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对原位聚合法制备微胶囊技术的研究 总被引:15,自引:0,他引:15
本文讨论了用原位聚合法制备微胶囊的工艺,研究了影响微胶囊粒径大小,分布和影响微胶囊释放性能的各种因素。实验结果表明:随乳化分散剂用量的增加,搅拌速度和搅拌时间的增加,微胶囊粒径变小,粒径分布变窄。微胶囊壁材的聚合反应速率大,交联密度高,则孔隙率大,释放速率快;而壁膜厚度增大,则其释放速率减慢。 相似文献
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近年来,微胶囊技术在生物医药、化工、食品等行业得到了广泛应用和发展.以液中干燥法制备阿司匹林微胶囊,研究了微胶囊的形成过程、表观形貌、粒度及其体外释放行为.研究结果表明,阿司匹林微胶囊形成过程中,乙基纤维素分散成球,继而在各微球表面析出,微球越来越细密,表面空洞减小,最终形成完整的微胶囊.微胶囊表面致密、光滑,有少量细小的孔洞,多数呈球形,但粒度不均匀,有不规则杂片存在.粒度基本呈正态分布,平均粒径为1 445 nm.随着制备微胶囊过程中阿司匹林原料药加入量的增加,微胶囊成品的实际载药量增加,但其包覆率却随之减小.在体外释放初始阶段,微胶囊中阿司匹林的释放较快,继而释放速率减慢呈缓慢上升趋势.加入少量药品制备的微胶囊中阿司匹林释放速度较大. 相似文献
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不溶性硫黄的研究现状及微胶囊硫黄的研究构想 总被引:2,自引:1,他引:2
概述不溶性硫黄的研究现状,并提出硫黄表面包覆微胶囊的构想.不溶性硫黄主要采用高温法和低温法制备,现有生产方法存在燃烧和爆炸、静电、有毒、腐蚀等危险性;微胶囊的制备方法有Wurster流化床法、气相沉积法和液相化学法等,微胶囊释放性能的表征参数包括表观扩散系数和渗透性常数,释放性能的影响因素包括膜厚和平均粒径;表面包覆微胶囊硫黄将会替代传统不溶性硫黄. 相似文献
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超临界CO2抗溶剂法制备酶微胶囊过程研究 总被引:1,自引:0,他引:1
研究了以木瓜蛋白酶为芯材,乙基纤维素为膜材的超临界流体抗溶剂(GAS)法制备酶微胶囊过程。在正交实验结果初步表明压力、温度、芯膜比和膜材料浓度依次是GAS法制备微胶囊过程较主要的影响因素基础上,进一步较系统地考察了这些因素对制备的微胶囊的粒径分布、包裹率、释放等性能的影响。 相似文献
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[目的]探究嘧菌酯微胶囊单体对其释放行为的影响。[方法]采用界面聚合法制备嘧菌酯微胶囊,使用显微镜和扫描电镜观察微胶囊的形貌和释放行为,并用高效液相色谱对其包覆率和释放性能进行表征。[结果]显微镜观察微胶囊形貌圆整,包覆率均在90%以上,扫描电镜和风干释放率的检测结果显示,TDI和DETA作单体时,微胶囊基本不释放,属于保护型微胶囊;油相单体为TDI和HDI的复配,水相单体为DETA,微胶囊起始释放速度快,且可以持续释放,属于速释型微胶囊。[结论]不同结构的单体使嘧菌酯微胶囊具有不同的释放行为,对农药满足应用场景的特殊需求或解决原药本身的性质缺陷具有指导意义。 相似文献
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流体流动诱导微胶囊膜起皱和变形是一个普遍存在的现象。针对这一现象已有一些模拟和实验研究,但是对于微通道内不同因素对于微胶囊褶皱情况的影响以及褶皱的存在对于微胶囊实际膜面积和粒径的影响等方面却鲜有探讨。针对这一问题,本文制备了具有褶皱膜的聚酰胺微胶囊,并提出通过溶剂浸泡法将微胶囊膜褶皱伸展开,以分析微胶囊的实际膜面积和实际粒径。同时,定义了褶皱度的概念,将抽象的褶皱情况数值化,使分析更为方便。最终,通过研究分析发现,由于与流体剪切力正相关,流体流量和黏度的增大会导致微胶囊褶皱度增加;当这两者固定时,微胶囊粒径的改变对其褶皱度基本无影响。在应用方面,微胶囊壁面褶皱情况的分析为制备单核双壁式微胶囊提供了一种新思路。 相似文献
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农药2,4-D微胶囊悬浮剂的研制 总被引:1,自引:0,他引:1
以脲醛树脂为壁材,采用原位聚合法制备2,4-D微胶囊悬浮剂。在固定合成脲醛树脂反应条件的基础上,通过改变成囊过程中囊心与囊壁比、固化剂种类及用量、搅拌速度、固化时间、固化温度、加酸时间、终点pH等的不同,进一步研究上述不同条件对微胶囊粒径大小、粒径分布范围、微胶囊包囊率的影响,从而筛选最优的成囊反应条件。实验结果显示该微胶囊能够满足实际需要。 相似文献
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以石蜡、癸酸为芯材,脲醛树脂为壁材,间苯二酚为固化剂,采用原位聚合法制备相变微胶囊,采用ESEM、DSC、TGA来研究相变微胶囊颗粒形貌、粒径分布、热力学性能,以及相变微胶囊掺入水泥基体中的微观形貌.结果表明:微胶囊表面光滑,结构紧致;石蜡微胶囊的相变温度和相变焓分别是54.6℃和61.43 J/g,而癸酸微胶囊的相.变温度和相变焓分别是29.7℃和90.73 J/g;加入固化剂使得微胶囊产率从50%提升到78%以上;30次温度循环石蜡微胶囊相变晗无损失,癸酸微胶囊相变焓损失了31%;微胶囊在水泥基中分布均匀,形貌保存良好. 相似文献
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R. Arshady 《Polymer Engineering and Science》1989,29(24):1746-1758
A methodological survey of preparation of microspheres and microcapsules by suspension cross-linking is presented. Thus, basic features of suspension cross-linking, i.e., the formation of small droplets of a polymer solution (or melt) in an immiscible liquid followed by hardening of these droplets by covalent cross-linking, are discussed. Typical microspherical and microcapsular products manufactured by suspension cross-linking of naturally occurring and preformed synthetic polymers, including agarose and cellulose beads, albumin microspheres and microcapsules, polystyrene beads and epoxy resin microcapsules, are described. Manufacturing parameters controlling microsphere/microcapsule characteristics are also briefly outlined. 相似文献
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为了解决混凝土开裂提高建筑物的使用寿命以及耐久性能,本文以脲醛树脂作为微胶囊囊壁、环氧树脂E-44作为微胶囊囊芯,采用原位复合法分两步合成微胶囊.本实验探究通过控制囊芯与囊壁质量比为3:10、尿素和甲醛的摩尔比为4:1、温度85 ℃、搅拌时间为3 h等因素,配制出结构完整致密的微胶囊.双掺固化剂和微胶囊制备不同微胶囊掺量的自修复砂浆,探究固化剂和微胶囊掺量对自修复砂浆强度的影响,并对自修复砂浆试件施加不同比例的预压力和空白试验做对照以探究自修复砂浆强度的影响因素以及修复率高低.研究表明,当微胶囊掺量为6%、预压力为50%时自修复砂浆的修复率最高. 相似文献
