油藏环境对高温交联聚合物凝胶成胶性能的影响

采用高温高压稠化法在稳态剪切条件下模拟凝胶溶液自井口注入地层时的升温加压过程,研究高温高压下成胶环境即溶液初始p H值、温度、金属盐离子对PAM/PEI体系的凝胶化过程和成胶强度的影响。通过高温高压稠化曲线,可将高温高压下PAM/PEI体系的凝胶化过程分为诱导期、加速反应期、平衡期3个阶段。结果表明：引入H+改变凝胶溶液初始p H值,发现凝胶溶液初始黏度先增加后降低,体系可在碱性和中性条件下稳定成胶,而在酸性条件下,体系无法凝胶化。凝胶体系中引入Na⁺、Ca²⁺后,成胶时间被不同程度的延长,且Ca²⁺对凝胶体系的影响远大于Na⁺。体系中Na⁺质量浓度增加,其缓交联作用有限,且不会大幅度降低凝胶成胶强度;Ca²⁺质量浓度增加,凝胶成胶时间明显延长,但其对凝胶成胶强度影响较大,Ca²⁺质量浓度过高,会导致凝胶脱水。     

固定床反应器的压降及其对组分浓度的影响

本文讨论了固定床反应器的设计计算中,用厄根方程考虑床层压降的两种简化处理,分别用于恒密度情况和变密度情况,提出了压强的变化对组分浓度的影响及其关联式。     

非胶组分对天然橡胶性能的影响研究

天然橡胶（NR）中非胶组分对其结构和性能有很大影响,在NR的分子结构构建过程中有助于NR分子链由线性结构变为网状结构。传统烟胶片和标准胶的制备过程采用酸凝工艺,加之剪切造粒和高温干燥等加工方式,均造成大量非胶组分的流失。本工作采用薄膜干燥法制备的NR在极大程度上避免了非胶组分的流失,通过此法制备的全组分NR胶料表现出良好的力学性能,与分别去除各非胶组分的NR进行性能对比发现：脱除磷脂导致NR胶料的门尼粘度降低26.92%,硫化诱导期缩短24.91%,耐老化性能有所提高;脱除蛋白质导致NR胶料的门尼粘度降低1.72%,硫化诱导期缩短50%,耐老化性能有一定程度提高。     

缓蚀剂对丙烯酸酯胶性能影响的研究

从固化时间、剪切强度、金属腐蚀结果的影响等方面进行了系统研究,分析了改变缓蚀剂用量对丙烯酸酯胶腐蚀效果的影响。结果表明,当缓蚀剂苯丙三氮唑占到反应系统总剂量的1.5%时,丙烯酸酯胶固化时长为15.5min,剪切强度为16.6MPa,对铜的单位面积侵蚀为32%。     

剪切作用对交联聚合物凝胶成胶性能的影响分析

<正>引言交联聚合物凝胶是一种由疏水聚合物和交联剂形成的以分子间交联为主、分子内交联为辅的三维网络结构的凝胶体系。在实际堵水应用中,低浓度疏水聚合物与交联剂在地面混合配制好后,从油井注入地层。在配制体系和注入地层时,由于受到地面管线、注入泵以及油藏孔隙介质的剪切速率较大,可能会影响注入的交联聚合物凝胶的反应过程。同时,疏水     

化学剂浓度对大庆油田乳状液稳定性的影响

使用全能红外稳定分析仪、生物荧光显微镜、瓶试法,从宏观和介观角度监测乳状液体积浓度、粒径、析水率的变化,研究了不同化学剂浓度对大庆油田乳状液稳定性的影响。结果表明,聚合物浓度增加可以提高乳状液的稳定性,提升乳状液稳定性最佳聚合物浓度为2 000 mg/L。乳状液的稳定性系数、平均粒径与表面活性剂浓度呈近似线性变化,浓度增加可以增加乳状液的稳定性。碱浓度应当适宜,浓度过高或过低均不利于乳状液稳定,提升乳状液稳定性最佳碱浓度为0.4%。     

