金锥-聚合物球壳靶制备初步研究

 报道了研制快点火物理实验用带金锥固体球壳靶时,采用多次乳化技术制备聚合物空心微球,精密车床加工和电镀技术制备金锥,精密加工实现聚合物微球表面打孔的工艺。窄分布聚苯乙烯制备的空心微球直径与壁厚分布较窄。电镀液的配方、pH值、镀前处理、尖端效应等对镀层的表面质量和镀层与芯轴之间的结合力有重要的影响。采用精密车床加工可以在聚合物微球表面获得直径约120 μm的孔,初步实现金锥与聚合物微球的连接。     

ICF氘代固体靶的研制

 以自制全氘代苯乙烯单体(氘代率99%)为原料, 以偶氮二异丁腈为引发剂, 经自由基本体聚合反应, 先制得全氘代聚苯乙烯, 最后采用乳液微封装技术制得了直径150～450μm、壁厚2～15μm、球形度≥99.5%、同心度95%～98%、表面粗糙度＜30nm的ICF固体靶用空心微球。介绍了制备工艺,并对全氘代聚笨乙烯分子量及其分布的控制,微球壁内气泡形成机理,微球储存稳定性等进行了初步探讨。     

载气环境对液态空心玻璃微球运动状态的影响

 研究了载气组份、温度、压力以及微球直径和壁厚对液态空心玻璃微球在炉内运动状态的影响。结果表明：在用干凝胶法制备空心玻璃微球工艺的常用载气组份、温度和压力范围内,载气的组份、温度和压力对相同直径和壁厚的液态玻璃微球在炉内运动速度的影响小于8.3%,但载气组份和压力对液态玻璃微球运动雷诺数和韦伯数的影响很显著。玻璃微球的直径和壁厚是液态玻璃微球运动速度、雷诺数和韦伯数的重要影响因素。提高载气中的氦气含量或降低载气压力可以降低载气对液态玻璃微球的非球形化作用,提高载气温度可以降低其球形化的阻力。     

微封装法制备聚苯乙烯空心微球的改进

 主要介绍了密度匹配微封装技术，利用此项技术制备的聚苯乙烯空心微球 球形度好于99%，同心度好于98%。另外还对球壳内壁气泡问题及大直径球壳的制备进 行了讨论。     

二乙烯基苯泡沫空心球微流体成型技术

基于微流体成型技术,设计开发了一套用于微胶囊制备的T型微通道乳粒发生器,并利用该装置实现了二乙烯基苯空心泡沫微球的连续制备。以二乙烯基苯的邻苯二甲酸二丁酯溶液为油相,以聚乙烯醇的水溶液为外水相,去离子水为内水相,成功制备出二乙烯基苯双重微乳液,并采用水平旋转加热装置使其凝胶固化,再经过溶剂交换、CO2超临界干燥等过程,制备出直径700～1200μm、壁厚60～100μm、密度90～120mg.cm-3的二乙烯基苯空心泡沫微球。利用光学显微镜、扫描电镜和X-透射显微镜表征,结果显示:微胶囊球形度、同心度和壁厚均匀性较好,成活率较高,直径单分散性较好,外表面较粗糙。     

液滴法制备高尺度比玻璃微球壳的研究

 定量给出了液滴法制备玻璃微球壳（HGM）的直径与壁厚之间的依存关系,确定了制备大直径薄壁HGM的液滴炉温度分布、抽气速率、溶液浓度和液滴发生器操作参数等工艺条件,制备出直径为300～450μm、壁厚为0.7～1.2μm、尺度比为300～700的HGM,表面粗糙度优于10nm,球形度和同心度均优于97%,耐外压能力大于0.91MPa,耐内压能力至少大于0.43MPa。     

PS-RF双层空心微球的制备

 采用聚苯乙烯(PS)空心微球为模板,间苯二酚-甲醛(RF)为前驱体溶液,邻苯二甲酸二丁酯为分散剂,以界面聚合反应为基础初步总结出一条PS-RF双层聚合物空心微球的制备工艺,并就制备过程中RF溶液与分散剂油相的选择、预聚时间、搅拌速率、固化温度等影响因素进行了讨论。当RF溶液质量分数为25%,间苯二酚与碳酸钠的物质的量之比为100,预聚24 h,搅拌速率120～200 r/min,固化温度35 ℃时,制得了球形度和同心度达到95%以上,表面粗糙度小于10 nm的PS-RF双层空心微球。     

