复凝聚法制备磁性微胶囊及其磁响应特性

采用复凝聚法,以亲油改性的纳米Fe3O4为磁性颗粒,白油为分散介质,明胶、阿拉伯胶为壁材,在不同工艺条件下制备磁性微胶囊.通过激光粒度分析仪测试微胶囊的粒径及粒径分布,采用光学显微镜和扫描电子显微镜(SEM)观察微胶囊的表面形貌及分散状态,借助磁铁和振动样品磁强计(VSM)测试微胶囊的磁响应性能.结果表明,反应溶液pH=3.8、芯壁比1∶1时,微胶囊收率最高;搅拌速率为600r/min时,微胶囊的粒径分布最均匀;在pH=3.8、芯壁比1∶1、搅拌速率600r/min条件下制备的微胶囊形状规整性及单分散性好,且囊壁透明、表面光滑,具有良好的磁响应性能,可应用于磁泳显示和靶向药物传输领域.     

Neue Entwicklungen in der Galvanotechnik

New Developments in Electroplating Electrodeposited composite coatings are well known for wear reduction or friction reducing applications. A new development are microcapsules containing composite coatings. Microcapsules have a solid, liquid or gaseous core with a shell from different plastics with a diameter from 0.3 up to 50 μm. Self lubricating coatings, for example, are able to reduce the coefficient of friction from 0.7 to 0.1 (Nickel vs. steel). Wear‐indicating coatings containing micro‐encapsulated perfumes, fluorescent dyes or other detectable substances were developed. New processes for the electroplating on light metals are developed. These coatings are more corrosion resistant than the commercially available layers. The increased corrosion resistance results either by the embedding of encapsulated inhibitors in an interlayer or by an electrically non‐conducting interlayer which separates coating and substrate.     

纳米微球在生物医药领域的应用

纳米微球技术是近年来在生物技术应用中最为热门的前沿技术之一。各种微球产品的应用给生物技术研究带来了新的课题,形成了众多新的研究领域。从生物技术的发展现状和未来方向出发,对纳米微球在生物医药研究中几个重要领域的应用前案进行了综述。     

石蜡微胶囊的制备及改性研究进展

目的概述石蜡相变材料微胶囊在相变温控、能量利用和热交换等主要应用领域内的研究状况,并对未来的应用与发展进行展望,旨在为石蜡微胶囊的改性研究提供一定思路。方法通过分析和总结近年来国内外有关石蜡微胶囊材料的文献,主要从石蜡微胶囊材料的制备方法和改性手段等方面对目前的石蜡微胶囊材料进行综述。结果石蜡微胶囊的壁材结构和芯材成分对石蜡微胶囊的热性能有非常重要的影响,通过对壁材和芯材的改性,提升了石蜡微胶囊的热性能。结论石蜡微胶囊的改性能够实现更高热性能的目标,达到更多热应用的要求,具有很大的发展潜力,在主要应用领域内能得到更加广泛的应用,但仍存在着一些亟待解决的问题。     

脲醛树脂包覆α-烯烃减阻聚合物微胶囊的制备与性能

在阐述了尿素与甲醛聚合制备微胶囊壁材反应原理的基础上,以尿素与甲醛为壁材原料,运用原位聚合法研究了包覆α-烯烃减阻聚合物微胶囊的制备工艺,利用粒度分析仪、红外光谱仪、同步热分析仪和模拟环道油品减阻率评价系统等,对微胶囊制备、储存稳定和溶解性能进行了研究。结果表明:在酸性条件下,以尿素与甲醛为微胶囊化原料,采用原位聚合法制备包覆石油减阻聚合物颗粒的微胶囊,制备工艺具有反应温和、缩聚反应可控,可有效缩短反应时间等特点。制备的脲醛树脂包覆α-烯烃减阻聚合物微胶囊粒度分布主要集中在200μm处,微胶囊可长期保持较好的圆润小球状态,具有良好的热力学稳定性。静压耐压储存稳定性和热力学稳定性研究结果表明,微胶囊可完全满足储存稳定性的要求。脲醛树脂包覆α-烯烃减阻聚合物微胶囊在输送油品中具有优良的溶解性,与未包覆的减阻聚合物颗粒减阻率接近,微胶囊溶解后减阻率较未包覆时略有延迟,但减阻率峰值依然与未包覆时相当,可满足现场工程实际应用。     

