PEP聚醚型非离子表面活性剂复配体系的研究

主要讨论了聚氧丙烯－聚氧乙烯－聚氧丙烯（PEP）嵌段共聚醚型非离子表面活性剂分别与十二烷基硫酸钠（SDS0、十六烷基三甲基溴化铵（C16TAB）复配体系的水溶液的表面张力随浓度的变化及其盐效应的影响,计算了二元复配体系水溶液的表面吸附层分子相互作用参数（βσ）及胶束中分子相互作用参数（βm）的值,比较了复配体系的协同效应,并对结果作了理论解释。     

盐引发阴离子/非离子表面活性剂复配体系中囊泡自发形成

在无盐时, 阴离子表面活性剂十二烷基苯磺酸钠(SDBS)与非离子表面活性剂壬基酚聚氧乙烯(10)醚(TX-100)的复配体系中只有混合胶束存在, 而盐的加入即可以引发体系中囊泡的自发形成, 这使得囊泡的形成变得更加简单. 引发机理可以归因于盐对离子表面活性剂的极性头双电层的压缩作用, 减少了极性头的面积, 加上非离子表面活性剂的参与使得堆积参数P增加, 导致了半径更大的聚集体的形成. 制作了SDBS/TX-100/盐水拟三元相图, 通过目测和表面张力的变化确定了囊泡形成的带状区域, 并用负染色电镜(TEM)对囊泡进行了表征, 同时测定了盐度以及相同盐度下表面活性剂浓度对囊泡粒径的影响, 发现囊泡的粒径随着盐度的增加而增加, 而在同一盐度下, 囊泡的粒径基本不受表面活性剂浓度的影响.     

阴离子与非离子表面活性剂复配体系反胶团的电导研究

在SDS/Tween60/正己醇/环己烷/水形成的反胶团复配体系中,电导率(κ)与水和表面活性剂的摩尔比(W0)关系曲线上存在最大值,随着复配体系中SDS的摩尔分数(xSDS)增大,最大增溶水量(W0,max)向W0值更大的方向移动.xSDS≤0.5时,随着xSDS的增大,W0,max所对应的电导率值增大;xSDS≥0.5时,其电导率值减小.在AOT/Tween60/环己烷/水体系中,出现了与SDS/Tween60/正己醇/正己烷/水体系类似的现象,但W0,max所对应的电导率值,随着xAOT的增大而增大,不会出现极大值,两者的差异主要是由于助表面活性剂醇的影响.在SDS/TritionX-100/正己醇/环己烷/水体系中也印证了该结论.     

PEP型嵌段共聚醚非离子表面活性剂的研究

以聚乙二醇和环氧丙烷为原料，用常压法合成了一系列氧丙烯—氧乙烯—氧丙烯嵌段共聚醚，对合成产物进行了结构表征，并对产物的浊点、泡沫稳定性、临界胶束浓度、乳化性能等进行了测定。研究结果表明，氧丙烯—氧乙烯—氧丙烯嵌段共聚醚作为非离子表面活性剂，其性能与嵌段序列长度和含量密切相关。     

