激光光散射研究丙烯酰胺丙烯酸共聚物的溶液行为

用激光光散射技术研究了丙烯酰胺 丙烯酸共聚物 (简称P(AM AA) )的溶液行为 .结果表明 ,纯水中P(AM AA)分子的流体力学半径Rh的分布存在 10 0～ 5 0 0nm的范围 ,与溶液中的网状结构对应 .当加入NaCl后 ,Rh 分布变窄 ,集中在 10 0nm以下的范围内 ,10 0～ 5 0 0nm这一范围消失 ,说明P(AM AA)在纯水溶液中主要以网状结构存在 ,小分子盐如NaCl的加入会破坏这种网状结构 .网状结构的破坏导致溶液稳定性下降 ,在0 1mol LNaCl溶液中 ,当c c 时 ,放置一段时间后 ,溶液中出现白色絮状沉淀 .     

钾离子响应型单分散智能凝胶微球制备与表征

采用沉淀共聚反应成功地制备出了温敏单体N-异丙基丙烯酰胺(NIPAM)和具有钾离子识别能力的苯并-18-冠-6-丙烯酰胺(BCAm)交联共聚的P(NIPAMc-o-BCAm)凝胶微球。采用动态激光光散射(DLS)方法研究了凝胶微球的温敏及钾离子响应特性。实验结果表明,P(NIPAM-co-BCAm)凝胶微球具有很好的单分散性和温敏特性,并且在33℃的5mM钾离子溶液中,其水化直径比在纯水中显著增大,显示出了离子响应性。     

液相色谱-电感耦合等离子体质谱联用研究两种铂类化合物的稳定性及分解产物

基于液相色谱-电感耦合等离子体质谱联用方法,研究了低浓度奈达铂在纯水、9 g/L NaCl溶液和人血浆中的稳定性和分解产物。结果表明,72 h内奈达铂在纯水和血浆中稳定,在9 g/L NaCl溶液中易分解为顺铂。基于凝胶色谱-电感耦合等离子质谱联用方法,研究了低浓度顺式-二碘-(1R,2R)-(-)-1,2-环己二胺合铂(II)(DPI)在纯水、9 g/L NaCl溶液和人血浆中的稳定性和分解产物。结果表明,DPI在3种体系中均不稳定,方法检出限为0.4ng/mL(以铂计)。研究了DPI在9 g/L NaCl溶液中的水解过程,通过同时分析铂元素和碘元素形态确定了水解机理。     

聚硼酸酯表面活性剂囊泡自发形成

通过直接引发聚合, 以偶氮二异丁腈为引发剂, 用N-羟甲基丙烯酰胺、硼酸三乙酯和N,N-二羟乙基十二烷基胺制备了聚硼酸酯(PMBE)表面活性剂, 用红外光谱、核磁共振谱和凝胶色谱对其结构进行了表征; 用透射电镜(TEM)研究了PMBE在纯水和0.1 mol/L NaCl水溶液中的自组装形态. 结果表明, PMBE在水和0.1 mol/L NaCl溶液中皆可自发形成聚合囊泡; 在水溶液中PMBE囊泡粒径约为20 nm, 而NaCl溶液中囊泡直径增大, 在150~250 nm之间, 分布较为均匀; 结合两亲性分子排列参数理论和一定的近似处理方法对PMBE聚合囊泡的形成机理进行了初步探讨.     

聚丙烯酰胺稀溶液的分子模拟

聚丙烯酰胺(PAM)是一类重要的线性水溶性聚合物,具有"百业助剂"之称,因此对其溶液性质的研究意义重大.在溶液质量浓度约为1g·mL-1的基础上,分别构建了含有不同水分子数的溶液模型.采用分子动力学(MD)方法模拟分析了不同温度下非离子型的聚丙烯酰胺(PAM-H)和阴离子型的聚丙烯酰胺(HPAM)在纯水溶液及含不同质量分数NaCl的水溶液中的回旋半径(Rg).结果发现,不同温度下PAM-H和HPAM的抗盐性能的模拟结果与实验数据基本吻合,水分子数不同的溶液模型所得模拟结果趋势没有明显变化,为了提高模拟效率,选取含有2000个水分子的溶液模型分析HPAM链中氧负离子及氧原子的径向分布函数,从微观结构模拟说明了HPAM水溶液粘度随NaCl质量分数增加而减小,且HPAM比PAM-H具有较好的增粘效果及较差的抗盐性能的原因.     