浅议醋酸铜氨液组分浓度的确定

应用沉淀反应原理、络合物的离解平衡原理,结合铜氨液的特性及其净化反应过程,推导出铜液总氨及其它各组分浓度解析式,并计算出各组分的浓度值。     

化学剂浓度对大庆油田乳状液稳定性的影响

使用全能红外稳定分析仪、生物荧光显微镜、瓶试法,从宏观和介观角度监测乳状液体积浓度、粒径、析水率的变化,研究了不同化学剂浓度对大庆油田乳状液稳定性的影响。结果表明,聚合物浓度增加可以提高乳状液的稳定性,提升乳状液稳定性最佳聚合物浓度为2 000 mg/L。乳状液的稳定性系数、平均粒径与表面活性剂浓度呈近似线性变化,浓度增加可以增加乳状液的稳定性。碱浓度应当适宜,浓度过高或过低均不利于乳状液稳定,提升乳状液稳定性最佳碱浓度为0.4%。     

水质对弱凝胶体系成胶性能影响研究

弱凝胶体系成胶率是评价体系调驱效果的关键因素。为了评价水质对弱凝胶体系成胶性能的影响,以有机铬/聚合物弱凝胶体系作为研究对象,开展了不同水质条件下弱凝胶体系成胶性能实验。研究结果表明:矿化度对弱凝胶成胶性能具有较大的影响,随着矿化度的增加,体系黏度下降,矿化度高于20 000 mg/L后,成胶效果及稳定性明显变差。当水溶液pH值为6~8时,体系成胶黏度及成胶稳定性较好。随着悬浮物含量增加,初始黏度不断降低,当悬浮物含量达40 mg/L时,弱凝胶初始黏度即可降低50%。     

双尾疏水缔合聚合物弱凝胶成胶性能影响因素分析

针对常规聚合物不能耐高温高盐的特点,选用耐温抗盐的新型双尾疏水缔合聚合物(DTHAP)为弱凝胶主剂。研究了聚合物质量浓度、交联剂质量分数、温度、矿化度和多孔介质剪切等对凝胶体系成胶性能的影响;并用扫描电镜(SEM)对其微观结构进行探究。实验结果表明:弱凝胶的成胶时间、成胶强度可以通过调节聚合物和交联剂浓度来控制。在80℃下,聚合物质量浓度为1 000~2 250 mg/L,交联度质量分数为0.6%时,体系成胶时间1~6 d可调控,最大成胶强度能达到F级。该体系在温度为80~90℃,矿化度为2×104~8×104mg/L的条件下具有较好的成胶稳定性,经多孔介质剪切后仍具有较好的稳定性,SEM表明弱凝胶体系有致密的空间网络结构。结果表明,该体系能应用于高温高盐油藏。     

Na+浓度对化学增强钠铝硅酸盐玻璃性能的影响

熔盐中少量的Na⁺并不会对玻璃的离子交换效果产生明显影响,但当熔盐中Na⁺浓度不断增大时,化学增强钠铝硅酸盐玻璃的性能开始受到影响。本文采用一步法离子交换工艺研究了熔盐中Na⁺浓度对不同厚度化学增强钠铝硅酸盐玻璃表面压应力、应力层深度和弯曲强度等性能的影响。研究表明:熔盐中Na⁺浓度不断增大时,化学增强钠铝硅酸盐玻璃的表面压应力、弯曲强度下降;弯曲强度下降最多可达175 MPa,此时玻璃的表面压应力下降了57.4 MPa;熔盐中Na⁺浓度变化未对化学增强钠铝硅酸盐玻璃的应力层深度和可见光透过率产生明显影响。     

