疏水缔合型阳离子聚丙烯酰胺的合成及絮凝性能

以甲基丙烯酸三氟乙酯(TFEMA)为疏水单体、丙烯酰胺(AM)为主单体、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为阳离子单体,以过硫酸铵和亚硫酸氢钠为复合引发剂,采用自由基胶束聚合法合成了共聚物P(AM-DMC-TFEMA)。分别考察了反应温度、引发剂用量、单体总质量分数及反应时间对P(AM-DMC-TFEMA)的产率及阳离子度的影响。确定较佳工艺条件为:反应温度65℃,引发剂用量占单体总质量的2%,单体总质量分数26%,反应时间3 h。采用红外光谱(FT-IR)、核磁共振氢谱(~1H NMR)和环境扫描电镜(ESEM)对其结构进行了表征。同时考察了P(AM-DMCTFEMA)对硅藻土悬浮液的絮凝效果,结果表明,其对硅藻土具有良好的絮凝效果,絮凝时间仅为20 s,合成的共聚物上清液透过率为97.31%。     

疏水改性阳离子型丙烯酰胺共聚物的微结构与絮凝性能

用自由基胶束聚合法合成了丙烯酰胺（AM）/丁基苯乙烯（BS）/二甲基二烯丙基氯化铵（DMDAAC）疏水缔合型高分子絮凝剂PBAD。通过UV、FT-IR表征了共聚物的分子结构,AFM研究表明,由于丁苯基疏水基团强的分子间作用,0.005 g.dL-1 PBAD在水溶液中已形成了缔合体,并随着聚合物浓度的增加,缔合结构的尺寸和数量显著增加。在3%硅藻土溶液中,PBAD絮凝的最佳用量为0.005 g.dL-1,此时的透光率为96.5%,污水中的NaCl浓度能明显影响聚合物的架桥吸附作用,Ca2+和Al3+能增强聚合物的絮凝效果。     

Preparation and evaluation of fluorinated hydrophobically associating polyacrylamide

A twin-tailed fluorinated macro-monomer AMPD was prepared by dodecylamine, POSF and acryloyl chloride. Then the hydrophobically associating copolymers (PFPAM) were prepared by micellar copolymerization of acrylamide (AM) and AMPS with AMPD in an aqueous solution. The structure and composition of PFPAM were characterized by FT-IR, ¹H-NMR, ¹⁹F-NMR and Tg. Macroscopic and microscopic self-assembly associative properties in solutions of PFPAM as well as the effects of salt on the associative behavior were studied via viscosimetry, SEM, surface tension and AFM. The results show that with the polymer concentration increase, the viscosity increased and the surface tension decreased, so as to the salt solution. The concentration corresponding to the onset of increase in the viscosity was close to the onset of decrease in the surface tension. That lead to the CAC values from viscosity measurements are mostly in accordance with the data obtained from surface tension measurements.     

Solution properties of ionic hydrophobically associating polyacrylamide with an arylalkyl group

Copolymers of acrylamide, 2‐acrylamide‐2‐methylpropanesulfate (AMPS), and hydrophobic monomer N‐arylalkylacrylamide (BAAM) were synthesized by free‐radical micellar copolymerization. The effects of the copolymer, BAAM, AMPS, and NaCl concentrations and the pH value on the apparent viscosity of the copolymers were studied. The solution viscosities increased sharply when the copolymer concentration was higher than the critical associating concentration. The apparent viscosities of aqueous solutions of poly(N‐arylalkylacrylamide‐co‐acrylamide‐co‐2‐acrylamide‐2‐methylpropanesulfate) (PBAMS) increased with increasing BAAM and AMPS concentrations. PBAMS exhibited good salt resistance. With increasing pH, the apparent viscosities first increased and then decreased. Dilute PBAMS solutions exhibited Newtonian behavior, whereas semidilute aqueous and salt solutions exhibited shear‐thickening behavior at a lower shear rate and pseudoplastic behavior at a higher rate. Upon the removal of shear, the aqueous solution viscosities recovered and became even greater than the original viscosity, but the salt solution viscosities could not recover instantaneously. The elastic properties of PBAMS solutions were more dominant than the viscous properties, and this suggested a significant buildup of a network structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 316–321, 2005     

