共查询到18条相似文献,搜索用时 109 毫秒
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采用原位聚合法以三聚氰胺-甲醛树脂为壁材制备了甲维盐微胶囊。 探讨了不同黏均相对分子质量羟乙基纤维素作为乳化剂对微胶囊表面形貌、粒径及其分布、包覆率与载药量的影响,对使用不同黏均相对分子质量羟乙基纤维素作为乳化剂制备的微胶囊的释放性能进行了表征。 结果表明,以相对分子质量较小的羟乙基纤维素制备的微胶囊外形规则、致密且无黏连现象。 随羟乙基纤维素黏均相对分子质量的增加所得微胶囊的平均粒径及粒径分布逐渐增大,包覆率与载药量逐渐减小。 释放性能的研究表明,采用相对分子质量较小的羟乙基纤维素制备的微胶囊的释放性能较好。 相似文献
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为了指导高性能自修复微胶囊的制备研究, 利用偏光显微熔点仪、红外光谱和核磁共振氢谱定量研究了微胶囊预聚物组成随反应条件如反应温度、pH 值和甲醛-尿素物质的量比的变化. 研究结果表明, 升高体系温度和pH 值都会显著促进副反应的发生从而降低产物中二羟甲基脲的产率; 而提高甲醛-尿素的物质的量比, 二羟甲基脲的产率增加,同时三羟甲基脲的产率降低. 此外, 还研究了升温过程中反应体系的温度变化情况. 研究发现: 升温速率一定时, 反应体系的温度变化均匀, 没有温度骤变阶段. 相似文献
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甲胺基阿维菌素苯甲酸盐微胶囊的制备与表征 总被引:6,自引:1,他引:5
以三聚氰胺-甲醛树脂为壁材,采用原位聚合法制备了甲胺基阿维菌素苯甲酸盐微胶囊,研究了三聚氰胺与甲醛的质量比、芯壁比、乳化剂、搅拌速度与时间、pH值、温度等因素对微胶囊形成的影响,对制备的微胶囊进行了表征,测定了甲维盐微胶囊化前后的光解率。结果表明,三聚氰胺与甲醛质量比为1∶2、芯材与壁材质量比为3∶2、以质量分数1%羟乙基纤维素(HEC)为乳化剂、在1000r/min搅拌速度下、pH=5.0和50℃保温2h可制备出形貌较好、平均粒径4.4μm的甲维盐微胶囊。红外光谱分析证明,甲维盐已完全被包覆在微胶囊中。紫外分光光度法测定其缓释性能良好。光解实验表明,微胶囊化可有效降低甲维盐原药的光解。 相似文献
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设计了以脲醛树脂为壁材,聚硫橡胶密封剂为囊芯的微胶囊.在弱酸性条件下,尿素和甲醛在经乳化分散后的聚硫橡胶密封剂微粒表面发生原位聚合,制备了颗粒均匀、形貌规整、分散性好的密封剂微胶囊.通过红外光谱和表面观察技术对微胶囊进行了表征,并且对微胶囊中密封剂含量进行测定.通过对不同物料和反应影响因素(乳化剂浓度、搅拌速度、反应温度和p H值等)进行了系统考察,获得了优化的微胶囊制备工艺条件.为进一步拓展聚硫橡胶密封剂预涂敷技术和工程化应用提供了有益参考. 相似文献
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以聚磷酸铵微胶囊阻燃剂的包覆壳材料为重点,综述了聚磷酸铵微胶囊阻燃剂的无机材料包覆、有机材料包覆、双层或多层包覆以及纳米材料包覆,总结了国内外关于原位聚合法制备聚磷酸铵微胶囊的最新研究进展。介绍了聚磷酸铵微胶囊形成过程中,包覆壳材料与聚磷酸铵的原位聚合方法及机理。并且提出了聚磷酸铵阻燃剂在材料燃烧过程中存在的协同效应。最后,结合聚磷酸铵微胶囊阻燃剂在阻燃过程中存在的问题,展望了原位聚合在微胶囊阻燃领域中的未来发展方向。 相似文献
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固体芯材微胶囊制备技术研究进展 总被引:1,自引:0,他引:1
文章主要介绍了微胶囊研究背景、用途及制备方法。从固体芯材料水溶性的角度,可把芯材分为亲水性和疏水性两种类型。对于水溶性芯材微胶囊的制备方法,介绍了原位聚合法、油相相分离法、喷雾干燥法和喷雾冷凝法的技术进展;对于疏水性芯材,介绍了界面聚合法、原位聚合法、水相相分离法等方法包覆微胶囊的技术进展。此外,本文还对不同类型的固体芯材所适应的制备方法及壳材料进行了探讨,从试验条件、芯材料的特性及目标产品性能等角度来选取适当的微胶囊壳材及制备方法,以期探索出更经济、实用、高效的固体芯材微胶囊化制备方法。 相似文献
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电子墨水微胶囊及电泳显示原型器件的制备 总被引:11,自引:0,他引:11
TiO2 particles coated with polystyrene which were prepared via in situ polymerization and oil green dye were dispersed in tetrachloroethylene and xylene, the mixture came to be electrophoretic ink and was encapsulated in to microcapsules by complex coacervation from gelatin and a hydrolyzed copolymer of styrene and maleic anhydride(SMA). It was demonstrated that the membranes of the microcapsules were formed from nano sized coacervate droplets resulting from gelation and hydrolyzed SMA, which leads to a compact membrane structure. Microcapsules were characterized in terms of microstructure, morphologies by scanning electron microscopy(SEM). Electrophoretic display prototype was prepared by coating electrophoretic ink microcapsules slurry on ITO glass with nearly single layer and sealed by UV curable adhesires. The characters “Zheda” in Chinese was firstly displayed at a low volt 9 V D. C.. 相似文献
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K. S. Kim J. Y. Lee B. J. Park J. H. Sung I. Chin H. J. Choi J. H. Lee 《Colloid and polymer science》2006,284(7):813-816
A microcapsule containing titanium dioxide (TiO2) and halocarbon oil was synthesized via an in situ polymerization using urea, melamine, and formaldehyde (UM/F) as a wall material to examine its potential application as a microcapsule-based electronic ink display technique. Poly(sodium styrene sulfonate) was used as an anionic polymeric surfactant to stabilize a droplet of the suspension, and easily combined with the UM/F prepolymer through ionic adsorption. The microcapsules obtained had an average diameter and wall thickness of approximately 50 μm and 500 nm, respectively. The electrophoretic TiO2 particles in the microcapsules responded to electric fields with a response time of few seconds. 相似文献
