孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N-二己基丙烯酰胺共聚物水溶液的黏度行为

采用先加碱共聚-共水解方法制备了孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N 二己基丙烯酰胺共聚物[P(AM/NaAA/DiC6AM)],经容量滴定法测试,P(AM/NaAA/DiC6AM)的水解度=14 37%～15 80%,接近理论水解度15%。当x(疏水单元)=0 0641%～0 372%时,P(AM/NaAA/DiC6AM)在c(NaNO3)=1 000mol/L水溶液中的特性粘数[η]值为12 60～10 33dL/g、Huggins常数值为0 83～1 39。P(AM/NaAA/DiC6AM)在矿化度为19334μg/g盐水溶液中的表观黏度随疏水单元摩尔分数的增加而增加,随温度、剪切速率的增加而降低。在ρ(NaCl)=2～10g/dL、ρ(CaCl2)=0 2～1 0g/dL的水溶液中,出现盐增黏现象;且疏水单元摩尔分数越高,盐增黏效应越显著。P(AM/NaAA/DiC6AM)的疏水单元摩尔分数越高,与后加的SDS[ρ(SDS)=0～0 050g/dL]的疏水缔合作用越强,溶液的增黏效果越明显。     

孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N-二丁基丙烯酰胺共聚物的合成与性能

以十二烷基硫酸钠(SDS)为表面活性剂,丙烯酰胺(AM)的水溶液为连续相,N,N-二丁基丙烯酰胺(DiC4AM)为分散相,采取先加碱共聚-共水解的方法合成了孪尾疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-二丁基丙烯酰胺)[P(AM/NaAA/DiC4AM)]。用FT IR1、H NMR对其结构、组成进行了表征和测定。用稀释外推粘度法测定了共聚物的特性粘数[η]、Huggins常数KH。用芘荧光探针法及表观粘度法研究了大分子链间的疏水缔合作用,考察了疏水单体用量对其水溶液表观粘度的影响。     

表面活性剂对孪尾缔合聚合物水溶液表观黏度的影响

用黏度法研究了孪尾疏水缔合水溶性聚合物聚（丙烯酰胺／丙烯酸钠／N,N-二己基丙烯酰胺）[P（AM／NaAA／DiC6AM）]与十二烷基硫酸钠（SDS）、十六烷基三甲基溴化铵（CRAB）、OP-10的相互作用。结果表明,水溶液的表观黏度随SDS、CTAB质量浓度的增加急剧上升,超过一定浓度后水溶液黏度又急剧下降;黏度上升的幅度随疏水单体用量的增加、表面活性剂与疏水单体的摩尔比率（SMR值）的减小而增大;随水解度的增加,黏度上升的幅度较小。P（AM／NaAA／DiC6AM）的临界缔合浓度cac约为30g/mL,当加入SDS、CTAB时,能显著地降低。随OP-10质量浓度的增加,水溶液表观黏度几乎不变。表明P（AM／NaAA／DRAM）与SDS、CTAB的疏水缔合作用较强,而与OP-10的疏水缔合作用较弱。     

新型孪尾疏水改性聚合物／表面活性剂的溶液性能研究

采用前加碱胶束共聚-共水解法制备了丙烯酰胺、丙烯酸钠和新型孪尾疏水单体N,N-二正辛基丙烯酰胺的三元共聚物P(AM/NaAA/DiC8AM),利用FTIR和1H-NMR确定了共聚物的结构,测定了共聚物/表面活性剂复合体系水溶液的表观粘度,研究了表面活性剂种类、温度、电解质、剪切速率等因素对复合体系溶液表观粘度的影响。P(AM/NaAA/DiC8AM)/SDS和P(AM/NaAA/DiC8AM)/CTAB复合体系的溶液表观粘度与HPAM共聚物溶液相比有明显的提高,疏水单体含量越大,复合体系的溶液表观粘度越大,且其溶液具有一定的耐温、耐盐和抗剪切性。     

孪尾疏水缔合水溶性聚合物P(AM/NaAA/DiC_8AM)水溶液的黏度行为

研究了胶束共聚法制备的孪尾疏水缔合水溶性聚合物P(AM/NaAA/D iC8AM)的水溶液的黏度行为。当疏水单元摩尔分数为0.05%~0.40%时,P(AM/NaAA/D iC8AM)在30℃、c(NaC l)=1.000 mol/L水溶液中的特性黏数[η]为2 149~367 mL/g、Huggins常数KH为0.220~3.90;随疏水单元摩尔分数增加,特性黏数[η]减少、KH增加。在矿化度为19 334μg/g的盐水溶液中,P(AM/NaAA/D iC8AM)的表观黏度随疏水单元摩尔分数的增加而增加、随剪切速率的增加而降低。随疏水单元摩尔分数的增加,临界缔合质量浓度降低;与后加的SDS[ρ(SDS)=0~6.0 g/mL]的疏水缔合作用增强,黏度增加的幅度增大。表观黏度随温度的变化也与疏水单元摩尔分数有关,当x(H)=0.3%、温度升至45℃左右时,出现最大值。在NaC l、CaC l2的离子强度分别为1.26×10-3~4.88×10-3mol/kg、1.07×10-4~5.28×10-4mol/kg的水溶液中,出现盐增黏现象。     

