Rheology and Rheokinetics of Photosensitive Micelle Composed of 3-Chloro-2-Hydroxypropyl Oleyl Dimethyl Ammonium Acetate and trans-4-Phenylazo Benzoic Acid

A novel rheological reversible photosensitive micelle composed of 3-chloro-2-hydroxypropyl oleyl dimethyl ammonium acetate (ODAA) and trans-4-phenylazo benzoic acid (trans-ACA) was investigated. The mixed micelle system under a suitable molar ratio (ODAA:ACA = 1.25:1) shows great viscoelastic property. Before UV irradiation, the ODAA/ACA micelle system exhibits high viscosity and good viscoelasticity. Upon irradiation by UV light (365 nm), ACA undergoes a photoisomerization from its trans to its cis form, causing a change of the molecular structure, which leads to viscosity decreases obviously; thixotropy and viscoelasticity almost disappear. The above changes of rheological properties can be reversible by exposing to visible light. Furthermore, the rheokinetics process of ODAA/ACA micelle system during UV irradiation was studied and rheokinetics equation was established, which can well describe the changing processes of viscosity and viscoelasticity. The viscoelasticity process is divided into two sections to be simulated by rheokinetics equation. In addition, these photosensitive phenomena are repeatable easily and the mechanism can be validated by UV-vis spectra.     

Rheological Properties of a Novel Photosensitive Micelle Composed of Cationic Gemini Surfactant and 4-Phenylazo Benzoic Acid

A new and simple reversible photorhelogical (PR) micelle system was investigated, which is composed of the cationic Gemini surfactant propylene-(dimethyldioctadecylammonium chloride) (18-3-18) and the photoresponsive counter ion, trans-4-phenylazo benzoic acid (trans-ACA). Before UV irradiation, the 18-3-18/trans-ACA mixtures with proper compositions formed highly viscoelastic fluids, showing good viscoelasticity, thixotropy, and shear thinning properties. After UV irradiation, the rheological properties of 18-3-18/ACA micelles changed obviously, exhibiting UV photothinning properties, because the trans-ACA was isomerized to cis-ACA. For the 18-3-18/ACA (8 mM/10 mM) micelle system, after 1 hour UV irradiation at 365 nm, the reduction percentage of the relative viscosity of the micelle was nearly 90%, and its thixotropy loop disappeared. It was revealed that the rheological properties of micelles changed gradually during the process of UV irradiation. In addition, the rheological properties of UV-irradiated micelles can recover after visible light irradiation. The proposed mechanism was validated by ultraviolet-visible (UV-vis) spectra of 18-3-18/ACA micelles.     

Intrinsic Crosslinking and Gel-Breaking Rheokinetics of CMHEC/CTAB Systems

The intrinsic rheokinetics of carboxymethyl hydroxyethyl cellulose and cetyltrimethyl ammonium bromide (CMHEC/CTAB) synergistic fracturing fluid in static crosslinking and gel-breaking processes were studied in this work. Microrheological properties including solid–liquid balance (SLB) and elasticity index (EI) during the static crosslinking and gel-breaking processes were obtained. The effects of temperature on the crosslinking process, concentration of gel-breaker (ammonium persulfate), and temperature on the gel-breaking process were investigated. The novel intrinsic crosslinking and gel-breaking rheokinetics equations were established, respectively. The results show that the crosslinking process can be divided into two stages, and the intrinsic crosslinking rheokinetics equation can well describe EI curves during the static crosslinking process at different temperatures. The EI curves during the gel-breaking process can be well described by the intrinsic gel-breaking rheokinetics equation. The parameters for these two rheokinetics equations are well-defined and reasonable.     

胶束催化体系中的对映选择性环醚化反应

The enantioselective cycloetherification of substituted keto phenols into their corresponding dihydrobenzofuran derivatives was carried out using hydrogen peroxide and chiral quaternary ammonium iodide in micellar media. This approach increased the conversion rate of cycloetherification and also widened the scope of this particular reaction for various substituted keto phenols with electron withdrawing as well as electron donating functionalities. The use of a surfactant in the cycloetherification reaction ...     

聚硼硅氮烷的表征及其流变性能

以二氯甲基硅烷、三氯化硼、六甲基二硅氮烷为起始原料,采用缩聚法合成了新型SiBNC陶瓷前驱体--聚硼硅氮烷(PBSZ),其产率达90%. 通过调节二氯甲基硅烷的用量可获得不同软化点的前驱体. 采用改进的毛细管流变仪,首次对熔融纺丝状态时PBSZ的流变特性进行了研究. 结果表明,PBSZ熔融纺丝时,剪切速率在10～110 s~(-1)范围内时,为切力变稀流体,非牛顿指数为0.83～0.90,表观粘度为440～2 460 Pa·s,粘流活化能约为142 kJ/mol. PBSZ纺丝性能良好,纤维连续无断头长度＞1 600 m,纤维直径＜20 μm.     

