Rheology Properties and Plugging Performance of Fluorescent Polyacrylamide Microspheres in Fractures

Polyacrylamide microspheres have recently drawn great attention in conformance control due to their advantages over traditional gel treatments. One important question that has been raised is whether the tiny particles can be produced from production wells. However, current products are difficult to use for detecting fluids generated by production wells. In this paper, the fluorescent polyacrylamide microspheres were successfully synthesized; they can emit blue fluorescence under ultraviolet irradiation. Their swelling property, fluorescence characteristics, rheology property, creep-recovery property, and plugging performance were evaluated in the laboratory. The results indicated that the microspheres could emit blue fluorescence under ultraviolet irradiation after passing through a fracture model. Their creep-recovery ability after deformation was very high, and their elastic recovery rate extended to 94.1%, which suggests that the microspheres almost recover to their original shape and size after deformation. The transparent fracture model plugging test shows that the microspheres can migrate and plug a fracture with a width of 0.3 mm, which is much smaller than the diameter of the microspheres.     

分散聚合法制备耐盐型两性絮凝剂及絮凝性能

以丙烯酰胺(AM)为主体,同时引入正、负2种电荷基团单体,在盐水介质中采用分散聚合法,成功制备了耐盐型两性絮凝剂（P（AM/AA/DMBAC）,简称AAB系列）。 系统地考察了分散介质、分散剂、单体浓度和链转移剂（次磷酸钠、甲酸钠）用量对两性絮凝剂AAB特性粘数和表观黏度的影响,确定了最佳反应条件为：n(AM)∶n(AA)∶n(DMBAC)=90∶5∶5,w（单体含量）=13%、w（PDAC）=6%(基于单体总质量)、w（硫酸铵）=25%(基于体系质量)、w（引发剂（VA-044））=0.2%(基于单体总质量)、ρ（次磷酸钠）=0.05 g/L、ρ（甲酸钠）=1.0 g/L,反应温度35 ℃,反应时间24 h,并通过絮凝试验评价了该两型絮凝剂的絮凝性能和耐盐性。 结果表明,在最佳反应条件下,两性絮凝剂具有较大的特性粘数（5.2 dL/g）和良好的稳定性;在高盐浓度的模拟污水中,两性絮凝剂具有使用剂量小（30×10-6）,絮团沉降速率快（2.56 s-1）等优点,表现出优异的絮凝能力和良好的耐盐性。     

分散聚合法制备聚丙烯酰胺水包水乳液

采用甲醇一水为分散介质,聚乙烯吡咯烷酮(PVP)为稳定剂,过硫酸钾(KPS)为引发剂,用分散聚合的方法制备了聚丙烯酰胺水包水乳液。研究了醇／水比、稳定剂的种类和用量对聚丙烯酰胺水包水乳液稳定性的影响及单体浓度、引发剂用量和聚合温度对分散聚合法制备聚丙烯酰胺反应速率及分子量的影响。     

Preparation and Characterization of Vanillin Cross-Linked Chitosan Microspheres of Pterostilbene

A vanillin cross-linked chitosan microsphere delivery system was established for stabilization and controlled release of pterostilbene. The prepared microspheres were characterized by SEM images, FT-IR spectra, thermogravimetry, and X-ray diffraction. FT-IR spectra results indicated that chitosan was cross-linked by vanillin successfully. Thermal analysis showed that pterostilbene had been totally incorporated into the microspheres and the encapsulation of pterostilbene decreases the rate of degradation and increases the stability. XRD analysis was conducted to confirm the results of DSC analysis. The release rate of pterostilbene from microspheres in pH 3.6 buffer solution could be up to 58.1 % within 48 h.     

