共查询到19条相似文献,搜索用时 125 毫秒
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悬浮聚合法制备聚甲基丙烯酸甲酯微球的研究 总被引:1,自引:0,他引:1
以明胶为稳定剂采用悬浮聚合法合成了微米级聚甲基丙烯酸甲酯微球。通过研究搅拌速度、聚合温度及稳定剂用量,确定了较理想的合成工艺条件。 相似文献
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悬浮聚合法制备PGMA-MMA-EGDMA共聚物交联微球 总被引:3,自引:0,他引:3
以甲基丙烯酸缩水甘油酯(GMA)为主单体、甲基丙烯酸甲酯(MMA)为共单体、乙二醇二甲基丙烯酸酯(EGDMA)为交联剂、聚乙烯醇(PVA)为分散剂,采用悬浮聚合法制备了三元共聚交联微球GMA-MMA-EGDMA,采用FT-IR和SEM对其化学结构和微球进行了表征,考察了分散剂用量、搅拌速度、油/水相比、交联剂用量、NaCl用量对交联微球的成球性能及粒度的影响规律. 结果表明,分散剂用量、搅拌速度与油/水相比是影响交联微球制备的主要因素,当分散剂用量<1%、搅拌速度<250 r/min、油/水相比>1:4(j)时,共聚合体系中均不能成球. 在水相中加入电解质NaCl有助于成球,交联微球的粒径随NaCl用量增大而减小. 控制悬浮聚合的反应条件可以制备出球形度好、粒径在100~400 mm范围内可控的交联微球GMA-MMA-EGDMA. 相似文献
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悬浮聚合制备微米级聚苯乙烯微球 总被引:2,自引:0,他引:2
以羟乙基纤维素和白明胶为稳定剂、甲苯和庚烷为致孔剂,经悬浮聚合制备了单分散交联聚苯乙烯微球。考察了单体用量、引发剂和交联剂含量、搅拌速度对微球粒径的影响。结果表明,最佳的悬浮聚合条件为:单体苯乙烯的用量为水相的质量分数20%、交联剂二乙烯基苯为单体的质量分数4%、引发剂过氧化苯甲酰为单体的质量分数1%、聚合温度为60 ℃、搅拌速度为500 r/min、反应时间为24 h。在此条件下制备的交联聚苯乙烯微球平均直径为40 μm左右,扫描电镜观察结果显示,合成的交联聚苯乙烯微球的形态良好且表面有微孔,分散性好。 相似文献
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悬浮聚合法制备磁性微球的粒度分布特性 总被引:9,自引:0,他引:9
本文研究了含有微细铁黑颗粒的混合单体悬浮聚合产物的粒度分布特性。分析了分散剂、超声预分散和无机铁黑颗粒对形成粒度多峰分布的影响。结果表明,分散剂是体系中形成小颗粒的主要因素;超声波的预分散作用使悬浮体系的液滴破裂以“腐蚀破碎(erosive breakage)”为主;无机铁黑颗粒由于其表面亲水性,倾向于分布在油性单体液表面,不仅有利于悬浮液滴的“磨蚀破碎”,同时也对分散液滴具有良好的稳定作用。上述因素的共同作用使得聚合产物的粒度呈三峰分布。 相似文献
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用作活性物载体聚苯乙烯-二乙烯苯多孔交联微球的悬浮聚合制备及表征 总被引:1,自引:0,他引:1
Functional porous microspheres used for the slow release carrier of actives in cosmetics or pharmaceuticals were prepared by modified suspension polymerization of styrene (ST) with divinylbenzene (DVB) in the presence of toluene, cyclohexanol and heptane as porogenic diluents. The use of ultrasonic dispersion decreases the beads' size and improves the uniformity. The effects of the porogen mixture, DVB content and solvent extraction on the surface performance of the synthesized beads were studied. The microspheres were characterized by scanning electron microscopy (SEM) and BET surface area determination. It was found that a great proportion of the non-solvating porogen increases the pore diameter and the specific surface area. High DVB concentration also results in the great specific surface area and porosity. When the ratio of toluene/cyclohexanol is 1:2, DVB content is at the range of 40%-60% and methylene chloride was used as extractant, the beads with good spherical shape and pore size were obtained. The prepared porous microspheres were applied as active carriers and showed satisfactory slow release effect. Over 10h constantly sustained release was observed in vitro releasing test for hydroquinone-loaded microspheres. Great surface area promoted high concentration of released hydroquinone. 相似文献
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用V(环己烷)∶V(淀粉溶液)=4∶1构成反相悬浮体系,m(Span60)∶m(Tween60)=2∶1复配为分散剂,在60℃下以K2S2O8-NaHSO3引发N,N’-亚甲基双丙烯酰胺(MBAA)与淀粉的接枝共聚,制备了淀粉接枝共聚物微球。正交实验表明,合成共聚微球的较优工艺条件为:淀粉液浓度20%,引发剂用量0.2 g,MBAA用量0.4 g,油水比为3∶1,乳化剂用量1.0 g。用SEM和粒度分析仪对微球形貌和粒度分布进行了研究,用FT-IR对其结构进行了表征,用XRD,TGA对其物性进行了分析。结果显示,共聚物微球形态圆整,平均粒径50.2μm,微球中存在酰氨基结构,与淀粉颗粒相比,结晶度降低,热稳定性提高。 相似文献