Gemini表面活性剂/C12En混合体系的界面吸附、扩张粘弹与泡沫稳定性

用表面张力法研究了阳离子gemini表面活性剂乙基-1, 2-双(十二烷基二甲基溴化铵)(简写为12-2-12)和非离子表面活性剂十二烷基聚氧乙烯醚(C₁₂E_n,其中n = 4, 10, 23)混合体系在气液界面上的吸附行为;用扩张流变技术研究了吸附膜的扩张粘弹行为,实验数据用Lucassen-van den Tempel (LVT)模型进行拟合并根据模型得到了极限弹性值.最后研究了混合体系的泡沫行为,用泡沫塌陷到初始高度一半所对应的时间(t_1/2)来表征泡沫的稳定性.结果表明,所有的非离子表面活性剂C₁₂E_n均与12-2-12产生了吸引作用.在12-2-12浓度相同的情况下,混合吸附层中吸附分子的最小分子占据面积的顺序为12-2-12/C₁₂E₂₃ > 12-2-12/C₁₂E₁₀ > 12-2-12/C₁₂E₄,而极限弹性的顺序为ε_{0, fit}(12-2-12/C₁₂E₄) > ε_{0, fit}(12-2-12/C₁₂E₁₀) > ε_{0, fit}(12-2-12/C₁₂E₂₃).与单组分12-2-12形成的吸附膜相比,只有12-2-12/C₁₂E₄形成更加紧密的结构.具有较小亲水头基的非离子表面活性剂C₁₂E₄的加入,可增强12-2-12吸附膜的弹性,进而增强了对应体系泡沫的稳定性.     

阻抑褪色光度法测定水样中阴离子表面活性剂

在弱酸性的HCl-NaOAC缓冲介质中,溴化十六烷基吡啶(CPB)和曙红Y(EY)染料的混合溶液发生褪色,在该褪色的溶液中分别加入十二烷基硫酸钠(SDS)及十二烷基苯磺酸钠(SDBS)等阴离子表面活性剂(AS),溶液颜色发生改变,最大吸收波长都在514 nm处,并分别在548、546 nm处产生明显褪色。在吸收或褪色波长处,阴离子表面活性剂的浓度与增色或褪色程度呈良好线性关系,从而建立测定阴离子表面活性剂的光度法。在最大吸收波长处,SDBS体系、SDS体系中AS的浓度在0~2.06×10-5mol/L、0~2.63×10-5mol/L范围内遵守比尔定律,表观摩尔吸光系数分别为1.30×104、1.01×104L.mol-1.cm-1,检出限分别为8.14×10-7、9.96×10-7mol/L。若用双波长叠加,表观摩尔吸光系数达2.07×104、1.78×104L.mol-1.cm-1,检出限为4.82×10-7、8.34×10-7mol/L。方法具有较高的灵敏度和良好的选择性,用于水样中AS的测定。     

磷酸酯甜菜碱两性表面活性剂的合成与性能

磷酸酯甜菜碱从皮肤溶出的氨基酸量少,脱脂低,毒性和刺激性低,易降解,是一类性能优良两性表面活性剂[1,2]。它的合成大多以长链卤烷或胺为原料,成本较高。本文以高级脂肪醇、氯乙醇以及二甲胺为原料、P2O5为磷酸化剂,合成了C12H25OCH2CH(OOCCH3)CH2N+(CH3)2CH2CH2OP(O)(O )(OH)磷酸酯甜菜碱。测定了表面张力、泡沫性能、钙皂分散力及增溶能力。1　合成十二烷基缩水甘油醚(Ⅰ)[2]　在500ml三颈烧瓶中加入月桂醇0 2mol,正已烷200ml和四丁基溴化铵0 01mol;在室温和强烈搅拌下加入50%的NaOH水溶液48g,滴加环氧氯丙烷0 4mol后升…     

非离子表面活性剂囊泡包封药物头孢唑啉钠的研究

实验通过超声波法制备了吐温类非离子表面活性剂囊泡，研究了它们对药物质奖励不孢唑啉钠（CEZ）的包封作用以及被包封的CEZ在模拟胃液及模拟肠液中的释放情况。实验表明，吐温40与胆固醇体积比为1：1时形成的非离子表面活性剂囊泡对1mg/mL的CEZ的包封率是20％，而且在模拟胃液和模拟肠液中，对包封的药物都有一定的缓释作用，因此有可能作为临床上的药物缓释剂。     

阴离子表面活性剂存在下吖啶橙—罗丹明B混合体系能量转移研究

本文以吖啶橙和罗丹明Ｂ作为能量转移中的给予体和接受体，分别探讨了不同阴离子表面活性剂对染料问能量转移影响。从染料分子所处微环境变化的角度阐明了分子聚集状态的变化是影响能量转移效率的重要因素。     