水溶性疏水缔合型聚(丙烯酰胺-丙烯酸十六酯)溶液性质的研究

采用沉淀聚合法制备水溶性的丙烯酰胺－丙烯酸十六疏水缔合型共聚物,研究了共聚物水溶液的性质及其影响因素。随着疏水基团含量增加,共聚物在纯水中及NaCl溶液中的特性粘数[η]均减小,疏水基团临界缔合浓度降低。共聚物溶液浓度高于监界缔合浓度时,溶液表现粘度急剧增加,表明溶液中分子间缔合大量形成。     

氯盐溶液中甲烷水合物高压分解条件及影响因素

向水合物储层注入盐类溶液是水合物常规开采技术之一,所以必须掌握储层压力条件下盐类溶液中水合物分解条件及其影响因素.本文研究了NaCl、MgCl2、CaCl2氯盐溶液中甲烷水合物分解条件,结果表明NaCl(2.0、1.0、0.5 mol·L-1)、MgCl2 (1.0、0.5 mol·L-1)和CaCl2 (1.0、0.5 mol·L-1)溶液中甲烷水合物的分解温度比纯水中分别降低了(4.8、2.4、1.0 K (NaCl))、(5.3、1.5 K (MgCl2))和(4.3、1.8 K (CaCl2)).以van der Waals 和Platteeuw 热力学模型为基础,结合电解质溶液中水的活度方程(Pitzer-Mayorga 方程),给出了氯盐溶液中水合物分解条件热力学模型,进而比较了模型计算值与实验值,结果显示两者非常吻合.分析表明,氯盐溶液中离子静电作用产生的水分子溶剂化效应和盐析效应降低了水的活度而导致水合物分解温度降低.     

正离子PVA基温敏性聚合物的合成与表征及其温敏性研究

通过对聚乙烯醇(PVA)进行正离子化和缩醛化改性,制备了一种新型PVA基温敏性聚合物(CAPVA),其盐水溶液表现出最低临界溶解温度(LCST).在LCST温度以下,CAPVA能溶解于水中,其水溶液清澈透明;温度高于LCST后,CAPVA聚集并从水中分离析出.利用元素、表面电荷分析和核磁共振谱对CAPVA的结构进行了表征,并用浊度法研究了正离子接枝率、缩醛度和溶液中NaCl浓度对CAPVA温敏性的影响.     

肌醇在碱金属氯化物溶液中的体积性质

使用精密数字密度计测定了298.15和308.15 K肌醇在不同浓度的LiCl-H2O、NaCl-H2O或KCl-H2O溶液中的密度, 计算了肌醇的表观摩尔体积Vφ和极限偏摩尔体积Vθφ , 得到了其由纯水溶剂转移至混合溶剂中的迁移偏摩尔体积⊿trsVθ椎 .结果表明, LiCl, NaCl和KCl在溶液中对肌醇的体积性质影响显著, 极限偏摩尔体积Vθφ和极限迁移偏摩尔体积⊿trsVθφ都随盐浓度的增大而增加;温度对肌醇的极限偏摩尔体积和极限迁移偏摩尔体积只有轻微影响. 从分子-离子间的相互作用角度对实验结果进行了讨论.     

应用离子选择性电极进行溶液热力学研究IV: 氯化钠5-45℃间九个温度下由水至二甲基甲酰胺-水混合溶剂的标准转移Gibbs自由能及转移熵的测定

本文应用钠离子玻璃电极及氯离子选择性电极组成无液界可逆电池, 即Cl^-选择电极|NaCl(m), w或s|Na^+玻璃电极测定电池的标准电动势, 计算NaCl从纯水到DMF-H2O混合溶剂的标准转移Gibbs自由能ΔGt°, 测定相应的电池在5℃至45℃九个温度下的电动势温度系数, 求得标准转移熵ΔSt°. 得出ΔGt°及ΔSt°随有机组份含量及温度变化的规律. 对NaCl由纯水至混合溶剂的溶剂化作用的变化, 及DMF和水的液体结构作了讨论.     

SEM Morphologies of a Water-Soluble Terpolymer with Vinyl Biphenyl in Aqueous and Brine Solutions

A terpolymer PAAP, synthesized from acrylamide (AM), vinyl biphenyl (VP), and sodium 2-acrylamido-2-methylpropane sulfonate (NaAMPS), exhibits intermolecular hydrophobically associating behavior in water and aqueous brine solutions. A scanning electron microscope (SEM) was used to observe the conformations of polymer chains and morphologies of their associating microstructures in pure water and in brine solutions. This was done to reveal the relevant relationships between solution properties and associated microstructures for the PAAP polymer in pure water and brine solutions, and the mechanisms for the previously reported viscoelastic behavior of PAAP solutions. Continuous supermolecular associating network structures are formed via strong intermolecular hydrophobic association of biphenyl groups in an aqueous 0.1 g⋅dL⁻¹ PAAP solution, which leads to the excellent viscoelastic character of aqueous PAAP solutions. With increasing polymer concentration, the network structures of the polymer become much larger and more compact in aqueous solution, which results in the excellent thickening properties of their solutions. The SEM results reveal that the elongated conformations of molecular chains in aqueous PAAP solutions are favorable for intermolecular hydrophobic association. With the addition of NaCl, the associating network structures of PAAP are destroyed because of electrostatic shielding effects on the –SO₃^-\mathrm{SO}_{3}^{-} groups, and huge tree-like associated structures are formed. This results in a decrease in the solution viscosity and a loss of viscoelastic properties of PAAP solutions. However, with increasing NaCl concentration, the number and size of the aggregates increase, which results in the salt-thickening behavior of PAAP brine solutions.     

