十二烷基磺酸钠/醇/烷烃/NaCl水溶液四元体系微乳液相行为研究

用Winsor相图研究了十二烷基磺酸钠(AS)/正丁醇/烷烃/N2Cl水溶液体系中相微乳液的相行为.结果表明,随醇浓度的增加,四元体系发生由水包油(O/W)型经中相微乳液(B.C.)到油包水(W/O)型微乳液的转变;表面活性荆浓度越大,得到的中相微乳液体积越大;形成中相微乳液时需要醇的量增加;中相微乳液形成和消失时对应的单位质量表面活性剂需要的醇量随表面活性剂浓度的增加而减小.本文研究了不同碳链长度的烷烃、脂肪醇和盐溶液对微乳液相行为的影响.     

助乳化剂对双连续微乳液聚合稳定性的影响

采用电导法确定单相微乳液的相区发现，水相分率＜18wt%为反相微乳液，水相分率在18－80wt%的区域是双连续相，水相分率大于80wt%则为正相微乳液区。利用高效的KMnO4-H2C2O4氧化还原引发体系引发双连续微乳液聚合，通过改变体系中助乳化剂的含量，考察了微乳液聚合的稳定性，得到了透明多孔的聚合物材料，并对双连续微乳液初始组成对聚合产物孔结构的影响进行了初步探讨。     

基于界面反应的液滴破裂现象制备油包水型纳米乳液

报道了一种利用油水界面反应导致液滴界面失稳并破裂、从而简便可控地制备纳米级油包水型(W/O)乳液液滴并用于活性物质包载的新方法。采用氢氧化钠水溶液为分散相、含有油酸的苯甲酸苄酯溶液为连续相,通过氢氧化钠和油酸在水/油界面反应生成具有更好界面稳定性的油酸钠以降低界面张力,从而导致界面失稳使得液滴破裂,实现了对W/O纳米乳液的可控制备。利用界面张力仪验证了反应过程对液滴界面张力的影响,并用高速摄像显微系统观察研究了液滴的微观破裂过程。系统考察了分散相液滴中氢氧化钠含量、分散相液滴黏度以及连续相中油酸含量对所制得的纳米液滴粒径的影响规律。同时,通过在分散相中加入活性物质,方便地实现了活性物质在W/O纳米乳液内的有效包封。     

SDS/正丁醇/正庚烷/水微乳液体系结构参数测定

用稀释法测定SDS/正丁醇/正庚烷/水体系W/O型微乳液的结构参数,求得不同ω(水和SDS的摩尔比)时体系的水内核半径Rw、颗粒有效半径Re、界面层厚度l、颗粒总数Nd、分散相所占总界面积Ad和平均聚集数(n).研究了不同水量时,醇从油连续相转移到界面层时自由能变化△G0c→i.     

丙烯酰胺反相微乳液稳定性影响因素的研究

使用复配乳化剂,以液态烷烃为连续相,丙烯酰胺溶液为分散相制备均匀的油包水(W/O)型微乳液。通过测定体系电导率及观察稳定性,以水相的最大增溶度为指标,研究了连续相的种类、乳化剂复配、丙烯酰胺(AM)单体浓度、电解质浓度对微乳液体系稳定性的影响。结果表明:以异构烷烃Isopar M为连续相,乳化剂Span80/OP-10复配且当复配乳化剂中Span80含量占80%时,体系对水相增溶量最大;提高AM浓度、加入适量电解质Na Ac,都会增强微乳液的稳定性;电解质的加入还会提高乳化剂的最佳HLB值。     

高内相乳液法制备聚丙烯酸丁酯/二乙烯基苯多孔材料

以丙烯酸丁酯、二乙烯基苯为原料、山梨糖醇酐单油酸酯(span80)为乳化剂,过硫酸钾为引发剂,无水氯化钙为电解质,水做分散相,通过高内相W/O体系制备多孔结构的材料。探讨了聚合反应温度对乳液稳定性的影响及乳化剂用量、分散相体积分数和连续相的性质及组成对聚丙烯酸丁酯(PBA)/二乙烯基苯(DVB)多孔材料结构的影响,并通过扫描电镜对泡孔结构进行了表征。结果表明:聚合反应温度宜控制在55℃;随着乳化剂体积分数增加,材料孔径逐渐减小,且孔间的通道数量增多;随着分散相体积分数的增加,多孔材料的孔径逐渐增加,孔间通道的直径也增大;随着二乙烯基苯与丙烯酸丁酯比值的增加,材料孔径变小。     

