共查询到19条相似文献,搜索用时 62 毫秒
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以乳液聚合法制备粒径分布均匀、球形度良好的聚甲基硅氧烷微球(MPSQ)、聚乙烯基硅氧烷微球(VPSQ)、聚巯丙基硅氧烷微球(MPPSQ),采用SEM、DLS、FT-IR、XRD、TGA、接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。研究结果表明,有机基团对微球的耐热性与疏水性有重要影响,MPSQ和VPSQ的耐热性优于MPPSQ,疏水性从高到低依次为:MPSQ>VPSQ>MPPSQ。聚硅氧烷微球的形成过程可能是单体首先在催化剂的作用下,水解生成硅醇,硅醇开始缩聚形成核,之后通过吸取溶液的硅醇,不断成长,最终形成微球,其中同时存在核生成和核生长,两过程相互竞争,哪个过程占优势取决于反应条件。提高反应温度,使得核生成占优势,最终生成的微球粒径变小,单分散性变差。 相似文献
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以苯基三甲氧基硅烷(PTMS)和γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)为原料,通过溶胶-凝胶法制备粒径介于1.13.8μm的聚环氧基苯基硅氧烷微球,研究了NH4OH浓度、油水比(O/W)、单体配比以及反应温度等条件对微球形态和组成的影响。结果显示将NH4OH的浓度控制在0.01~1.28wt%,投料油水比在1/2到1/30,KH560占总单体含量在0~20mol%之间,可以有效制得微球。随着PTMS/KH560、O/W比值的下降,以及NH4OH浓度的增加,微球粒径变小。 相似文献
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二氧化硅微球的制备与形成机理 总被引:2,自引:0,他引:2
在酯-醇-水-碱体系中以正硅酸乙酯为硅源、氨水为催化剂、乙醇为溶剂,采用改进的溶胶-凝胶法合成了二氧化硅球形颗粒。采用红外光谱、BET吸附曲线、扫描电镜等手段重点研究了正硅酸乙酯加料方式对二氧化硅粒径和形貌的影响。分析表明,采用正硅酸乙酯分步滴定法能提高二氧化硅微球的球形度、窄分布、单分散与致密性。同时,在反应温度25℃、正硅酸乙酯浓度0.12mol/L、氨浓度为15.0mol/L、去离子水浓度0.90mol/L、无水乙醇浓度2.35mol/L、pH值为9~12的条件下,获得了直径约200~250nm、粒径一致性约为0.5、分布偏差约为7.5%的球形二氧化硅单分散颗粒;研究和讨论了二氧化硅微球的形成机理。 相似文献
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采用了一种新的微球制备方法液滴-冷凝法,以左旋聚乳酸[Poly(L-lactic-acid),PLLA]和羟基磷灰石(Hydroxyaptite,HA)为原料制备了复合微球。采用正交试验,以复合微球的粒径、球形度、成球率和孔隙率为考察指标,研究了PLLA溶液浓度、PLLA/HA质量比及冷凝液的温度梯度对复合微球成型和性能的影响,应用扫描电镜(SEM)对聚乳酸微球的微观形貌、孔隙结构进行了观察和表征。研究结果表明,应用该工艺制备的微球粒径均一,球径可控,其表面和内部都存在丰富的微孔,且孔间互相贯通。当采用较低浓度的PLLA溶液和适中的冷凝液温度梯度时,复合微球的各项指标均较好。该微球材料有望在骨缺损填充等领域得到应用。 相似文献
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以乳液聚合法制备粒径分布均匀、球形度良好的聚硅氧烷微球。采用扫描电镜(SEM)、动态光散射(DLS)、红外光谱(FT-IR)、X射线衍射(XRD)、热重分析(TGA)和接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。将平均粒径为1.5μm的聚硅氧烷微球作为光散射剂添加到光学级聚甲基丙烯酸甲酯(PMMA)树脂中,可制备出性能优良的光散射材料。当聚硅氧烷微球添加质量分数约0.6%时,光散射材料的透光率是86.1%,雾度是91.25%,拉伸强度达到最大值77.2 MPa,弯曲强度是87.2 MPa,简支梁缺口冲击强度是2.16 kJ/m2,悬臂梁缺口冲击强度是2.71 kJ/m2,综合性能良好。 相似文献
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空心微球是一种兼具一般空心球和超细功能材料优势的新型结构,在生物医学、化工、功能材料等领域具有应用前景。介绍了模板辅助水热法、无模板水热法制备空心微球技术的原理和特点,并概括了其涉及的反应机理,最后提出了水热法合成空心微球存在的问题并预测了其发展趋势。 相似文献
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Yang Fan Wu Shan-Guang Pan Yu-Fang Song Feng-Lan 《Drug development and industrial pharmacy》2013,39(6):639-645
Background: If erythromycin is micronized into microspheres with suitable particle size, it can improve pulmonary drug concentration to maximize its effectiveness and minimize the adverse side effects. Aim: In this study, erythromycin gelatin microspheres (EM-GMS) were prepared and some characteristics of EM‐GMS were investigated. The drug-targeting index (DTI) of EM-GMS was evaluated to predict their potential as a targeted delivery system. Method: Erythromycin was