聚丙烯腈/离子液体溶液流变性能的研究

采用应力流变仪对聚丙烯腈/1-丁基-3-甲基咪唑氯化物(PAN/[BMIM]Cl)溶液体系的稳态和动态流变性能进行了研究,讨论了PAN相对分子质量(Mη)对溶液稳态和动态流变性能的影响。结果表明:PAN/[BMIM]Cl溶液在低剪切速率区表现出牛顿流体特征,在高剪切速率区随着剪切速率的增大粘度降低,表现为切力变稀流体;溶液的粘度大于常规溶剂体系,随着PAN的Mη增大,PAN/[BMIM]Cl溶液表观粘度明显增大,非牛顿指数减小,粘流活化能增大;溶液的损耗模量和储能模量越大,溶液更容易表现出弹性效应。     

一种部分水解聚丙烯酰胺的合成及性能评价

分别选用丙烯酰胺、丙烯酸、DMMAC作为主链单体、亲水单体及疏水单体,合成了一种三元共聚高相对分子质量部分水解聚丙烯酰胺,其具有较大的分子量,较好的化学稳定性和热稳定性。同时,该聚合物产品的固含量较高,可达51.35%。此聚合物溶液在0.0008416 g/mL的浓度下就具有较高的黏度,高达1.4614,是一种不错的增稠剂。本次研究所合成的聚合物材料的粘均分子量约为166万,分子量较大,具有优良的溶胀特性,在聚合物驱中应用前景广阔。     

基于离子液体的聚丙烯腈/纤维素溶液的动态流变性能研究

采用旋转流变仪分别对以离子液体1-烯丙基-3-甲基咪唑氯盐[AMIM]Cl,1-丁基-3-甲基咪唑氯盐[BMIM]Cl,1-乙基-3-甲基咪唑醋酸盐[EMIM]Ac为溶剂的聚丙烯腈/纤维素共混溶液(分别标记为溶液A,B,E)的动态流变性能进行了研究,讨论了溶液的储能模量(G′)、损耗因子(tanδ)及角频率(ω)之间的关系。结果表明:A、B溶液lgG′-lgω曲线分别在70,90℃开始呈现"第二平台",且随温度升高,平台宽度变大;A,B溶液时温叠加主曲线分别在70,100℃下的低频区域发生偏离,表明时温等效原理在低频下对于G′失效,E溶液不符合时温等效原理;A,B溶液tanδ随ω增大而降低,E溶液则升高;A,B溶液lgG′～lgG″曲线分别在80,110℃时发生偏离,在测试温度范围内对温度具有依赖性,E溶液lgG′-lgG″呈非线性关系;A,B溶液的Cole-Cole曲线出现拖尾现象。     

二醋酸纤维素/离子液体溶液流变性能的研究

以离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4)为溶剂,制备了不同质量分数的二醋酸纤维素(CDA)/[Bmim]BF4溶液,采用旋转流变仪研究了溶液的稳态和动态流变行为,讨论了剪切速率、温度和CDA含量等因素对CDA/[Bmim]BF4溶液黏度的影响,并考察了Cox-Merz法则对CDA//[Bmim]BF4溶液体系的适用性。结果表明:CDA/[Bmim]BF4溶液为假塑性流体,表观黏度和零切黏度均随着质量分数的增加和温度的降低而增大;溶液的黏流活化能随着溶液质量分数增加增大;溶液不符合Cox-Merz法则;随着CDA/[Bmim]BF4溶液浓度增加,溶液中CDA大分子相互作用加剧,高浓度的CDA/[Bmim]BF4溶液需要更长的松弛时间。     

离子液体在聚硫密封胶中的应用

为研究ILs(离子液体)不同于传统助剂的特殊功能,在聚硫密封胶中加入了不同种类的ILs,随后对密封胶的硫化特性、力学性能、耐热性及耐油性等进行了考察。研究结果表明:不同种类的ILs在硫化过程中的促进(或延缓)作用并不相同;在力学性能方面,ILs与普通增塑剂的作用相似,加入后会使密封胶的强度降低、韧性提升;与传统增塑剂相比,ILs明显增强了密封胶的耐热性和耐油性,并且ILs具有特殊的触变作用,可有效改善密封胶的施工性能。     