单体N,N-双烯丙基十二胺的合成及其疏水缔合水溶性聚合物的性能

以双烯丙基胺和1-溴代十二烷为原料合成了疏水单体N,N-双烯丙基十二胺(DiAC12),采用前加碱二元单体胶束共聚-后水解法制备三元共聚物丙烯酰胺/丙烯酸钠/N,N-双烯丙基十二胺[P(AM/NaAA/DiAC12)],以芘为荧光探针,利用荧光光谱研究了P(AM/NaAA/DiAC12)在水溶液、1.000 mol/L NaCl水溶液中的缔合行为。结果表明,当疏水单元摩尔分数x(DiAC12)=0.10%～0.40%时,随聚合物浓度、疏水单体用量的增加,芘的I1/I3值减少,缔合作用增加。     

疏水缔合水溶性聚合物P(AM/NaAA/DiAC14)的合成与性能

以双烯丙基胺和1-溴代十四烷为原料成了疏水单体N,N-双烯丙基-N-十四烷基胺(DiAC14);采取前加碱二元胶束共聚-共水解法合成了疏水缔合丙烯酰胺/丙烯酸钠/N,N-双烯丙基-N-十四烷基胺共聚物[P(AM/NaAA/DiAC14)],研究了其在水溶液中的缔合行为.结果表明P(AM/NaAA/DiAC14)缔合行为取决于其Mη的大小、疏水单体摩尔分数及其嵌段长度和分布.     

疏水缔合水溶性聚合物P(AM/NaAA/DiAC14)水溶液的黏度行为

采取前加碱二元胶束共聚-共水解法合成了三元疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十四胺)〔P(AM/NaAA/D iAC14)〕,研究了其水溶液的黏度行为。当x(D iAC14)=0.10%~0.40%时,在30℃、c(NaC l)=1 mo.lL-1水溶液中,P(AM/NaAA/D iAC14)的特性黏数[η]、黏均相对分子质量Mη、Huggins常数KH、平均线团密度ρequ分别为18.88~22.22 dL.g-1、9.98×106~12.24×106g.mol-1、0.117~0.299和0.112~0.132 g.dL-1;KH小于0.8,表明其分子内缔合作用较弱。P(AM/NaAA/D iAC14)在矿化度为19 334μg.g-1盐水溶液中的表观黏度随疏水单体摩尔分数的增加而增加,随温度、剪切速率的增加而降低。在NaC、lCaC l2的离子强度分别为1.26×10-3~4.88×10-3mol.kg-1、1.073×10-4~5.28×10-4mol.kg-1的水溶液中,P(AM/NaAA/D iAC14)出现盐增黏现象,疏水单体摩尔分数越大,盐增黏效应越显著。随疏水单体摩尔分数的增加,临界缔合质量浓度(CAC)降低;与后加的十二烷基硫酸钠(SDS)〔ρ(SDS)=0~0.07 g.dL-1〕的疏水缔合作用增强,黏度增加的幅度增大。     

光引发合成阴离子聚丙烯酰胺及其应用

以丙烯酸钠(NaAA)、丙烯酰胺(AM)为单体,在光引发剂作用下,通过水溶液共聚法合成阴离子型聚丙烯酰胺(APAM)。采取单因素优化实验,研究了单体配比、单体质量分数、引发剂用量、光照时间、p H值等因素的影响,探究最优合成条件,以合成特性粘数高、絮凝性能好的产品为控制指标。得到最优制备条件:摩尔比为n(AM)∶n(NaAA)=1∶0.35,单体质量分数为32%,引发剂用量为0.04%,光照时间2h,p H为6.5时,APAM特性粘数最高,为1213m L/g。通过IR表征,产品与APAM特征基团相符合。絮凝实验表明,其具有良好的絮凝效果。     