疏水缔合聚丙烯酰胺固沙剂的制备及性能研究

研发了一种具有良好固沙性能的水溶性固沙剂,该固沙剂是一种可持续的固沙材料。首先就疏水缔合阳离子聚丙烯酰胺-腐植酸的化学固沙机理讨论了固沙剂与沙粒之间的粘附力。研究了凝固机理,测试了固沙剂的固化时间。然后研究了固沙剂的渗透性能。通过扫描电子显微镜(SEM)分析了固沙层的微观结构。在不同浓度的固沙剂条件下,研究了固沙层的抗压强度。最后,通过模拟风机实验研究了固沙层的抗风蚀性。结果表明,固沙剂水溶液与沙粒表面具有极好的亲和力,并且固沙剂与沙粒之间的粘附力主要是氢键作用和静电作用。固沙层的固结时间随着温度和浓度的增加而降低。     

Intrinsic viscosity,rheological property,and oil displacement of hydrophobically associating fluorinated polyacrylamide

The surface‐active polymer (FPAM) was synthesized by free‐radical polymerization of acrylamide (AM), 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) and N ‐dodecyl‐N ‐perfluoro octane sulfonyl acrylamide (AMPD), which was prior prepared by reacting dodecylamine, perfluoro‐1‐octanesulfonyl fluoride, and acryloyl chloride. Parameters affecting the intrinsic viscosity ([η]) and apparent viscosity (η) of FPAM, such as reaction temperature, AMPD concentration, AMPS concentration, monomer concentration, initiator concentration, and pH were examined. Apparent viscosity and interfacial tension (IFT) of FPAM solution were evaluated. Subsequently, temperature tolerance and shear tolerance were investigated by comparing with hydrolyzed polyacrylamide (HPAM), and results indicated that the FPAM displayed better performances than HPAM. FPAM can reduce the IFT between crude oil/water, and the IFT values are around at 2.91 and 3.9 mN m^?1 corresponding to FPAM and HPAM/FC‐118. The sandpack model oil displacement experiment showed that water flooding can further increase the oil recovery to 15.01% (FPAM), compared with 9.26% oil recovery for HPAM, and 10.99% oil recovery for HPAM/FC‐118. The glass micromodel techniques for studying enhanced oil recovery get a good result and provide a useful reference for understanding the displacement behaviors in polymer flood process. It could be concluded that the introduction of fluorinated groups in the polymer chain was helpful in enhancing the oil displacement efficiency. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44672.     

Dilute solution properties of hydrophobically associating polyacrylamide: fitted by different equations

In this paper six different equations were used to fit the data of dilute solution of both nonionic (PBAM3) and ionic (PBAMS) hydrophobically associating polyacrylamide with and without the addition of NaCl. The results showed that Fedors equation was the most accurate equation to describe the dilute solution properties of these kinds of polymers. The lower value of the polymer concentration parameter (C_m) in Fedors equation was corresponded to the higher value of the constant k in Schulz-Blaschke equation for PBAM3 system. Two types of polymers had anti-polyelectrolyte effect. In dilute solution the PBAMS polymer chains had a more extended conformation than those of PBAM3 due to the existence of ionic groups.     

丙烯酰胺/丁基苯乙烯衍生物疏水缔合共聚物的溶液性能

采用自由基胶束聚合法合成了丙烯酰胺（AM）/丁基苯乙烯（BS）疏水缔合水溶性共聚物(PSAM).凝胶渗透色谱（GPC）测试结果显示,PSAM的重均分子量为1.6868×10⁵,环境扫描电镜（ESEM）照片显示,PSAM在水溶液中形成了疏水缔合网络结构,结果表明,PSAM的增黏能力主要依赖于疏水结构单元的分子间疏水缔合作用.PSAM溶液性能的研究结果表明,溶液质量浓度超过0.1 g·dl^-1时,共聚物具有优良的增黏、耐盐及耐温性能,在80℃时显示良好的抗老化性能;PSAM亚浓溶液为假塑性流体,具有良好的触变性,低剪切速率下在最初一段时间内呈现剪切增稠性质.     