含离子液体的复配表面活性剂微乳液的电导性质

研究了CTAB和TritionX-100复配表面活性剂在氯仿作为溶剂时,增溶离子液体bmimBF(IL)时所形成非水微乳液的电导性质,并且与含水体系的微乳液作了比较,发现两者存在较大的差别.在非水微乳液中,随着离子液体质量分数的增加,体系经历了IL/O型微乳液、双连续相、O/IL微乳液三种状态,并且采用循环伏安法对此结论进行了验证.两种表面活性剂复配后,在IL/O型微乳液阶段电导率随着CTAB的摩尔分数(α)增大而增大,在双连续相和O/IL微乳液阶段,体系的电导率随着α增大而减小.在含水微乳液中,只出现O/W型微乳液,而且随着增溶水质量分数的增加电导率下降.增溶水量一定的情况下,电导率随着α值增大而增大.     

水溶助长剂在农药微乳剂中的应用研究

研究了3种水溶助长剂对TX-100/正丁醇/庚烷/水体系相行为的影响,表明只有尿素扩大了微乳液区的面积。同时还研究了仲丁威对TX-100/正丁醇/庚烷/尿素溶液体系相行为的影响,结果表明,当仲丁威质量分数小于15%时对体系相行为基本无影响;随仲丁威质量分数增加,透明的微乳液区面积逐渐减小,而乳液区面积增加。通过电导法研究了仲丁威质量分数10%时相图中微乳液的结构。当m(TX-100 正丁醇 仲丁威)∶m(庚烷 仲丁威)=9∶1时,微乳液经历了由W/O到双连续再到O/W型结构转变,而当m(TX-100 正丁醇 仲丁威)∶m(庚烷 仲丁威)=6∶4时,未观察到明显的微乳液结构转变。     

白油W/O/W型多重乳状液的稳定性研究

以多重乳状液相对体积为衡量标准,用显微镜直接观察,探讨了乳化剂的HLB值、质量分数、亲油亲水乳化剂体积比及油水的相比等对白油W/O/W型多重乳状液体系稳定性的影响。结果表明单一乳化剂体系中适宜的制备条件:乳液中乳化剂质量分数为12.2%,V(Span80)/V(Tween80)=7.5;适合多重乳液稳定的油水相比为:第一相体积比为2.5,第二相体积比为0.2。复合乳化剂体系中适宜的制备条件:第一相乳化剂的HLB值为6.5,V(复合乳化剂)/V(Tween80)=27.5,乳液中乳化剂质量分数为9.5%。     

水分散体系中原子转移自由基聚合研究进展

水分散体系中原子转移自由基聚合(ATRP)具有自由基聚合、乳液聚合和活性/可控聚合的优点,因此近年来关于水分散体系中ATRP的研究日益增多。本文综述了近年来水分散体系(包括乳液体系、细乳液体系、微乳液体系)中原子转移自由基聚合的研究进展,对应用在水分散体系中的几种ATRP反应机理做了简要介绍,包括正向AT-RP、反向ATRP(RATRP)、正向/反向同时进行的(SR&NI)ATRP、电子转移活化剂(AGET)ATRP,并对RATRP、SR&NI、ATRPAGET ATRP的优缺点进行了总结。     

