ACPDA引发丙烯酰胺聚合反应动力学的研究

以４，４‘－偶氮二（４－氰基戊酰（对－二甲氨基）苯胺）作为引发剂研究了丙烯酰胺水溶液聚合反应动力学，测定了丙烯酰胺水溶液聚合反应速率常数和聚合反应活化能。其聚合速率方程：Ｒｐ＝Ｋ（ＡＣＰＤＡ）＾０．４８（ＡＭ）＾１．０２，聚合反应表观活化能为６６．８ｋＪ／ｍｏｌ；同时讨论了影响本聚合反应的不同因素。     

Reactant partitioning in free-radical heterophase polymerization: The case of inverse microemulsion polymerization of acrylamide

Conversion curves have been determined at 60°C for the polymerization of acrylamide in percolating inverse microemulsions. Ammonium peroxo-disulphate (APS) and dibenzoyl peroxide (DBP) were used as initiators of free-radical polymerization in the presence or absence of potassium nitrosodisulphonate (Fremy's salt, FS). The percolation decreases the rate of polymerization of acrylamide initiated by APS. The polymerization is inhibited by FS. After an inhibition period, retardation of acrylamide polymerization is more pronounced in non-percolating microemulsions. No inhibition periods were observed for DBP-initiated polymerization of acrylamide. The percolation shortens the time interval of the ‘slow’ polymerization of acrylamide, but the rates of rapid acrylamide polymerization above 10% conversion are the same for percolating and for non-percolating inverse microemulsions. The polymer particle diameter is a function of acrylamide/water weight ratio and of [water]/[AOT] (AOT: bis(2-ethylhexyl)-sulphosuccinate sodium salt) molar ratio. No effect of the initiator's nature either in the presence or in the absence of FS was found. The results are interpreted on the basis of initiator and/or nitroxide radical partitioning between oil and water phases of the inverse microemulsion, and are discussed with respect to the mechanism of acrylamide polymerization and polymer particle formation proposed for non-percolating inverse microemulsions.     

耐温抗盐聚合物TS-45流变性及驱油效率研究

在45℃(大庆主力油藏温度)下,以超高分子量(2.8×107)HPAM为对比,实验考察了耐温抗盐聚合物TS-45溶液的流变性能和驱油能力.TS-45为丙烯酰胺、强极性(含-SO3H)支链单体及少量疏水缔合单体的共聚物.实验聚合物溶液含盐(NaCl)5 g/L,含聚合物1 g/L.两种聚合物溶液在0.02～600 s-1范围均为假塑性流体,TS-45溶液的粘度大于HPAM溶液.溶液的G′和G″随振荡频率增加(0.1～50 Hz)而增大;TS-45的G′(和G″)大于HPAM的相应值;G′和G″曲线的交点,TS-45为0.1 Hz,此时G′=G″=0.078 Pa,HPAM为0.147 Hz,此时G′=G″=0.0088 Pa,表明TS-45溶液的弹性大于HPAM溶液.与NaCl浓度1 g/L的聚合物溶液相比,实验溶液的G′和G″均下降,在2.81 Hz下的保留率对于TS-45分别为48.2%和38.3%,对于HPAM分别为24.1%和17.2%,说明TS-45的耐盐性较好.TS-45在岩心中的阻力系数和残余阻力系数(38.6和9.6)大于HPAM的相应值(25.4和5.7).在岩心驱油实验中,注入0.38 PV聚合物溶液提高采收率的幅度,1 g/L的TS-45污水溶液、HPAM清水和污水溶液分别为12.6%、10.5%、8.9%,0.8 g/L的TS-45污水溶液为10.7%;在注入量0.2～2.0 PV范围内提高采收率的幅度,1 g/L的TS-45污水溶液恒大于HPAM污水溶液.图6表2参5.     

含氟丙烯酸酯AFSN及其与丙烯酰胺、丙烯酸的共聚物PAMF的合成与共聚物水溶液粘度性能

将杜邦公司的商品氟表面活性剂Zonyl FSN(含全氟烷基的脂肪醇)与丙烯酰氯(AC)等在低温下反应,合成了含氟丙烯酸酯AFSN,按产物收率和纯度确定最佳摩尔比FSN∶AC=1∶1.05,最佳反应时间为11～12小时.用IR谱表征了AFSN的结构.将AFSN、AM、AA在水溶液中共聚,得到了含氟疏水缔合水溶性聚合物PAMF-3和PAMF-5(混合单体总质量中AFSN分别占0.3%和0.5%).PAMF共聚物在水溶液中的增粘性、抗盐性和耐温性远高于超高分子量HPAM.室温下浓度为1.5 g/L的HPAM、PAMF-5、PAMF-3水溶液不含盐时粘度分别为520、690、530 mPa·s,NaCl浓度为15 g/L时粘度分别为41、410、325 mPa·s,粘度下降率分别为92%、40%、38%.1.5 g/L PAMF-3水溶液在90℃时保有的粘度高达300 mPa·s,而1.5 g/L HPAM水溶液在90℃时粘度为14 mPa·s.PAMF共聚物可望用作耐温抗盐的驱油聚合物.图5参9.     