疏水缔合型阳离子聚丙烯酰胺的溶液性能与应用研究

以丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)、丙烯酸十八酯(OA)为单体,用氧化-还原引发体系,通过自由基胶束共聚法制得疏水缔合型阳离子共聚物PADO。研究了共聚物组成对PADO溶液性能的影响,以及PADO对造纸中段废水的絮凝效果。结果表明,PADO水溶液中存在强烈的分子间缔合作用,在处理造纸中段废水时,其应用效果优于聚合硫酸铁、聚合氯化铝和非离子PAM。     

疏水缔合聚合物在搅拌槽中的溶解特性

Enhanced oil recovery (EOR) by means of polymer flooding is an important technology for the strategic development of offshore oilfields in China. Hydrophobically associating polyacrylamide (HAPAM) has been recently proposed as a new flooding agent. The solubility of HAPAM is low, which is the bottleneck for further improving the oil recovery through polymer flooding in offshore oilfield. Stirred tanks have been used on offshore platforms to enhance HAPAM dissolving. But there is little literature on the study of HAPAM dissolving characteristics in stirred tanks. In this paper, effects of temperature, salinity, stirring speed, impeller type and stirring method on the dissolution of HAPAM are reported. The experimental results manifest that the dissolving rate of HAPAM increases with temperature and stirring speed, but the viscosity of the polymer solution decreases. There is an optimal range of salinity for polymer dissolving. Combining the operation mode of up-pumping with varying stirring speed, hydrofoil impeller can accelerate the dissolution of HAPAM and maintain a high solution viscosity.     

Novel,rosin‐based,hydrophobically modified cationic polyacrylamide for kaolin suspension flocculation

A novel, hydrophobically modified cationic polyacrylamide (HMPAM) was synthesized via the copolymerization of acrylamide, diallyl dimethyl ammonium chloride (DMDAAC), and diallylmethyl dehydroabietic acid propyl ester ammonium bromide. Optimum conditions for preparing HMPAM were such that the amount of initiator was 0.075 wt % of the total monomer mass, the monomer concentration was 20 wt %, and the amount of DMDAAC was 18 mol % of the total monomer molar mass. HMPAM was characterized with an UV–visible spectrometer, ¹H‐NMR, Ubbelohde viscometer, rotational viscometer, and rotational rheometer. HMPAM solutions exhibited strong hydrophobic associations, and the critical association concentration of the HMPAM aqueous solution was about 0.7 wt %; the HMPAM solutions also showed salt thickening and shear resistance. The surface morphologies of the freeze‐dried HMPAM samples (1 wt %) were also observed via scanning electron microscopy. Compared with unmodified cationic polyacrylamide, Synthesis of HMPAM‐0.5 exhibited a stronger flocculation capacity, and the optimal transmittance of the supernatants was above 95%. HMPAM‐0.5 showed significant flocculation performances for 3–4 and 3–5 wt % kaolin suspensions at 40 and 50 mg/L, respectively. Moreover, the flocculation performance was enhanced with the addition of NaCl and CaCl₂. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46637.     

Intrinsic viscosity, surface activity, and flocculation of cationic polyacrylamide modified with fluorinated acrylate

A novel cationic polyacrylamide modified with fluorinated acrylate had been synthesized of acrylamide (AM), methacryloxyethyl trimethylammonium chloride (DMC), and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing cetyl trimethylammonium bromide (CTAB) as the surfactant and potassium persulfate (KPS)/sodium bisulfite (SBS) as the redox initiator. Some factors affecting synthesis, such as the amount of FEA, CTAB, and KPS, were described. Surface activity and flocculation of the polymer were studied. The results showed that with the incorporation of FEA, the intrinsic viscosity decreased until the modified polymer was not able to dissolve in water; and with the increase of CTAB and KPS, the intrinsic viscosity decreased firstly then increased slowly. The polymer exhibited good surface activity in both water and salt solution. Its flocculation properties were evaluated with kaolin suspensions using a standard jar test. The results demonstrated the superiority of the copolymer over the no-modified cationic polyacrylamide as a flocculant.     

