不同油相对负载茶多酚的多重乳液稳定性的影响

采用高压均质和高速剪切的方法,观察其制备的初乳对多重乳液稳定性的影响,并研究了大豆油、芥花油、油茶籽油和葵花籽油四种不同的植物油作为油相对多重乳液稳定性的影响,实验结果表明,用高压均质方法制备的初乳能够获得稳定的、外观细腻的多重乳液。四种不同的油相制备的多重乳液在4000r/min,15min的离心条件下不分层;大豆油作为油相制备的多重乳液在室温下放置两个月分层,芥花油、油茶籽油和葵花籽油,在室温下放置三个月不分层。对四种不同油相制备的多重乳液的粒径进行测量,实验结果表明,油茶籽油的D0.1,D0.5和D0.9三个数据的粒径的稳定性比较好。     

微波辐射甲基丙烯酸甲酯与丙烯酸丁酯的乳液共聚合

在微波辐射下,进行了甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)的乳液共聚合。用称量法测定反应的转化率,研究反应动力学;用差示扫描量热仪(DSC)对共聚产物进行了玻璃化温度(Tg)的测试,并通过Tg计算了共聚物中MMA、BA的质量分数;采用透射电子显微镜(TEM)、激光光散射粒度仪(PCS)表征了乳胶粒形态、粒径大小及分布。结果表明,微波辐射乳液共聚合的诱导期短、反应速率快、转化率高;共聚产物只有一个Tg,并随MMA/BA质量配比的减小,Tg从91.4℃降低到-35.4℃;制得粒径小于100 nm的单分散乳胶粒;随着乳化剂浓度增大,乳胶粒水合粒径从194 nm减小到60 nm左右。     

乳液分散度测定方法的研究

本文根据分光浊度法的基本原理,研究了乳液分散度测定方法,其结果与透射电镜法做比较,误差０．０５４微米,该法对乳液的生产控制和应用研究是很有实际意义的。     

LAS与聚醚复合乳液体系中苯乙烯的聚合

苯乙烯的初始浓度为36.33%时,在十二烷基笨磺酸钠(LAS)/聚醚复合乳液体系中制备了粒径在90.1nm、多分散系数在0.1的聚苯乙烯纳米微球.用红外光谱仪、透射电子显微镜、Zeta电位粒度仪对产物的化学结构,粒径大小、形貌,单分散性进行了表征.研究了体系中各组分质量浓度的改变对产物粒径及单分散性的影响.     

不同介质酸度对乙—丙乳液粒径的影响

本文用ＬＫＹ－１型微粒粒径测定仪对于我室自制的乙－丙乳液在不同ｐＨ介质中的粒径变化作了测定。对于包含羧酸单体的乙－丙聚合物乳液通过粒径变化证明加碱增稠的能力。     

苯丙乳液与聚丙烯酸酯乳液对透水混凝土性能影响的试验研究

聚合物乳液可改善浆体新拌状态,提高透水混凝土强度,本工作采用苯丙乳液(SAE)、聚丙烯酸酯乳液(PAE)对透水混凝土进行改性,研究两者对透水混凝土浆体流变性能、力学性能和透水性能的影响。结果表明,掺入SAE会降低浆体塑性黏度,对新拌浆体流动度影响不显著,透水混凝土抗压强度随着其掺量的增加先提高后降低,聚灰比为1.5%时,浆体的28 d抗压强度相比于对照组R-0提高了8.2%,透水混凝土28 d抗压强度最高为35.5 MPa,相比对照组高了4.1%;掺入PAE会提高浆体的塑性黏度,新拌浆体流动度逐渐减小,透水混凝土抗压强度先提高后降低,透水系数降低,PAE聚灰比为6%时,浆体28 d抗压强度相比于对照组R-0提高了9.6%,透水混凝土28 d强度达到36.8 MPa,相比于对照组R-0提高了7.9%,透水系数达到2.47 mm/s。     

乳液种子生长法制备亚微米单分散聚苯乙烯微球

采用乳液种子生长法设计生长500～600nm范围的单分散聚苯乙烯微球,研究了种子生长法中新核产生的条件,当乳化剂对苯乙烯磺酸钠浓度等于1.298mmol/L=CCMC/10时,不产生新核心.同时为避免单体自聚结块,采用多次投料的方法,成功制备单分散性良好的聚苯乙烯微球.     

可聚合乳化剂改性对弹性丙烯酸酯乳液粘度的影响

使用烯丙基羟烷基磺酸钠(SAHS)作为可聚合乳化剂,改性合成了弹性丙烯酸酯乳液.并用CaCl2电解质溶液、高速剪切机、旋转粘度计和透射电镜(TEM)对乳液进行了表征.研究了可聚合乳化剂对乳液稳定性和乳液粘度的影响;探讨了乳液粘度的变化机理.研究结果表明:烯丙基羟烷基磺酸钠的改性使乳液更稳定,可使乳化剂的总用量减少.随着烯丙基羟烷基磺酸钠用量的增加,乳液的粘度降低;在其用量由0增加至0.75%的过程中,乳液粘度的降低速度较快;随着其用量的进一步增加,乳液粘度降低缓慢,并最终降到20cp.     