Characterization of short chain fatty acid microcapsules produced by spray drying

Microcapsules containing short chain fatty acids (SCFA) were produced by spray drying technique using different proportions of gum arabic and maltodextrin as wall materials. Proportions of 5% and 10% of gum arabic and maltodextrin isolated, and a mixture of 5% of maltodextrin and 5% of gum arabic were added to samples of fermented permeate containing SCFA, and spray dried. The microstructure of microcapsules was studied by scanning electron microscopy (SEM) and the size distribution was obtained by laser diffraction. SEM observations showed that the microcapsules structures were affected by type and proportion of wall material tested. Most of the microcapsules containing gum arabic as wall material had surface dents or invaginations. Microcapsules containing maltodextrin were spherical with few surface dents and some of them had pores. The larger microcapsule sizes were observed in those containing maltodextrin. Our results show that microstructure and size of microcapsules are affected by type and proportion of biomaterial used. The samples containing 5% of maltodextrin and the mixture of 5% of gum arabic with 5% of maltodextrin presented smooth surfaces and homogenous size distributions. The corresponding microcapsules are considered optimal to food industrial uses due to the flowability property. Besides, these capsules were found to present a homogenous distribution of diameters, which may give a homogenous flavor distribution to the food products.     

微胶囊相变材料的制备与特性研究

采用原位聚合法制备以石蜡为芯材、脲醛树脂为壳材的微胶囊相变材料,并通过丝网印刷技术,结合热固性聚氨酯网印粘合剂将微胶囊涂布于棉布上.考察了乳化剂的种类及用量和人工汗液对微胶囊性能的影响,分析了对经MCPCM涂布的棉布布料的热性能.研究结果表明,使用复合乳化剂制备的微胶囊相变材料表面光滑,密封良好.微胶囊相变温度和相变潜热分别为34.10℃和143.8J/g,经过20次热循环后,相变温度和相变潜热都变化不大.微胶囊经人工汗液分别浸渍20min、40min和60min 后,其相变温度和相变潜热无明显变化.微胶囊与网印粘合剂结合的复合材料涂布于棉布上,其相变温度和相变潜热均有降低.     

尿素三聚氰胺甲醛三组分复合树脂包覆苯乙烯微胶囊的制备研究

针对热塑性材料的自修复,以尿素、三聚氰胺、甲醛共聚物为囊壁,苯乙烯为囊芯合成了包覆苯乙烯的改性脲醛树脂微胶囊,并采用红外光谱、扫描电子显微镜、纳米粒度电位仪等分析了微胶囊的化学成分及表面形貌,发现其表面粗糙致密,形状基本呈球形,粒径分布较集中,包封率为72%,有望应用于自修复材料。     

包覆石油醚的脲醛微胶囊的制备

以脲醛树脂为壁材,石油醚为芯材,通过原位聚合法制备微胶囊。利用光学显微镜(OM)、气相色谱(GC)、红外光谱(FT-IR)、差示扫描量热法(DSC)和热重分析法(TGA)等手段研究了芯壁材质量比、乳化剂用量、搅拌速率对微胶囊表面形态和性能的影响。结果表明,当芯壁材质量比为0.8∶1,乳化剂十二烷基苯磺酸钠(SDBS)用量为7%,搅拌速度控制在600 r/min时,得到的微胶囊产率为81.14%,形态较好,平均粒径为50μm,在200℃时失重率为14%。     

微胶囊相变材料的储能特性分析

以硬脂酸丁酯为囊芯,密胺树脂(MF)和聚酯树脂(PET)为囊壁,合成了两种具有相变储热功能的胶囊.采用扫描电子显微镜(SEM)观察胶囊的形貌,差示扫描量热仪(DSC)研究胶囊的储热性能,发现MF/硬脂酸丁酯微胶囊表面粗糙,储能效果明显,稳定性好.利用MF/硬脂酸丁酯微胶囊制备了具有相变储能功能的建筑材料,微胶囊在水泥和...     