两性疏水缔合聚丙烯酰胺的室内性能研究

以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和一种疏水长链烷基烯丙基氯化铵(M-18A)为单体,以溶剂油为油相,采用反相乳液聚合法合成一种两性疏水缔合聚丙烯酰胺增稠剂(AP-AM18)。在最佳合成条件下,利用核磁共振氢谱(¹H NMR)、红外光谱(FTIR)、X-射线衍射(XRD)和热重分析仪(TGA)对AP-AM18进行了表征。红外光谱结果表明,单体发生聚合;XRD图显示其具有非晶体结构;对聚合物AP-AM18的热稳定性分析发现,分解温度超过500℃后,样品质量基本不变,表明聚合物具有良好的耐温性;对AP-AM18进行增稠、耐盐性能测试发现,随着浓度的升高,表观黏度逐渐上升,当浓度为2%时,聚合物AP-AM18在清水中的表观黏度达到893 m Pa·s,在5×101H NMR)、红外光谱(FTIR)、X-射线衍射(XRD)和热重分析仪(TGA)对AP-AM18进行了表征。红外光谱结果表明,单体发生聚合;XRD图显示其具有非晶体结构;对聚合物AP-AM18的热稳定性分析发现,分解温度超过500℃后,样品质量基本不变,表明聚合物具有良好的耐温性;对AP-AM18进行增稠、耐盐性能测试发现,随着浓度的升高,表观黏度逐渐上升,当浓度为2%时,聚合物AP-AM18在清水中的表观黏度达到893 m Pa·s,在5×10⁴mg/L矿化水中,表观黏度达到391 m Pa·s,表明其具有较好的增稠、耐盐性能。     

两性疏水缔合聚丙烯酰胺的室内性能研究

以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和一种疏水长链烷基烯丙基氯化铵(M-18A)为单体,以溶剂油为油相,采用反相乳液聚合法合成一种两性疏水缔合聚丙烯酰胺增稠剂(AP-AM18)。在最佳合成条件下,利用核磁共振氢谱(~1H NMR)、红外光谱(FTIR)、X-射线衍射(XRD)和热重分析仪(TGA)对AP-AM18进行了表征。红外光谱结果表明,单体发生聚合;XRD图显示其具有非晶体结构;对聚合物AP-AM18的热稳定性分析发现,分解温度超过500℃后,样品质量基本不变,表明聚合物具有良好的耐温性;对AP-AM18进行增稠、耐盐性能测试发现,随着浓度的升高,表观黏度逐渐上升,当浓度为2%时,聚合物AP-AM18在清水中的表观黏度达到893 m Pa·s,在5×10~4mg/L矿化水中,表观黏度达到391 m Pa·s,表明其具有较好的增稠、耐盐性能。     

Synthesis,characterization, and properties of novel hydrophobically associating fluorinated copolymers for DNA delivery

Novel fluorinated associative copolymers poly(ethylene glycol)-b-poly(2-(perfluorohexyl)ethyl methacrylate (PFHEMA)-co-3-[N-(2-methacroyloylethyl)-N,N-dimethylammonio]-propane sulfonate (DMAPS)) (PEG-b-PPFHEMA/PDMAPS) were prepared as a type of non-viral gene vector. The series of PEG-b-PFHEMA/DMAPS with different molecular weights and compositions were characterized by gel permeation chromatography–multi-angle light scattering, ¹H NMR, ¹⁹F NMR, and elemental analysis. The interactions of the copolymers with calf thymus DNA and the morphologies of the resulting complexes were studied by fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. In addition, the DNA–polymer interaction, as determined by the gel retardation assay, and the low cytotoxicity of PEG-b-PPFHEMA/PDMAPS demonstrated that these copolymers have good DNA binding capacity and potential for high performance in the practical application of DNA delivery.     