乳液法制备单分散纳米二氧化锰

以亚硫酸氢钠(NaHSO3)和高锰酸钾(KMnO4)为原料,通过W/O乳状液模板技术制备了单分散纳米MnO2.用SEM和FT-IR手段对样品的形貌和成分进行了表征,并与均相反应制得的样品进行了比较.结果发现用本方法制得的纳米MnO2微粒单分散好,球形更规整,粒径大.FT-IR谱图也同时反映了粒径不同的两种样品所出现的量子尺寸效应.结合实验事实和样品特性,初步探讨了单分散纳米MnO2的形成机理.     

有机硅改性丙烯酸酯弹性乳液的制备方法

本发明涉及有机硅改性丙烯酸酯弹性乳液的制备方法。该方法用有机硅对丙烯酸酯大分子进行改性，提高了丙烯酸涂料的耐水性、附着性、抗污性和抗龟裂等性能。该乳液所用单体组成为以单体总质量计4％～15％质量的有机硅单体，以单体总质量计1％～5％质量的烯属不饱和酸单体和以单体总质量计80％～95％质量的烯属丙烯酸系单体。本发明制备的有机硅改性丙烯酸酯弹性乳液不但具有有机硅树脂的优良特性，而且也具有良好的稳定性，     

Stability study of W/O/W viscosified multiple emulsions

Stable multiple emulsions with a small proportion of primary emulsion containing different viscosifying agents in the outer aqueous phase were formulated. The multiple systems were assessed by evaluating several parameters, such as the macroscopic aspect, droplet size, release rate, and accelerated stability under elevated temperatures. The effect of different viscosifying agents at different concentrations on the stability and the multiplicity of the multiple emulsions was examined. The viscosity increased by increasing the concentration of the viscosifying agents. It also appeared that the viscosifying agents increased the temperature stability of the multiple emulsions. As a result, the formulation viscosified with Klucel was more stable, while the one prepared with carbomer viscosified the outer phase at much lower concentrations with much better skin feel.     

The determination of iridium in photographic emulsions by flow injection micro-emulsion sampling inductively coupled plasma mass spectrometry

Abstract

Flow injection micro-emulsion sampling inductively coupled plasma mass spectrometry (FI-MES-ICP-MS) was used for the determination of iridium in in-house made emulsion reference materials. The sample was stabilized by a surfactant (Triton X-100) to ensure homogeneous sampling and to prevent sedimentation. A commercially available flow injection analysis system (FIAS) was modified and easily connected to the inductively coupled plasma mass spectrometer (ICP-MS) after optimization of conditions (instrument, flow injection, concentration of surfactant, etc.). The final result is a quantitative determination of iridium in photographic emulsions with a determination limit of 0.07 μg/kg and an accuracy of 3 per cent relative standard deviations (RSD) and a precision of ±0.2 μg/kg (n = 3). The precision and accuracy of the results obtained show the applicability of this method to the determination of iridium at ultratrace levels in various photographic emulsions.     

Protective effect of polysaccharides on the stability of parenteral emulsions

The main purpose of this study is to investigate the influence of two polysaccharides (dextran, hydroxyethyl starch) on the stability of parenteral emulsions. All parenteral emulsions were prepared by high-pressure homogenization. The influence of polysaccharides concentration was studied. The stabilities of autoclaving sterilization, centrifugation and freeze-thawing process were investigated extensively. Following the addition of polysaccharides, the stabilities of the parenteral emulsions were improved. A high-concentration polysaccharides solution (13%, w/v) produced better protection than a low one (1.3%, w/v), especially during freeze-thawing process. The protective mechanisms of polysaccharides were attributed to increasing systematic viscosity, non-frozen water absorbed by polysaccharides, formation of a linear bead-like structure and thicker mixed emulsifier film. Overall, polysaccharides can offer greatly increased protection for parenteral emulsions, and represent a novel protective strategy for improving the stability of this delivery system.     

