疏水缔合聚合物溶解工艺的室内研究

由于疏水缔合聚合物存在溶解性差的问题,制约了聚合物驱油技术在海上油田采收率的进一步提高。本文模拟了海上平台的聚合物熟化工艺,考察了管道混合机对聚合物的溶解熟化的影响,研究了疏水缔合聚合物的溶液黏度变化及溶解时间。实验表明经过高速剪切的管道混合机有利于加速聚合物的溶解且粘度较高。     

组合式搅拌器对疏水缔合聚合物溶解特性的影响

机械搅拌是目前加速疏水缔合聚合物溶解熟化所广泛采用的一种方法。然而,聚合物溶解是一个从多相到单相、从低黏到高黏的变化过程,单一搅拌器用于聚合物的溶解过程存在诸多的问题。本文采用适用中低黏度的翼型搅拌器（KCX）和适用高黏度的锚框式搅拌器（MS）的组合,通过实验研究了翼型搅拌器不同操作方式（上翻或下压）和锚框式搅拌器不同转速等操作工况对聚合物溶解熟化过程中的作用,并将翼型搅拌器功率的实验数据与数值模拟的结果进行了比较。研究结果表明：翼型和锚框式搅拌器在聚合物不同的溶解熟化过程中其作用是不一样的;双搅拌器的同向运行可以促进罐内的流动和整体循环,加速聚合物的溶解和熟化;采用翼型搅拌器下压操作（KCXD）与MS搅拌器同向运转操作方式最利于聚合物的溶解和熟化。     

海上油田聚合物熟化过程双搅拌器的优化

自渤海油田实施聚合物驱油以来,海上油田注聚配注系统为适应海上作业条件和聚合物性质在持续优化。由于搅拌设备对聚合物的溶解熟化起着至关重要的作用,因此,熟化过程搅拌系统的优化一直是配注系统优化设计的一个重要方向和一项重要工作。文中在聚合物溶解熟化过程内外组合搅拌器流场特性数值模拟基础上,开展了室内优化实验,实验结果表明:采用同向运转翼型搅拌器KCX和较低转速锚式搅拌器MS的内外组合双搅拌,可显著提升聚合物溶解熟化速度,与数值模拟结果基本一致。     

疏水缔合聚合物高效溶解方法研究进展

疏水缔合聚合物在提高采收率领域中展现出巨大应用潜力,但其疏水基团结构特征使溶解性成为关注焦点。综述了近年来疏水缔合聚合物高效溶解的研究进展,分析了面临的挑战及未来的发展方向。重点介绍了添加化学试剂屏蔽疏水基团的缔合作用,采用筛网切割和胶体研磨等方式增加水与聚合物颗粒的接触面积,以及通过改变聚合物自身溶解性、提高溶液质量浓度或温度、优化搅拌器类型及搅拌方式以增大体系熵变等方法加速疏水缔合聚合物的溶解。化学方法虽然能够快速溶解疏水缔合聚合物且不损害其性能,但其使用成本和环境影响仍需考量。而物理方法尽管经济有效,但可能导致溶液的机械降解和热降解,进而影响增黏性能和驱油效果,同时还需要解决机械设备的运输、能耗以及空间限制问题。因此,研发新型环保溶剂和优化工艺设备对于实现疏水缔合聚合物高效溶解具有重要意义。此外,综合考虑多种高效溶解方法的协同作用,依据实际应用情况进行调整,以期扩大疏水缔合聚合物的规模应用。     

环糊精加速疏水缔合聚合物溶解机理研究

利用环糊精(CD)对疏水基团的包合作用,在疏水缔合聚合物溶解过程中向溶剂中加入环糊精,加快疏水缔合聚合物的溶解速度。当环糊精与疏水基团摩尔比(CD∶[H])≤1,随CD∶[H]增大,溶解时间大幅下降。当CD∶[H]=10时,缔合聚合物的溶解时间缩短至与聚丙烯酰胺相当。流变学结果证明,环糊精通过包合作用破坏疏水基团的缔合结构,大幅缩短缔合聚合物解缠结时间来加速疏水缔合聚合物的溶解速度。     

国内外驱油聚合物研究进展

综述了近年来国内外聚合物驱的研究现状,对聚合物驱的机理及应用做了简单阐述,并着重介绍了几种常见的驱油聚合物近几年的研究进展,主要包括交联聚合物、生物聚合物(黄原胶)、疏水缔合聚合物、梳性聚合物和星形聚合物等。通过这些驱油聚合物性能的评价和对比,对驱油聚合物今后的研究方向提出了建议。     

疏水缔合聚丙烯酰胺溶解槽内流动特性的数值模拟

将疏水缔合聚丙烯酰胺AP-P4溶解过程划分为三种混合状态(搅拌槽中刚加入聚合物颗粒、溶胀刚结束和溶解完成),并采用计算流体力学方法分别对采用二斜叶桨式搅拌器XJD和新型翼型上推式搅拌器KCXU时溶解聚合物AP-P4的三种混合状态的流动进行了数值模拟,获得了两种搅拌器槽内的流场特性和XJD、KCXU搅拌器不同状态时的循环...     