用于高通量药物筛选的PMMA-Alq3荧光微球的制备

八羟基喹啉铝(Alq3)存在下,在甲醇介质中由过氧化苯甲酰(BPO)引发甲基丙烯酸甲酯(MMA),通过分散聚合制得粒径为2μm～7μm的PMMA荧光微球,其粒径分布接近单分散,一致性系数为0．237。研究了影响微球粒径和粒度分布的多个因素。并对在Alq3存在下体系的反应机理进行了探讨。研究发现Alq3用量对产物的粒径和粒度分布影响显著。研究结果为制备大粒径荧光微球提供了技术依据。     

窄分散大粒径交联聚苯乙烯功能微球的合成研究

用分散聚合法，以聚乙烯吡咯烷酮（PVP）为稳定剂，偶氮二异丁腈（AIBN）为引发剂，乙二醇二甲基双丙烯酸酯（EGDMA）为交联剂，一次加料法在醇水介质中制备数个微米交联聚苯乙烯（PS）微球。研究了苯乙烯（St)、丙烯酸（AA）、EGDMA的用量对粒子大小，粒径分布的影响。测量了微球表面羧基的含量。     

Preparation and Kinetic Modeling of Cross-Linked Chitosan Microspheres Immobilized Zn(II) for Urea Adsorption

The preparation of Zn(II)-immobilized glutaraldehyde-crosslinked chitosan microspheres which was modified with epichlorohydrin, tetraethylenepentamine, and bromoacetic acid was presented in this work. The Zn(II)-immobilized value of the microspheres (Ac-TEPA-CS) is 43.6 mg g^?1, which is higher than the blank microspheres. The adsorption of urea onto Zn-Ac-TEPA-CS was studied in a batch system. Langmuir and Freundlich adsorption models were applied to describe the experimental isotherm and isotherm constant, and the kinetic of adsorption process were estimated. These data fits well with Langmuir isotherm and also indicated that the adsorption process is exothermic and follow the pseudo-second-order kinetics. The adsorption capacity depends upon the pH, the temperature and the initial concentration of urea. It observed that Zn-Ac-TEPA-CS could be repeatedly used by elution and regeneration without significant loss of adsorption capacity.     

极低剪切速率下聚丙烯酰胺溶液在毛细管中的流变特性 Ⅱ.毛细管尺寸和盐浓度对流变性能的影响

流变性能;流变行为;极低剪切速率下聚丙烯酰胺溶液在毛细管中的流变特性 Ⅱ.毛细管尺寸和盐浓度对流变性能的影响     

聚合物模板微球表面电性对中空二氧化硅微球形貌的影响

分别以过硫酸钾和偶氮二异丁基脒盐酸盐为引发剂,以聚乙烯吡咯烷酮(PVP)为分散剂,在水中引发苯乙烯聚合制备了2种表面分别带负电性和正电性基团的聚苯乙烯(PS)模板微球.在氨水催化下,利用正硅酸乙酯的水解缩合,形成PS/SiO_2复合微球,去除模板后得到中空SiO_2微球,并对其进行FTIR、电子显微镜、TGA以及氮气吸附等分析表征.结果表明,PS模板微球表面的电性决定了OH-的分布,从而导致PS模板微球表面SiO_2壳层不同的形成机制.当以表面带负电的PS微球为模板时,可得到树莓状的中空SiO_2微球;而以表面带正电的PS微球为模板时,得到是表面光滑的,具有介孔结构的中空SiO_2微球.     

部分水解聚丙烯酰胺/柠檬酸铝胶态分散凝胶体系的剪切稠化现象

一般认为 ,能够产生剪切稠化现象的体系为分散稳定的固 -液浓悬浮体 ,分散相 (固相 )体积分数 30 %～ 6 0 % [1～ 4] .最近 ,我们在研究固含量仅为 0 .0 3%的部分水解聚丙烯酰胺 (简称PHPA) /柠檬酸铝胶态分散凝胶体系流变性时 ,也发现了剪切稠化现象 .胶态分散凝胶( CDG)主要由交联剂在单个聚合物分子中通过内交联形成[5,6] ,形成条件是低聚合物质量分数 (一般为 0 .0 1 %～ 0 .1 2 % )和低交联剂 /聚合物质量比 (一般为 1∶ 2 0～ 1 0 0 ) .由于不能象常规凝胶一样形成三维网络结构 ,因而 CDG的分子结构状态介于常规聚合物凝胶和自由…     

