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具有核壳结构的包覆型复合粉末,兼具包壳层材料和内核材料两种物质的优良性能。溶胶-凝胶法用于制备陶瓷包覆型复合粉体,可以实现涂层包覆,且包覆层组织结构均匀致密。该文对溶胶-凝胶法制备陶瓷包覆型复合粉体的制备原理、方法及制备过程中各环节的影响因素进行了概述和分析;介绍了溶胶-凝胶法制备包覆型复合粉末的各类应用及其发展趋势。 相似文献
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《化工进展》2017,(Z1)
含硅氧化铝载体因其兼具SiO_2和Al_2O_3的共同优势,即具有较好的结构性能、力学性能和一定的表面酸性,在加氢催化剂领域得到广泛应用。本文详细介绍了含硅氧化铝催化剂载体的制备方法,包括溶胶-凝胶法、NaAlO_2-Al_2(SO_4)_3法、混合法、浸渍法及化学气相沉积法。对比了制备方法对载体物化性质的影响,其中采用溶胶-凝胶法制备的载体纯度高,物化性质较好。分析了不同制备方法导致含硅氧化铝载体物化性质存在差别的作用机制。在体相中引入硅有利于调变载体孔结构,反之硅暴露于亚表面或表面有利于调变载体酸性。并指出了当前研究中存在的问题及含硅氧化铝的发展方向。 相似文献
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《高科技纤维与应用》2004,29(6):54
一种纤维增强复合材料连续抽油杆及其制备方法。该抽油杆采用包覆复合结构,且包覆层结构以横向排列的芳纶或超高分子量聚乙烯纤维束为纬线,纵向是由玻璃纤维间隔开的芳纶或超高分子量聚乙烯纤维带状结构, 相似文献
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以石蜡作包覆剂,采用两种包覆工艺制备了的4种HMX基含铝炸药,用小型密闭燃烧装置测试了其燃烧过程中压力随时间的变化,通过比较准静态压力得到其燃烧能量大小的关系。用气相色谱仪测量气相燃烧产物的含量,通过化学计算研究了不同包覆工艺制备的含铝炸药中铝粉的反应率。用扫描电镜(SEM)表征了含铝炸药的微观形貌。结果表明,黏结剂的包覆工艺直接影响含铝炸药的微观形态;采用包覆工艺1制备的含铝炸药中未包覆的铝粉更有利于在燃烧初期的吸热,使铝粉的反应率提高约5.8%,燃烧总能量也相应提高。 相似文献
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聚苯胺包覆玻璃鳞片复合物的制备与表征 总被引:2,自引:0,他引:2
采用化学聚合和乳液聚合两种方法制备聚苯胺包覆玻璃鳞片复合物。通过XRD、红外光谱、SEM、表面接触角测试、电导率测试、EIS等手段对复合材料的结构、形貌和性能进行了表征。结果表明:不同方法制备的聚苯胺包覆玻璃鳞片复合材料在结构、微观形貌和电导率上有较大差别,其中乳液法制备的复合材料,聚苯胺在玻璃鳞片载体上能够生长成较长的纤维,具有较高的结晶度,电导率高达2.281 S/cm。最后以之为导电填料,制备环氧防腐导电涂料,经研究表明其具有优异的导静电、防腐性能和机械性能。 相似文献
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使用液晶乳化剂与传统油包水乳化剂通过两步法制备了一种多重乳状液,显微镜观察结果显示,油水界面存在层状液晶,即该多重乳为水包液晶包油包多元醇的结构(P/O/LC/W)。系统考察了液晶乳化剂种类以及乳化温度、均质速率对多重乳微观结构的影响。实验结果表明,当液晶乳化剂使用IST-LC001,制备工艺控制乳化温度60~75℃,油包醇乳液制备阶段均质速率7 000~8 400 r/min,水包液晶包油包醇乳液制备阶段均质速率4 400~6 000 r/min时,可以获得理想的多重乳。使用该多重乳分别包覆活性物质白藜芦醇与紫草素,实验结果显示,该乳液不仅可以解决难溶于水、油的功效成分在配方中的运用,有效包覆、缓释活性物质,还能够掩盖包裹成分的颜色、改善产品的肤感。乳液稳定性良好,在医药、食品、化妆品等领域都有广阔的应用价值。 相似文献
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Junyang Xu Guanhua Liu Ying He Liya Zhou Li Ma Yunting Liu Xiaobing Zheng Jing Gao Yanjun Jiang 《Frontiers of Chemical Science and Engineering》2023,17(6):784
In situ encapsulation is an effective way to synthesize enzyme@metal–organic framework biocatalysts; however, it is limited by the conditions of metal–organic framework synthesis and its acid-base stability. Herein, a biocatalytic platform with improved acid-base stability was constructed via a one-pot method using bismuth-ellagic acid as the carrier. Bismuth-ellagic acid is a green phenol-based metal–organic framework whose organic precursor is extracted from natural plants. After encapsulation, the stability, especially the acid-base stability, of amyloglucosidases@bismuth-ellagic acid was enhanced, which remained stable over a wide pH range (2–12) and achieved multiple recycling. By selecting a suitable buffer, bismuth-ellagic acid can encapsulate different types of enzymes and enable interactions between the encapsulated enzymes and cofactors, as well as between multiple enzymes. The green precursor, simple and convenient preparation process provided a versatile strategy for enzymes encapsulation. 相似文献