改性聚丙烯酰胺化学驱的制备与乳化性能研究

化学驱是用于提高原油采收率的重要技术之一,其中,聚表二元复合驱是化学驱中的主要选择。聚丙烯酰胺类聚合物来源广泛,成本低廉,具有优异的波及效率,成为化学驱中应用最广泛的聚合物。但是聚丙烯酰胺聚合物由于存在较大的水解基团,耐温和抗盐抗钙性不足,影响波及和驱油效率。为了提高聚丙烯酰胺聚合物的抗温、抗盐抗钙性,采用丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和纳米SiO₂通过自由基共聚方法制备了两种丙烯酰胺类聚合物（AM-AMPS、AM-AMPS-纳米SiO₂）。对其进行结构表征,探究流变和驱油性能。结果表明,AM-AMPS-纳米SiO₂聚合物的热稳定性能更好。当溶液浓度在1.5%～2.0%时,聚合物的增稠性最优。随着NaCl浓度的增大,两种1.5%聚合物溶液的抗盐性先急剧减小后逐渐增大,随着CaCl₂浓度的增大,先减小后趋于平缓。相比之下,AM-AMPS-纳米SiO₂具有更好的洗油效率和乳化驱油作用。制备的两种聚丙烯酰胺共聚物与传统的聚丙烯酰胺相比在抗温、抗盐、驱油、乳化方面均表现出了更好的性能。     

液体聚硫橡胶的性能与应用

介绍了液体聚硫主链含硫原子和饱和的分子结构,具有耐油、耐老化等性能,能用喷涂、浇注等加工方法施工,广泛用作各工业部门的胶粘剂、密封剂、涂层材料等。     

改性聚硫密封胶的制备及性能研究

为提高聚硫密封胶与金属的粘接性能,以EP(环氧树脂)和PF(酚醛树脂)作为聚硫密封胶的复合增黏树脂,并着重探讨了增黏树脂配比对聚硫密封胶制备工艺、力学性能及粘接性能等影响。研究结果表明:当m(EP)∶m(PF)=10∶10时,聚硫密封胶的综合性能相对较佳,此时其拉伸强度、断裂伸长率和180°剥离强度分别为2.26 MPa、338%和1.95 kN/m。     

聚硫硫代聚脲的结构与性能

以液态聚硫橡胶、异氟尔酮二异氰酸酯和扩链剂3,6-二甲硫基-2,5-二甲苯胺为原料,合成了不同硬段质量分数的聚硫硫代聚脲。IR,DMTA,DSC和应力-应变分析表明,各试样的软硬段中存在着相分离;硬段质量分数减少或是液态聚硫橡胶相对分子质量增加时,试样拉伸强度降低而扯断伸长率增加。     

金属阳离子对部分水解聚丙烯酰胺溶液黏度影响的研究进展

综述了金属阳离子对部分水解聚丙烯酰胺溶液（HPAM）黏度影响的研究现状,解释了不同价态金属阳离子对HPAM的降黏作用机理,介绍了采油污水处理中金属离子的脱除技术。对目前金属离子与HPAM作用研究中存在的问题以及未来的发展方向进行了总结。     

次氯酸钠氧化法测定聚丙烯酰胺浓度的研究

阐述了次氯酸钠氧化法（浊度法）测定部分水解聚丙烯酰胺浓度的反应机理，研究了聚丙烯酰胺的相对分子质量、次氯酸钠溶液浓度、反应时间对吸光度值的影响，针对大庆油田杏二中三元复合驱采出水中含有碱和表面活性剂、pH值高、黏度大、富集硫化物和亚硫酸根等特点，提出采用过硫酸铵一浊度法检测三元复合驱采出水中聚丙烯酰胺浓度。     

Studies on determination of molecular weight for ultrahigh molecular weight partially hydrolyzed polyacrylamide