Rheological property and rheokinetics of novel photogelling fluids

A novel photorheological fluid composed of cationic Gemini surfactant N, N’-bis (octadecyl dimethyl)-1, 2-dichloride-propyl ammonium salt (C₁₈-3-C₁₈) and trans-ortho-methoxycinnamic acid (trans-OMCA) was investigated. When C₁₈-3-C₁₈ and trans-OMCA are mixed in equimolar quantities, the result is a low-viscosity Newtonian fluid with no thixotropy. After irradiation by UV light (365?nm), trans-OMCA is converted to cis-OMCA, and in turn, the solution undergoes more than 50 fold increase in the relative viscosity and exhibits shear thinning and thixotropy. The viscosity rise is associated with the formation of wormlike micellar network in the solution, which was confirmed by cryo-scanning electron microscopy (cryo-SEM). Furthermore, the rheokinetics process of the C₁₈-3-C₁₈/trans-OMCA solutions during UV irradiation was studied and rheokinetics equation was established, which can well describe the dynamic changing of the rheological properties. Critical packing parameter was introduced to explain the mechanism of photo-induced micelle transition.     

聚醚砜-羟基磷灰石混合溶液的流变性能

采用N,N-二甲基乙酰胺（DMAc）为溶剂配制含羟基磷灰石（HAP）的聚醚砜（PES）溶液,研究了PES-HAP-DMAc体系的流变曲线以及HAP的质量分数、混合溶液温度等对流变性能的影响。结果表明：混合溶液的非牛顿指数（n）随着温度的升高、HAP质量分数的增大而降低,表现为非牛顿流体。     

蛋白质膜界面流变行为研究进展

随着界面流变测量技术以及相关的光学辅助仪器的发展,近10年来界面流变学在食品、化妆品、医药等领域发挥了重要作用。本文介绍了近年来蛋白质膜界面流变行为的研究进展,着重介绍了蛋白质界面流变学在泡沫和乳液方面的研究。本文主要分为3个部分,内容包括:蛋白质膜界面流变学行为与泡沫、乳液稳定性的相互关系,蛋白质-多聚糖的界面流变行为研究,蛋白质-表面活性物质的界面流变行为研究。界面流变学在泡沫和乳液方面取得的较快研究进展不仅促进了人们对蛋白质膜界面流变行为更为深刻的理解,而且为更好地开发和应用蛋白质及其混合物作为表面活性物质和胶体稳定剂而提供重要的理论依据和指导。     

新型羧甲基壳聚糖水凝胶流变性能,药物释放及细胞相容性研究

羧甲基壳聚糖含有丰富的羧基和氨基, 通过1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)共催化交联羧甲基壳聚糖形成新型水凝胶. 调节EDC/NHS用量, 制备不同交联度的羧甲基壳聚糖水凝胶(CMCS hydrogels). 研究水凝胶的流变行为, 结果表明, 高交联度的水凝胶具有较好的弹性形变能力, 较高的储存模量, 这是因为随着交联度的升高, 羧甲基壳聚糖水凝胶化学交联网络结构趋于完善. 以胸腺五肽(TP-5)为模型药物, 初步评价CMCS水凝胶药物释放行为, 结果表明水凝胶交联度越高, 胸腺五肽释放速度越慢. MTT法初步评价了水凝胶细胞毒性, 细胞形态和细胞相对增值速率, 结果表明水凝胶毒性很低. 由此可见, 水凝胶具有良好的生物相容性, 在药物缓释和组织工程领域具有广阔的应用前景.     