Influence of temperature on the phase inversion of chlorinated polypropylene

In this study, the maleic anhydride modified chlorinated polypropylene (MCPP) resin was emulsified by mixed ionic surfactants comprising sodium dodecyl sulfate (SDS) and sulfonated castor oil (SCO). The influence of temperature on the morphology of emulsion was studied through transitional and catastrophic inversion methods. The transitional inversion of emulsion from water‐in‐oil (W/O) to oil‐in‐water (O/W) was triggered by decreasing the temperature and the catastrophic inversion was achieved by increasing the weight fraction of water. The results of transitional and catastrophic inversion both indicated that the phase inversion of “ionic surfactant–MCPP–water” system is easier to trigger at low temperatures than at high temperatures, which could be interpreted by the thermodynamic and hydrodynamic theory. Incomplete phase inversion occurred at low temperatures when the volume of water phase was small and emulsions with small particle size and narrow particle size distribution could only be obtained at an intermediate temperature. These results are of great importance for the preparation of stable polymer emulsions in food, cosmetics and paints industry. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40325.     

Mechanical Entrainment in W/O/W Emulsion Liquid Membrane

Abstract

An experimental study of mechanical entrainment in W/O/W emulsions is conducted. W/O/W emulsions are stirred for various stirring times under the conditions that mechanical entrainment solely occurs, and changes in volume of the W/O emulsions and size distribution of the internal water droplets are measured. The rate of change in number of the water droplets entrained is found to be proportional to the volume fraction of W/O emulsions. Based on this result, a new model for mechanical entrainment is developed. The calculated change in W/O emulsion volume with time agrees with the observed ones except in the region near phase inversion. Then, phase inversion is discussed.     

N-苯基马来酰亚胺与苯乙烯共聚物乳液的研究

采用种子乳液聚合法制备了N-苯基马来酰亚胺(NPMI)与苯乙烯(St)共聚物乳液,讨论了单体配比对共聚物乳液的聚合稳定性、转化率、流变性、表面张力、粒径大小及分布的影响。结果表明:随着混合单体中NPMI含量的增加,NPMI与St混合单体的转化率降低,聚合物乳液的凝胶量增大,聚合稳定性减弱,黏度逐渐增加。所得共聚物乳液粒径为70~80nm,粒径分布均匀。     

Evidences of correlation between polymer particle size and Raman scattering

This work describes evidences of correlation between polymer particle size and Raman scattering and shows that it is possible to use Raman scattering to monitor the evolution of average particle size during emulsion polymerization reactions. The main focus is the estimation of the average polymer particle diameter from spectra collected in a short acquisition time and consequently low signal-to-noise ratio. Finally, a multivariate linear model, (Partial Least Square-PLS), is fitted from the reaction data and a good linearity between spectra and average polymer particle diameter is found. It is shown that despite varying monomer and polymer concentrations it is possible to monitor average particle sizes during emulsion polymerization reactions using Raman spectroscopy.     

CO2‐Switchable Oil/Water Emulsion for Pipeline Transport of Heavy Oil

By mixing an aqueous solution of tertiary amine, N,N‐dimethylethanolamine (DMEA), with naphthenic acid (RCOOH) derived from heavy oil, a CO₂ switchable zwitterionic surfactant (RCOO^?DMEAH⁺) aqueous system was constructed. The CO₂ switchability of this zwitterionic surfactant was confirmed by visual inspection, pH measurements, and conductivity tests, i.e., the RCOO^?DMEAH⁺ decomposed into RCOOH, DMEAH⁺ and HCO₃^? after bubbling CO₂ through but switched back to its original state by subsequent bubbling N₂ through at 80 °C to remove the CO₂. The interfacial tension tests of heavy oil in DMEA aqueous solutions indicated that the solution containing 0.5 wt% of DMEA and 0.2 wt% of NaCl resulted in the lowest interfacial tension. The O/W emulsion formed when aqueous solutions of DMEA were used to emulsify heavy oil exhibited the best performance when the oil/water volume ratio, DMEA concentration, and NaCl concentration were 65:35, 0.5 and 0.2 wt%, respectively. The feasibility of pipeline transport of the O/W heavy oil emulsion was evaluated. The results illustrated that the demulsification of the O/W emulsion after transport could be easily realized by bubbling CO₂ through. Although demulsification efficiency still needs to be improved, the recycling of the aqueous phase after demulsification by removal of CO₂ looks promising.     