The molecular weight characterization of partially hydrolyzed polyacrylamide (HPAM) for enhanced oil recovery use is rather difficult because of its ultrahigh molecular weight copolymer and polyelectrolyte behaviors in solution. In this work the effects of aqueous NaCl solution concentration and degree of hydrolysis of polymer on molecular dimension were studied. A simple and precise method for determining molecular weight of HPAM is presented. The molecular weight of HPAM with any degree of hydrolysis can be calculated from the [η]−M_w equation of unhydrolyzed PAM in an H₂O system by measuring , of HPAM obtained in aqueous NaCl solutions by extrapolating salt concentration to infinity. Because the values of of HPAM of different degrees of hydrolysis are all equal to the corresponding [η] value of the unhydrolyzed PAM of the same degree of polymerization, the molecular weight of HPAM of any degree of hydrolysis can thus be calculated from the [η] − M_w equation for PAM homopolymer. © 1996 John Wiley & Sons, Inc.     

On the correlation between the viscosity of partially hydrolyzed polyacrylamide solution and the diffusion coefficient in the semidilute concentration regime

The solution viscosity of neutral polyacrylamide (PAM), the partially hydrolyzed polyacrylamide (70% HPAM), and polyacrylic acid (PAA) were measured concurrently with the apparent diffusion coefficient in the dilute and semidilute concentration regimes. We identified the scaling relation η − η_s = A/D in the semidilute regime, where η is the solution viscosity, η_s is the solvent viscosity, D is the coefficient of the slow diffusion mode obtained from dynamic light scattering, and A is a prefactor found to have a unique value of ∼1.0 × 10⁻⁸ cP cm²/s. The scaling relation as well as the prefactor are independent of the the ionic strength, the solvent quality, the molecular weight, the charge density, the polyelectrolyte, and salt concentrations. For the neutral PAM, the product [η – η_s]D is proportional to the polyelectrolyte concentration C_p, consistent with Rouse theory and previous experimental findings.     

A modified method to detect surface rheological behavior of mixed partially hydrolyzed polyacrylamide (HPAM)/surfactant systems

The visualization of monolayers at the air/water interface by Brewster Angle Microscope (BAM) was used to watch the movement of the domains of surfactant or surface‐active complexes without any adscititious probe materials, and to examine the changes in surface rheology of partially hydrolyzed polyacrylamide (HPAM)/surfactant systems. Clear indications of rheological properties at the air/water interface are obtained over substantial concentration regions of the HPAM/Sodium Dodecyl Benzene Sulfonate (SDBS) and HPAM/Triton X‐100/SDBS systems, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 704–706, 2000     

Flow-induced degradation of hydrolyzed polyacrylamide in porous media

Summary In this work we present an experimental study of flow-induced degradation of hydrolyzed polyacrylamide in aqueous solutions flowing through porous media. The degradation is analyzed by passing the solution repeatedly through the medium at a constant flow velocity and the degraded solution is then characterized by porous media and opposed jets flows. When the polyacrylamide is dissolved in deionized water, it exhibits a gradual extension thickening in the flow through porous media and opposed jets. In this case, the polymer degrades as it passes through the porous medium even at relatively low flow rates. When the polyacrylamide is dissolved in an NaCl solution, it exhibits critical extension thickening in porous media flows, and it only degrades at Reynolds numbers that are higher than the onset of the extension thickening behavior. Chain degradation is therefore only encountered when extension thickening is produced. The results also show that the extent of degradation decreases as the pore size decreases.     

The preparation of high-viscosity,partially hydrolyzed polymethacrylamides

Due to the high chain transfer to monomer, the homopolymerization of methacrylamide yields polymers of extremely low molecular weight. On partial alkaline hydrolysis, the viscosities of these polymers in aqueous solution are much inferior to those of partially hydrolyzed polyacrylamide (HPAM). However, polymethacrylamides prepared by room temperature, persulfate-initiated polymerization in the presence of small amounts of N,N′-methylenebisacrylamide demonstrate posthydrolysis reduced viscosities in 0.01% NaCl comparable to typical commercial HPAM materials.     