阴离子表面活性剂与蛋白质的共振瑞利散射及分析应用

在酸性条件下，蛋白质与阴离子表面活性剂结合形成离子缔合物，使共振瑞利散射(RRs)急剧增强。以十二烷基硫酸钠与牛血清白蛋白反应体系为例，研究了相应的光谱特征，影响因素和适宜的反应条件。在此条件下，不同蛋白质在0-5mg／L或0—l0mg／L范围内与散射强度呈直线关系。方法灵敏度较高，其检出限在17-180μg/L之间，线性范围宽，选择性和重现性较好，可用于多种蛋白质的测定。本法用于合成样品以及人血清样品中蛋白质量的测定，结果满意。     

Effect of Structure on Surfactant Properties

The surface tension and foaming properties of sodium oleate were altered by adding a large and electronegative moiety bromine, to its unsaturation. These properties were measured and compared to the original oleic soap. It was found that sodium oleate has a lower CMC than both of the brominated surfactants. The bromine moiety slows down the rate of adsorption with the doubly brominated surfactant being the slowest. Foamability of the brominated analogues were not affected, however its foam were found to be less stable. Bromination also caused the coalescence and bursting of large bubbles.     

微波发泡制备三聚氰胺甲醛泡沫塑料及其性能

用三聚氰胺、甲醛和DJ-1型增韧剂在碱性条件下制备了改性三聚氰胺甲醛树脂,将其与表面活性剂、发泡剂、固化剂充分混合搅拌,采用微波发泡炉在一定的功率下进行发泡制备三聚氰胺泡沫塑料.研究了增韧剂的用量、微波功率和发泡时间对泡沫结构和性能的影响.并用光学显微镜、TGA、驻波管对三聚氰胺泡沫塑料的泡孔结构、热学性能和声学性能进行了测试和分析.研究表明:当发泡液质量为50 g时,最佳发泡功率为2 kW,最佳发泡时间为60 s;DJ-1型增韧剂的加入使泡沫的韧性提高,当其质量分数为10％时,泡沫的拉伸强度达到0.112 MPa;泡沫的分解温度约400℃,此时的质量残留率接近60％;泡沫在中高频(≥1 000 Hz)区域的吸声系数高达0.9以上.     

Competitive Destabilization/Stabilization of β‐Lactoglobulin Foam by PEO‐PPO‐PEO Polymeric Surfactants

The effect on β‐lactoglobulin foamability and foam stability of the poly(ethylene oxide)‐poly(propylene oxide) block copolymers F127 (PEO₉₉‐PPO₆₅‐PEO₉₉), molecular weight 12500 g/mol, and P85 (PEO₂₆‐PPO₃₉‐PEO₂₆), molecular weight 4600 g/mol, has been investigated at constant protein concentration, 10 µM (0.2 mg/L), and varying block copolymer concentrations, ranging from 0.02 to 1600 µM. Foam was generated by means of air sparging and the foam volume and liquid volume of the foam were measured for one hour. It was found that foam stabilized by F127 or P85 in the concentration range 20–1600 µM contained a larger liquid volume initially than pure β‐lactoglobulin foam. Furthermore, β‐lactoglobulin foamability was only marginally affected by the presence of F127, while it was reduced in an interval of low P85 concentrations. The protein foam stability was retained in the presence of the larger polymer F127, whereas P85 largely reduced the stability, indicating that the size of the polymeric surfactant is important. The results are discussed in relation to surface rheological properties and forces acting across foam films. Steric repulsion generated between the surfaces of foam films is suggested to be the main stabilizing factor in dry foam containing F127. The instability of the mixed β‐lactoglobulin/P85 system is suggested to be caused by two effects. First, there are incompatible stabilization mechanisms of block copolymer and protein, as supported by previous surface rheological data. Second, there is a reduced importance of long‐range steric repulsion when P85 is added, compared to the case where F127 and β‐lactoglobulin are mixed.     