乳液聚合法制备单分散性PS磁性微球的研究

用改进的乳液聚合法，以乙醇／水为反应介质，十二烷基苯磺酸钠为乳化剂，过硫酸钾为引发剂，制备出单分散性聚苯乙烯磁性微球。通过SEM观察其表面形貌、粒径大小及分布，表明具有良好的球形度和一定均匀性。为了制备出粒径小、粒径分布均匀的聚苯乙烯磁性微球，设计了正交实验来优化实验条件；探讨了反应聚合温度、引发剂用量、乳化剂用量及醇水比对微球粒径及粒径分布的影响。实验表明在实验范围内，较低的反应温度、较低的引发剂用量、较高的乳化剂用量、较低的醇水比有利于得到小粒径、高均匀性的PS磁性微球。     

Study and Optimization of Amino Acid Extraction by Emulsion Liquid Membrane

Abstract

A batch extraction of an essential amino acid, phenylalanine, from an aqueous solution of different concentrations by an Emulsion Liquid Membrane (ELM) was developed using D2EHPA as a cationic carrier, Span 80 as the surfactant, paraffin, and kerosene as the diluents, and HCl as the internal electrolyte. All effective parameters such as the initial pH of the aqueous external phase, the electrolyte concentration in the aqueous internal phase, carrier, and surfactant concentration in the emulsion, the volume ratio of the organic to aqueous internal phase (Roi), the volume ratio of the W/O emulsion to the aqueous external phase (Rew) and time were examined and optimized using the Taguchi method. Applying the Taguchi method to analyze the experimental results, the effects and contribution of each of the factors on the extraction efficiency were obtained. The results obtained from the experiments illustrated that with a stable emulsion, by optimizing all the effective parameters, a considerable amount of phenylalanine can be extracted in a short time with an acceptable ratio of swelling and breakage.     

Hydrate formation from high water content-crude oil emulsions

Methane hydrate formation and dissociation studies from high water content ( water) - crude oil emulsions were performed. The hydrate and emulsion system was characterized using two particle size analyzers and conductivity measurements. It was observed that hydrate formation and dissociation from water-in-oil (W/O) emulsions destabilized the emulsion, with the final emulsion formulation favoring a water continuous state following re-emulsification. Hence, following dissociation, the W/O emulsion formed a multiple o/W/O emulsion (60 vol% water) or inverted at even higher water cuts, forming an oil-in-water (O/W) emulsion (68 vol% water). In contrast, hydrate formation and dissociation from O/W emulsions ( water) stabilized the O/W emulsion.     

外部因素对稠油乳状液稳定性的影响研究

研究了搅拌速度、搅拌时间以及温度等外部因素对稠油乳状液稳定性的影响。实验表明:随着搅拌时间增加,乳状液分散相平均粒径减小,粒径分布更加均匀,所得乳状液更加稳定;在搅拌作用初期,随着搅拌速度增加,乳状液分散相平均粒径变小,乳状液稳定性增强,但当搅拌速度达到某一值时,乳状液分散相平均粒径不再继续减小反而增加,乳状液稳定性降低;温度越高,乳状液分散相平均粒径越大,乳状液稳定性越差。     

Investigation into the effect of carboxylic acid monomer on particle nucleation and growth in emulsifier-free emulsion copolymerization of styrene-butadiene-acrylic acid

Latexes of carboxylated styrene-butadiene rubber were prepared via batch emulsion copolymerization with different amounts of acrylic acid in the absence of emulsifier. The effect of acid monomer was investigated in the particle formation and growth. It was observed that the amount of acrylic acid strongly affected the particle formation. The number of particles and thus polymerization rate increased with increasing of the acid content. There was no significant difference in the polymerization rate per particle in all experiments. The results show that in this case particle growth process is less dependent on the acrylic acid amount in comparison with its influence on nucleation stage and then particle number. Several parameters such as polymerization rate and number of latex particle per unit volume of the aqueous phase were calculated. Attempt was made to evaluate the average number of growing chain per particle. Also average particle diameter of the above carboxylated SBR latexes was obtained through some calculations from the direct measurement of average particle diameter in the swollen state by light scattering technique for the first time.