有机硅改性丙烯酸酯乳液的流变性

聚合物乳液;流变性能;反应性乳液;有机硅改性丙烯酸酯乳液的流变性     

反胶束萃取醇脱氢酶的研究

本文报道了用反胶束体系萃取醇脱氢酶(ADH)的研究结果。在此萃取体系中,以十六烷基三甲基溴化铵(CTAB)作为表面活性剂,辛烷和己醇作为溶剂及助溶剂。考察了振荡时间、水相pH值和离子强度、表面活性剂及助溶剂浓度等因素对醇脱氢酶萃取率的影响,确定了最佳萃取条件。     

Effect of Mineral Salts on Steady Rheological Properties of Nonionic Hydrophobically Modified Polyacrylamide and Its Stress-Relaxation Behavior

A micelle-forming polymerizable surfactant monomer, octylphenol polyoxyethylene acrylate (OP-10-AC), was synthesized, and then OP-10-AC was copolymerized with acrylamide (AM) to form nonionic hydrophobically modified polyacrylamide P(AM/OP-10-AC) through micellar copolymerization. In the absence of surfactants, it was investigated in detail that the effect of mineral salts and temperature on steady rheological properties of P(AM/OP-10-AC) solutions and the effect of concentrations on reduced viscosity of P(AM/OP-10-AC) in a dilute solution. The results indicate that concentrations of the copolymer, mineral salts and temperature had a strong influence on shear viscosity of P(AM/OP-10-AC) solutions, and the trend of reduced viscosity of P(AM/OP-10-AC) solutions was distinctly different from polyacrylamide with increasing concentrations of testing solutions. In addition, it was also investigated that stress-relaxation behavior of an aqueous solution of P(AM/OP-10-AC)/KCl. As a result, a stress-relaxation model of the copolymer solutions was proposed, which can further verify the correctness of the conclusion on stress-relaxation behavior of hydrophobic association hydrogels in the paper reported previously.     

Mg-Al-CO3水分散液的稳定性及流变性

水滑石;水分散体系;层状结构;Mg-Al-CO3水分散液的稳定性及流变性     

Ga^3＋的新萃取体系的界面特性和胶团化作用研究

研究了Ｇａ~（３＋）协萃体系（Ｇａ~（３＋）－Ｄ_２ＥＨＰＡ－Ｈ_２ＭＰＡ－正十二烷－Ｈ_２ＳＯ_４）的界面吸附和胶团形成热力学，发现该萃取体系中［Ｈ_２ＭＰＡ］影响Ｄ_２ＥＨＰＡ和Ｈ_２ＭＰＡ的界面吸附性质。在中、高［Ｈ_２ＭＰＡ］范围内Ｄ_２ＥＨＰＡ与Ｈ_２ＭＰＡ的界面吸附行为相反，Ｄ_２ＥＨＰＡ的存在也影响Ｈ_２ＭＰＡ的界面吸附行为。研究了界面张力与各因素关系的数学模型，并获得某些胶团形成和界面吸附特性的物化参数。     

Synthesis,Characterization, and Property Evaluation of a Hydrophobically Modified Polyacrylamide as Enhanced Oil Recovery Chemical

A novel hydrophobically modified polyacrylamide p(AM/NaA/OP-10-AC/BOAM) was successfully synthesized via an aqueous micellar copolymerization method from acrylamide (AM), sodium acrylate (NaA), octylphenol polyoxyethylene acrylate (OP-10-AC), and small amounts of N-benzyl-N-octylacrylamide (BOAM), with the aim of investigating the copolymer's rheological behaviors under various conditions such as polymer concentration, shearing, temperature, and salinity. The copolymer was characterized by infrared spectroscopy, scanning electron microscopy, and atomic force microscope. Scanning electron micrographs show large aggregates in solution formed by the association from the hydrophobic groups of the copolymer. Compared with partially hydrolyzed polyacryamide (HPAM), the copolymer shows a much higher thickening capability and a much greater ability to resist shearing, heat, and salts. This good property of the copolymer is attributed to its three-dimensional dimensional network structure. According to the core flooding test, it can be obtained that oil recovery is enhanced about 4.3% by the copolymer flooding contrasted to the HPAM flooding in mid-low permeability cores under conditions of 1500 mg/L of polymers and 45°C. All the results prove that the copolymer has the capability of increasing oil recovery by improving waterflood sweep efficiency in high-salinity reservoirs.     

甲壳素溶液流变性能的初步研究

用热重分析仪和高级流变扩展系统分别研究了提纯工艺对甲壳素的影响和甲壳素／二氮乙酸溶液的流变特性。结果表明，提纯后的甲壳素为纯白色，且杂质含量减少。甲壳素／二氯乙酸溶液的表观粘度随剪切速率的增加而减小，结构粘度指数随浓度的增加而减小。剪切应力一剪切速率的曲线随着溶液浓度的增加而上移，浓度越大，其非牛顿指数n越小。该结构为确定合理的甲壳素纤维原丝生产工艺提供了科学依据。     

Physicochemical and Rheological Properties of Novel Magnesium Salt-Polyacrylamide Composite Polymers