microencapsulated with gelatin by a double emulsion solvent evaporation method. Some characteristics of EM-GMS, including morphology, particle size, in vitro release, and safety were researched. Results: EM-GMS had a spherical shape and smooth surface morphology. The drug loading and encapsulation efficiency of EM-GMS were 13.56 ± 0.25% and 55.82 ± 2.23%, respectively. The release of erythromycin from EM-GMS showed an initial burst and following a sustained release, with an accumulate release of 80% at 4 hours. The EM-GMS was safe since there was no vein irritation and no hemolysis on the erythrocyte of rabbit at 3.5 mg/mL and a LD50 of 173.07 mg/kg. After administering EM-GMS to rabbits, the concentration of erythromycin in lung was 15.92 times higher than that in plasma and the DTI of EM-GMS in lung was 6.65 as compared with erythromycin lactobionate. Conclusions: The preparation technology of EM-GMS for lung targeting was successful and the quality of microspheres was good. 相似文献
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Di ZhaoWenhai Huang Mohamed N. RahamanDelbert E. Day Deping Wang Yifei Gu 《Materials science & engineering. C, Materials for biological applications》2012,32(2):276-281
Composite microspheres were prepared by coating yttrium-aluminum-silicate (YAS) glass microspheres (20-30 μm) with a layer of Fe3O4 nanoparticles and evaluated for potential use in brachytherapy and hyperthermia treatment of cancer. After neutron activation to form the β-emitting 90Y radionuclide, the composite microspheres can be injected into a patient to destroy cancerous tumors; at the same time, the composite microspheres can generate heat upon application of a magnetic field to also destroy the tumors. The results showed that the composite microspheres were chemically durable when immersed in a simulated body fluid (SBF), with ~ 0.25% weight loss and ~ 3.2% yttrium dissolved into the SBF after 30 days at 37 °C. The composite microspheres also showed ferromagnetic properties as a result of the Fe3O4 coating; when immersed in water at 20 °C (20 mg in 1 mL of water), the application of an alternating magnetic field produced a temperature increase from 20 °C to 38−46 °C depending on the thickness of the Fe3O4 coating. The results indicate that these composite microspheres have promising potential in combined brachytherapy and hyperthermia treatment of cancerous tumors. 相似文献
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制备N--烷基化改性壳聚糖微球, 研究了溶液pH值、2,4-二硝基酚浓度、温度和氯化钠含量等因素对其吸附性能的影响. 结果表明,庚醛改性壳聚糖微球具有较好的抗酸碱性能;溶液的pH值对庚醛改性壳聚糖微球吸附性能的影响较大, pH值为3.6、吸附时间为1 h时,对2, 4--二硝基酚的吸附量最大(达到400 mg×g-1);2, 4--二硝基酚浓度对吸附的影响符合Freundlich等温方程;改性壳聚糖微球对2, 4-二硝基酚的吸附性能明显优于未改性的壳聚糖,对浓度为15 mg×L-1的2, 4--二硝基酚溶液的吸附量分别为3.0 mg×g-1和1.45 mg×g-1. 相似文献