偶氮复合发泡剂对交联聚氯乙烯泡沫结构和性能的影响

采用异氰酸酯和环氧树脂作为交联剂,偶氮二异丁腈（AIBN）和偶氮二甲酰胺（AC）作为发泡剂制备了交联聚氯乙烯泡沫材料。 通过扫描电子显微镜分析了两种发泡剂的粒径、比例以及用量对泡孔结构的影响。 结果表明,AIBN的粒径对泡沫的泡孔结构影响不大,但其用量增加导致泡沫密度减小;AC的粒径对泡孔结构产生一定的影响,最优的粒径范围为8～20 μm,并且随着用量增加,泡孔尺寸变小,但对密度影响不大。 采用DSC研究了AIBN和AC在预混料中的分解情况,提出了两种发泡剂影响泡沫的泡孔结构的机理。 对泡沫材料力学性能的分析表明,泡沫的强度随密度的增加而增加,剪切变形则在60～80 kg/m3密度范围内出现最大值。     

The Impact of Foaming Effect on the Physical and Mechanical Properties of Foam Glasses with Molecular-Level Insights

Foaming effect strongly impacts the physical and mechanical properties of foam glass materials, but an understanding of its mechanism especially at the molecular level is still limited. In this study, the foaming effects of dextrin, a mixture of dextrin and carbon, and different carbon allotropes are investigated with respect to surface morphology as well as physical and mechanical properties, in which 1 wt.% carbon black is identified as an optimal choice for a well-balanced material property. More importantly, the different foaming effects are elucidated by all-atomistic molecular dynamics simulations with molecular-level insights into the structure–property relationships. The results show that smaller pores and more uniform pore structure benefit the mechanical properties of the foam glass samples. The foam glass samples show excellent chemical and thermal stability with 1 wt.% carbon as the foaming agent. Furthermore, the foaming effects of CaSO₄ and Na₂HPO₄ are investigated, which both create more uniform pore structures. This work may inspire more systematic approaches to control foaming effect for customized engineering needs by establishing molecular-level structure–property–process relationships, thereby, leading to efficient production of foam glass materials with desired foaming effects.     

Dynamics of Foaming of Polystyrene Particles

September 24, 2006 Summary: In this work, we address the industrially relevant problem of the foaming of expandable polystyrene (PS) impregnated by pentane as a traditional down-stream processing in the suspension polymerization of styrene. Once the polystyrene foam is formed by means of a proper foaming agent, e.g., pentane or fluoro- or chloro-hydrocarbons, the blowing agent diffuses out from the cellular structure. Environmental efforts call for the reduced consumption of blowing agents. The dynamics of foaming of polystyrene particles was recorded video-microscopically in our laboratory as the sequence of images of expanding particle located in the small pressure cell placed under the microscope with sufficient depth of focus. The amount of pentane sorbed in PS was controlled by the length of the impregnation period and was determined independently by gravimetric measurements. Strong dependence of the structure of the produced foam and of the foaming dynamics on the amount of sorbed pentane, temperature and particle size is reported and explanations for some observed foaming phenomena are provided.     

Study on Foaming Properties and Dynamic Surface Tension of Sodium Branched-alkyl Benzene Sulfonates

Foaming properties and the dynamic surface tension (DST) were carried out with aqueous solutions of sodium branched-alkyl benzene sulfonates to elucidate the relationship between foaming properties and surfactant structures. The parameters of the DST (t*, n, R _1/2 ) are correlated with the foaming ability for alkyl benzene sulfonates with benzene ring substituting at positions 2, 4, and 8 of hexadecane. The parameters of the DST (t*, n, R _1/2 ) are correlated with the foaming ability of the same surfactant solutions. The results indicated that the molecular diffusion in the solution, adsorption, and arrangement at the air/water interface were changed with different molecular structures: changing the substituted position of benzene ring from 2 to 8 of hexadecane, the value of t* and n decrease, and the value of R _1/2 increases, which lead to the high dynamic surface activity and high foam volume. The foam stability is correlated with the high surface dilational elasticity and the strength of surface monolayer: changing the substituted position of benzene ring from 2 to 8 of hexadecane, the branched-alkyl chain becomes more flexible, which is characterized by densely packed adsorbed molecules and high film elasticity of the adsorption film. Therefore, the foam stability increases.     