The effect of additives on the treatment of oil-in-water emulsions by vacuum evaporation

A simple batch vacuum evaporation process for the treatment of several oil-in-water (O/W) emulsions is reported. The experiments were carried out with waste emulsions from an industrial copper rolling process and with model emulsions prepared in the laboratory. No detailed information on the formulation of the industrial waste O/W emulsions was available. Several model emulsions were formulated using the same base oil (an 85–15% (w/w) mixture of a synthetic poly-α-olefin and a trimethylol propane trioleate ester, respectively) and one of the three following surfactants: Brij-76 (polyethylene glycol octadecyl ether, non-ionic), CTAB (hexadecyltrimethyl ammonium bromide, cationic), and Oleth-10 (glycolic acid ethoxylate oleyl ether, anionic). Experimental results show a strong influence of operating conditions, such as pressure or bath temperature, on the evaporation performance. As a general trend, the higher the values of these parameters, the higher the pollutant content in the obtained aqueous effluent. The presence of surfactants increase the evaporation rate, especially at low operating vacuum pressures, the solubility of oil molecules in water and the evaporation temperature of model O/W emulsions. Furthermore, COD reductions higher than 99.5% for the treated waste O/W emulsions were achieved.     

The boundary node method for three‐dimensional linear elasticity

The Boundary Node Method (BNM) is developed in this paper for solving three‐dimensional problems in linear elasticity. The BNM represents a coupling between Boundary Integral Equations (BIE) and Moving Least‐Squares (MLS) interpolants. The main idea is to retain the dimensionality advantage of the former and the meshless attribute of the later. This results in decoupling of the ‘mesh’ and the interpolation procedure.For problems in linear elasticity, free rigid‐body modes in traction prescribed problems are typically eliminated by suitably restraining the body. However, an alternative approach developed recently for the Boundary Element Method (BEM) is extended in this work to the BNM. This approach is based on ideas from linear algebra to complete the rank of the singular stiffness matrix. Also, the BNM has been extended in the present work to solve problems with material discontinuities and a new procedure has been developed for obtaining displacements and stresses accurately at internal points close to the boundary of a body. Copyright © 1999 John Wiley & Sons, Ltd.     

The influence of cell geometry on the elasticity of softwood

The cellular microstructure of softwoods such as spruce may be approximated as an irregular two-dimensional honeycomb. The nine macroscopic elastic constants of the wood, regarded as an orthotropic continuum, are governed by the geometric configuration of this honeycomb, together with the intrinsic material properties of the cell walls. Simple modelling is developed to allow all nine of these constants to be estimated from detailed microscopic measurements of the cell geometry, using assumed values for the cell-wall properties. Account is taken both of the cell-to-cell variations in growth and of the larger-scale modulation of cell properties in the annual growth rings. Results based on study of four samples of Norway spruce show very encouraging agreement with published measurements, and allow the relative importance of various effects to be assessed quantitatively.     

一种适合潜热输送的高温相变石蜡乳状液的热性能

针对太阳能利用、余热利用、集中供暖等应用背景,采用差示扫描量热法(DSC)遴选了一种相变温度合适(相变峰值87℃)、相变潜热值较大(203.9J/g)的工业石蜡,并以此为相变材料,采用非离子型乳化剂及助乳剂复配的方法研制了3种浓度的石蜡乳状液高温潜热输送材料。测定了石蜡乳状液高温潜热输送材料的相变点、相变潜热等热物性,并研究了其蓄热特性。结果表明,该材料是一种在80～90℃之间存在相变的储、传热工质,在相变区间内的储、载热密度远大于水,是一种良好的潜热输送材料。     

A new weight‐function enrichment in meshless methods for multiple cracks in linear elasticity

A new enriched weight function for meshless methods is proposed for the numerical treatment of multiple arbitrary cracks in two dimensions. The main novelty consists in modifying the weight function with an intrinsic enrichment which is discontinuous over the finite length of the crack, represented by a segment, but continuous all around the crack tips. An analytical function is used to introduce discontinuities that are incorporated in the kernel in a simple, multiplicative manner. The resulting method allows a more straightforward implementation and simulation of the presence of multiple cracks, crack branching and crack propagation in a meshless framework without using any of the existing algorithms such as visibility, transparency, and diffraction and without using additional unknowns and additional equations for the evolution of the level‐sets, as in extrinsic partition of unity‐based methods. Stress intensity factors calculated using the J‐integral demonstrate excellent agreement with analytical solutions for classical fracture mechanics benchmarks. Copyright © 2011 John Wiley & Sons, Ltd.     

The traction boundary contour method for linear elasticity

This paper presents a further development of the boundary contour method. The boundary contour method is extended to cover the traction boundary integral equation. A traction boundary contour method is proposed for linear elastostatics. The formulation of traction boundary contour method is regular for points except the ends of the boundary element and corners. The present approach only requires line integrals for three‐dimensional problems and function evaluations at the ends of boundary elements for two‐dimensional cases. The implementation of the traction boundary contour method with quadratic boundary elements is presented for two‐dimensional problems. Numerical results are given for some two‐dimensional examples, and these are compared with analytical solutions. This method is shown to give excellent results for illustrative examples. Copyright © 1999 John Wiley & Sons, Ltd.