高单体浓度下反相微乳液聚合

选择丙烯酰胺（ＡＭ）、丙烯酸胺／丙烯酸钠（ＡＭ／ＳＡ）和丙烯酰胺／（２－甲基丙烯酰氧乙基）三甲基氯化铵（ＡＭＡＩＭ．ＭＣ）为单体（对），在相同的实验条件下进行反相微乳液（共）聚合，得到各自的动力学关系式，并对其做了解释．     

对酞内酰胺苯甲酰氯柱前衍生反应HPLC法检测痕量芳香胺

建立了一种快速、灵敏检测痕量芳香胺的新方法。对苯胺、邻甲苯胺和间甲苯胺与对酞内酰胺苯甲酰氯（简称ＰＩＢ－Ｃｌ）的衍生反应条件、衍生物色谱分离及定量检测条件等进行了研究。衍生试剂在有机溶剂中与３种芳香胺反应迅速，衍生物用乙腈＋水（４８＋５２）作流动相，在反相色谱系统中得到了良好的分离。３种芳香胺的检出限分别为：苯胺１．５ｐｍｏｌ，邻甲苯胺和间甲苯胺均为２．０ｐｍｏｌ。     

用气相色谱法测定粮谷和油籽中氯苯胺灵残留量

确立了粮谷和油籽中氯苯胺灵残留量的气相色谱测定方法，试样采用甲醇提取，经与正己烷液液分配，再以弗罗里硅土柱净化，毛细管柱气相色谱－氮磷检测器测定。方法简便、准确、检出限０．０２μｇ／ｇ，添加回收率为８７．５－９２．９％，相对标准偏差为３．５－７．０％。     

十二烷基磺酸钠对丙烯酰胺－烯丙基磺酸钠共聚物溶液粘度的影响

丙烯酞胺-烯丙基磺酸钠共聚物(PASA)优良的絮凝性能已在前文^[1]中报道.本文主要考察阴离子表面活性剂R₁₂SO₃Na对其溶液粘度的影响,并与PAM做了对照.     

交联聚丙烯酰胺负载的氧化β—环糊精的合成及其对尿素的吸附性能

以交联聚丙烯酰胺为载体，合成了高分子负载的氧化β—环糊精，并研究了它在不同条件下对尿素分子的吸附性能。结果表明交联聚丙烯酸胺负载的氧化β—环糊精对尿素具有良好的吸附效果，最大吸附容量可达到９６．８ｍｇ／ｇ（尿素浓度为１３０ｍｇ／ｄＬ，ｐＨ＝７．４，０．０１Ｍ磷酸盐缓冲液，吸附温度３７℃）。     

N-[4-(磺酰胺)苯基](甲基)丙烯酰胺的合成

以对氨基苯磺酰胺、丙烯酰氯(或甲基丙烯酰氯)为原料合成了N-[4-(磺酰胺)苯基]丙烯酰胺(ASPAA)和N-[4-(磺酰胺)苯基]甲基丙烯酰胺(ASPMAA),其结构经^1H NMR,IR和元素分析表征。合成ASPAA的最佳条件：对氨基苯磺酰胺13．76g(80mmol),n(对氨基苯磺酰胺)：n(丙烯酰氯)=1．0：1．1,n(丙烯酰氯)：n(NaHCO3)：1．00：1．14,0℃～2℃反应3h,反应液倾入10倍体积的的甲醇-水[V(甲醇)：V(水)=1：10]中析出产物,收率在60％以上。合成ASPMAA的最佳条件：对氨基苯磺酰胺6．88g(40mmol),n(对氨基苯磺酰胺)：n(甲基丙烯酰氯)=1.00：1．05,n(三己胺)：n(甲基丙烯酰氯)：1．0：1．0,在0℃～2℃滴加甲基丙烯酰氯后先在室温下反应1h,然后在60℃反应1h,反应液倾入700mL石油醚中析出产物,收率50％～60％．     

辐射引发丙烯酰胺微乳液聚合

辐射引发丙烯酰胺微乳液聚合徐相凌，张志成，张曼维（中国科学技术大学应用化学系合肥２３００２６）关键词丙烯酰胺，微乳液聚合，辐射引发聚合聚丙烯酸胺（ＰＡＭ）及其共聚物是广泛应用的水溶性高分子．８０年代中期，Ｃａｎｄａｕ等’‘－”首先开始研究了丙烯酸胺的...     