Microstructure and association property of hydrophobically modified polyacrylamide of a new family

A new family of hydrophobically modified polyacrylamides was synthesized via copolymerization of acrylamide (AM) and anionic surface-active monomer of acrylamide-type, sodium 2-acrylamido-tetradecane sulfonate (NaAMC₁₄S), in aqueous solution. In the copolymerization, by varying various factors, such as the feed ratio of NaAMC₁₄S to AM and the amount of added electrolyte NaCl and initiator, we prepared copolymers NaAMC₁₄S/AM with different block structures. The relationship between structures and hydrophobic association properties of copolymer chains was studied by using fluorescence probe and viscosimetry. Effects of the content and length of the hydrophobic blocks and the total molecular weight on hydrophobic association of the copolymers in pure water and in brine solution were examined, respectively. The results show that in pure water, hydrophobic association of the copolymers was enhanced as the content and length of the hydrophobic block increase. On the other hands, for a given content and length of the hydrophobic block, the hydrophobic association of the copolymers was enhanced as the total molecular weight increases. For all the copolymers studied, the apparent viscosity of their solutions in pure water has a limited value, but the apparent viscosities of the copolymer brine solutions are much higher than that of their corresponding water solutions, and show strong positive salinity sensitivity. Similarly, the hydrophobic association of the copolymer in brine solutions was enhanced as the content and length of the hydrophobic block increase.     

Formation of FeCl(2)/NaCl-nanoparticles in supercritical water investigated by molecular dynamics simulations: nucleation rates

Nucleation and growth of FeCl(2) in supercritical water containing NaCl at different state points between temperatures of 798 and 873 K and system densities between 0.24 and 0.14 g cm(-3) have been studied by molecular dynamics simulations. The number of NaCl ion pairs was chosen to simulate particle formation in seawater and brine of higher salinity. Rigid SPC/E water was used to model the water molecules while a combination of Coulomb and Lennard-Jones potentials was used for the ions. Two different methods for determination of nucleation rates are applied and their results compared. We find decreasing nucleation rates with both increasing temperature and decreasing system density. Our results are also compared to those we recently obtained in an investigation of pure FeCl(2) from supercritical water. We find both increasing nucleation rates and a decreasing size of the critical cluster with increasing amount of NaCl.     

Prediction of water content of sour and acid gases

Estimating the feasibility of acid gas geological disposal requires the knowledge of the water content of the gas phase at moderate pressures and temperatures (typically below 50 MPa, below 380 K) and up to 6 mol NaCl. In this paper, a non-iterative model is developed to predict the water content of sour and acid gases at equilibrium with pure water and brine. This model is based on equating the chemical potential of water and using the modified Redlich–Kwong equation of state to calculate the fugacity of the gas phase. The water content of pure CH₄, CO₂ and H₂S are represented with average absolute deviations of less than 3.36, 7.04 and 8.4%, respectively. Experimental data of the water content of mixtures of the acid gases were reproduced with average absolute deviations of less than 6.32%.     

Phase Behavior and Aggregate Structure in Aqueous Mixtures of Sodium Cholate and Glycerol Monooleate

The phase behavior of the glycerol monooleate (GMO)-sodium cholate-water (or 0.9 wt% NaCl) system has been examined in the solvent-rich part, using small-angle X-ray scattering and conventional methods. Addition of cholate up to 7% of the total amphiphile swells the cubic phase of the binary GMO-water system so that it takes up almost 70% of water in the salt-free case and 55% in salt. With more bile salt the lamellar phase also appears highly swollen (up to 85% in water, 75% in brine). In the salt solution a small isotropic L3-phase region replaces the lamellar phase at a solvent content of about 79%. The lamellar phase can accept only about 0.2 cholate molecule per GMO, in both water and brine, and a phase with globular micelles (L1) follows and dominates the diagram. No threadlike micelles appear in this system. Investigation of the particle structures with cryo-transmission electron microscopy (TEM) in dilute systems (99% solvent) show globular micelles and coexisting vesicles and globular micelles. In the presence of salt, dilution of the L3 phase results in dispersed globular particles with an irregular internal morphology that suggests they are a dispersed L3 phase. These particles coexist with faceted particles having an inner structure giving a hexagonal pattern in projection, suggested to derive from the cubic phase. The cubic phase in the salt-free systems did not give dispersions stable enough for cryo-TEM examination. Copyright 1999 Academic Press.     

