疏水缔合型丙烯酰胺共聚物P(AA-AM-TP)的制备及溶液性质

疏水缔合型聚合物(HAPAM)具有优异的增黏能力,因此被认为是一种潜在的用于条件苛刻油田的驱油剂。本文以丙烯酰胺、丙烯酸、三苯基-1-戊烯为原料使用胶束共聚法成功制备出一种新型聚合物。研究了聚合物浓度、盐度、温度对溶液黏度的影响。结果表明,当浓度超过1500mg/L时,黏度大幅增高;三元共聚物具有一定的抗温耐盐性质。并使用红外光谱表征了聚合物的结构。     

乙烯基三乙氧基硅烷改性丙烯酸乳液的研究

以丙烯酸酯、乙烯基硅氧烷为主要原料,以OP-10和十二烷基硫酸钠（SDS）为复合乳化剂,采用连续滴加法进行乳液聚合,制备了有机硅改性丙烯酸酯乳液。结果表明：当甲基丙烯酸甲酯（MMA）与丙烯酸丁酯（BA）的质量比为1.2～1.0、有机硅用量占单体质量分数3%～10%、复合乳化剂（OP-10∶SDS=3∶1）占4%～5%时,可制得性能良好的硅丙乳液。     

乙烯基三乙氧基硅烷改性丙烯酸乳液的研究

以丙烯酸酯、乙烯基硅烷为主要原料,以OP-10和十二烷基硫酸钠（SDS）为复合乳化剂,采用连续滴加法进行乳液聚合,制备了有机硅改性丙烯酸酯乳液。实验结果表明：当甲基丙烯酸甲酯（MMA）与丙烯酸丁酯（BA）的质量比为1．2～1．0、有机硅单体用量占单体质量分数的3％～10％、复合乳化剂（OP-10：SDS=3：1）占单体质量分数的4％。5％时,可制得性能良好的硅丙乳液。     

超临界CO2下三元含氟疏水缔合聚合物的合成及溶液性能研究

设计聚合物的分子结构并在超临界CO2下以丙烯酰胺(AM)、2-甲基-2-丙烯酰胺基丙磺酸(AMPS)及甲基丙烯酸十二氟庚酯(G04)为单体合成三元含氟疏水缔合聚合物,并用FTIR和元素分析对结构进行表征。研究反应温度、压力及引发剂加入量对产物聚合反应转化率及相对分子量的影响,并对三元含氟疏水聚合物浓度对溶液表观粘度的影响进行研究。结果表明:在超临界CO2体系下可制备三元共聚含氟聚合物,且由于含氟疏水基团的存在,该聚合物水溶液具有明显的疏水缔合作用。     

一种疏水缔合聚合物的合成及溶液性能

将十八烷基-二甲基甲代烯丙基氯化铵(C18DMMAAC)作为疏水单体,与丙烯酸(AA)、丙烯酰胺(AM)在水溶液中通过自由基聚合得到疏水缔合聚合物HAPAM-18,通过1HNMR和红外光谱对其结构进行了表征。最佳的聚合反应条件为:n(AM)∶n(AA)∶n(C18DMMAAC)=74.94∶25∶0.06,AA的摩尔中和度为95%,单体总质量分数为20%,引发剂质量分数为0.05%(以单体总质量计),温度45℃,反应时间12 h。研究表明,聚合物溶液的临界缔合质量浓度为2 g/L;聚合物溶液对温度较为敏感,80℃时黏度保留率为70.93%;聚合物溶液仍为剪切变稀的假塑性流体,但表现出良好的抗剪切性能,剪切1 h后黏度保留率达115%;由于设计为含较多阴离子的聚合物,该聚合物的抗盐性较差。     

超临界二氧化碳对聚合物的增塑作用及应用

简要介绍了超临界二氧化碳的性质及其与聚合物的相互作用 ,着重论述了超临界二氧化碳对聚合物的增塑作用及应用 ,包括小分子渗透、溶胀聚合、抽提分级、聚合物脱挥及微孔材料的制备等     

超临界CO2中丙烯酸与乙烯基吡咯烷酮的共聚研究

研究了65℃,偶氮二异丁腈(AIBN)为引发剂,不同反应压力和引发剂浓度等条件下,超临界CO2中丙烯酸与乙烯基吡咯烷酮的共聚,旨在为聚乙烯基吡咯烷酮的制备提供一种新型的简便的方法。用红外光谱(IR)、凝胶渗透色谱(GPC)和元素分析法对产物的结构及形态进行了表征。结果表明,共聚产物为白色固体粉末,产物相对分子质量10万～20万。用超临界CO2可对产物进行纯化,4次后单体残余率为0 26%。改变引发剂用量可以得到不同相对分子质量的聚乙烯基吡咯烷酮化合物。     

