Preparation of self-bursting microcapsules by interfacial polymerization

Here, we describe a new technique for microencapsulating pyriproxyfen, a widely used insect growth regulator. Using interfacial polymerization, we successfully prepared self-bursting microcapsules that retained their shape when suspended in water but break open quickly after the water evaporates. In order to investigate the self-bursting phenomenon, we studied the relationship between formulation factors such as volume median diameter (D) or wall thickness (T) and the physical strength of the obtained polyurethane films. As a result, it was found that T and the structure of isocyanate affected the self-bursting phenomenon.     

液相/微胶囊复合体系相变特性实验研究

相变微胶囊材料因其环保性与经济性的优势,已成为相变储能领域的研究热点,但其导热性能过低,严重限制了相变微胶囊材料的推广与应用。本文分别用无水乙醇和蒸馏水填充于微胶囊的颗粒间隙中,获得复合相变体系,研究了无水乙醇和蒸馏水体积分数分别为20.0%、40.0%、60.0%时复合体系相变特性。实验结果表明,相比于空白体系,两液体填充复合体系的相变速率均有明显提高,无水乙醇/微胶囊复合体系相变速率提升了87.5%~266.7%,微胶囊/蒸馏水复合体系提升了125.0%~368.8%。蒸馏水对微胶囊材料的强化效果优于无水乙醇,同时两复合体系的相变速率均随着填充液体体积分数的增加而上升。研究结果对微胶囊相变强化技术的发展提供了理论指导。     

液芯CMC-ALG微胶囊的制备、扩散性能及初步应用研究

制备了液芯羧甲基纤维素钠一海藻酸钙(CMC-ALG)微胶囊，考察了葡萄糖、谷氨酸、酪氨酸、赖氨酸、苯丙氨酸、乳糖及乳酸等七种底物从溶液向微胶囊内的扩散性质并计算了扩散系数．比较了微胶囊固定化的枯草杆菌与游离培养的生长情况．结果表明，底物在微胶囊中的混合扩散系数约为在纯水中的92％，在微胶囊囊膜中的扩散系数约为在纯水中的70％．固定化枯草杆菌与游离的相比较，没有明显的生长受阻现象，表现出了良好的生物相容性和固定化培养潜力．     

壳聚糖包覆肉桂精油对葡萄保鲜的应用研究

以壳聚糖为壁材、肉桂精油为芯材,采用乳化-固化法制备了壳聚糖微胶囊,并将其应用于葡萄保鲜包装中。通过光学显微镜、扫描电子显微镜、傅里叶转化红外光谱仪等,确定了微胶囊的最佳工艺参数、芯壁比及添加质量分数,研究了添加不同微胶囊质量分数的壳聚糖溶液对葡萄保鲜效果的影响。结果表明:壳聚糖质量分数为1.5%,乳化剂添加质量分数为1.5%,油相与水相的体积比为5:1,交联剂添加体积为1.0 m L时,制备的壳聚糖微胶囊成球效果较好;壳聚糖包覆肉桂精油芯壁比为3:1,微胶囊在壳聚糖溶液中的添加质量分数为4%时,以其涂膜的葡萄保鲜效果最佳。     

液体微胶囊复合电沉积铜的研究

讨论了用水相分离法制备含有液体微胶囊的技术，并将以有机硅树脂为囊心的液体微胶囊加入到酸性镀铜液中进行复合共沉积，得到了含有液体微胶囊的复合镀铜层，通过对这种镀层的表面，断面形貌和表面成分分析，这种含有液体微胶囊的复合镀铜层得到了证实和确认。     

含有液体微胶囊的复合电沉积铜镀层性能的研究

研究了含有有机硅树脂为囊心的液体微胶囊复合镀铜层的性能.通过进行25%氨水溶液腐蚀试验、10%硝酸溶液腐蚀试验和耐磨试验,测定了这种复合镀层的耐蚀性和耐磨性.结果表明,由于复合镀铜层中含有液体微胶囊,其耐腐蚀性和耐磨性能都得到很大提高.     

单体固化特性对光热敏微胶囊显影密度的影响

利用界面聚合技术制备了以不同单体为囊芯的新型感光材料光热敏微胶囊.借助于傅里叶红外光谱及原子力显微技术对不同单体的双键交联固化及固化产物的表面形貌进行了分析,利用热显影打印技术检测了光热敏微胶囊显影密度随曝光时间的变化.实验结果表明,不同单体的双键交联固化速度主要与单体官能度有关,并且单体固化产物的表面形貌与单体的双键...     