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淀粉微球吸附胭脂红动力学研究 总被引:1,自引:0,他引:1
以模型药物胭脂红为吸附质,考察淀粉微球的吸附动力学特性。分别采用5种常用的吸附动力学方程对不同吸附质初始质量浓度的实验数据进行拟合,结果显示淀粉微球对胭脂红的吸附过程较好地符合Lagergren二级吸附动力学模型。然后通过考虑胭脂红初始质量浓度、体系温度和微球平均粒径对吸附的影响,运用多元回归方法建立了平衡吸附量与质量浓度、温度和平均粒径之间的综合吸附动力学模型。该模型确定了影响淀粉微球吸附载药各种因素的主次关系,为研究淀粉微球的吸附载药作用提供了一种研究方法。 相似文献
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Molecularly imprinted polymer microspheres were prepared by precipitation polymerization using a sacrificial covalent bond. In the present model, cholesteryl (4‐vinyl)phenyl carbonate was used as a template monomer. The imprinted microspheres were prepared using ethylene glycol dimethacrylate (EDMA) and divinylbenzene (DVB) as crosslinker. The base‐labile carbonate ester bond was easily hydrolyzed to leave imprinted cavities in the resulting polymers. Radioligand binding analysis, elemental analysis, and scanning electron microscopy were used to characterize the imprinted materials. Imprinted microspheres prepared from DVB crosslinker had larger and more defined spherical shape, and displayed better imprinting effect than did the EDMA‐based microparticles. For comparison, imprinted bulk polymers were also prepared in the same reaction solvent as that used in precipitation polymerization. Elemental analysis results indicated that imprinted microspheres contained more template monomer units than bulk materials. The efficiency of template removal by hydrolysis treatment for microspheres was also higher than that for bulk polymers. For DVB‐based polymers, imprinted microspheres displayed higher specific cholesterol uptake than did the corresponding bulk polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1390–1398, 2006 相似文献
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Monodisperse hydrophilic polymer microspheres having carboxyl acid group with spherical shape in the range of 160 nm and 1.52 μm were prepared by distillation copolymerizations of (meth)acrylic acid with either ethyleneglycol dimethacrylate (EGDMA) or divinylbenzene (DVB) as crosslinker. Polymerization was carried out with 2,2′-azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile without stirring. The polymer microspheres were formed and precipitated out from the reaction medium during the distillation of the solvent from the reaction system through an entropic precipitation polymerization manner. The effects of the crosslinker degree on the morphology and the loading capacity of the carboxylic acid group of the resultant polymer microspheres were investigated. The growth procedures of poly(DVB-co-AA) microspheres were traced by SEM characterization. The steric stabilization through the pendent chains and surface gel and the electrostatic repulsion from the carboxyl acid groups contribute to the formation of monodisperse polymer microspheres. 相似文献
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为了优化采用反相悬浮法合成的交联淀粉微球(CSM)的工艺,采用响应曲面法(RSM)分析了交联剂质量分数、反应温度和引发剂浓度对于CSM品质(溶胀度、平均粒径)的影响,并建立了相应的预测模型。方差分析的结果表明:交联剂质量分数、反应温度和引发剂浓度对于CSM溶胀度和平均粒径这2项指标都有着极为显著的影响。优化所得的较优工艺参数:交联剂质量分数为0.5%,交联温度为48℃,引发剂浓度为3.7 mmol/L。对应的CMS溶胀度及平均粒径的预测值分别为246%和16.5μm。经实验证明:应用响应曲面法所得到的CMS合成工艺参数是可行的。 相似文献