丙烯腈-丙烯酰胺共聚物的合成与性能研究

采用水相沉淀聚合法制备了含有0～25mol％丙烯酰胺（AM）的丙烯腈（AN）-丙烯酰胺共聚物，采用傅立叶变换红外光谱（FTIR）、核磁共振光谱（NMR）、差示扫描量热仪（DSC）、热重分析（DTG）和X射线衍射分析（XRD）等方法对聚合产物进行了表征。结果表明，聚合产物中AM的摩尔含量略高于投料比，随AM摩尔含量的增加，共聚物的分解温度先降低后又升高。共聚物中AM含量为20mol％时分解温度仅为262．5℃；放热量先减少后增加。AM的引入将聚合物的环化机理从自由基环化机理过渡为离子基环化机理。     

MA-AA-AM-SMAS四元共聚物的阻垢性能研究

以马来酸酐(MA)、丙烯酸(AA)、丙烯酰胺(AM)、甲代烯丙基磺酸钠(SMAS)等为原料,以过氧化氢为引发剂,通过水溶液聚合反应和膦酰化反应合成出含膦酰基、羧基和磺酸基的四元共聚物阻垢剂MA-AA-AM-SMAS(PMAAS).探讨了共聚物的投加量、钙离子质量浓度、溶液的pH值和温度等因素与共聚物阻垢率的关系,并用环境扫描电镜观测了碳酸钙与硫酸钙晶形的变化.经国标法测得,当pH=7,PMAAS用量为7 mg/L时,其对CaCO3阻垢率可达99%,对CaSO4阻垢率达88.5%,与同类的产品相比,在碳酸钙垢和硫酸钙垢的阻垢性能上具有一定的优势.     

有机硅—醋酸乙烯酯复合乳液的合成

用含氢聚硅氧烷与醋酸乙烯酯、羟甲基丙烯酰胺进行共聚，制得有机硅－醋酸乙烯酯复合乳液。讨论了温度对聚合反应转化率的影响，并进一步得到了该反应的表观活化能Ea=84.96kJ/mol；考察了含氢聚硅氧烷对复合乳液的稳定性，粘度及胶膜性能的影响。结果表明，随着反应温度的增加，反应的聚合速率和最终转化率都相应增加，最佳反应温度为346－356K；随着含氢聚氧烷的用量增多，复合乳液的粘度增加，胶膜的拉伸强度和断裂伸长率呈先增加后下降的趋势。     

Characterization of stabilized porous magnetite core–shell nanogel composites based on crosslinked acrylamide/sodium acrylate copolymers

Stabilized and dispersed superparamagnetic porous nanogels based on sodium acrylate (AA‐Na) and acrylamide (AM) in a surfactant‐free aqueous system were synthesized via solution polymerization at room temperature. The formation of magnetite nanoparticles was confirmed and their properties characterized using Fourier transform infrared spectroscopy. Extensive characterization of the magnetic polymer particles using transmission electron microscopy (TEM), dynamic light scattering and zeta potential measurements revealed that Fe₃O₄ nanoparticles were incorporated into the shells of poly(AM/AA‐Na). The average particle size was 5–8 nm as determined from TEM. AM/AA‐Na nanoparticles with a diameter of about 11 nm were effectively assembled onto the negatively charged surface of the as‐synthesized Fe₃O₄ nanoparticles via electrostatic interaction. Crosslinked magnetite nanocomposites were prepared by in situ development of surface‐modified magnetite nanoparticles in an AM/AA‐Na hydrogel. Scanning electron microscopy was used to study the surface morphology of the prepared composites. The morphology, phase composition and crystallinity of the prepared nanocomposites were characterized. Atomic force microscopy and argon adsorption–desorption measurements of Fe₃O₄.AM/AA indicated that the architecture of the polymer network can be a hollow porous sphere or a solid phase, depending on the AA‐Na content. © 2013 Society of Chemical Industry     

Controlled conversion of polyacrylamide into polyacrylic acid

Interaction of nitrous acid with aqua solution of poly(acrylamide) gives poly(acrylic acid) in quantitative conversion yields. The reaction proceeds smoothly, with simultaneous evolution of nitrogen, provided that the temperature below 5 °C. The procedure presented provides a versatile route to prepare acrylic acid-acrylamide copolymers in any desired composition, by adjusting molar ratio of nitrous acid. Received: 29 January 1997/Revised: 24 July 1997/Accepted: 6 August 1997     

交联聚丙烯酰胺纳米微球的制备及性能评价

以丙烯酰胺(AM)单体水溶液为分散相,Span80/Tween80为乳化剂,煤油为分散介质,绘制了AM/H2OSpan80/Tween80-煤油体系的拟三元相图。依据拟三元相图配制了含油相质量分数52.0%、Span80/Tween80(质量比4∶1)复合乳化剂质量分数7.8%、水相质量分数40.2%的W/O微乳液(以体系总质量计),在70℃利用反相微乳液聚合法制备了纳米级交联聚丙烯酰胺微球。结合激光衍射粒度分析仪(LPSA)探讨了交联剂、引发剂用量及搅拌速率等合成条件对交联PAM微球粒径及吸水溶胀性能的影响,并采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)对微球形貌进行了表征,确定具有较高吸水倍率的交联PAM微球的优化合成条件为:交联剂(N,N-亚甲基双丙烯酰胺)MBA用量0.60%、引发剂(过硫酸铵)APS用量0.50%(以单体质量计)、搅拌速率1 000r/min。溶胀实验显示,该条件下合成的微球在1.0×105mg/L矿化度地层水中吸水倍率为1 690,表现出良好的耐盐性,高吸水倍率。SEM和TEM结果显示,微球具有较好的球形度、单分散性好,粒径分布较为均一,约为150~200 nm。岩心封堵实验表明,聚合物微球胶乳对地层有良好的封堵性,具有封堵、突破、深入、再封堵的逐级调剖特性。