Two series of novel inorganic-organic composite polymers have been prepared through physical blending of magnesium chloride and magnesium hydroxide respectively with polyacrylamide aqueous solution. The physicochemical properties of the magnesium salt-polyacrylamide composite polymers were tuned by varying the ratio between the magnesium salt (e.g., magnesium chloride and magnesium hydroxide) and polyacrylamide. Characterizations of magnesium salt-polyacrylamide composite polymers were carried out via FTIR and TEM. Parameters such as solution conductivity and viscosity were also taken into account to characterize the physicochemical properties of the composite polymer aqueous solutions. Magnesium chloride-polyacrylamide (MCPAM) composite polymer aqueous solutions have a higher conductivity compared to magnesium hydroxide-polyacrylamide (MHPAM) composite polymer aqueous solutions. The viscosities of the MHPAM composite polymer aqueous solutions were found higher than MCPAM composite polymer aqueous solutions. The rheological properties of the composite polymer aqueous solutions were investigated using steady-state flow and oscillatory frequency sweep within the linear viscoelastic region. Shear-thinning effect was observed for both composite polymer systems when the shear rate increases. In oscillatory frequency sweep tests, both composite polymer systems show that the viscoelastic behaviors depend strongly on the magnesium salt concentrations. Viscous behavior was found to be dominant for both composite polymer systems.     

Rheological properties of UHMWPE/iPP blends

The effects of isotactic polypropylene (PP) on the rheological properties of ultra high molecular weight polyethylene (UHMWPE) have been measured in a broad range of composition (0, 5, 15, 30 wt% PP) at various temperatures (110, 130, and 150°C) and a specific gel concentration of 6 wt%. The result showed that the viscosity of the UHMWPE significantly decreased with the addition and increasing amount of PP. Regardless of temperature, the viscosity function followed the power‐law behavior. Copyright © 2009 John Wiley & Sons, Ltd.     

Nanomechanical and Chemical Mapping of the Structure and Interfacial Properties in Immiscible Ternary Polymer Systems

It is a challenge to identify each phase in a multi-component polymer system and uniquely determine the interfacial properties between the different phases. Using atomic force microscopy nanomechanical mapping(AFM-NM) and AFM-based infrared spectroscopy(AFMIR), we identify each phase, visualize structural developments, and determine the interfacial properties in a blend of three polymers: high-density polyethylene(HDPE), polyamide(PA6) and poly(styrene-b-ethylene-co-butylene-b-styrene)(SEBS). Each phase can be identified from the Young's modulus, along with the structural development within the phases before and after compatibilization. The interfacial widths between HDPE/PA6,HDPE/SEBS and SEBS/PA6 were determined independently in one measurement from a Young's modulus map. The structural, mechanical property development and identity of the phases were determined by AFM-NM, while AFM-IR, providing complementary chemical information,identified interfacial reactions, showed the chemical affinity of a compatibilizer with the component phases, and mapped the distribution of the compatibilizer in the ternary polymer blends. The chemical, structural and interfacial information obtained by these measurements provide information that is essential for producing mechanically robust materials from incompatible mixtures of polymers.     

苯乙烯-苯乙烯磺酸钠共聚物的制备及其流变性能

采用乳液聚合合成了一种可作为聚丙烯(PP)纤维可染改性添加剂的苯乙烯-苯乙烯磺酸钠共聚物P(St-co-NaSS)。通过傅里叶转换红外光谱仪(FT-IR)和核磁共振氢谱仪(~1 H-NMR)对共聚物的苯乙烯磺酸钠结构单元进行了表征,研究了反应条件对共聚物磺化度的影响;通过差示扫描量热仪(DSC)和热重分析仪(TG)研究了磺酸基团的引入对共聚物的玻璃化转变温度和起始分解温度的影响;通过旋转流变仪研究了磺化度对共聚物剪切黏度的影响;初步探讨了PP/P(St-co-NaSS)共混体系的染色性能。结果表明:当反应时间为2h,反应温度为70℃,引发剂质量分数为0.6%,苯乙烯磺酸钠的摩尔分数为0.01时,共聚物的磺化度f=6.68%(零切黏度η0=19 620Pa·s,属牛顿流体);在10~(-2)~10~(-1) s~(-1)的剪切速率范围内,P(St-co-NaSS)表现出假塑性流体的特征,具有较好的加工流动性。对于PP/P(St-co-NaSS)共混体系,使用阳离子染料染色时,染色深度(K/S值)为2.603 2,使用分散染料染色时,K/S值为10.168 8。P(St-co-NaSS)适合作为聚丙烯纤维的可染改性添加剂。