pH敏感瓜胶-聚丙烯酸水凝胶的流变和溶胀性能研究

以可生物降解的多糖羧甲基羟丙基瓜胶、敏感功能性单体丙烯酸为主要原料、在性能增强剂粘土存在下,合成一类具有pH敏感性质的新型杂化水凝胶,同时探索所得杂化水凝胶的流变性能及其溶胀行为。结果表明,粘土的加入不仅提高凝胶的力学强度,并可显著增强凝胶的溶胀性能和pH敏感性能。     

磁性半纤维素接枝聚丙烯酰胺水凝胶的制备及其性能研究

以半纤维素和丙烯酰胺为原料,利用自由基聚合法制备了多孔半纤维素接枝聚丙烯酰胺水凝胶,并且通过原位共沉淀法在凝胶上负载Fe3O4粒子,从而得到了磁性水凝胶。分别用FT-IR和SEM对水凝胶的结构和表面形态进行分析;考察了多孔半纤维素接枝聚丙烯酰胺凝胶的溶胀性能并对溶胀动力学进行了数学拟合。研究表明多孔半纤维素接枝聚丙烯酰胺水凝胶的平衡溶胀率随着交联剂量的增大而减小,随着半纤维素/丙烯酰胺比例的增大而增大,随着pH的增大而增大,水凝胶在pH=5.6的溶胀符合Schott溶胀动力学模型。振动样品磁强计(VSM)磁性能测试表明,磁性半纤维素接枝聚丙烯酰胺凝胶具有超顺磁性特征,其饱和磁化强度为10 emu/g。     

聚乙烯醇/膨润土杂化水凝胶的力学性能和溶胀行为

利用冷冻-解冻法制备了聚乙烯醇/膨润土杂化水凝胶. X射线衍射结果表明,膨润土以剥离形式分布在水凝胶基体中. 研究结果表明,与纯PVA5水凝胶相比,经过5个冷冻-解冻循环制备的含2%(w)膨润土的杂化水凝胶的拉伸模量、拉伸强度和断裂伸长率分别增加了44.0%, 74.2%和25.2%,而溶胀行为与5个循环的纯水凝胶相近. 含0.5%(w)膨润土的杂化水凝胶的拉伸模量和拉伸强度高于基体水凝胶,其在溶胀400 min时的溶胀度高于所有的样品.     

戊二醛对壳聚糖-聚醚水凝胶溶胀动力学的影响

以壳聚糖和聚醚为原料、戊二醛为交联剂合成了壳聚糖-聚醚水凝胶。研究了壳聚糖-聚醚水凝胶溶胀机理,探讨了戊二醛浓度对该水凝胶的溶胀度、溶胀速率和溶胀动力学的影响。结果表明,戊二醛浓度不仅是影响水凝胶溶胀度的主要因素,随着戊二醛浓度的增大,壳聚糖-聚醚水凝胶的溶胀度逐渐减小,而且影响其溶胀动力学类型,当戊二醛浓度为0.107 mol·L^-1,该水凝胶的溶胀过程属于Fickian类型,当戊二醛浓度为0.320、0.533 mol·L^-1,其溶胀过程属于non-Fickian类型。     

pH敏感高分子水凝胶的合成及性能研究

从分子设计的角度出发,选用具有优良pH敏感的丙烯酸(AAc)为基本原料,制备了pH敏感水凝胶,系统研究了水凝胶的基本物理性能(密度、平均分子量、交联密度、平衡态水含量、固定电荷密度等),测试了水凝胶在不同离子强度下的溶胀、退溶胀性能,并对其响应机理进行了探讨,同时对水凝胶的机械性能进行测试.结果表明:pH敏感水凝胶的机械性能随着pH值增大而变化,其变化幅度最大可达到80%;其机械性能强烈依赖于平衡态溶胀率;离子强度的大小也对水凝胶的机械性能有着决定性影响.     

Cs-AA-HEMA复合水凝胶的合成及溶胀性能

以壳聚糖、丙烯酸、甲基丙烯酸羟乙酯为原料,硝酸铈铵、过氧化二苯甲酰为引发剂,戊二醛为交联剂,制备了壳聚糖-丙烯酸-甲基丙烯酸羟乙酯复合水凝胶,探讨了凝胶溶胀过程和理论,研究了凝胶合成条件及溶剂性质对凝胶平衡溶胀度的影响.结果表明：随着丙烯酸浓度、甲基丙烯酸羟乙酯添加量的增加,凝胶平衡溶胀度先增大再减小,凝胶溶胀度随着戊二醛浓度增加而减小.壳聚糖-丙烯酸-甲基丙烯酸羟乙酯复合水凝胶是pH/离子/温度敏感型凝胶.     