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Based on the deficiency of traditional acidification or acid pressure technology in the development of carbonate oil and gas resources, a microcapsule which wraps hydrochloric acid and can be released through temperature control was prepared by using microcapsule technology. The microcapsules were prepared with polyurethane prepolymer (PUA) and 1,6-hexadiol diacrylate (HDDA) polymer as wall material and hydrochloric acid as core material by two emulsification and photocatalysis methods. Its parcel rate is 61.9%. Fourier transform infrared spectroscopy characterization confirmed the successful photopolymerization of PUA prepolymer and HDDA in a strong acid environment. The microscopic morphology analysis of electron microscope showed that the microcapsule was regular and uniform spherical with smooth and dense surface. The particle size analysis showed that the microcapsules were mainly distributed between 40 and 300 μm, and the average particle size was 114.02 μm.The glass temperature of microcapsule wall material was 97°C by DSC method. The release rate of microcapsules was accelerated with the increase of release temperature. The cumulative release rate of acid solution of microcapsules for 3 h reached 28.4%, and the final release rate of microcapsules for 12 h reached 90.7% under 100°C. In addition, the release of microcapsules is less affected by the formation salinity. At 90°C, the maximum release rate of 7.5 g/L CaCL2 was 49.1%, lower than that of 59.4% in pure water, showing the good salt resistance of the wall materials of microcapsules. 相似文献
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Preparation and characterization of poly(urea-formaldehyde) microcapsules filled with epoxy resins 总被引:5,自引:0,他引:5
The preparation of microcapsules applied to the fabrication of self-healing composites has been paid more attentions. A new series of microcapsules were prepared by in situ polymerization technology with poly(urea-formaldehyde) (PUF) as a shell material and a mixture of epoxy resins (diglycidyl ether of bisphenol A: DGEBPA) and 1-butyl glycidyl ether (BGE) as core materials. The microencapsulating process of core material was monitored using optical microscopy (OM). The chemical structure of microcapsule was characterized using Fourier-transform infrared spectroscopy (FTIR). Morphology and shell wall thickness of microcapsule were observed using metalloscope (MS), scanning electron microscopy (SEM) and OM, respectively. The effects of different pre-polymers, weight ratios of urea to formaldehyde (U-F) and the agitation rates on the physical properties of microcapsules were investigated. The storage stability of microcapsules at different times and temperatures was analyzed. The thermal properties of microcapsules were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicate that PUF microcapsules containing epoxy resins can be synthesized successfully, and during the microencapsulation, the epoxide rings in epoxy resins are hardly affected by the surrounding media. The rough outer surface of microcapsule is composed of agglomerated PUF nanoparticles. The size and surface morphology of microcapsule can be controlled by selecting different processing parameters. The microcapsules basically exhibit good storage stability at room temperature, and they are chemically stable before the heating temperature is up to approximately 238 °C. 相似文献
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微胶囊自修复技术是将自修复微胶囊埋植于基体,在破坏后实现自我修复。IPDI作为低官能度异氰酸酯在湿气中固化修复能力有限,本文设计基于六官能度异氰酸酯DiPE-IPDI/DiPE-TDI合成用于自修复防腐涂料的新型微胶囊,着重对六官能度异氰酸酯DiPE-IPDI合成过程中溶剂、温度进行反应条件优化,通过傅里叶红外光谱、核磁等对产物结构进行表征。同时对微胶囊制备过程中粒径结构进行可控组装, 通过TGA/DSC表征该自修复微胶囊热力学性能。制备负载微胶囊的自修复环氧树脂基防腐涂料,盐雾试验结果显示其具有优异的自修复性能。 相似文献