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61.
采用双乳液法研制配糖蛋白B的肠溶微胶囊,考察了微胶囊的形态、粒径及其分布,在摸拟肠液的缓冲液中进行溶解释放试验。配制了两种口服微胶囊混悬制剂,并考察了它的稳定性。 相似文献
62.
利用聚合物乳液合成聚甲基丙烯酸甲酯/二氧化硅纳米杂化材料 总被引:10,自引:0,他引:10
通过正硅酸乙酯分别在聚甲基丙烯酸甲酯乳液和四氢呋喃溶液中的溶胶-凝胶反应制备出不同的聚甲基丙烯酸甲酯/二氧化硅复合材料。利用扫描电镜、透镜电镜、差热分析和热失重对试样进行了分析。结果表明,利用聚合物乳液可以获得纳米分散的聚甲基丙烯酸甲酯/二氧化硅复合材料,并且在某种程度上其分散尺度小于利用聚合物溶液获得的复合材料。同时,利用聚合物乳液来制备聚甲基丙烯酸甲酯/二氧化硅杂化材料更有利于凝胶过程中二氧化硅网络的形成。 相似文献
63.
乳状液膜法提取L-谷氨酸的研究徐占林(四平师范学院化学系四平136000)严忠张河哲(东北师范大学化学系长春130024)关键词L-谷氨酸乳状液膜载体萃取中图分类号O623.736氨基酸作为重要的生化产品,广泛应用于食品、饲料、医药、化工等许多领域,... 相似文献
64.
研究了烷基硫酸钠纯度,烷基碳链分布对甲基丙烯酸甲酯种子乳液聚合反应的影响。结果表明,烷基硫酸钠中乙醇不溶物含量的增加,可提高MMA乳液聚合反应速度,在采用K2S2O8-NaHSO3-Cu^2+三元氧化-还原引发体系的MMA乳液聚合中,Fe^2+降低反应速率,而Fe^3+则提高聚合反应速率; 相似文献
65.
66.
阳离子无皂含氟丙烯酸酯的合成与表面性能 总被引:1,自引:0,他引:1
在合成甲基丙烯酸全氟辛酰氧基乙酯(FA)基础上,用半连续法制备了无皂阳离子含氟丙烯酸酯乳液。当乳液的粒径在100~200 nm、ζ电位大于40 mV时,乳液较稳定。阳离子亲水单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)在含氟丙烯酸酯中质量分数为0.10~0.18、固含量小于20%时乳液的稳定性好,且随DMC含量的增加稳定性提高;含氟丙烯酸酯乳胶膜的附着力与耐磨性好,乳胶膜的透湿率随DMC的增加而增加。随热处理温度的提高,膜表面自由能下降;经160℃热处理后膜发生了交联,表面自由能为18 mN/m,与聚四氟乙烯(PTFE)的表面能相近,DMC含量对膜表面自由能影响不大。XPS分析也表明膜表面氟含量随热处理温度的提高而增加。 相似文献
67.
羧基丙烯酸酯涂料合成及其防雾性能研究 总被引:3,自引:2,他引:3
采用种子乳液聚合法合成了一种互穿网络型羧基丙烯酸酯类聚物乳液,研究了加料方式对羧基分布的影响,结果表明丙烯酸加入到核单体中有利于羧基分布在乳胶粒表面。在体系中引入离子键交联结构提高了乳液涂料的硬度和耐水性能,离子键交联PILN型涂料具有优良的防雾性能。 相似文献
68.
We studied thermal transitions and physical stability
of oil-in-water emulsions containing different milk fat compositions, arising
from anhydrous milk fat alone (AMF) or in mixture (2:1 mass ratio) with a
high melting temperature (AMF–HMT) or a low melting temperature (AMF–LMT)
fraction. Changes in thermal transitions in bulk fat and emulsion samples
were monitored by differential scanning calorimetry (DSC) under controlled
cooling and reheating cycles performed between 50 and –45°C (5°C
min–1). Comparison between bulk fat samples
and emulsions indicated similar values of melting completion temperature,
whereas initial temperature of fat crystallization (Tonset)
seemed to be differently affected by storage temperature depending on triacylglycerols
(TAG) composition. After storage at 4°C, Tonset
values were very similar for emulsified and non-emulsified AMF–HMT blend,
whereas they were lower (by approx. 6°C) for emulsions containing AMF
or mixture of AMF–LMT fraction. After storage at –30°C, Tonset values of re-crystallization
were higher in emulsion samples than in bulk fat blends, whatever the TAG
fat composition. Light scattering measurements and fluorescence microscopic
observations indicated differences in fat droplet aggregation-coalescence
under freeze-thaw procedure, depending on emulsion fat composition. It appeared
that under quiescent freezing, emulsion containing AMF–LMT fraction
was much less resistant to fat droplet aggregation-coalescence than emulsions
containing AMF or AMF–HMT fraction. Our results indicated the role of
fat droplet liquid-solid content on emulsion stability. 相似文献
69.
A versatile nonaqueous emulsion polyaddition process for the one-step fabrication of spherical polyurethane nanoparticles
is presented. Three different emulsion systems were used consisting of N,N′-dimethylformamide (DMF) dispersed in n-hexane, acetonitrile dispersed in cyclohexane, and acetonitrile dispersed in tetradecane. After successful stabilization
of the emulsion systems by using a poly(isoprene)-poly(methylmethacrylate) block copolymer, the fabrication of the polyurethanes
was carried out within the dispersed polar phase. The polyurethane particles showed average diameters as small as 35 nm. Additionally,
infrared (IR) characterization revealed that the formation of any urea, which decreases the mechanical properties of the polyurethanes,
was prevented during the polyaddition. This was attributed to the anhydrous reaction conditions. Gel permeation chromatography
(GPC) analysis demonstrated the average molecular weights (M
n) of the polyurethanes to be as high as 16,500 g/mol, corresponding to conversions of 0.98. Comparable molecular weights and
conversions have not previously been achieved without the formation of urea. 相似文献
70.
Monodisperse thermosensitive particles prepared by emulsifier-free emulsion polymerization with microwave irradiation 总被引:2,自引:0,他引:2
The emulsifier-free emulsion polymerization of styrene (St) and N-isopropylacrylamide (NIPAAm) was successfully carried out with microwave irradiation, and the monodisperse thermoresponsive
poly(styrene-co-N-isopropylacrylamide) (poly(St-co-NIPAAm)) particles with diameters in the range 100–130 nm were prepared. The morphology, size and size distribution of the
poly(St-co-NIPAAm) particles were characterized by transmission electron microscopy, scanning electron microscopy (SEM) and photon correlation
spectroscopy (PCS), respectively. The results showed that poly(St-co-NIPAAm) particles had spherical morphology, and the poly(St-co-NIPAAm) particles prepared by emulsifier-free emulsion polymerization with microwave irradiation were smaller, more uniform
than those obtained with conventional heating. The hydrodynamic diameters of poly(St-co-NIPAAm) particles were decreased as the temperature increased from 25 °C to 40 °C, and poly(St-co-NIPAAm) particles collapsed remarkably at 32 °C, which is the lower critical solution temperature of the poly(N-isopropylacrylamide). The morphology of the assembled poly(St-co–NIPAAm) particles was observed by SEM, it was found that monodisperse poly(St-co-NIPAAm) particles could assemble to form the two-dimensional order structures. 相似文献