聚苯乙烯相对分子量对薄壁聚苯乙烯空心微球质量的影响北大核心CSCD

激光惯性约束聚变(ICF)作为探索受控核聚变的有效途径,有望获得清洁无污染的能源,而薄壁聚苯乙烯(PS)空心微球是ICF物理实验中亟需的一类微球。针对薄壁空心微球因径厚比(直径/壁厚)增大导致其在干燥、使用中易开裂的问题,研究了PS原料对薄壁微球质量的影响,探讨了其影响机制。结果表明:当油相PS质量分数为4%时,随着油相粘度增加,W1/O/W2复合乳粒稳定性逐渐提高;当油相质量分数不低于8%时,复合乳粒稳定性良好。PS原料对微球表面粗糙度影响较小,微球球形度和壁厚均匀性随初始油相粘度的增大而降低,在干燥过程中微球开裂率随原料力学性能提高而减小。在外水相中引入氟苯(FB)液滴,延缓固化速率,可减小油相粘度增加对微球球形度和壁厚均匀性的不利影响。     

强场物理与快点火靶

氘代聚合物空心微球采用多次乳化技术制备。氘代聚合物采用氘代苯乙烯单体的本体自由基聚合反应制备，重均分子量Mw=189000，分散度d=2．72。采用上述氘代聚苯乙烯制备的空心微球无色透明。研究了聚合物分子量对微球直径与壁厚的影响。与普通聚苯乙烯微球相比，采用窄分布聚苯乙烯制备的空心微球的直径与壁厚较小，并且分布较窄。     

界面缩聚法PS-PVA 双层聚合物空心微球的研制

 以界面缩聚反应为基础初步总结出一条PS-PVA双层聚合物空心微球制备工艺,并就工艺中间苯二酰氯（IPC）浓度、交联反应时间、搅拌速度和固化温度等影响因素进行了初步讨论。通过该工艺成功地制得了球形度≥99%、同心度>90%及表面光洁度<10nm的PS-PVA双层空心微球。     

制备大直径无气泡聚苯乙烯空心微球

 高品质聚苯乙烯（PS）空心微球是惯性约束聚变（ICF）实验用多层塑料微球靶的重要芯轴,常由乳液技术制备。针对由乳液技术制备的PS微球壳壁内容易形成气泡而且大直径微球制备困难的问题,实验研究了对壳壁内存在的气泡以及消除方法和制备大直径PS微球的制备技术。     

干凝胶炉法制备聚苯乙烯空心微球

研究了一步乳化法制备初始粒子的过程中相比及搅拌强度对初始粒子直径的影响 ,初步探讨了干凝胶炉内成球过程中 ,炉温、炉内气氛、压力等对聚苯乙烯 (PS)空心微球产率及同心度的影响。以分子量为 2 2万的聚苯乙烯制得了直径在 70～ 550μm的初始粒子 ,经乙醇浸泡后 ,制得了含 2 %质量分数发泡剂的干凝胶粒子 ,并在 Polymer-70 0干凝胶炉上制备出了外直径为 4 0 0～ 90 0 μm、壁厚为 2～1 0 μm、同心度≥ 95%的     

Effect of the shell on the transport properties of poly(glycerol) and Poly(ethylene imine) nanoparticles

Dendritic core–shell architectures containing poly (glycerol) and poly (ethylene imine) cores and poly(lactide) shell (PG-PLA and PEI-PLA respectively) were synthesized. Analogous of these core–shell architectures containing the same cores but poly (L-lactide) shell (PG-PLLA and PEI-PLLA, respectively) were also synthesized. In this work PG and PEI were used as macroinitiator for ring opening polymerization of the lactid and L-lactide monomers. Different molar ratios of monomer to end functional groups of PG ([LA]/[OH]) and PEI ([LA]/[NHn] (n = 1 or 2)) were used to prepare the core–shell architectures with different shell thickness. These core–shell architectures were able to encapsulate and transport the small guest molecules. Their transport capacity (TC) depended on the type and thickness of the shells. TC of core–shell architectures containing PLLA shell was higher than that for their analogs containing PLA shell. The diameter of core–shell architectures was between 20–80 nm. The rate of release of guest molecules from chloroform solution of nanocarriers to water phase was investigated and it depended on the type of the core, shell and solvent.     