P(AM/NaAA/DiAC_n)与十二烷基硫酸钠的相互作用

以芘为荧光探针,用稳态荧光光谱法、粘度法研究了疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基N-烷基胺)[P(AM/NaAA/D iACn)(n=12,14,16)]与阴离子型表面活性剂十二烷基硫酸钠(SDS)的疏水缔合行为。随SDS浓度的增加,I1/I3比值不断减小,得到SDS的临界胶束浓度(cm c)约为8×10-8mol/L。水溶液的表观粘度随SDS质量浓度的增加急剧上升,超过一定浓度后又急剧下降;粘度增加的幅度随疏水链长度增加。结果表明,P(AM/NaAA/D iACn)与SDS可形成混合胶束,发生较强的疏水缔合作用。     

Nanocomposite smart hydrogel based on sepiolite nanochannels/N-isopropyl acrylamide/itaconic acid/acrylamide for invertase immobilization

ABSTRACT

Novel nanocomposite smart hydrogel (NSH) and smart hydrogel (SH) are prepared to be used as a support for invertase. Spectrophotometric and thermal analysis methods were used for the characterization. Lower critical solution temperature values of SH and NSH were found as 32.68°C and 30.44°C, respectively. From the pH-responsive swellings performed at three different temperatures, the inflection point values of NSH were found at higher pHs compared to SH. Invertase was immobilized onto SH and NSH (SH?I and NSH?I). The optimum pH and temperature values were found. Michaelis constant and maximum reaction rate were calculated. NSH?I showed excellent thermal, operational and pH stability.     

Synthesis,characterization, rheological properties and hydrophobic nano-association of acrylamide/styrene and acrylamide/sodium styrene sulfonate/styrene co- and terpolymers

Hydrophobically modified polyacrylamides (HMPAMs) are used as rheological modifier and thickening agent, for example, in enhanced oil recovery, drilling fluids and dying technology. In this work, acrylamide/ styrene (AM/St) copolymers and AM/St/ sodium styrene sulfonate (AM/St/SSS) terpolymer were synthesized by heterogeneous and micellar radical copolymerization methods. Final copolymer composition was determined using ¹H-NMR spectroscopy. In comparison to initial mole fraction of St (0.0137), mole fraction of St incorporated into the copolymer chains for heterogeneous sample decreased to 0.0093 while that for micellar sample increased to 0.01386. Microstructures of the synthesized samples were investigated by calculating sequence length of the hydrophobic (St) and hydrophilic monomers. Depending on the polymerization conditions, viscosity- average molecular weight of the synthesized samples varied in the range of 4?×?10⁵ g.mol^?1 and 1?×?10⁶ g.mol^?1. In the heterogeneous copolymerization method, St was incorporated randomly into the copolymer chains while in micellar copolymerization method, a multi-block distribution of St in the copolymer chain was observed. Strong thickening behavior was observed by increasing copolymer concentration and NaCl concentration. Among other co- and terpolymers, AM/St/SSS revealed the best rheological and thermal properties. Shear thinning behavior was observed for all co- and terpolymers. It was found that rheological properties of the synthesized HMPAMs can be affected significantly by the microstructural parameters and hydrophobic interchain nano-association.     

丙烯酰胺/甲基丙烯酸丁酯改性纤维素的研究

以纤维素为基体,丙烯酰胺(AM)、甲基丙烯酸丁酯(BMA)为接枝单体,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,聚乙烯吡咯烷酮为分散剂,通过悬浮接枝聚合法制备出了纤维素基吸水吸油材料;考察了单体用量、引发剂用量、反应时间、反应温度及交联剂用量等因素对接枝聚合物的吸水、吸油性能的影响。结果表明:在单体与纤维素的质量比为3.0∶1.0,AM∶BMA的质量比为2.0∶1.0,相对于单体,引发剂质量分数为6.0%,交联剂质量分数为0.5%,分散剂质量分数为0.5%,反应温度为70℃,反应时间为4 h的条件下,得到纤维素-AM-BMA接枝共聚物,其吸油倍率为11.55 g/g,吸水倍率为23.51 g/g,聚合度为534.6。     

Gelcasting of ceramic suspension in acrylamide/polyethylene glycol systems

A new polyethylene glycol/acrylamide-based gelcasting system has been developed. The new system performs at least as well as, and in some cases better than, the original acrylamide-based system. The development of this system is for the sake of eliminating the surface-exfoliation phenomenon of green bodies gelcast in air. This study concentrates attention on dispersion, rheological and gelation behavior in the new system and flexural strength of green body.     