硫代反义寡聚核苷酸在线性聚丙烯酰胺-毛细管电泳中的分离行为

通过对硫代反义寡聚核苷酸在毛细管线性聚丙烯酰胺胶（LPA）中的电泳行为的研究，发现在10％浓度的LPA和100mmol/L Tris-borate及7mol/L尿素的缓冲溶液中（pH=8.2），这类被分析物质有着较好的分离效果和重现性，能使相差一个碱基的硫代反义寡聚核苷酸片断得到基线分离。非常适合用于对合成的反义寡聚核苷酸的定性分析并进一步应用于纯度测定。     

聚丙烯酰胺对石油磺酸盐／正丁醇混合胶束体系流变性的影响

研究了一定矿化度下，不同分子量、不同水解度的聚丙烯酰胺对石油磺酸盐／正丁醇混合胶事体系的流型、粘度等充变性质的影响。     

Investigation on the Adaptability of the Polymer Microspheres for Fluid Flow Diversion in Porous Media

Large amounts of water producing from producers have been a great concern for petroleum engineers. In an attempt to inhibit water production and promote oil productivity, various water control agents and techniques have been devised for enhanced oil recovery purpose for decades with some good successes reported commercially. Mainly field-targeted specifically, however, these chemicals are limited in expansive reservoir applications for failing to tolerate harsh formation conditions of high temperature (HT) and high salinity (HS). Besides, their low injectivity is also another proper impediment. In this presentation, we synthesized a new agent of polymer microspheres using inverse emulsion polymerization technique to divert fluid patterns in deep porous media for reservoirs encountered recovery enhancement problems. These microspheres are made to tolerate HT and HS conditions, and can be pumped into deep pore space with relative ease. With the help of nuclear magnetic resonance (NMR) and nuclear pore membrane filtration techniques, a series of experimental procedures were conducted to test the adaptability of newly produced polymer microspheres to targeted pore structure in enhancing the sweeping efficiency of injection fluids. Both laboratory core tests and NMR data show good characteristics of polymer microspheres in modifying injection profile, demonstrating a good capability to divert fluid flow patterns in deep porous media and enhance oil productivity.     

阴离子聚丙烯酰胺/三乙醇胺超分子体系的表征及性能

研究了水溶液和模拟矿化水溶液中带有负电荷的磺化聚丙烯酰胺(SPAM)与三乙醇胺(TEA)之间的相互作用及形成的超分子体系的结构特征,考察了超分子体系的形成对SPAM形貌、流体力学直径、zeta电位、黏度及流变学性质的影响.研究结果表明,超分子体系的形成有利于提高磺化聚丙烯酰胺的黏度、抗剪切性、剪切回复性及抗温耐盐性.     

甲基丙烯酸在生物相容性微球CPVA表面的引发接枝聚合

交联聚乙烯醇（CPVA）微球表面含有大量的羟基,具有良好的生物相容性。在水溶液体系中利用这些羟基,与铈盐构成氧化还原引发体系,实施了甲基丙烯酸（MAA）的表面引发接枝聚合,制备了接枝微球CPVA—g—PMAA,考察了主要因素对接枝聚合的影响。采用红外光谱（FT—IR）及扫描电子显微镜（SEM）对接枝微球进行了表征。结果表明,羟基-铈盐氧化还原引发体系可有效地引发MAA在CPVA微球的表面接枝聚合,当铈盐浓度为4．9×101mol／L、硫酸浓度为0．17mol／L、反应温度为45。C、单体浓度为0．54mol／L时,每1。0g接枝微球CPVA—g—PMAA可接枝PMAA30g。     

Effects of Ethanol on the Stability of Pigment Colloidal Dispersion

The effects of ethanol on the thickness and ionization of adsorbed polymer layer on pigment were investigated. The results showed that the thickness of adsorbed polymer layer decreased with the increase of the ethanol concentration, and then the pigment particles aggregated when the concentration of ethanol is higher than 40%. The zeta potentials became more negative with the increasing of the ethanol concentration, and then changed reversely when the ethanol concentration was higher than 16%. The thickness and structure of adsorbed polymer layer on the particle determined the stability of pigment dispersion.     