耐温耐盐复合交联调剖体系实验研究

使用部分水解聚丙烯酰胺、有机铬和水溶性酚醛为主剂,制备了一种复合交联调剖体系,考察了聚合物及交联剂浓度、矿化度、温度等因素对体系成胶性能的影响。结果表明,体系在矿化度为15 000 mg/L,温度低于90℃的条件下,仍可生成较高强度的凝胶,具有良好耐温耐盐性能。通过单管和双管并联岩心封堵实验来模拟体系对地层的调剖过程,结果表明,体系对单管岩心的封堵率高于96%,突破压力梯度大于35 MPa/m;双管并联岩心实验时,体系对高渗管岩心的封堵率在95%以上,而对低渗管岩心的封堵率低于15%。     

Effect of Polymer Concentration on Autoclaved Cryogel Properties

Biomaterial sterilization is a prerequisite prior to patient's use, especially for scaffold implantation or injection. Various sterilization processes are mandated by the Food and Drug Administration including high‐pressure steam sterilization. Although high‐pressure steam or autoclave sterilization eliminates pathogens, it often leads to irreversible damages on soft materials such as hydrogels. In the current study, the impact of autoclave sterilization on cryogels made from several naturally‐derived polymeric precursors (alginate, hyaluronic acid, and gelatin) is analyzed. Specifically, the impact of polymer concentration on the structural and physical properties of autoclaved cryogels such as mechanics, swelling ratio, pore interconnectivity, and shape‐memory features is studied. The results demonstrate that at a given optimal polymer concentration, unique for each biopolymer investigated, autoclave sterilization does not substantially alter the microarchitectural or physical characteristics of cryogels, including their syringe injectability signature. In summary, when formulated under optimized polymer concentrations, autoclavable cryogels hold great potential for several biomedical applications, as they can be easily translated into clinical practice to benefit public health.     

杨木预水解液中化学组分质量浓度的P因子调控

为研究P因子对木质纤维原料预水解液中化学组分质量浓度的调控机制,分析了不同预水解温度（170~210℃）和预水解时间（30~120 min）条件下,杨木预水解液中固形物、木质素、木糖和葡萄糖质量浓度的变化规律。结果表明：升高预水解温度和延长预水解时间,固形物、木质素和葡萄糖质量浓度均逐渐增大。而木糖质量浓度随温度的升高而降低;190℃时,木糖质量浓度随预水解时间延长迅速减小。P因子对杨木预水解液中化学组分的质量浓度具有调控作用。固形物、木质素和葡萄糖质量浓度随P因子增加呈指数增大。而木糖质量浓度随P因子增加呈指数减小,P因子小于3 300时,木糖质量浓度随P因子增加迅速减小。     

高浓度二氧化碳入侵对土壤理化性质的影响

在地质储存CO_2(GCS)泄漏对生态环境的影响中,土壤作为生态系统中物质与能量交换的主要介质,其理化性质的变化研究尤为重要。采用人工模拟CO_2泄漏地表的方式,并分析土壤pH值、总有机碳、氮、磷、钾、水溶性盐浓度的变化及地表植物响应。结果表明:CO_2入侵使土壤总有机碳相比于对照增加了1.56%~43.75%,总氮下降了0.88%~13.25%,氨氮与硝氮也同比下降,磷、钾、水溶性盐总体也是减少的,但土壤pH值有所上升,且各植物长势均较好,尤其是豌豆与萝卜的生长较好。结论:高浓度CO_2入侵会对土壤理化性质产生一定影响,而且对植物的生长有促进作用。     

氯化钠含量对明胶凝胶强度的影响

明胶具有溶胶-凝胶可逆性,在食品中应用广泛。作为食品添加剂通常体系中会含有盐类等。这些盐类对其体系的凝胶强度的影响,将直接影响到其产品的质量和性能。因此,本文研究了食品中常用的氯化钠对明胶食品体系凝胶强度的影响,揭示其影响规律。研究结果表明,氯化钠能降低明胶凝胶强度,特别是添加少量氯化钠的时候,作用尤为明显。     