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硬脂酸丁酯微胶囊的制备与表征 总被引:3,自引:0,他引:3
采用原位聚合法用脲醛树脂包覆硬脂酸丁酯,制得相变储热微胶囊.利用激光粒径分布仪、扫描电镜、差示扫描量热仪(DSC)和傅立叶转换红外光谱仪分别研究了微胶囊的粒径分布、表面形态、热性能和壳结构.结果表明,所得微胶囊粒径分布均匀,表面光洁,具有良好的韧性和致密性.不同的制备工艺对微胶囊粒径分布有一定的影响,其中在28 000 r/m in下乳化5 m in时,所得微胶囊的粒径分布集中在1~4μm.DSC测定结果显示硬脂酸丁酯微胶囊的最大相变焓为68 J/g. 相似文献
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A series of microcapsules containing n-octadecane with a urea-melamine-formaldehyde copolymer shell were synthesized by in-situ polymerization. The surface morphology, diameter, melting and crystallization properties, and thermal stability of the microcapsules were investigated by using FTIR, SEM, DSC, TGA and DTA. The diameters of the microcapsules are in the range of 0.2–5.6 m. The n-octadecane contents in the microcapsules are in the range of 65–78wt%. The mole ratio of urea-melamine has been found to have no effect on the melting temperature of the microcapsules. Two crystallization peaks on the DSC cooling curve have been observed. The thermal damage mechanisms are the liquefied n-octadecane leaking from the microcapsule and breakage of the shell due to the mismatch of thermal expansion of the core and shell materials at high temperatures. The thermal stability of materials can be enhanced up to 10 °C by the copolymerization of urea, melamine and formaldehyde in a mole ratio 0.2:0.8:3. The thermal stability of 160 °C heat-treated microcapsules containing 8.8% cyclohexane can be further enhanced up to approximately 37 °C. 相似文献
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J Hidalgo-Carrillo J Sebti A Marinas JM Marinas S Sebti FJ Urbano 《Journal of colloid and interface science》2012,388(1):67-73
The design of the oppositely charged ink particles based on titanium dioxide and carbon black for the monochrome electrophoretic display (EPD) was reported. The white ink particles with acidic surface and black ink particles with basic surface were synthesized and sterically stabilized by long alkyl chains, which were charged oppositely by mixing with basic surfactant (OLOA 1200) and acidic surfactant (Span 80), respectively. The electrophoretic mobility and the Zeta potential were −3.87 × 10−10 m2 V−1 s−1 and −25.1 mV for the white ink particles, 3.79 × 10−10 m2 V−1 s−1 and 24.6 mV for the black ink particles. In addition, the block copolymer, poly(lauryl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (PLMA-b-PDMAEMA) synthesized by atom transfer radical polymerization (ATRP), was first incorporated in the modification of the pigments for the fine encapsulation. Then, a stable dual-particle electronic ink with contrast ratio of 120:1 was prepared and encapsulated with the gelatin (GE)/sodium carboxymethylcellulose (NaCMC)/sodium dodecyl sulfate (SDS) microcapsules by complex coacervation method. Finally, the matrix character display prototype driven at a low voltage exhibited excellent performance, the contrast ratio of which was 8:1 at 9 V DC. 相似文献
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Synthesis of functional microcapsules containing suspensions responsive to electric fields 总被引:2,自引:0,他引:2