温度及pH敏感性互穿网络水凝胶的制备研究

采用分步法制备了聚丙烯酸/N-异丙基丙烯酰胺互穿网络水凝胶,研究了互穿网络水凝胶的溶胀性能。结果表明,当水溶液的pH增大时,水凝胶的溶胀率显著增加。在一定的温度范围内,水凝胶的溶胀率随温度升高而减小。聚丙烯酸/N-异丙基丙烯酰胺互穿网络水凝胶表现出显著的温度及pH敏感双重特性。     

聚乙烯醇-壳聚糖互穿网络水凝胶的合成与性能研究

以聚乙烯醇和壳聚糖为原料合成了聚乙烯醇-壳聚糖互穿网络水凝胶,研究了聚乙烯醇与壳聚糖质量比、溶剂醋酸溶液体积、交联剂戊二醛浓度等对聚乙烯醇-壳聚糖互穿网络水凝胶溶胀性能和硬度的影响,得到了最佳合成条件.随着聚乙烯醇与壳聚糖质量比、交联剂戊二醛浓度的增大及溶剂醋酸溶液体积减小,凝胶溶胀度减小而硬度增大.聚乙烯醇-壳聚糖凝胶具有良好的生物相容性.     

CMC-P(AA-AM)水凝胶的制备及溶胀性能测定

以羧甲基纤维素钠(CMC)为原料、丙烯酸(AA)和丙烯酰胺(AM)为单体、偶氮二异丁咪唑啉盐酸盐(VA-044)为引发剂、N,N-亚甲基双丙烯酰胺(NMBA)为交联剂制备了CMC-P(AA-AM)水凝胶，研究了聚合条件对其溶胀性能的影响，通过单因素试验确定最佳聚合条件；利用傅里叶红外光谱、热失重对水凝胶结构进行表征；重点考察了水凝胶在不同盐、pH及表面活性剂溶液中的溶胀性能。结果表明，CMC、VA-044、NMBA、AM占AA的质量分数分别为9%、0.7%、0.7%、33.3%时，水凝胶溶胀倍率最大，为253.2 g/g。CMC-P(AA-AM)在不同盐溶液中的溶胀性能差距较大，对重金属离子更为敏感。水凝胶在pH 5～9范围内保持了较高的溶胀性能，表现出良好的pH响应性能。CMC-P(AA-AM)在阴离子表面活性剂溶液中溶胀性能优于非离子、阳离子溶液，在油酸钠中的吸水倍率为210.0 g/g。     

NVP-HEMA-KH570共聚水凝胶的合成及其溶胀性能研究

以N,N’-亚甲基双丙烯酰胺为交联剂,偶氮二异丁氰（AIBN）为引发剂,合成不溶于水的乙烯吡咯烷酮（NVP）／甲基丙烯酸β-羟乙酯（HEMA）／γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（KH-570）共聚水凝胶,研究了PVP水凝胶的平衡溶胀度及脱水性能。结果表明,随着NVP在水凝胶中含量的增大,水凝胶的平衡溶胀度逐渐增大;环境温度升高,KH570、BIS的含量及浸泡溶液的离子浓度增大,水凝胶的平衡溶胀度逐渐减少;在相同的时间内,环境温度越高,水凝胶的脱水率也越大;在同一温度下,HE-MA含量越大,凝胶脱水的速度就越慢,而浸泡的溶液离子浓度越高,脱水率就越大。     

Water-Permeation Swelling of Emulsion Liquid Membrane

Abstract

Water-permeation swelling resulting from osmotic pressure was studied both theoretically and experimentally. Flat-bed and hollow-sphere models considering the change of permeation area with agitation time were proposed. Mean rate coefficients of water-permeation swelling were obtained from the models. The so-obtained rate coefficients predict the solubility of water in the membrane containing surfactants. The model prediction fits the experimental data well. This model can be used to calculate the permeation-swelling ratio for all swelling cases, such as pure water as inner or outer aqueous phase, or two aqueous phases with different electrolyte concentration. It was found that at the late stage of swelling, the hollow-sphere model gives a better prediction. Experimental studies indicate that control of the swelling can be achieved by surfactants that have lower water solubility, such as EM-301. As for effective factors, increasing surfactant concentration resulted in an increased swelling ratio. Different carriers had different effects on the water-permeation swelling ratio, and addition of all kinds of nonphosphatic carriers to the Span-80 membrane caused severe breakage of the membrane.     