Study on preparation and self-assembly properties of hydrophobically associating polyacrylamide by emulsifier-free ultrasonic assisted radical polymerization

Through ultrasonic assisted radical polymerization, hydrophobically associating polyacrylamide (U-HAPAM) was prepared by acrylamide (AM), 2-acrylamido ?2- methyl propane sulfonic acid (AMPS), and hydrophobic monomer octadecyl acrylate (ODA). The effects of concentration of initiator, ultrasonic frequency power and concentration of total monomers, had great influences on total monomer conversion, relative molecular mass and the viscosity of its aqueous solution. The macroscopic and microscopic self-assembly behaviors of the product was studied through apparent viscometry, fluorescence spectroscopy(FS) and atomic force microscope(AFM) respectively. The results showed that, the ultrasound possessed the certain ability of initiating and 0.3 % of initiator was advisable to use during the ultrasonic assisted radical polymerization to enhance the efficiency without substantially affecting the M_w; the thickening ability of the product was best under120W ultrasonic frequency power, of which the apparent viscosity attained 153.3 mPa?·?s as the concentration of U-HAPAM was 0.30 wt.%. Weighting the reaction efficiency and M_w, the concentration of total monomers was set as 10 % optimally. U-HAPAM achieved more excellent self-assembly performance and the critical association concentration of U-HAPAM prepared under these conditions was 0.27 wt.% (CAC) obtained from apparent viscometry and 0.23 wt.% (CAC') from FS.     

Study on preparation and solution properties of hydrophobically associating polyacrylamide by emulsifier-free ultrasonic assisted radical polymerization

Removal of heavy metals from aqueous solutions has attracted much attention worldwide. Many processes and technologies have been developed to remove heavy metals ions. In our previous study, a silica-poly acrylic amphoteric hybrid hydrogel was successfully prepared with double-network (DN) structure using ??-aminoporpyltriethoxysilane as precursor through a two-step sequential network formation technique. In the present research, the absorption behavior of this hydrogel was investigated carefully using Cu²⁺ ions and Cr₂O ₇ ^2? ions as representatives of negative and positive ions respectively. Under different adsorption conditions, the adsorption behaviors of the hydrogel were studied in detail, including initial concentration of the adsorbed ions, adsorption time, pH and ionic strength. The results showed the absorption capacity to Cu²⁺ can reach 700?mg/g with an initial Cu²⁺ concentration of 1,200?mg/L within 2?h. The experimental results show that the Freundlich adsorption law is applicable to the adsorption of Cu²⁺ and Cr₂O ₇ ^2? on the hydrogel.     

Synthesis, structure and properties of hydrophobically associating polymers

Hydrophobically modified water-soluble polymers have recently become the subject of extensive research because of their use as aqueous viscosity modifiers in oil recovery and latex paint systems. In this study, poly(acrylamide) samples modified with small amounts of a hydrophobic monomer (ethylphenylacrylamide) have been prepared by free radical copolymerization using an aqueous micellar process in which the use of a surfactant ensures the solubilization of the hydrophobe. The copolymers exhibit improved thickening properties with respect to homopoly(acrylamide) analogs due to intennolecular hydrophobic associations. The aqueous solution-copolymer properties strongly depend on the amount of surfactant used in the synthesis. The differences observed between the samples are directly related to the copolymer microstructure, that is to a more or less block distribution of the hydrophobic units. The interactions in aqueous solution of a surfactant (sodium dodecylsulfate (SDS)) with these copolymers have been examined. A strong increase in viscosity is observed upon the addition of SDS below its critical micelle concentration, owing to the formation of mixed micelles of SDS and hydrophobic monomers. The complex rheological behavior observed is explained in terms of the balance between inter and intrachain liaisons. The effects of hydrolysis on the hydrophobic interactions are also discussed.     

Solution properties of anionic hydrophobic association polyacrylamide modified with fluorinated acrylate

The anionic hydrophobic association polyacrylamide (AFPAM) modified with fluorinated acrylate have been synthesized of acrylamide (AM), 2-acrylamide-2-methyl propanesulfonic acid (AMPS) and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing sodium dodecyl sulfate(SDS) as the surfactant and potassium persulfate(KPS)/sodium bisulfite(SBS) as the redox initiator. The solution properties of these polymers were investigated. The results show that there are strong hydrophobic associations in the AFPAM aqueous solution. The intrinsic viscosity decreases and Huggins constant increases with the increase of hydrophobic FEA content. The addition of NaCl and CaCl₂ results in an increase of solution viscosity which indicate the good salt-resistant performance. The polymers exhibit good temperature tolerance property, shear-thickening and thixotropy behavior. Additionally, the AFPAM has higher surface activity in salt solution than in water.