新型疏水缔合水溶性聚合物的合成及溶液性能研究

以十八碳醇、TDI和丙烯酸为原料制备了一种带苯基和长链烷基的N-取代丙烯酰胺类疏水单体NSAM。该单体和丙烯酰胺以单体比n(NSAM)：n(AM)为0．75：99．25，采用自由基胶束共聚合成了一种疏水缔合水溶性高分子AM—co-NSAM。研究了AM—co-NSAM在NaCl、KCl、BaCl2、CaCl2溶液中比浓黏度的盐效应；初步探讨了不同盐溶液、不同盐浓度对大分子之间相互作用的影响。实验结果表明：在不同盐溶液中，AM—co—NSAM都表现出盐增黏效应，其二价盐的影响较一价盐显著；随着盐质量浓度的升高，特性黏数[η]下降且低于纯水中的相应值5.841dL／g，而Huggins常数KH增大且高于0．3。     

超临界二氧化碳中合成聚乳酸-聚乙二醇共聚物

聚乳酸(PLA)具有良好的生物相容性,聚乙二醇(PEG)是较为常用的亲水嵌段聚合物,将二者共聚可得到性能良好的生物材料.在超临界二氧化碳中,通过调节乙二醇与丙交酯的摩尔比,可以合成一系列的PLA-PEG嵌段共聚物.介绍了聚乳酸和聚乙二醇的特性,阐述了超临界二氧化碳合成技术的优势,综述了医用聚酯常用的聚合方法,并对超临界...     

疏水缔合聚合物P(AM-AMPS-SA)的合成与性能研究

采用2-丙烯酰胺基-2-甲基丙磺酸(AMPS)与丙烯酸十八酯(SA)、丙烯酰胺(AM)通过自由基胶束共聚法合成疏水缔合聚合物P(AM-AMPS-SA)。经红外和核磁共振表征聚合物结构,并测定在不同剪切速率、NaCl、CaCl2浓度及温度条件下的聚合物溶液表观黏度的变化以及聚合物溶液的临界缔合浓度。结果表明,所制备的疏水缔合聚合物P(AM-AMPS-SA),它的临界缔合浓度在0.25~0.3g/dL,具有一定的抗温、抗盐性以及抗剪切性,且对二价盐的抗盐性比一价盐要好。     

Cross-linking polymerization of acrylic acid in supercritical carbon dioxide

Cross-linking polymerization of acrylic acid in supercritical carbon dioxide (scCO₂) was studied in a batch reactor at 50 °C and 207 bar with either triallyl pentaerythritol ether or tetraallyl pentaerythritol ether as the cross-linker and with 2,2′-azobis(2,4-dimethyl-valeronitrile) as the free radical initiator. All polymers were white, dry, fine powders. Scanning electron microscopy showed that the morphology of the polymer particles was not affected by cross-linking. As the cross-linker concentration was increased, the polymer glass transition temperature first decreased, then increased. Water-soluble and water-insoluble polymers were synthesized by adjusting the cross-linker concentration. Viscosity measurements showed that the polymer thickening effect strongly depended on the degree of cross-linking. Finally, cross-linking polymerization of acrylic acid in scCO₂ was carried out in a continuous stirred tank reactor. The use of cross-linker decreased the monomer conversion in this system.     

超临界二氧化碳介质中聚合物玻璃化转变温度

研制了一套原位光学法测定超临界二氧化碳（SC-CO₂）介质中聚合物玻璃化转变温度（T_g）的仪器装置。该仪器装置由带石英视窗的高温高压平衡釜、数据采集系统、加热与温度控制系统、压力控制系统、CO₂输送系统5部分组成。采用该仪器装置,测定了温度为50、60、70、80、90、100、120℃,压力为0.1、5、10、15、20 MPa范围内,PET聚酯薄膜样品的体积溶胀率及相应的玻璃化转变温度。常压测量结果与DSC差示扫描量热仪的测量值吻合很好,在10 MPa下的实测结果与文献值亦具可比性,表明该实验装置的可靠性及研究方法的可行性。因此,本仪器装置及方法可用于测量SC-CO₂介质中聚合物的玻璃化转变温度。     

超临界CO2清洗技术

介绍了超临界CO2清洗的工艺及其应用,分析了超临界CO2清洗在技术、经济及环保方面的特点。     

超临界二氧化碳技术的应用进展

超临界流体(SCF)因其具有很多优异特性而广泛应用于各个领域。主要介绍了超临界二氧化碳流体技术在萃取、制备超细颗粒材料、化学反应、酶催化、高分子科学、化学分析以及精密仪器清洗几个领域中的应用进展。     

Synthesis of copper–polystyrene nanocomposite particles using water in supercritical carbon dioxide medium and its antimicrobial activity

Copper‐encapsulated polystyrene nanocomposite particles were prepared through ex situ dispersion of Cu nanoparticles into monomer droplets and subsequent polymerization using water in supercritical carbon dioxide (water‐in‐sc‐CO₂) at 70°C. First, colloidal dispersion of copper nanoparticles was synthesized by chemical reduction of copper chloride (CuCl₂) using sodium borohydrate (NaBH₄) as reducing agent. Colloidal dispersion of copper nanoparticles was added slowly during the polymerization of styrene using water‐in‐sc‐CO₂ medium at 70°C and 20.68 MPa. Cu nanoparticle encapsulated polymer particles were characterized by UV, X‐ray diffraction, thermogravimetric analysis, SEM, and TEM. Cu nanoparticles were uniformly distributed inside the polymer matrix during the polymerization process. This work represents a simple way to prepare a variety of metal nanoparticles encapsulated polymer particles using water‐in‐sc‐CO₂ medium. The Cu/polystyrene nanocomposite particles exhibit antimicrobial activity against a number of bacteria. The current work represents a simple, cheap and universal way to prepare a variety of metal–polymer nanocomposite materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Formation of reverse micelles in supercritical carbon dioxide and its thermodynamics