改进型疏水缔合聚合物性能的实验研究

在室内对疏水缔合聚合物及一种改进型疏水缔合聚合物溶液的耐温、抗盐及抗剪切性质进行对比实验研究,同时通过放大实验对聚合物溶解的功率消耗、溶解时间及溶液的粘度进行了研究。实验表明:改进型的疏水缔合聚合物更加具有优良的耐温、抗盐及抗剪切的特性。放大实验证实改进型的疏水缔合聚合物具有优良的增粘效应,以及可以降低功率消耗、节约能源,但溶解速率有所下降。     

卫95-1缔合聚合物驱提高采收率效果评价

缔合聚合物驱油是一种新兴的提高采收率的技术之一,经过驱油效率的室内研究和评价,证明在高温、高矿化度的油藏或存在高渗透层油藏驱油效果较好,具有广阔的应用前景。本文针对卫95—1块的地层特点,经过缔合聚合物体系配方优化、性能指标评价等实验,综合岩芯驱油效果评价的岩芯驱油试验,选出了具有良好抗温、抗盐及剪切恢复性能的缔合聚合物体系,在此基础上制定了卫95—1块的缔合聚合物驱油方案并评价和分析了缔合聚合物驱油效果。     

疏水缔合水溶性聚合物在油田领域研究进展

疏水缔合水溶性聚合物是一类分子链上带有少量疏水基团的水溶性聚合物。由于疏水基的作用使溶液具有特别的流变性能,在油田开采领域有巨大应用价值。本文从疏水缔合聚合物在界面的吸附行为和疏水缔合聚合物的疏水基类型及含量、分子量、温度、表面活性剂浓度等因素对流变性能的影响两方面综述了研究进展。综述了疏水缔合水溶性聚合物在调剖堵水、酸处理、钻井和完井、聚合物驱油、油田污水处理、减阻剂等方面的潜在应用价值和已经取得的实际进展,展望了今后的研究方向。     

Investigation of Adhesion Performance of Aqueous Polymer Latex Modified by Polymeric Methylene Diisocyanate

Aqueous polymer isocyanate (API), which has good adhesive properties at ambient temperature and excellent resistance to warm/boiling water, and is friendly to the environment, is widely used in the timber-processing industry. To prepare high performance API, vinyl acetate homopolymer and copolymer emulsion were respectively cross-linked by three types of polymeric methylene diisocyanate (p-MDI). The potlife, curing time, bonding strength, and water resistance of API adhesives were tested with different cross-linkers and varying loadings (5-20%). Also the effect of polyvinyl alcohol (PVOH) content of aqueous vinyl latex on the performance of API was investigated. It was shown that the potlife and curing time of API were obviously influenced by the types of cross-linker and its loading. Correct loadings of p-MDI as crosslinker can remarkably improve the adhesive performance of aqueous polymer emulsion at ambient temperature. Excess cross-linker cannot maintain such an effect of strengthening and may decrease considerably the bond properties of API. The warm- and boiling-water resistance of API improved markedly with increasing cross-linker loading, where emulsifiable isocyanate gave better cross-linking performance, and p-MDI mixed with organic solvent was the secondbest. With the increase of PVOH content, the curing time of API increased, but no statistically apparent differences in the potlife of API were found. The bonding performance of API was improved as PVOH content increases, but excess PVOH also weakenes the warm- and boiling-water resistance of the joint.     