聚合方法对一种正离子聚丙烯酰胺结构与性能的影响

对相同进料比下,以过硫酸胺/亚硫酸氢钠为氧化还原引发剂,分别用溶液法和反相微乳液法合成的丙烯酰胺(AM)与2-甲基丙烯酰氧乙基三甲基氯化胺(MADQUAT)的共聚物P(AM-MADQUAT),根据单体竞聚率计算了两种共聚物的序列分布和组成分布.考察了两种聚合物结构对高岭土絮体尺寸、zeta电位降以及絮体压缩屈服应力的影响,初步建立了不同聚合方法合成的阳离子聚丙烯酰胺结构与絮凝性能之间的相关性.     

N－丙烯酰基－N＇－苯基脲及其衍生物的合成与聚合反应

以三种合成路线分别合成了含有脲键的一类单体，Ｎ－丙烯酰基－Ｎ’－苯基脲（ＡＰＵ）、Ｎ－甲基丙烯酰基－Ｎ’－苯基脲（ＭＰＵ）、Ｎ－甲基丙．烯酰基－Ｎ’－对甲苯基脲（ＭＴＵ），通过单体的自由基聚合与共聚合，制备了均聚物和共聚物，经ＩＲ、１Ｈ—ＮＭＲ表征和ＴＧＡ、ＤＳＣ测定．     

丙烯酰胺—丙烯酸交联共聚凝胶结构与分子运动的^1HNMR自旋…

用＾Ｈ ＮＭＲ方法测定了交联度分别为１０％，７．％，５％，２．５％，１％，０．５％及０．２５％４ 丙烯酰胺－丙烯酸与Ｎ，Ｎ‘－亚甲基双丙烯酰胺交联共聚水凝胶中水及主链质子的化学位移谱及自旋晶格驰豫时间Ｔ１，并用ＢＢＰ模型进行了讨论。     

Role of ionic species and valency on the viscoelastic properties of partially hydrolyzed polyacrylamide solutions

The effects of ionic species and valency on the viscoelastic properties of partially hydrolyzed polyacrylamide solutions were examined. Two viscoelastic parameters were considered, i.e., average relaxation time, _M ⁰ and steady state compliance, Je⁰. Both these parameters are independent of ionic species of monovalent salts. However, _M ⁰ decreases with increasing salt concentrations. Divalent salts reduce the values of _M ⁰ by as much as 10 times. On the other hand, Je⁰ is independent of salt concentrations and valency. The effects of monovalent salt on three different polyacrylamide samples of varying degree of hydrolysis and MW were also examined.     

Polyacrylamide Na-kaolinite interactions: Effect of electrolyte concentration on polymer adsorption

The variation in polyacrylamide adsorption on Na-kaolinite as a function of the electrolyte concentration of the clay suspension, was determined under three pH conditions, where the clays display varying charge characteristics. Interpretation of the results is based on two arguments: non-charged polyacrylamide adsorption is restricted to the edge faces of the colloidal platelets and hydrogen bonding between the amide groups of the polymer and the isolated hydroxyl sites of these faces is the mode of surface attachment. At constant pH, when Na-kaolinite bears charged surface groups, the polymer adsorption, which is related to the density of the anchoring sites, parallels the state of ionization of the edge surface. The mechanism by which the salt modifies the adsorption properties of the kaolinite in neutral medium is not established with certainty. Nevertheless, no polymer-clay association occurs if the surface is entirely uncharged. This result is in line with the fact that while hydroxyl groups are engaged in internal hydrogen bonds, they cannot hydrogen-bond to the polyacrylamide. Variations in the clay-polymer affinity are attributed to a modification of the interfacial structure of the adsorbed polymer, associated with changes in the surface density of the anchoring groups.     