Experimental Study on Foam Properties of Mixed Systems of Silicone and Hydrocarbon Surfactants

Silicone surfactants are inevitably involved in industrial applications in combination with hydrocarbon surfactants, but properties of the mixtures of silicone and hydrocarbon surfactants have received little attention, especially foam properties of the mixtures. In this study, aqueous solutions of respective binary mixtures of a nonionic silicone surfactant with anionic, cationic, and nonionic hydrocarbon surfactants were prepared for evaluation of their foam properties. Surface tension of aqueous solutions of the mixtures were measured with the maximum bubble pressure method. Foaming ability and foam stability of the mixtures were then evaluated with the standard Ross–Miles method. The findings show that the addition of the silicone surfactant results in a decrease in surface tension for aqueous solutions of the hydrocarbon surfactants. The critical micelle concentration (CMC) of the hydrocarbon surfactants is also changed by the additive silicone surfactant. Additionally, clear foam synergistic effects were observed in the mixtures of silicone and hydrocarbon surfactants, regardless of the ionic types of the hydrocarbon surfactant. The foam stability of the hydrocarbon surfactant was shown to generally improve with the increasing concentration of the silicone surfactant. Even so, aqueous solutions of different ionic hydrocarbon surfactants in the presence of the silicone surfactant will give different foam stabilities. The results of the present study are meant to provide guidance for the practical application of foams generated by the mixtures of the silicone and hydrocarbon surfactants.     

Advantage of Sodium Polyoxyethylene Lauryl Ether Carboxylate as a Mild Cleansing Agent

Five anionic surfactants widely used in commercial skin cleansers were studied: sodium polyoxyethylene lauryl ether carboxylate (EC), sodium polyoxyethylene alkyl ether sulfate (ES), sodium dodecyl sulfate, potassium laurate, and N-cocoyl-l-glutamic acid monosodium salt. The amount of surfactant from aqueous solution adsorbed into the stratum corneum (SC), the degree of SC swelling, the change of the secondary structure of SC proteins (denaturation). The surface tension of surfactant–zein mixed solutions, and the solubilization behavior of zein were measured. Results showed that EC had the lowest adsorption into SC, the lowest SC swelling, and lowest denaturation of SC proteins. Low interactions between surfactants and SC proteins were also observed for EC/ES mixture solutions as well as. Mixing EC with ES good foaming performance. The EC/ES mixture, at about 1:1 ratio, is an excellent surfactant system for skin cleanser applications having cleansing characteristics and mildness to the skin.     

季铵盐双子表面活性剂与HPC在水溶液中的相互作用

采用稳态荧光和电导方法研究了系列季铵盐阳离子双子表面活性剂C12-S-C12·2Br(S代表亚甲基的个数)与水溶性高分子羟丙基纤维素(Hydroxypropyl cellulose,HPC)在水溶液中的相互作用。实验结果表明:在低于双子表面活性剂自身临界胶团浓度(Critical miceue concentration,cmc)时,在HPC分子上发生了聚集。当E12-S-C12·2Br/HPC体系混合溶液中C12-S-C12·2Br。的浓度达到c2(c2>cmc)时才有表面活性剂自由胶团生成。揭示了临界聚集浓度(Critical aggregation concentration,cac)和C12-S-C12·2Br/HPC体系混合溶液中自由胶团生成浓度c2与系列C12-S-C12·2Br表面活性剂cmc的比例关系及与链接链S的关联。     

AM-DMC反相乳液共聚合研究

以白油为连续相，Span、Tween、OP为乳化剂，进行了丙烯酰胺—甲基丙烯酰氧乙基三甲基氯化铵的反相乳液共聚合反应。考察了乳化剂种类及用量、引发剂种类及用量、油水比、单体质量分数等因素对所得产物分子量的影响。     

Synthesis and Properties of Two Amino Carboxylic Acid Gemini Surfactants

The number of hydrophilic and hydrophobic groups of a surfactant has a great influence on its property. Two Gemini surfactants, N,N″‘-didodecyl-N,N',N″,N″‘-tetrapropionate triethylenetetramine and N,N'-didodecyl-N,N'-dipropionate ethylenediamine (referred as DTPTT and DDPED), were prepared by Michael addition reaction of the didodecyl secondary amines with methyl acrylate. The didodecyl secondary amines were synthesized by nucleophilic substitution reaction of triethylenetetramine or ethylenediamine with bromododecane. The DTPTT and DDPED surfactants were characterized by mass spectrometry and proton nuclear magnetic resonance spectrometry. The surface activities of the DTPTT and DDPED aqueous solutions were studied by surface tension measurements. The surface tension and critical micelle concentration (cmc) of DDPED is smaller than that of DTPTT. The DDPED can reduce the surface tension of water to approximate 34 mN m⁻¹ at concentration levels of 10⁻⁵ mol L⁻¹. The aggregation behavior of the DTPTT and DDPED aqueous solution were studied by dynamic light scattering and transmission electron microscopy. Both surfactants can form spherical vesicles at a solution of about 3–5 times cmc of the Gemini surfactants. The foam property was determined by nitrogen blowing method. The DTPTT has relatively good foaming ability and DDPED has excellent foam stability. The foam volume of DDPED barely change within 1000s. The emulsion stability of the Gemini surfactants was determined by separation time of water from the emulsion. The emulsion stability of DDPED is equivalent to Tween 80. The DDPED Gemini surfactant with two hydrophilic carboxylic groups has better surface activity, foam stability, and can be used as an O/W emulsifier.     