Investigation of Adhesion Performance of Aqueous Polymer Latex Modified by Polymeric Methylene Diisocyanate

Aqueous polymer isocyanate (API), which has good adhesive properties at ambient temperature and excellent resistance to warm/boiling water, and is friendly to the environment, is widely used in the timber-processing industry. To prepare high performance API, vinyl acetate homopolymer and copolymer emulsion were respectively cross-linked by three types of polymeric methylene diisocyanate (p-MDI). The potlife, curing time, bonding strength, and water resistance of API adhesives were tested with different cross-linkers and varying loadings (5–20%). Also the effect of polyvinyl alcohol (PVOH) content of aqueous vinyl latex on the performance of API was investigated. It was shown that the potlife and curing time of API were obviously influenced by the types of cross-linker and its loading. Correct loadings of p-MDI as crosslinker can remarkably improve the adhesive performance of aqueous polymer emulsion at ambient temperature. Excess cross-linker cannot maintain such an effect of strengthening and may decrease considerably the bond properties of API. The warm- and boiling-water resistance of API improved markedly with increasing cross-linker loading, where emulsifiable isocyanate gave better cross-linking performance, and p-MDI mixed with organic solvent was the secondbest. With the increase of PVOH content, the curing time of API increased, but no statistically apparent differences in the potlife of API were found. The bonding performance of API was improved as PVOH content increases, but excess PVOH also weakenes the warm- and boiling-water resistance of the joint.     

Consistent model predictions for isothermal cure kinetics investigation of high performance epoxy prepregs

An accurate kinetics model is essential for understanding the curing mechanism and predicting the end properties of polymer materials. Graphite/epoxy AS4/8552 prepreg is a recent high‐performance thermosetting composite modified with thermoplastic, which is being used in the manufacture of aircraft and military structures. The isothermal cures of this system along with another thermoplastic toughened high‐performance prepreg, the T800H/3900‐2 system, were investigated by real‐time Fourier transform infrared (FTIR) spectroscopy. The cure rate was quantitatively analyzed based on the concentration profiles of both the epoxy and primary amine groups. Three autocatalytic models were used to determine kinetics parameters for both composite systems. The model which utilizes an empirical term, the final relative conversion (at different isothermal curing temperatures), describes the experimental data of both systems more satisfactorily than the model which applies a diffusion factor. The modeling results suggest that the curing of epoxy within both prepregs can be assumed to be a second order process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Studies on corrosion resistant properties of inhibitive primed IPN coating systems in comparison with epoxy-PU systems

Though blending polymers to obtain high performance materials is an old practice, the new trend in such an approach is the emergence of interpenetrating polymer networks (IPNs) as binders for protective coatings with improved properties. In this study, one ambient curing IPN-type polymer alloy developed out of epoxy and acrylic polyurethane systems as a high performing binder was formulated into paints and evaluated in comparison with the currently used conventional epoxy polyamide and polyurethane systems. A three-coat system consisting of a zinc phosphate primer, a micaceous iron oxide (MIO) undercoat, and a topcoat was formulated out of the IPN along with a similar system of epoxy primer, epoxy undercoat, and a PU topcoat. A two-coat system of the same primer with an IPN clear topcoat and a similar system with epoxy has also been studied. All the systems were studied under accelerated laboratory tests and field tests at a corrosive location. The results are reported and conclusions are drawn in this article. An erratum to this article can be found at     

Isocyanate‐Free Curing of Glycidyl Azide Polymer with Bis–propargylhydroquinone

Bis‐propargylhydroquinone (BPHQ) is an alkyne functionalized isocyanate‐free curing agent for hydroxyl terminated azido polymers. Conventionally, glycidyl azide polymer (GAP) is cured by isocyanate based curatives, which are toxic and hygroscopic in nature. The reaction between hydroxyl end group of GAP and isocyanate is highly sensitive to moisture causing voids in the propellant, leading to poor mechanical properties. Herein, an alternate approach was adapted to exploit 1,3‐dipolar cycloaddition reaction between azido group of GAP and the triple bond (–C≡CH) of BPHQ without catalyst at 50 °C forming triazole crosslinked polymer. The curing behavior of GAP‐BPHQ system was studied by rheological method and based on the results the gel time was determined. In addition, the reaction between GAP and BPHQ was carried out with various GAP/BPHQ ratios (0.9 to 2.5) and effects on mechanical properties of resulting triazole polymers were investigated. Post curing hardness of GAP‐BPHQ binder system was tested by surface Shore‐A hardness measurement. The compatibility of BPHQ with energetic oxidizers such as ammonium dinitramide (ADN) and hydrazinium nitroformate (HNF) were also studied by differential scanning calorimetery (DSC) technique and showed good compatibility. The activation energy (E _a) of cured GAP‐BPHQ binder was evaluated by DSC using Ozawa and Kissinger methods and are found to be 33.55 and 33.16 kcal mol^–1, respectively. The advantage of this curing system between GAP and BPHQ is unaffected by moisture as compared to isocyanate based urethane systems and also no need to control humidity during the processing of propellant. The experimental results reveal that triazole crosslinked polymer system could be a better choice to develop novel energetic binder systems for explosives as well as propellants composition with improved performance and eco‐friendly nature.     