Synthesis, characterization and flocculation performance of zwitterionic copolymer of acrylamide and 4-vinylpyridine propylsulfobetaine

A novel zwitterionic polyacrylamide AMVPPS copolymer containing sulfobetaine groups was synthesized by copolymerizing acrylamide (AM) and 4-vinylpyridine propylsulfobetaine (4-VPPS) in 0.5 mol/L NaCl solution with potassium persulfate (K₂S₂O₈) and sodium bisulfite (NaHSO₃) as initiator. The structure and composition of AMVPPS copolymer were characterized by FT-IR spectroscopy, ¹H NMR and elemental analyses. Thermal stability and solution properties of AMVPPS copolymer were studied by thermogravimetry analysis (TGA) and viscometry. Anti-polyelectrolyte behavior was observed and was found to be enhanced with increasing 4-VPPS content in copolymer. The flocculation performance for 2.5 g/L kaolin suspension and 2.5 g/L hematite suspension was evaluated by transmittance measurement and phase contrast microscopy. The effects of 4-VPPS content in the copolymer, intrinsic viscosity and the added salt on the flocculation performance were investigated. It was found that AMVPPS copolymer was a good flocculant for both anionic kaolin and cationic hematite suspensions and the flocculation performance of copolymer was much better than that of pure polyacrylamide (PAM). A very wide range of the optimum flocculation concentration, named as “flocculation window”, was found for both suspensions. These flocculation characteristics were mainly dependent on the charge neutralization, the intragroup conformation transition from water to NaCl solution and then the interchain bridging of the zwitterionic AMVPPS copolymer.     

Detection of irradiated food by the changes in protein molecular mass distribution

Protein constituents were extracted from chicken drumstick and chicken white meat, separated according to the molecular mass (Mm), using discontinuous SDS–polyacrylamide electrophoresis (SDS–PAGE) and quantified by scanning densitometry. The obtained profiles were compared with the profiles corresponding to the meat samples which were irradiated at −20, +4, and +20°c. It was observed that the irradiation of chicken white meat led to protein scission which was partially unselective (e.g. the amount of proteins whose Mm>20 kDa decreased, while the amount of those whose Mm<20 kDa increased), and partially selective (e.g. the appearance of Mm16 kDa fragment). In the case of chicken drumstick meat the irradiation caused both protein scission and protein cross-linking (unselective and selective, and appearance of 16 kDa fragment). However, in the case of aerated dehydrated egg white proteins, irradiation led only to unselective protein scission. The obtained results are discussed in view of possible application of discontinuous analytical SDS–PAGE combined with laser scanning densitometry for detection of previously irradiated foodstuff.     

Role of ionic species and valency on the steady shear behavior of partially hydrolyzed polyacrylamide solutions

Polyacrylamides are anionic polymers with a large number of charges along the polymer chains. The rheological properties of aqueous polyacrylamide solutions can be significantly modified by varying the solvent environment with the addition of salt. The presence of cations substantially reduces the inter- and intra-molecular interactions of the macroions. It was found that the valency of the cation has a strong effect on the rheological behavior of polyacrylamide solutions, but the size and type of salt have a negligible effect.The reduction in the solution viscosity with di-valent salts (e.g., CaCl₂, MgCl₂, BaCl₂, and MgSO₄) can be as high as an order of magnitude compared with mono-valent salt (KI, KC1, NaCl, and NaBr), depending on the salt concentration and shear rate. An identical viscosity function can be obtained for different types of polyacrylamide solutions by varying the salt content in solution. This interesting feature provides a useful means in the development and preparation of certain ideal fluids for simulation studies of complex flow problems.     

Mobility and activation energy of single-stranded DNA in denaturing cross-linked polyacrylamide slab gels

An original apparatus based on laser-induced fluorescence detection is presented. One lane migration combined to four equidistant detection points allows the study of the dynamics of DNA bands during electrophoresis. We focus this article on the study of the mobility of DNA sequencing fragments as a function of temperature; mobility is determined in 4% T, 5% C and 4.3% T, 5% C cross-linked polyacrylamide gels at an electric field of 45 V/cm [T=(g acrylamide+g N,N'-methylenebisacrylamide)/100 ml solution; C=g N,N'-methylenebisacrylamide/% T]. Activation energy has been investigated under these experimental conditions with a temperature varying from 25 to 50 degrees C. The activation energy for migration through the cross-linked polyacrylamide gel decreases with fragment length under our experimental conditions and it varies along the migration.     

