by measuring the immersion time, sinking time and capillary effects of nature cotton grey fabric in NaOH solutions. The surfactivity of the surfactants was characterized by measuring the surface tension. The effect of the complex on the surface appearance of cotton grey fabric was also investigated with a scanning electron microscope (SEM). The results show that all the surfactants exhibit good wettability for cotton grey fabric in 0.5–5.0 mol/L of NaOH solutions, the complex system exhibits better wettability in 5.0–7.0 mol/L of NaOH solutions, in comparison with either corresponding single surfactant component employed, and wettability is well correlative with the surfactivities of the surfactant. SEM images indicate that the cotton grey fabric is well wetted by the alkaline surfactant solution and the quality of fabric is improved.     

Effects of dispersant on performance of Ni-Zn batteries

A new additive of sodium hexametaphosphate (SHMP) was introduced to the paste of zinc electrode, with the purpose of preventing the zinc active materials from agglomerating and improving the stability of batteries. The properties of the zinc electrodes were characterized by scanning electron microscopy (SEM), constant current charge/discharge measurement, self-discharge test and hydrogen collection experiment. The photographs of zinc electrode show that SHMP can significantly break up the agglomeration, uniformize the particle distribution and increase the surface area, which are advantageous to improve the electrochemical performance of zinc electrode. The experimental battery shows a 97 times cycling life and a 30.2% remaining capacity after 4 d storage. The hydrogen collection experimental results indicate that the SHMP can decrease the ratio of hydrogen evolution. Therefore, the corrosion of zinc electrode is suppressed and the charge/discharge efficiency is enhanced.     

纳米糊精微球对头孢曲松钠的吸附及其释药性能

以糊精为原料,三偏磷酸钠为交联剂,利用反相微乳液法制备糊精纳米微球,并对头孢曲松钠的吸附载药和释药性能进行了研究。为模拟人体血液环境,选取了pH 7.4的磷酸二氢钠-磷酸氢二钠缓冲液为介质考查了糊精微球的吸附载药及降解性能。实验表明,纳米糊精微球对头孢曲松钠的载药率为9.44%,载药能力随着投药量的增加而增加,温度对载药能力的影响不显著,在α-淀粉酶存在的条件下,降解6 h后有23.94%的纳米糊精微球被降解。     

铝基原料对磷光粉SrAl2O4：Eu^2＋，Dy3＋发光性能的影响

采用高温固相反应法,分别以高纯氧化铝、自制纯净铝酸钠溶液及精制工业铝酸钠溶液为原料合成了黄绿色SrAl2O4：Eu^2＋Dy^3＋磷光粉,通过测量其激发光谱、发射光谱及余辉时间,考察了不同铝基原料对磷光材料发光性能的影响．结果表明,所制备的3种磷光粉的激发光谱和发射光谱的波长基本一致,激发光谱位于300-450nm之间,主发射波长在510nm左右．用工业铝酸钠溶液制备出的长余辉材料的发射强度不低于用另外两种原料制备的长余辉材料,余辉时间比用另外两种原料制备的长余辉材料稍长,效果较好,采用工业铝酸钠溶液制备铝酸盐基长余辉材料,可以降低能耗、节约成本．     

茶饮料中糖精钠的测定

建立了茶饮料中糖精钠的荧光分光光度测定方法。样品前处理采用盐酸酸化,加入氯化钠,乙醚萃取后再用2 g/L碳酸钠溶液洗涤乙醚萃取层,加热除去乙醚定容后用荧光光度计测定。测试条件为：激发波长265 nm,发射波长475 nm。方法检测限为2 mg/kg,线性范围在2～60 mg/kg之间,变异系数为1.97%,回收率96.8%。     

高铁酸盐降解偶氮染料酸性橙Ⅱ的研究

为研究高铁酸盐对废水的处理效果,以试验的方式研究了高效净水剂高铁酸盐对偶氮染料酸性橙Ⅱ的脱色效果,考察了紫外光照射、高铁酸钠浓度、pH值、添加剂对脱色效果的影响.结果表明,在原水样浓度为50 mg/L,高铁酸盐含量10 mg/L,NaHCO3浓度0.01 mol/L,在中性条件下处理30 min,脱色率可以达到94%左右.紫外光照射能有效提高染料的脱色速率;相同条件下脱色率可达97%以上,表明紫外光和高铁酸盐联合使用对染料的降解速率大大提高,产生了明显的协同作用.     

中等浓度含硅铝酸钠溶液深度脱硅过程物理化学性质的研究

通过对脱硅过程中含硅铝酸钠溶液表面张力和黏度的测定,研究脱硅温度、氧化铝浓度、苛性比等因素对溶液的表面张力和黏度的影响.实验结果表明：低温、高浓度、高苛性比的溶液表面张力和黏度较大,反之则较小.通过XRD检测手段对脱硅后的渣相进行分析,用衍射峰与结构的关系解释溶液的表面张力和黏度的变化对硅量指数的影响.     

靛蓝染液组分浓度在线检测系统

为实现靛蓝染液组分浓度的在线检测,提高检测的准确度和精确度,设计开发了采用电位滴定法在线实时检测靛蓝染液中各组分浓度的系统。系统以工控机为核心,基于研华板卡PCI1710,在C#环境下,实现工控机对设备的控制以及对检测数据的采集,采用二阶微商法确定电位滴定的终点。通过对检测结果的分析可知误差在2%以内,说明系统可以满足工业生产的需要。