节能型固化体系在环氧粉末涂料中的应用

本文提出ＬＣＡ－咪唑固化体系在环氧粉末涂料中的应用及其所显示的节能特性,对环氧粉末涂料的几种主要固化体系作了比较,分析了ＬＣＡ－咪唑固化体系显著的节能效果,从而揭示了ＬＣＡ－咪唑固化体系在这一领域广阔的应用前景。     

Monitoring of crosslinking of a DGEBA-PAMAM adhesive in composite/aluminium bonded joint using mechanical and ultra-sound techniques

Adhesive cure is an important and determining aspect of strength and stability of bonded structures. Crosslinking of the polymer leads to the adhesive strength, stiffness and durability. Depending on the resin and curing agent used, cure time can vary from minutes to weeks, even then 100% crosslinking not being guaranteed. Standard methods based on dynamic mechanical analysis (DMA) or calorimetric techniques (DSC, DTA) are valuable tools for evaluating short curing times. However, they are devoted specifically to the polymers alone, and not in situ in adhesive joints. In this contribution, we have analysed composite—aluminium joint bonded with a slow-curing DGEBA-PAMAM adhesive system with two new, non-destructive methods. The first is based on measurements obtained from strain gauges mounted on one bonded adherend. The second uses an ultrasound technique based on the through transmission method. Both methods point to the same curing kinetics. Contrary to the classic curing time evolution methods, they are directly applied to adhesive joints where the polymer is only one of the constituents.     

Cellulose nanocrystal (CNC)-based nanocomposites for UV curable high-solid coating systems

Demand for durable clear wood coatings is on the rise. Cellulose nanocrystals (CNC) constitute an organic nanomaterial widely studied in polymer composites for its reinforcing effect. In this study, CNC was used to enhance the performance of a UV curable high-solid content coating system intended for indoor environments. The CNC surface was modified by a cationic surfactant since the coating system was hydrophobic resin-based requiring hydrophobic nanomaterial reinforcement. Modified CNC was mixed with the coating system using a high-speed mixer and the ultrasonication technique. Mechanical, thermal and morphological properties and curing behavior of the newly developed UV-curing coatings were assessed. Inclusion of CNC in the coating increased the mechanical properties (hardness and reduced modulus) of the coating system to a large extent. Thermal stability of the coating system was also improved by CNC addition. The CNC did not affect the curing behavior of the coating, in contrast to most inorganic nanomaterials. The CNC dispersed well in the matrix at 1% loading. Results of this study show that CNC can be used successfully with high-solid content coating systems.     

Electron Beam Curing of the System Cycloaliphatic Diepoxide‐Epoxidized Natural Rubber‐Glycidyl Methacrylate in Presence of Cationic Initiators

Electron beam curing of the system cycloaliphatic diepoxide‐epoxidized natural rubber‐glycidyl methacrylate containing a cationic initiator was carried out. Storage modulus, glass transition temperature and pendulum hardness were measured as function of EB dose, photoinitiator concentration, content of epoxidized natural rubber, post cure temperature and post cure time. At electron beam doses larger than 100 kGy a highly cross‐linked polymer network is generated which shows a two phase morphology. Microscale elastomeric domains are incorporated into a continuous epoxy resin phase. Dynamical mechanical analysis and pendulum hardness measurement show that an increase of the ENR ratio leads to a more elastic polymer network. Post curing results in increased glass transition temperatures. This EB cured polymer system is believed to provide both toughness and favorable viscoelastic properties to be used as component of EB curable composites.     

热致型液晶增韧环氧树脂的研究进展

利用热致型液晶化合物对环氧树脂进行增韧改性,固化体系既融合了液晶的有序性又保留了环氧树脂网络交联的特点,其韧性、冲击强度大幅度提高,而不降低耐热性,这是环氧树脂的传统增韧方法所无法比拟的,是实现环氧树脂高性能化的重要途径之一。热致型液晶高分子(TLCP)增韧环氧树脂可以归纳为两类:液晶环氧树脂(LCEP)增韧和其他聚合物液晶共混增韧。概述了LCEP增韧的方法和增韧机理,TLCP共混增韧的方法和增韧机理,综述了热致型液晶增韧环氧树脂的研究进展,并对其今后研究作了展望。