聚磷腈微球的制备及其阻燃PET的研究

采用沉淀聚合法制备聚环三磷腈-co-(3,4-二羟基苯甲酸)(Poly(HCCP-co-PCA))微球,通过傅里叶变换红外光谱、扫描电镜和热重分析等测试手段对其进行表征,研究单体摩尔比对微球的结构、微观形貌以及热稳定性的影响,其中n(HCCP)/n(PCA)为1/0.5时,聚磷腈微球的粒径较为均一,分散均匀,直径为1.5μm左右,并且具有优异的热稳定性和成炭性能。采用熔融共混法制备PET/Poly(HCCP-co-PCA)复合材料,研究Poly(HCCP-co-PCA)的用量对复合材料阻燃性能的影响,并探究其阻燃机理。结果表明,随着Poly(HCCP-co-PCA)含量的增加,复合材料的阻燃性能明显提高。当Poly(HCCP-co-PCA)添加量为1.5(wt)%时,复合材料通过UL 94-V0等级测试,极限氧指数为28.8%,并且热释放速率峰值和总热释放量分别降低了75.26%和69.07%。其阻燃原理主要是燃烧时生成炭层较多,起到较好隔绝效果,同时产生不可燃气体,进一步提升阻燃效果。     

聚(4-乙烯基吡啶季铵盐-丙烯酰胺)的抗菌性能与机理研究

季铵盐型阳离子聚合物具有絮凝、缓蚀与杀菌等多种功能,据此,我们通过分子设计,先将丙烯酰胺与4-乙烯基吡啶（4-VP）进行共聚合,然后使用季铵化试剂硫酸二甲酯使共聚物阳离子化,制备了吡啶季铵盐型阳离子聚丙烯酰胺（QPAV）,本文报道QPAV的抗菌性能,并探讨其抗菌机理,结果表明,吡啶季铵盐型阳离子聚丙烯酰胺具有很强的抗菌性能,且其抗菌机理是基于杀菌而不仅仅是抑菌。     

The Stability of the Micelle Formed by Chain Branch Surfactants and Polymer Under Salt and Shear Force: Insight from Dissipative Particle Dynamics Simulation

The influence of salt and shear force on the stability of the micelle formed by surfactants and polymer are studied using dissipative particle dynamics (DPD) simulation method. The research system mainly includes four types of surfactants with different hydrophilic/hydrophobic chain branches and two kinds of polymers with hydrophilic/hydrophobic properties, respectively. The stability of the micelle is studied based on the analyses of the density peak and root mean square (RMS) of polymer chain under different salt and shear force. The calculated results show that the density peak reduced and RMS increased for all surfactants with the salt concentration and shear force increasing, and then indicate that the micelle has a certain degree of deformation. Whereas, the surfactant chain branch has important influence on the deformation extent of the micelle. For hydrophobic polymer, surfactants containing hydrophobic chain branch (T2H2T2) are beneficial to the stability of the micelle. On the contrary, for hydrophilic polymer, the micelle formed by surfactants with stronger hydrophilic nature such as the hydrophilic groups located in the both ends of the molecule (H1T4H1) have the best salt and shear resistance. The results have certain theoretical significance and can provide theoretical support for the selection of surfactants and polymers in practical application.     

乙酸乙酯/乙醇混合溶液中分散聚合制备单分散亚微米级聚丙烯酰胺微球

以乙酸乙酯/乙醇混合溶液为分散介质, PVP为分散剂, 通过分散聚合法合成了单分散亚微米级PAM微球. 在反应初期, 自动加速现象明显. 由于凝胶效应的影响, 分子量随着单体转化率的提高而逐渐增大. 考察了分散剂浓度对最终产物增率的影响, 并用IR光谱对产物的结构进行了表征, 证明分散聚合体系中吸附稳定机理和接枝稳定机理同时存在, 且以后者为主. 同时还研究了混合溶剂比例、分散剂浓度、初始单体浓度和引发剂浓度对微球粒径及粒径分布的影响. 结果表明, 乙酸乙酯/乙醇体积比在5∶5-7∶3范围内, 可得到粒径在200 nm左右, 且分布较窄的PAM微球; 分散剂浓度增大, 粒径减小; 引发剂浓度增加, 粒径增大; 初始单体浓度较高或较低时, 都得不到单分散性微球.