A sort of functional microcapsules, which contain a suspension responsive to electric fields, is prepared by in situ polymerization of urea and formaldehyde. The suspension is made up of pigment phthalocyanine green (PPG) and tetrachloroethylene. In order to solve the particles' separation from the suspension during the microencapsulation and to obtain microcapsules applying to electronic ink display, the dispersibility of the particles, the contact angles between the particles and the tetrachloroethylene, and the influences of different emulsifiers on the microencapsulation are investigated. It is found that the dispersion extent and lipophilicity of the PPG particles are improved due to their surface modification with octadecylamine. The contact angles between the modified PPG particles and the tetrachloroethylene increase, and the PPG particles modified with 2 wt% octadecylamine have the best affinity for tetrachloroethylene. The interfacial tension between C(2)Cl(4) and H(2)O with urea-formaldehyde prepolymer descends from 43 to 35 mN/m, which indicates that the polymer has certain surface activity. However, water-soluble emulsifiers have an important influence during the microencapsulation because they can absorb on the surfaces of internal phase and prevent the resin of urea-formaldehyde from depositing there. From the SEM images of shell surface and cross section, the microcapsules have relatively smooth surfaces and the average thickness is about 4.5 mum. When the microcapsules are prepared with agitation rates of 1000 and 600 rpm, the mean diameters of the obtained microcapsules are 11 and 155 mum, respectively. The particles in the capsules move toward positive electrode with a responsive time of several hundred milliseconds while providing an electric field. 相似文献
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Urease-loaded colloidosome microcapsules with SiO 2 nanoparticle shells and gellan gel cores were prepared facilely and highly efficiently by self-assembly of colloidal particles at the liquid-liquid interfaces and subsequently in-situ gelation of gellan gum. The urease-loaded colloidosome microcapsules were used as an enzymatic reactor to produce calcium carbonate precipitates by urease-catalyzed urea hydrolysis in the presence of calcium cations. The CaCO 3 /SiO 2 shells were formed finally around the gellan gel cores. The colloidosome microcapsules used as a biomimetic reactor has been demonstrated for the first time. 相似文献
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Preparation of microcapsules applied to the fabrication of self‐healing composites has attracted a lot of attention. However, the leakage of core material from the microcapsule is a major problem in self‐healing microcapsules. Proper dispersion of layered silicates within the wall of microcapsule is a strategy for improving the barrier properties of the microcapsule. In the present study, poly(urea‐formaldehyde) (PUF) microcapsules containing dicyclopentadiene (DCPD) were prepared by in situ polymerization. For the preparation of UF/clay nanocomposite microcapsules, acid‐modified montmorillonite (H‐MMT) was used as an effective catalyst for the condensation of urea and formaldehyde, and the condensation polymerization in the galleries resulted in the delamination of the clay, as confirmed by TEM and XRD analysis. Scanning electron microscopy (SEM) was applied to observe the morphology of the microcapsules and the barrier property of microcapsules was investigated by thermal gravimetry (TG) analysis and mass release method. On comparison with conventional microcapsules (CMs), nanocomposite microcapsules (NCMs) have better barrier property. This can be attributed to the nanocomposite structure of the microcapsules, where nanosized montmorillonite dispersed in UF to decrease the core material cross‐over. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献