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%.     

反应性乙烯基硅油/聚脲甲醛自修复微胶囊的制备

以聚脲甲醛为囊壁、乙烯基硅油(DY-V401-310硅油)为囊芯,采用原位聚合法成功合成了具有自修复功能的新型微胶囊-聚脲甲醛包覆乙烯基硅油微胶囊.研究了搅拌速度和表面活性剂对微胶囊物理性能的影响,并通过扫描电子显微镜(SEM)、金相显微镜(MS)、激光粒度分析仪和红外光谱(FTIR)对微胶囊的表面形貌、粒径尺寸与分布及其化学结构等性能进行了研究.结果表明,十二烷基苯磺酸钠(SDBS)和明胶均对微胶囊的形成有积极作用,SDBS所制备的微胶囊粒径更小.当SDBS的加入量为1%(质量分数)时,在搅拌速度为600r/min的作用下,可得到平均粒径为123μm、较为理想的微胶囊.     

The permeability and stability of microencapsulated epoxy resins

Microcapsules containing self-healing agents have been introduced into polymer to self-heal the microcracks and toughen the brittle matrix. Poly(urea–formaldehyde) (PUF) microcapsules containing epoxy resins are potential for the self-healing and toughening polymer. The resistance to medium surroundings of microcapsules is required. In the present study, PUF microcapsules containing epoxy resins were prepared by in situ polymerization. The effects of diameter, surface morphology and wall thickness on the permeability and stability of microcapsules in thermal and solvent surroundings were investigated. The morphology of microcapsule was investigated using optical microscope (OM), metalloscope (MS) and scanning electron microscope (SEM), respectively. The composition on the surface of microcapsule was analyzed by using energy dispersive analysis of X-ray (EDAX). The thermal properties of microcapsules were investigated using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The thermal permeability of core increases and the stability of microcapsule decreases with the enhancement of heating temperature mainly due to the expansion of epoxy resins below 251 °C and the decomposition of PUF above 251 °C. At room temperature, the permeability constants of core materials of microcapsules in acetone solvent are small and they are 1.20 × 10⁻³ m s⁻¹, 1.39 × 10⁻³ m s⁻¹ and 1.60 × 10⁻³ m s⁻¹ corresponding to the microcapsules with diameters of 400 ± 50 μm, 230 ± 40 μm and 120 ± 30 μm. Increasing the surface smoothness, diameter and wall thickness can decrease the permeability and improve the stability of microcapsules in thermal and solvent surroundings.     

改性蒙脱石/石蜡相变储热微囊的制备与性能表征

采用皮克林乳液法制备以改性蒙脱石为新型壁材,石蜡为芯材的储能相变微囊。采用光学显微镜、扫描电镜(SEM)、红外光谱分析仪(FTIR)、差示扫描量热仪(DSC)和热重仪(TG)等分析技术分别对蒙脱石/石蜡微胶囊的化学结构、微观形貌、热性能等进行详细的表征与解析。结果表明:改性蒙脱石壁材对石蜡芯材有良好的保护作用。微囊的FTIR特征峰与石蜡和改性蒙脱石对应的特征峰相似。DSC测试表明,改性蒙脱石/石蜡复合相变微囊储热材料的固-固相变温度与纯石蜡相近,石蜡含量为55%~80%的相变微囊的相变焓值为110.5~147.2J/g,调整石蜡含量可调控相变微囊的储能性能。TG分析表明改性蒙脱石/石蜡微囊的热稳定性能较好。研究表明,改性蒙脱石是石蜡相变微囊良好的壁材。改性蒙脱石/石蜡微囊具有成本低、性能优异的特点,具有推广应用价值。     

A Method to Analyze the Surface of Microcapsules Using Diffuse Reflectance

The diffuse reflectance of infra-red energy from microcapsules was shown to be a useful analytical technique to study the structural properties of microcapsules. The technique of diffuse reflectance is unique in that the anisotropic nature of reflected light enables spectral differences to be explained on the basis of molecular orientation. As a result of the collection and analysis of diffuse spectra, spectral differences that may correspond to structural differences in the capsule wall structure were found to be dependent on the core material. More specifically, in microcapsules of kaolin and talc, produced with a block copolymer of d-tartaric acid and 1,8-octanediol, the relative orientation of hydroxyl functional groups for the respective core materials differed by forty-nine degrees while carbonyl groups differed by 15 degrees.     