Phase diagram studies of microcapsule formation using hydroxypropyl methylcellulose phthalate

Abstract

Microcapsules of hydroxypropyl methylcellulose phthalate were prepared using a non-aqueous emulsion method. The study was designed to determine the region of microcapsule formation in the ternary system of mineral oil, acetone and polymer and to present the data by means of phase diagrams. Increasing amounts of sorbitan monooleate were added to mineral oil to determine the effect of surfactant concentration on the phase diagram. The effect of sorbitan monooleate, sorbitan trioleate and sorbitan monolaurate on the microcapsule region of the phase diagram was also investigated. Particle size analysis was carried out to determine if the concentration and type of surfactant used had a significant effect on the size of the microcapsules obtained. Tartrazine was encapsulated as a model drug and its dissolution was studied in acidic and neutral mediums. The results indicate that the addition of sorbitan monooleate increased the microcapsule region of the phase diagram and sorbitan trioleate had a similar effect. However, the microcapsule region in the phase diagram decreased when sorbitan monolaurate was used. The particle size increased with increasing concentration of polymer, irrespective of the type and concentration of surfactant used.     

纳米SiO_2改性相变储热微胶囊的制备及性能研究

以亲水型纳米SiO2粒子改性的三聚氰胺一甲醛树脂作为微胶囊壁材,以相变材料正十二醇为芯材,采用原.位聚合法,制备了纳米SiO2改性的相变储热微胶囊,研究了纳米SiO2粒子对微胶囊性能的影响,采用FTIR、DSC和SEM等方法进行了表征.结果表明,当壁材中加入适量的纳米SiO2时,纳米粒子在壁材里面分布均匀,微胶囊的相变焓提高,破损率降低,且纳米SiO2不会破坏预聚体的缩聚反应.当壁材中纳米SiO2质量分数为1%时,制备的微胶囊相变焓达148.7J/g,微胶囊破损率为23.1%.     

双乳液体系在微胶囊制备中的应用研究进展

双乳液是一类多重乳状液体系,它具有保护物质并且可以控制这些物质从一个相释放到另一个相的能力。近年来这类乳液体系与传统微胶囊制备方法的结合在药物输送(如抗癌药物、激素等)、食品等领域得到了一定的应用,解决了传统微胶囊制备方法无法有效封装高度水溶性物质等问题。基于此,综述了双乳液体系与微胶囊制备方法结合延伸出的一些新方法,包括双乳液-复凝聚法、复乳溶剂挥发法以及膜乳化复乳法等;同时,评述了影响双乳液体系制备微胶囊的各种因素,展望了双乳液体系在农药微胶囊制备中的应用前景。     

Preparation of calcium carbonate microparticles containing organic fluorescent molecules from vaterite

The encapsulation of fluorescent organic molecules into crystalline calcium carbonate was examined using calcium carbonate microcapsule, whose crystalline phase is vaterite as a metastable phase of calcium carbonate. A calcium carbonate microcapsule with impregnated pyrene that is a water insoluble fluorescent molecule was soaked into suitable aqueous solutions to promote the phase transition of vaterite toward calcite as the stable phase of calcium carbonate. When 0.2 M calcium chloride solution was used, the largest amount of pyrene (approximately 0.06 wt%) was encapsulated into the calcite particle. Pyrene thus included was not eliminated even after thorough washing with THF. The calcite particle thus prepared produced the excimer emission of pyrene by UV irradiation. Rhodamine B was also introduced into calcium carbonate by the immersion of the microcapsule into the aqueous solutions of Rhodamine B. The fluorescence of rhodamine B was observed from the calcium carbonate particles by visible light irradiation. Acetaminophen, a common drug poorly soluble in water, was also included in the calcium carbonate particle by the same procedures as the pyrene encapsulation. As acetaminophen thus encapsulated was released by the dissolution of the calcium carbonate particle in acidic solution, the particle is expected to be applied for a dissolution-triggered drug delivery.     

高分子材料在微胶囊新技术中的应用

对高分子材料在微胶囊新技术中的应用状况进行了综述。介绍了制做微胶囊的高分子材料种类，制备微胶囊的方法，讨论了影响微胶囊性能的因素，并展示了微胶囊新技术的应用场合。     

Formulation factors affecting drug release from poly(lactic acid) (PLA) microcapsule tablets

A sustained-release (SR) formulation of phenobarbital (PB) microcapsule tablet was prepared using low molecular weight (MW) DL- and high MW L-poly(lactic acid) (PLA) polymer. Microencapsulation of PB showed a unimodal size distribution (375 to 550 microns) of the microcapsules with high loading capacity (> 84%). Drug release from the microcapsule was influenced by the polymer ratios and increased with an increase in L-PLA amount. Microcapsules and physical mixtures of PB and the PLA were directly compressed independently to form microcapsule and matrix tablets, respectively. Drug release from the microcapsule tablets was significantly lowered (p < .001) compared to matrix tablets or free microcapsule (free microcapsule > matrices > microcapsule tablets). We also investigated the effect of tablet adjuvants, compression pressures, and microcapsule loading on the tablet performance in terms of friability, hardness, porosity, tensile strength, and the release kinetics of PB. The drug release rate increased with increasing compression pressure in the case of Emcompress or lactose, but not Avicel. The drug release rate was three- to fivefold increased with sodium starch glycolate compared to tablets without a disintegrant. With an increase in microcapsule loading, a decrease in the drug release rate was observed; however, the tablet performance remained satisfactory. The morphology of the microcapsules was monitored microscopically after the dissolution and the disintegration of tablets. The drug release accelerated with compression pressures and microcapsule loading from the tablets due to mechanical destruction of the microcapsule wall, which was more clearly seen after disintegration and dissolution of the tablets. Our data suggest that the PLA microcapsule can be tableted to make a SR product without significantly affecting its release kinetics.     