Influence of Nonionic Surfactant on Hydrolysis of Vinyl Sulfone Reactive Dye

Nonionic surfactants are widely used in reactive dyeing processes, and the interaction between surfactants and reactive dyes affect the hydrolytic property of reactive dyes. In this study, reactive brilliant blue KN‐R (C.I. reactive blue 19) was employed as a model dye, and fatty alcohol polyoxyethylene ether (AEO‐9) was selected as a model nonionic surfactant. The interaction was first investigated in aqueous solutions by a UV‐spectrophotometry method, then the effect of surfactant concentration on the hydrolytic behavior of KN‐R was studied using high performance liquid chromatography method. Below the critical micelle concentration, the surfactant served as dispersant; the hydrolysis of reactive dye was accelerated. However, when the concentration of surfactant was above its critical micelle concentration, the dye was solubilized into the micellar phase, which was revealed from the changes in absorbance intensity and wavelength of the maximum absorbance. This led to slowed hydrolysis of reactive dye. These findings are useful in understanding the effect of concentration of nonionic surfactant on the hydrolysis of vinyl sulfone reactive dyes.     

温度与pH敏感性大孔聚P（NIPAM-co-MAA）水凝胶的制备及性能研究

以乙醇水溶液作为反应介质,成功制备了温度与p H快速响应性聚（N-异丙基丙烯酰胺-co-甲基丙烯酸）[P（NIPAM-co-MAA）]水凝胶,研究了乙醇水溶液的浓度对凝胶性能的影响。通过红外光谱（FT-IR）﹑扫描电镜（SEM）﹑测溶胀比对凝胶性能进行了表征。结果表明,凝胶具有相同的化学组成与结构,但具有不同的微观形态;当乙醇浓度为30%-80%时,凝胶的溶胀率和退涨率随着反应介质中乙醇浓度的增加而增加。所制备的凝胶表现出较强的温度与p H敏感性以及较快的去溶胀速率。     

Synthesis and Properties of Quaternary Ammonium Surfactants Based on Alkylamine,Propylene Oxide,and 2‐Chloroethanol

New quaternary ammonium salts are synthesized by octylamine, nonylamine, dodecylamine, and hexadecylamine reacting with propylene oxide at a mole ratio of 1:2, followed by reaction with 2‐chloroethanol. By tensiometric measurements of aqueous solutions, their surface activity has been determined. Using the results of these measurements and electroconductometric studies, important parameters such as critical micelle concentration (CMC), efficiency of surfactant adsorption, surface pressure at the CMC, changes of Gibbs free energies for micelle formation, and adsorption were estimated. By application of the Gibbs adsorption isotherm, indices such as maximum surface excess concentration and minimum surface area/molecule at the air–water interface were also calculated. Petroleum‐collecting properties of these surfactants were investigated. Among these quaternary ammonium surfactants, the surfactant based on dodecylamine, propylene oxide, and 2‐chloroethanol exhibits the highest petroleum‐collecting capacity.     

Swelling behavior of sulfonated polyacrylamide nanocomposite hydrogels in electrolyte solutions: comparison of theoretical and experimental results

Nanocomposite hydrogels were prepared by cross-linking of aqueous solutions of sulfonated polyacrylamide/sodium montmorillonite with chromium triacetate as ionic cross-linker. The effect of montmorillonite content on equilibrium swelling in NaCl and CaCl₂ solutions, ultimate storage modulus and effective cross-link density was evaluated. The limiting storage modulus of the nanocomposite (NC) hydrogels dropped by increasing montmorillonite content up to 1,000?ppm, and then it increased by further montmorillonite loading. A mechanism is proposed for the formation of PAMPS/Na⁺-MMT/Cr³⁺ NC hydrogels. According to this mechanism, the drop in limiting storage modulus of the NC gels at low Na⁺-MMT concentration is due to ionic interactions between the negative layers of sodium montmorillonite and Cr³⁺, leading to decreased cross-link density. However, the increase of the limiting storage modulus of the NC gels at high clay concentration results from the strong interactions between the polyacrylamide chains and clay platelets. The equilibrium swelling ratio of the NC networks decreased with increase of montmorillonite content in both aqueous NaCl and CaCl₂ solutions. In addition, the experimental swelling data of these NC hydrogels were described by a modified Flory?CRehner theory. The modified model was sensitive to montmorillonite concentration and it described adequately the swelling data for NC gels in NaCl solutions. Nevertheless, theoretical predictions showed some deviations from experimental results for swelling of NC hydrogels in CaCl₂ solutions.