聚丙烯酸钠/丙烯酰胺复合物的制备及其吸附

以反相悬浮聚合法制备一系列聚丙烯酸钠和丙烯酰胺共聚物[P(AANa-co-AM)],运用傅里叶红外光谱(FT-IR)、热重分析(TG)等手段对其表征。研究了溶液pH值、单体配比、吸附时间、Pb~(2+)浓度和温度等因素对吸附性能的影响。结果显示,在最适pH值下,不同单体配比的聚丙烯酸钠/丙烯酰胺(AA/AM)吸附剂对Pb~(2+)的吸附效果不同,其中AA/AM单体配比为5∶5时,对Pb~(2+)的吸附效果最好。动力学研究表明,该复合材料对铅离子的吸附符合准二级模型;热力学实验数据显示,Langmuir模型比Freundlich模型更符合吸附等温线。当温度由298 K升高到318 K时,最大吸附量由591.7 mg/g增加到625.0 mg/g,热力学研究表明,P(AANa-co-AM)凝胶对Pb~(2+)的吸附为一自发吸热过程。     

树枝状大分子/聚(N-异丙基丙烯酰胺)纳米粒子的制备

使用溴乙酰溴对第四代聚丙烯亚胺树枝状大分子 (DAB-32)进行改性,成功合成了树枝状大分子引发剂DAB-32-Br。以DAB-32-Br/CuBr/Bpy为催化引发体系,分别在水和水/乙醇反应介质中,实现了N－异丙基丙烯酰胺（NIPAAm）的原子转移自由基聚合（ATRP）,得到粒径在60－150 nm范围内的树枝状大分子/聚（N－异丙基丙烯酰胺）纳米粒子。与水介质中ATRP相比,在水/乙醇介质中所得聚合物纳米粒子更加规则,而且粒子间聚集程度较低。     

Synthesis and characterization of hydroxyethyl methacrylate/acrylamide responsive hydrogels

Hydrogels based on an aqueous solution of hydroxyethyl methacrylate (HEMA) and acrylamide (AM) in the presence of trithioglycolic acid (TTGA) were prepared under the effect of gamma irradiation. These hydrogels were characterized by IR spectroscopy and thermogravimetric analysis and investigated for temperature‐ and pH‐responsive materials. It was found that TTGA is essential for the formation of HEMA/AM hydrogels at different compositions, in which the gel fraction depends on composition. A binary mixture of HEMA and AM at equal ratios was the critical composition that forms hydrogels, even in the presence of TTGA. The IR spectroscopic analysis showed that the formation of hydrogels depends on hydrogen bonding and crosslinking. The TGA investigations with respect to mass loss and the temperatures of the maximum value of the rate of reaction showed that HEMA/AM hydrogels possess higher thermal stability than that of pure HEMA and this stability increases with increasing ratio of the AM component. Also, it was observed that the temperature of the maximum value of the rate of thermal decomposition reaction depends on hydrogel composition. However, calculations of the activation energy showed that the hydrogel composed of 90% HEMA and 10% AM exhibits the highest thermal stability during the increasing or decreasing rate of reaction. Kinetic studies of swelling in water showed that HEMA/AM hydrogels displayed a temperature‐responsive character within the temperature range 25–30°C, and showed a stepwise swelling behavior in the pH range 2–10, depending on composition. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1105–1115, 2005     

Peroxydiphosphate/bisulfite-initiated polymerization of acrylamide and its retardation kinetics

The kinetics of aqueous polymerization of acrylamide with peroxydiphosphate/bisulfite redox pair was studied at 35 ± 0.2°C under atmospheric oxygen. The rate of polymerization was found to be of first power to monomer, half-power to catalyst, and 0.75 power to activator concentration. The overall energy of activation was calculated to be 11.0 kcal/deg mol between 25 and 45°C. The effect of addition of organic solvents and dinitrobenzenes as retarders on the rate of polymerization were studied kinetically and retardation constants for nitro compounds were evaluated by a newly proposed method (intercept method), when two retarders act simultaneously.     

丙烯酰胺/丙烯酸/甲基丙烯酸甲酯双水相共聚过程的成滴机理

在含聚丙烯酸钠（PAANa）的硫酸铵（AS）水溶液中,进行丙烯酰胺（AM）/丙烯酸（AA）/甲基丙烯酸甲酯（MMA）双水相共聚合反应,制备阴离子型聚丙烯酰胺水溶性聚合物分散液。采用动态激光光散射（DLS）在线检测了双水相聚合初期液滴形成及生长规律,发现液滴在反应初期存在聚并现象,滴径分布先变宽后变窄。采用气相色谱检测了共聚过程中各单体的残余量,推算聚合物链结构组成：反应前期聚合物链以AM和MMA链节为主,反应中期聚合物链以AM链节为主,反应后期聚合物链以AA和AM链节为主。提出了AM/AA/MMA双水相共聚过程的成滴机理,其中聚合物链上AA链节所带有的负电荷是聚合产物稳定分散、不易于凝聚的重要因素。