微胶囊萃取钪的动力学研究

用乙基纤维素、海藻酸钙为膜材,分别采用水浴干燥法、锐孔法制备微胶囊,从理论上对微胶囊萃取钪的动力学方程进行了推导,得到一级反应动力学方程．实验表明,乙基纤维素微胶囊的渗透系数大于海藻酸钙微胶囊的渗透系数,从而具有较小传质阻力,适合于钪的萃取．     

聚吡咯胶囊合成方法与应用研究进展

采用基于第一性原理密度泛函理论的CASTEP程序软件包,运用LDA＋U的方法,计算了Cd1-xZnxTe的电子结构和光学性质。计算结果表明：通过LDA＋U的修正计算,得到的Cd1-xZnxTe禁带宽度与实验值接近,消除了Cd1-xZnxTe材料在电子结构计算中禁带宽度被低估的问题;赝势U的加入增加了轨道电子数目,电子的...     

液体润滑油微胶囊复合电沉积镍的研究

讨论了用水相分离法制备含有液体微胶囊的技术，并且将以润滑油为囊心的液体微胶囊加入到氨基磺酸镍镀液中进行复合共沉积，得到了含有液体润滑油微胶囊的复合镀镍层。通过对这种镀层的表面、断面形貌和成分分析，证实和确认了这种含有液体微胶囊的复合镀镍层。通过阳极极化曲线、3．5％NaCl溶液浸渍腐蚀试验、耐磨试验等结果表明含有润滑油为囊芯的微胶囊的复合镀镍层具有优良的耐腐蚀性和耐磨性。     

Carbopol-gelatin coacervation and drug microencapsulation

Carbopol-gelatin coacervates were recovered as water-insoluble powder which when suspended in water gave a highly disperse system.

Glycerol as a protective against coacervate deformation, formaldhyde as a denaturant and some monohydric aliphatic alcohols as flocculating agents were variables studied. The hypothesis that solid particles may be protectively encapsulated by coacervation led to the investigation of the encapsulation of sulfadiazine at four coat-core ratios. The surface-adhering drug as well as the percentage of drug in the microcapsule increased on raising the core ratio. The size distribution was determined by use of standard sieves and the influence of four coat/core ratios was noted. Availability studies show that sulphadiazine was readily accessable to the leaching effect of the artifical intestinal fluids.     

牛至精油微胶囊的制备及其抑菌效果研究

以海藻酸钠为壁材制备牛至精油微胶囊,通过正交试验优化了微胶囊的最佳制备工艺条件,并对其进行了结构表征和抑菌效果研究。结果表明,制备牛至微胶囊的最佳工艺条件为:海藻酸钠质量分数2.5%、氯化钙质量分数1.5%、壁芯比为1∶1、乳化剂为0.2%的吐温-80和0.1%的单甘酯,在此条件下,微胶囊中牛至精油的包埋率为60.48%,其内部为多孔结构,且抑菌效果良好,当其用量达到0.02g时,对灰霉的抑菌圈直径达到90mm。     

疏水改性海藻酸钠衍生物包埋丁香油的释放性

目的通过化学方法将月桂醇与海藻酸钠接枝共聚形成两亲共聚物,对丁香油进行包埋形成微胶囊,使其具有一定的缓释性和良好的抗菌效果。方法利用两亲共聚物包埋丁香油形成包合物,采用单因素实验法,以包埋率为指标,评价月桂醇与海藻酸的接枝率对包埋率的影响,并在此基础上评价接枝率对缓释性以及不同环境下的稳定性和抗菌性能。结果在一定范围内包埋率随着接枝率的增大而升高;丁香油微胶囊的挥发率为14.11%,远低于丁香油的挥发率61.25%;释放试验中,丁香油微胶囊的缓释性明显优于未改性海藻酸纳,丁香油微胶囊能稳定缓慢地释放抗菌成分,控制大肠杆菌的生长。结论月桂醇改性海藻酸钠包埋丁香油形成的微胶囊具有一定的缓释和抗菌性能,突破了丁香油因挥发性强而存在的应用限制。     

富勒醇微囊的制备与自由基清除效应

采用以聚电解/盐复合体为模板的纳米粒子自组装微囊法,利用分子间的静电作用力,在不添加表面活性剂的条件下,首次将带负电的富勒醇纳米颗粒制备成具有核壳结构的聚丙烯铵盐酸盐/HPO42-/富勒醇复合微胶囊。采用扫描电子显微镜、动态光散射仪、Zeta电位仪等对其进行了表征,并采用邻苯三酚自氧化法测定了微囊对自由基的清除作用。结果发现,该复合微囊接近球形,分散良好且大小均一,微囊直径约为1~2μm,表面电势接近0mV;其对超氧阴离子自由基具有较强清除能力且呈现浓度依赖性。