基于自修复涂料的脲醛树脂微胶囊的制备及其表征

目前,关于包覆桐油的脲醛树脂微胶囊用于自修复涂料的制备研究较少。以桐油为芯材,采用原位聚合方式在桐油表面制备了脲醛树脂微胶囊;采用扫描电镜(SEM)、光学显微镜(OM)、热重分析仪(TGA)以及红外光谱(IR)对胶囊的微观形貌、热稳定性及化学结构进行了表征。结果表明:当预聚合反应p H=8.5,采用OP-10作为乳化剂,其用量为芯材质量的5%,搅拌转速为900 r/min,并控制酸化时间为90 min时,可制得外形完整、尺寸均匀的球形微胶囊,微胶囊表面略粗糙,其直径约为200μm,包封闭率达85.1%,其初始热分解温度为205℃左右。     

高温相变石蜡-脲醛树脂微胶囊的制备及表征

通过原位聚合法合成了以高温相变石蜡(相变区间为75~85℃)为芯材,三聚氰胺改性脲醛树脂为壁材的相变微胶囊。采用DSC、SEM、导热系数仪等分别对石蜡-脲醛树脂(Paraffin-UF)微胶囊的形貌、热性能等进行了表征。分析了NaCl溶液、三聚氰胺以及石墨烯的添加对微胶囊的影响。结果表明:适量NaCl的添加能改善微胶囊表面形貌,三聚氰胺的添加能提高微胶囊的生成量。添加质量分数为0.03%的石墨烯,在80℃时微胶囊的导热系数提高了55.56%,而且其热稳定性有所提高。     

自修复微胶囊复合材料的制备及力学性能研究

为了提高树脂基复合材料的使用寿命,以脲醛树脂为壁材,双环戊二烯为囊芯,通过原位聚合法制备了内含修复液的微胶囊,探讨了反应过程中脲醛量比及乳化剂用量等对微胶囊表面形貌和结构的影响.通过优化工艺条件制备出表面致密的微胶囊,并将微胶囊埋植在环氧树脂基体中制备复合材料.采用扫描电镜对胶囊进行形貌表征,运用快速傅里叶变换红外光谱...     

用于血液隔热相变材料微胶囊的制备及研究

研究采用了以三聚氰胺-甲醛为壁材，正十四烷为芯材原位聚合法制备微胶囊相变材料。通过SEM、DSC、Zeta激光粒度测定仪观察分析了微胶囊相变材料的表面形态、粒径分布。分析了乳液制备过程中乳化剂、系统调节剂、pH等对微胶囊工艺的影响，并对制成的微胶囊进行了血箱保温方面的实验，可以有效地在极限条件和室温下保持血液的所需温度。实验表明当系统调节剂SMA分子量为4万、非离子型OP-10为乳化剂和体系pH控制在3．5时能制得粒径分布为0．5～10μm、实际应用较理想的微胶囊相变材料。     

Mikrokapseln in der Galvanotechnik

Composite coatings with microcapsules Electrodeposited composite coatings are well known for wear reduction or friction reducing applications. A new development are microcapsules containing composite coatings. Microcapsules have a solid, liquid or gaseous core with a shell from different plastics with a diameter from 0.3 up to 50 μm. Self lubricating coatings, for example, are able to reduce the coefficient of friction from 0.7 to 0.1 (Nickel vs. steel). Wear‐indicating coatings containing micro‐encapsulated perfumes, fluorescent dyes or other detectable substances were developed.