水解聚丙烯酰胺对注聚后产出污水浮选效果的影响

以旅大10-1油田产出含聚污水为研究对象、浮选后除油率和水体浊度降低率为考核指标,研究了不同分子量和浓度残余水解聚丙烯酰胺(HPAM)对聚铝(PAC)、二甲基二烯丙基氯化铵/丙烯酰胺共聚物[P(DMDAAC-AM)]、丙烯酰氧乙基三甲基氯化铵/丙烯酰胺共聚物[P(DAC-AM)]等3种不同阳离子型浮选剂处理效果的影响。结果表明,随着HPAM分子量和浓度的增加,PAC处理效果变化不大,但处理效果差,除油率和浊度降低率均约72%;P(DMDAAC-AM)的处理效果逐渐变差,除油率和浊度降低率均低于85%;而对于P(DAC-AM)除油率和浊度降低率均维持在90%以上。进一步优化P(DAC-AM)的浮选条件,发现其浮选时间可缩短至5 m in,用量可降低至30×10-6。     

Improved cycling performance with ingestion of hydrolyzed marine protein depends on performance level

Background

The effect on performance of protein ingestion during or after exercise is not clear. This has largely been attributed to the utilization of different scientific protocols and the neglection of accounting for factors such as differences in physical and chemical properties of protein supplements and differences in athletic performance level.

Methods

We hypothesized that ingestion of unprocessed whey protein (15.3 g·h^-1) together with carbohydrate (60 g·h^-1), would provide no ergogenic effect on 5-min mean-power performance following 120 min cycling at 50% of maximal aerobic power (2.8 ± 0.2 W·kg^-1, corresponding to 60 ± 4% of VO_2max), compared to CHO alone (60 g·h^-1). Conversely, we hypothesized that ingestion of the hydrolyzed marine protein supplement NutriPeptin? (Np, 2.7 g·h^-1), a processed protein supplement with potentially beneficial amino acid composition, together with a PROCHO beverage (12.4 g·h^-1 and 60 g·h^-1, respectively) would provide an ergogenic effect on mean-power performance. We also hypothesized that the magnitude of the ergogenic effect of NpPROCHO would be dependent on athletic performance. As for the latter analysis, performance level was defined according to a performance factor, calculated from individual pre values of W_max, VO_2max and 5-min mean-power performance, wherein the performance of each subject was ranked relative to the superior cyclist whos performance was set to one. Twelve trained male cyclists (VO_2max = 65 ± 4 ml·kg^-1·min^-1) participated in a randomized double-blinded cross-over study.

Results and conclusions

Overall, no differences were found in 5-min mean-power performance between either of the beverages (CHO 5.4 ± 0.5 W·kg^-1; PROCHO 5.3 ± 0.5 W·kg^-1; NpPROCHO 5.4 ± 0.3 W·kg^-1) (P = 0.29). A negative correlation was found between NpPROCHO mean-power performance and athletic performance level (using CHO-performance as reference; Pearson R = -0.74, P = 0.006). Moreover, ingestion of NpPROCHO resulted in improved 5-min mean-power performance relative to ingestion of CHO in the six lesser performing subjects compared to the six superior performing subjects (P < 0.05). This suggests that with the current protocol, NpPROCHO provided an ergogenic effect on 5-min mean-power performance in athletes with a lower performance level.     

透析薄膜干燥法检测阴离子聚丙烯酰胺浓度研究

研究了一种油田矿场应用中检测样品中阴离子聚丙烯酰胺浓度的方法——透析薄膜干燥法.系统考察了聚合物浓度、相对分子质量及水解度变化对该方法测定结果的影响.结果表明,该方法具有较高的准确性,克服了常规的淀粉-碘化镉浓度检测法不适用于高温油藏产出液中阴离子聚丙烯酰胺浓度检测的缺点.     

关于驱油用水解聚丙烯酰胺生物降解性的初探

关于驱油用水解聚丙烯酰胺的生物降解特性(包括水解聚丙烯酰胺的热稳定特性、基本形态结构、腐蚀性、溶液性质以及粘性等在内)的基本规律已有大量研究学者做出了丰富的研究与讨论。本文基于对驱油用水解聚丙烯酰胺的生物降解特性分析,研究在差异性环境状态下,硫酸盐还原菌的生长对驱油用水解聚丙烯酰胺溶液粘性程度的影响。并通过液相色谱测定方式,量化了这一影响。本文旨在探究硫酸盐还原菌物质相对于水解聚丙烯酰胺溶液生物降解特性的影响机理。