A Study of Dynamic Interfacial Properties as Related to Foaming Properties of Sodium 2,5-dialkyl Benzene Sulfonates

In this article, foaming properties and dynamic interfacial properties of a series of sodium 2,5-dialkyl benzene sulfonates in aqueous solutions were carried out to elucidate the relationship between foaming properties and dynamic interfacial properties. The properties of foams generated from bubbling air through different surfactant solutions were measured using a modified Bikerman device. The dynamic surface tension and surface dilational elasticity were obtained from an image analysis technique based on the oscillating bubble method. The surfactants molecular adsorption at the air/water interface was introduced with Rosen empirical equation and the rate of adsorption was determined from measurements of the dynamic surface tension. The surfactant with the longest alkyl chain shows the lowest dynamic surface activity, which lead to the lowest foam volume. The short ortho straight alkyl chain has little effect on the arrangement of molecules at the interface and the foam stability changes a little with the changing of the ortho alkyl chain length. The foam stability is correlated with both the higher surface dilational elasticity and the larger surface monolayer strength.     

Investigation on properties of aqueous foams stabilized by aliphatic alcohols and polypropylene glycol

Foams stabilized by nonionic surfactants are usually moderately stable due to high drainage rate and intense bubble coalescence and coarsening. This study aimed to investigate comparatively the foam properties of aliphatic alcohols (methyl isobutyl carbinol (MIBC) and 2-octanol) and polypropylene glycol (PPG400). Experiments were conducted using the FoamScan method at various surfactant concentrations and gas flow rates where the foam volume, liquid content of foam and foam half-life were determined. The results showed that both foamability and foam stability of surfactant solution increased with increasing gas flow rate and surfactant concentration for all tested surfactants. PPG400 was an unusually strong surfactant having the largest surface activity compared with MIBC and 2-octanol, which exhibited the maximum foaming performance and foam stability at all tested gas flow rates and concentrations. The present study suggested that foam properties depended primarily on the type of surfactant and its concentration and secondarily on the gas flow rate. In addition, properties of interface are closely related to that of foam, which is a significant point if one wants to produce foams for specific applications.     

聚乙烯-g-聚苯乙烯对线性低密度聚乙烯/聚苯乙烯共混物机械性能和发泡行为的影响

以通过开环易位聚合、加氢反应和原子转移自由基聚合技术结合制备的聚乙烯-g-聚苯乙烯(PE-g-PS)作为增容剂,研究了加入不同PS支链长度的PE-g-PS对于线性低密度聚乙烯/聚苯乙烯(LLDPE/PS)共混物的机械性能和发泡行为的影响。 以典型组成m(LLDPE):m(PS)=70:30共混物为例,考察了PE-g-PS对共混物拉伸性能的影响。 相对于二元共混物,增容剂的加入使得断裂伸长率、拉伸强度和屈服强度皆提高,且含长PS支链的增容体系提高更明显。 采用超临界CO₂釜式发泡工艺,考察了PE-g-PS中PS支链长度对共混物发泡行为的影响。 结果表明,相对于短PS支链体系,加入PE-g-PS_1.59k(PS相对分子质量为1590)后的泡孔结构更加均一,完全没有“缝隙”形貌的出现。 当发泡温度降至80 ℃时,即使存在LLDPE发泡空间限制作用(LLDPE无法发泡),加入支链长度更长的PE-g-PS_1.59k后泡孔分布也更加均一。