Nitroxide-mediated radical polymerization of acrylamide in water solution

This study shows that reasonably controlled nitroxide-mediated polymerization of acrylamide is achieved in pure water solution at 120 °C and high concentration (40 wt%), using a combination of a conventional hydrosoluble radical initiator (Vazo56) and a β-phosphonylated nitroxide, SG1. Moreover, some chain extensions can be performed from a polyacrylamide macroinitiator. Under these experimental conditions, we have demonstrated the conservation of the acrylamide structure without hydrolysis side reactions. The physico-chemical characterizations of polymers obtained from this method demonstrates that the controlled growing chain arises as a star-like shape from the hydrophobic core composed of SG1-functionalized polyacrylamide in the presence of a slight excess of SG1.     

Activation energy associated with the electromigration of oligosaccharides through viscosity modifier and polymeric additive containing background electrolytes

The activation energy related to the electromigration of oligosaccharides can be determined from their measured electrophoretic mobilities at different temperatures. The effects of a viscosity modifier (ethylene glycol) and a polymeric additive (linear polyacrylamide) on the electrophoretic mobility of linear sugar oligomers with α1–4 linked glucose units (maltooligosaccharides) were studied in CE using the activation energy concept. The electrophoretic separations of 8‐aminopyrene‐1,3,6‐trisulfonate‐labeled maltooligosaccharides were monitored by LIF detection in the temperature range of 20–50°C, using either 0–60% ethylene glycol (viscosity modifier) or 0–3% linear polyacrylamide (polymeric additive) containing BGEs. Activation energy curves were constructed based on the slopes of the Arrhenius plots. With the use of linear polyacrylamide additive, solute size‐dependent activation energy variations were found for the maltooligosaccharides with polymerization degrees below and above maltoheptaose (DP 7), probably due to molecular conformation changes and possible matrix interaction effects.     

Sieving of ionic constituents across moving boundaries in gel electrophoresis

The representative beta-hydroxyethylmorpholinium-chloride-bicinate moving boundary with a trailing ion net mobility relative to Na+ of 0.41, detected by precipitation of chloride with silver nitrate, exhibits a decreasing chloride mobility at increasing polyacrylamide gel concentrations from 3.5 to 45%T, 5%CBis. This decrease, largely due to an increase of field strength at constant current, is described by a convex* plot of log (mobility) vs. %T (Ferguson plot) and signifies that chloride/bicinate are sieved by the gel. In agarose gels, the same plot of mobility vs. gel concentration is constant below 7% gel concentration, since in those gels field strength and migration rate remain the same within that gel concentration range. Both in polyacrylamide and in agarose gels the displacement rate of the chloride-bicinate boundary as a function of the time of electrophoresis or distance migrated remains invariant within 15%. The plot of log (mobility) vs. gel concentration extrapolated to 0%T is 5.85 and 5.41 (10(-5) cm2s-1V-1) for polyacrylamide and for agarose (SeaKem HGT-P,FMC) gels, respectively. The slightly decreased mobility intercept at 0%T for agarose is presumably due either to the electroendosmotic properties of agarose HGT-P and/or failure to Sufficiently take into account the flattening of the Ferguson plot in the polyacrylamide concentration range below 3% in which a transition from a gel to a fluid (sol) medium takes place.     

Structural parameters of polyacrylamide hydrogels obtained by the Equilibrium Swelling Theory

In this paper, the synthesis and structural characterization of a series of polyacrylamide hydrogels with different degrees of reticulation are reported. Although the Equilibrium Swelling Theory was recognized as a simple and reliable tool for the determination of structural hydrogels network parameters like equilibrium degree of swelling, cross-link ratio and mesh size, this is the first application of this methodology for polyacrylamide hydrogels. By changing the total monomer content in the synthesis solution (%T) from 5 to 30%, at a fixed value of cross-linker content in the total monomer amount (%C) of 5%, the final parameter obtained, the mesh size, can be tuned from 2 to 0.3 nm. It was also possible to change the mesh size (0.19-0.35) by varying %C from 5 to 12% (at %T = 20%). Scanning Electron Microscopy images for the most different formulations are shown and corroborate data obtained from the theory.