Rheological behavior of an acrylamide-based terpolymer with p-vinylbenzyl-terminated octylphenoxy poly(ethylene oxide)

A comb-like associating terpolymer PAOE was synthesized from acrylamide (AM), sodium 2-aciylamido-2-methylpropane sulphonate (NaAMPS) and a novel macromonomer: p-vinylbenzyl-terminated octylphenoxy poly(ethylene oxide) (VOE, degree of polymerization: 4??using aqueous free-radical copolymerization technique. The polymer chains were still comparatively extended in the brine solutions at low polymer concentrations. This leaded to the formation of continuous network structures via the intermolecular hydrophobic associations of the octylphenyl groups in despite of the addition of NaCl. As a result, PAOE predominantly exhibited significant elastic characters in brine solutions at 0.5?C9 g/dL NaCl, as well as in aqueous solutions. The viscous and elastic character decreased slightly with increasing temperature from 25 to 45°C for the PAOE brine solution with 0.5 g/dL NaCl. The PAOE aqueous and brine solutions displayed obvious shear thickening behavior upon consecutive steady shear cycles. The brine solution also showed the excellent thickening properties, salt-thickening behaviors twice, and resistance to salt.     

合成盐湖卤水体系Li-Na-K-Mg-Cl-SO_4-H_2O25℃下的等压研究和离子相互作用模型的应用

根据我国青海一里坪和东台吉乃尔盐湖晶间卤水Li-Na-K-Mg-Cl-SO_4-H_2O体 系的组成制备了两种合成卤水储备溶液，采用等压法和改进的实验装置在25 ℃下 ，从稀释到溶液中溶质NaCl达到饱和的浓度范围，对合成卤水溶液进行了等压测定 ，确定了它们的水活度a_(H_2O)，和渗透系数ψ；比较了两种卤水的热力学性质及 其变化的规律，揭示了其天然卤水浓度差异的物理化学成因。用盐湖卤水体系离子 作用模型对水活度、渗透系数的计算值与本文的实验数据比较，对于一里坪和东台 合成卤水，渗透系数的标准偏差分别为0.0078和0.0145；用该模型计算了东台晶间 卤水，及其在25 ψ等温蒸发实验不同阶段的浓缩卤水中，离子强度从9.766到20. 52mol·kg~(-1)范围可能析出的盐类的饱和度，给出了其变化规律，并与文献的盐 类沉积和析盐顺序相比较，获得了合理一致的结果，从而证实了我们在Pitzer离子 相互作用模型基础上所发展的盐湖卤水体系模型对描述和预测复杂天然盐湖卤水体 系的热力学性质和蒸发析盐规律的适用性。     

Thickening and Associating Behavior in Aqueous Solutions of a Terpolymer with Poly(ethylene oxide) Side Chains

A water-soluble terpolymer (PAVA) was synthesized by aqueous free radical copolymerization technique using acrylamide(AM), sodium 2-acrylamido-2-methylpropane-sulphonate (NaAMPS) and a macromonomer: p-vinylbenzyl-terminated octylphenoxy poly(ethylene oxide) (VPEO, degree of polymerization: 10). The remarkable intermolecular hydrophobic associations were formed in water and a brine solution for this polymer, which resulted in a good thickening effect, resistance to salt and salt-thickening. The hydrophobically associating microstructures of PAVA in aqueous solutions were measured by the fluorescent probe and scanning electron microscope. As polymer concentration was increased in water and brine solutions, the associating strength and non-polarity of hydrophobic microdomains increased remarkably. However, at the polymer concentrations higher than 0.20 g/dL, the non-polarity of hydrophobic microdomains tended to remain constant, and the I ₁/I ₃ value changed slightly in 0.5 g/dL NaCl. The continuous associating structures were formed by the expanded polymer chains in brine solutions, as well as in water. As the NaCl concentration increased, the non-polarity of associating microstructures increased slowly, but the compact degree of these microstructures increased.     

Effect of carboxymethyl cellulose and ionic strength on stability of mineral suspensions in potash ore flotation systems

The adsorption of sodium carboxymethyl cellulose from aqueous solutions varying in ionic strength from that of distilled water to 50% NaCl/KCl brine (about 3.5 mol/dm(3)) onto illite and dolomite has been studied. The purpose of this work was to investigate the solvency effects in the phenomena underlying the potash flotation process that is carried out in saturated brine. Based on viscosity measurements, the adsorption results were analyzed in terms of a simple model of polymer macromolecules in solution. Suspension stability measurements carried out concomitantly with adsorption tests showed the ranges of carboxymethyl cellulose concentration over which the tested suspensions either were aggregated or were restabilized.