Aggregation of a hydrophobically modified poly(propylene imine) dendrimer

The poly(propylene imine) dendrimer DAB-dendr- (NH2)8 was hydrophobically modified with dodecanoyl end groups. The modified dendrimer was deposited onto mica by adsorption from solution and observed by atomic force microscopy. With the decrease of adsorption time, the modified dendrimer varied from continuous film to scattered islands. For the adsorption time of 20s the dendrimer formed a sub-monolayer thin film that contained many fractal aggregates of fractal dimension 1.80 that were > 1 microm in diameter and no more than 0.8nm thick. After 5 months at 1#1 , the initial fractal aggregates transformed into disks and other less-branched shapes with average heights of the domains of 0.6nm and 0.4nm, respectively. Formation of the fractal aggregates is explained by diffusion-limited aggregation. The slow reorganization of dendrimer molecules in the fractal aggregates occurs at a temperature well above the Tg of the dendrimer.     

ICF靶用微球弹跳的影响因素分析

 通过对微球弹跳模型的建立,对微球弹跳过程进行了受力分析,解释了微球弹跳过程中遇到的微球粘连或“不跳”、弹跳率起伏不定及弹跳幅度高低不同等现象。通过对加载信号方向与大小、微球质量及尺寸大小、微球及反弹盘表面特性、环境湿度等影响微球弹跳效果因素的分析,提出了改善涂层表面粗糙度和弹跳效果的措施,包括根据微球大小调整微球弹跳激励方式、等离子体中和微球表面电荷、反弹盘表面改性减小球盘之间的相互作用力。     

Kanamycin A: imine formation in aqueous solution

Imine formation in aqueous solution of kanamycin A with pyridoxal 5'‐phosphate and other aldehydes was studied by potentiometry, NMR spectroscopy and computational chemistry. It was found that imines are formed with yields near 100 % at pH 7 in equimolar reactant ratio. In order to identify the kanamycin amino groups involved in the reaction, a NMR spectroscopic study was conducted. The structures of possible imines formed between kanamycin and FURAN or PLP were optimized by molecular mechanics with the OPLS‐2005 force field. The ¹H NMR spectra were calculated at the DFT‐GIAO B3LYP/6‐31G(d) level of theory for all structures and compared with the experimentally observed spectra. From these results a probable structure of the imines was proposed. The results obtained in this work show that kanamycin has the ability to form imine derivatives in high yields due to its anion recognition properties. Copyright © 2012 John Wiley & Sons, Ltd.     

PAMS微球制备过程中电解质的影响

为调控固化过程中双重乳液内径的变化和降低聚-α-甲基苯乙烯(PAMS)微球的表面粗糙度,研究了双重乳液固化过程中内外水相中电解质浓度对水在油相液膜中迁移和分相行为的影响。结果表明:仅在外水相中添加电解质时,内水相的渗透压高于外水相,使得内相水向外水相迁移,导致固化后的微球表面起皱。当在内外水相同时添加电解质时,由于平衡了三相之间水的化学势,抑制了水在油相液膜中的迁移和分相,导致PAMS微球壳壁内气泡体积和数量显著降低。同时,在内外水相中同时添加不同浓度的电解质,还可显著改善双重乳液三相之间的密度匹配度,从而提高微球的球形度和壁厚均匀性。     

A solid phospholipid-bile salts-mixed micelles based on the fast dissolving oral films to improve the oral bioavailability of poorly water-soluble drugs

Magnetic iron oxide nanoparticles surface covered with oleic acid layer followed by a second layer of hydrophobized oxidized dextran aldehyde were prepared and tested for physico-chemical properties and ligand- and cell-specific binding. It was demonstrated that oleic acid–iron oxide nanoparticles coated with an additional layer of hydrophobized oxidized dextran were dispersible in buffer solutions and possess surface aldehyde active groups available for further binding of ligands or markers via imine or amine bond formation. Hydrophobized dextrans were synthesized by periodate oxidation and conjugation of various alkanamines to oxidized dextran by imination. Physico-chemical properties, as separation using magnetic field, magnetite concentration, and particle diameter, of the prepared magnetic samples are reported. The biotin-binding protein, neutravidin, was coupled to the particle surface by a simple reductive amination procedure. The particles were used for specific cell separation with high specificity.