胶冻强度与明胶α组分关系的研究

用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)法测定了明胶的α组分含量;用胶冻强度测定仪测定了它们的胶冻强度。结果表明,这两组数据的比值呈线性的对应关系。作者曾在“α_1组分含量最高的明胶”一文中推测,胶冻强度与明胶α组分含量之间存在相互的影响,这一推测在本文的研究中得到证实。     

Adhesion Properties of Lightly Crosslinked Solvent-Swollen Polymer Gels

Polymer gels are crosslinked polymer networks, highly swollen with solvent. For practical gel applications adhesion to a wide range of substrates over a broad range of temperatures is desired. In this article the adhesive properties of two types of solvent-swollen elastomers were studied, utilizing a combination of tack, contact mechanics, and peel adhesion methods. The first gel was a crosslinked polybutadiene swollen with common polymer plasticizers, while the second was a commercially available silicone with high extractables content. Nominally, these solvent-swollen materials exhibit similar adhesive characteristics to nonsolvent swollen elastomers including: (1) an increase in tack adhesion energies with increasing pull-off rates and decreasing temperatures in the rubbery region, (2) qualitative correlation between the rheological loss tangent for the gel and the gel adhesion energy, (3) fibrillation and extension during adhesion testing for gels with a shear modulus value less than 10⁵ Pa in the plateau region, and (4) a decrease in the adhesion energy with increasing crosslink density. However, the presence of solvent in the elastomer can lead to solvent exclusion effects that degrade tack adhesion and must be considered for gel design in practical applications.     

动态光散射法测定凝胶中大分子有效扩散系数

引　言凝胶广泛应用于生化分离和医学材料等领域 ,其中溶质分子在凝胶中的扩散特性尤为关键[1] 凝胶中溶质分子有效扩散系数的测定方法主要有扩散法[2 ]、荧光恢复法[3]、强制瑞利散射法[4 ]、全息衰减法[5 ]和动态光散射法 (ＤＬＳ) [6～ 8],后者一般用于较软且透明的凝胶 前人在用ＤＬＳ法测定凝胶中溶质分子的扩散系数时均忽略凝胶结构的非均匀性 ,具有较大的局限 本文在处理含大分子凝胶体系的ＤＬＳ数据时 ,在考虑凝胶结构的非均匀性基础上提出了遍历介质非均匀校正法 ,并以溶菌酶在聚丙烯酰胺 (ＰＡＡ)凝胶中的扩散为例 ,验证了该方…     

Profile of Chemical Potential in Pressure-Driven Membrane Processes Accompanied by Gel-Enhanced Concentration Polarization

Abstract

A model for distribution of chemical potential and concentration polarization enhanced by gel accumulated on membrane surface has been proposed. It provides distribution of chemical potential and concentration in the liquid phase and within the gel layer. The model allows analyzing the influence of thickness of fouling gel layer on the CP degree, surface concentration and chemical potential.

The model is based on the following assumptions:

1. process is accompanied by accumulation of gel layer at membrane surface along with concentration polarization;

2. diffusion layer and deposited gel consist of different components and these layers are characterized by different values of diffusivity coefficients;

3. correlation for effective hindered back diffusion coefficient within deposited layer is adopted from [Boudreau, Geochim. Cosmochim. Acta, 60, 1996];

4. transverse transport is based on the following mechanisms: convection due to pressure difference and back diffusion owing to concentration gradient.

The following conclusions have been drawn: (A) diffusion resistance within the gel layer is getting dominant and cannot be ignored; (B) In the presence of a gel layer the membrane surface concentration, C_1M, is enhanced due to hindered back diffusion of salt ions that in turn, results in growth of osmotic pressure and chemical potential at the membrane surface. It provides elevated salt concentration in permeate and decreases the net driving force; (C) Analysis of calculated data indicates high sensitivity of CP degree to coefficient of hindered back diffusion within gel layer.