The solubilization behavior of methyl orange as a solvation probe in multiple systems composed of supercritical carbon dioxide, surfactants and co-solvents, is studied. It is concluded that some surfactants, such as sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) and isooctyl phenol polyethoxylate (TX-10), could form reverse micelles in supercritical carbon dioxide under the action of butanol. The formation of reverse micelles is a spontaneous process thermodynamically. Specifically for the nonionic surfactant TX-10, the formation of reverse micelles is dependent on the entropy increase in the system, while for the anionic surfactant AOT, the micellization is mainly dominated by the increase in enthalpy at higher temperatures, but by the increase in entropy at lower temperatures. Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(8): 66–69 [译自: 华南理工大学学报 (自然科学版)]     

苯甲酸在含夹带剂的超临界CO2中溶解度的研究

采用流动法研究和测定了苯甲酸在35、50℃下,10.0—30.0MPa范围内,在纯超临界CO2和含醇系列夹带剂的超临界CO2中的溶解度。实验研究表明,醇系列夹带剂的加入均可明显增大苯甲酸的溶解度,但4种醇的增强作用随着碳链的增加而略有减弱。论述了温度、压力对溶解度的影响,并用Sovova方程对实验数据进行了回归。     

Preparation of molecularly imprinted polymers in supercritical carbon dioxide

Molecularly imprinted polymer nanoparticles were prepared in supercritical carbon dioxide using a noncovalent imprinting approach. In the present work, propranolol was used as a model template, methacrylic acid as a functional monomer, and divinylbenzene as a crosslinker. Under a high dilution condition, the heterogeneous polymerization resulted in discrete crosslinked polymer nanoparticles. Compared with the nonimprinted polymers, the imprinted nanoparticles displayed much higher propranolol uptake in a low polarity organic solvent. The use of a single enantiomer (S)‐propranolol as the template clearly demonstrated that the imprinted binding sites are chiral‐selective, with a cross‐reactivity towards (R)‐propranolol of less than 5%. The overall binding performance of the imprinted nanoparticles was comparable to imprinted polymers prepared in conventional organic solvents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2863–2867, 2006     

Synthesis and aqueous solution properties of hydrophobically modified polyacrylamide

Hydrophobically modified polyacrylamide (HMPAM) is synthesized by a free radical micellar polymerization method with low amounts of anionic long‐chain alkyl, sodium 9‐(and 10)‐acrylamidostearate (NaAAS), which is derived from a renewable resource material, oleic acid. In this progress, the molar ratio of Sodium dodecyl sulfate (SDS) to NaAAS is adjusted, so polymers with different lengths of the hydrophobic blocks (NH = 3 and NH = 6) are obtained. The copolymers are characterized by ¹H NMR, and the polymer weight and polydispersity are determined by gel permeation chromatography. The solution behaviors of the copolymers are studied as functions of concentrations, pH, and added electrolytes by steady‐flow and oscillatory experiments. The viscosities of these HMPAMs increase enormously above the critical concentration (c*). The sample with longer hydrophobic blocks exhibits better thickening effect. The rheological behaviors of aqueous solutions of HMPAMs are also investigated at different pH and brine environments. Low pH or the presence of brine promotes the intramolecular associating of hydrophobes for the both copolymers in semidilute solutions. The introduction of ionizable carboxylic group on the long hydrophobic side chain significantly influences the aggregation behaviors of the copolymers, leading to unique solution behaviors of the poly(AAm/NaAAS) copolymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40754.     

Solubility of fatty acids in supercritical carbon dioxide

The solubilities of lauric, linoleic, myristic, oleic, palmitic and stearic acid in supercritical carbon dioxide (SC-CO₂) at different pressures and temperatures were measured. The solubility values obtained in this work were compared with previously published data, and possible causes for observed discrepancies were discussed. The solubilities of the six fatty acids were modeled by Chrastil’s equation, and estimated model parameters were used to plot the solubility isotherms of fatty acids at 313, 323 and 333°K (40, 50 and 60°C) as a function of SC-CO₂ density. The comparison of solubility isotherms of fatty acids and vegetable oil suggests that separation of fatty acids from triglycerides might be possible by using SC-CO₂ at densities less than 700 kg/m³. From the effect of temperature on fatty-acid and vegetable-oil solubility, it seems that the extraction yield could be increased without sacrificing the selectivity of SC-CO₂ for fatty acids by choosing a higher operating temperature. The data also suggest that fractionation of certain fatty acids might be possible by manipulating the processing conditions. Given the values of the constants, Chrastil’s equation could serve as a guideline for choosing appropriate processing conditions and predicting the effect of pressure and temperature of SC-CO₂ on solute solubility.