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采用溶剂注入法制备水杨酸壳聚糖/卵磷脂纳米粒。考察了粒子结构、形貌特征及表面电位等性能,并探讨了制备工艺对药物包封率的影响。确定最佳制备工艺为:卵磷脂质量浓度20 g/L、卵磷脂与壳聚糖及水杨酸与载体的质量比分别为3∶1和1∶6、水相pH=4。所制备的水杨酸壳聚糖/卵磷脂固体纳米粒子为球形粒子、表面电位+18.7 mV、包封率及载药量可分别达到55%和8.07%。 相似文献
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以多重乳液相对体积为衡量标准,探讨了石蜡油、乳化剂、以及第一相质量分数对石蜡油w/o/w型多重乳液稳定性的影响。结果表明制备石蜡油w/o/w型多重乳液的较佳条件为:第一相中石蜡油和乳化剂Span80质量分数分别为40%和8%,第一相质量分数为65%,乳化剂Tween80质量分数为1%。采用透析-紫外分光光度法研究了该多重乳液对维生素c的包裹能力,结果表明:多重乳液可以有效包裹维生素C,包裹率达98.55%,且能缓慢释放被包裹的维生素C。 相似文献
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目的建立脱氧氟尿苷(DFUR)脂质体的制备工艺。方法采用逆向蒸发法制备DFUR脂质体,并以包封率为参考指标,进行正交试验优化该脂质体的配方。以优化的配方制备脂质体,观察其微观形态,测定粒径、包封率及稳定性,并进行体外释药实验。结果制备DFUR脂质体的最佳配方为:卵磷脂/胆固醇(摩尔比)为2∶1,有机相/水相(体积比)为5∶1,DFUR浓度为2mg/ml,磷酸盐缓冲液pH值为7.0。以此配方制备,脂质体包封率可达52.15%。3批DFUR混悬液,粒径小于220nm的粒子比率均在70%以上,显微镜下观察可见,脂质体呈球形或椭圆形,粒径范围在0.15μm~1.00μm之间。4℃保存49d,脂质体的稳定性良好。其累积释放率远低于原料药浓度。结论已建立了DFUR脂质体的制备工艺,该工艺操作简便可靠,所需设备简单,稳定性较好,可用于包埋水溶性药物。 相似文献
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Water‐in‐oil‐in‐water (w/o/w) multiple emulsions are considered that could be suitable components of functional dairy products. Such emulsions enable the preparation of low‐calorie products, encapsulation of bioactive components or microorganisms, and their protection during digestion. Because of the large phase interface, w/o/w emulsions are thermodynamically unstable. Therefore, their preparation and stabilization requires specific conditions. This review describes a potential industrial application of w/o/w emulsions in dairy products in detail and summarizes the value, preparation, stabilization, and evaluation of w/o/w emulsions in a dairy system. 相似文献
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Bin Xu Hongjing Dou Ke Tao Kang Sun Rong Lu Weibin Shi 《Journal of Polymer Research》2011,18(1):131-137
Poly(lactide-ethylene glycol) (PLEG) and poly(lactide-methoxy poly(ethylene glycol)) (MePLEG) nanospheres used as drug carrier
were prepared by a double emulsion method. The influences of several parameters, such as copolymer structure, phase volume
ratios, emulsifer concentration and sonication parameters, on the preparation of these two copolymer nanospheres were investigated
for the nanospheres control. Critical values of the emulsifer concentration and the sonication intensity exist, allowing optimization
of the nanospheres of controlled size with a narrow distribution. Under the same condition, MePLEG nanospheres had a smaller
size than PLEG nanospheres because of their different length of hydrophilic blocks and steric hindrance. In addition, vascular
endothelial cell growth factor and cisplatin, as two water-soluble model drugs, were encapsulated in the MePLEG and PLEG nanospheres.
A higher encapsulation efficiency, above 90%, of the PLEG nanospheres could be obtained than that of the MePLEG nanospheres
because of their different hydrophilic blocks structure. 相似文献