Preparation and performance evaluation of slow-expanding hydrophobic polymer nanomicrospheres

Due to the shortage of traditional pre-cross linked particulate, such as suspension property, temperature and salt tolerance, and injectivity, this paper developed hydrophobic association polymer pre-cross linked particulate based on hydrophobic association polymer. The performance evaluation of rheological behavior, microstructure and mobility control ability demonstrate that hydrophobic association polymer pre-cross linked particulate can partly dissolved in water, and has certain viscosity thickening and suspension property; it partly cross linking forming mesh structure, and has strong resilience; it can deform through the porous media after swelling, and has good mobility control ability.

The demand for cellulosic fibres as a reinforcement in polymers is growing due to their renewable, biodegradable, and ecologically favourable properties. In addition, they are lower in density than e.g. glass fibres, which will help in making lightweight composites. Besides, there is no health hazard with ease of processing and minimum damage to the processing equipment. Despite their advantages and high demand, their utilization in industrial applications is still limited. This is due to their inherent polar and hydrophilic nature and their consequent incompatibility with hydrophobic polymers. Therefore, it is often necessary to do hydrophobic modification treatment. The review examines a range of strategies for modifying ramie surfaces, encompassing physical, chemical, and biological processes. It also analyzes the procedures and techniques involved in the preparation and manufacturing of ramie-reinforced polymeric biocomposites. Moreover, an investigation is conducted to evaluate the performance of the composites produced. The performance evaluation includes both before and following fibre treatment, covering surface morphology, wettability, chemical composition, mechanical properties, and flame retardancy. Most of the researchers reported that alkaline and silane coupling agent treatments are the most prevalently applied pretreatments. Compared to biological and physical methods, the application of chemical agents enables excellent adhesion of fibre to polymer resins. However, the utilization of solvents such as ethanol and methanol increases the amount of waste produced and toxic compounds released.

ABSTRACTPoor adhesion between hydrophobic polymers and hydrophilic inorganic fillers is a challenge that encumbers a high separation performance of mixed matrix membrane (MMM). In this study, Titanium(IV) oxide (TiO2) nanoparticles were functionalized using ethylenediamine (EDA) before embedment in poly(ether sulfone) (PES) polymer matrix. MMMs were synthesized through dry phase inversion technique. Membranes morphology and nanoparticles dispersion was drastically enhanced posterior amine modification indicating an improved adhesion between the polymer and filler particles. Membranes thermal stability was likewise improved as higher degradation temperatures were perceived for PES/EDA–TiO2 MMMs. Gas separation evaluation for pure carbon dioxide (CO2) and methane (CH4) gases revealed a remarkably enhanced separation performance upon amine‐grafting of TiO2 as EDA‐TiO2 MMMs exhibited a higher separation performance as compared to MMMs with pristine TiO2. The highest ideal separation factor achieved was 41.52 with CO2 permeability of 10.11 Barrer at an optimum loading of 5% wt of EDA‐TiO2 which is threefold higher as compared to neat PES membrane and approximately twofold higher than MMMs with pristine TiO2, respectively, at the same filler loading. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45346.

The characteristics of tight matrix, underdeveloped natural fractures, small pore throat radius, poor pore connectivity, and abundant clay minerals result in a high potential for damage to the tight sandstone reservoirs of the Shaximiao Formation in the Qiulin Block in the Sichuan Basin. In order to reduce the retention damage caused by fracturing fluid to the tight sandstone reservoir, a low damage fracturing fluid system applicable to the target reservoir is developed in this work, and the indoor performance meets the requirements of on‐site fracturing operation. A low‐damage, heat‐resistant, shear‐stable amphiphilic polyacrylamide (PAAD) was prepared by free radical polymerization in aqueous solution using acrylamide, acrylic acid, and methacryloyloyloxyethyl dimethyloctadecyl ammonium bromide (DM18) as the monomers. The amphoteric polyacrylamide was characterized by Fourier infrared spectroscopy, nuclear magnetic resonance spectroscopy (1H NMR), light scattering molecular weight determination, and thermogravimetric analysis. Fracturing fluids were formulated with the amphiphilic hydrophobic associative polymer PAAD as a drag‐reducing agent, the fluorine‐containing and nonionic complex surfactant FD1 as a clean‐up additive, CT10‐4B as a bactericide and CT1‐12 as an emulsion breaker. The fracturing fluid formulation was preferred, and the performance of the fracturing fluid was evaluated in terms of temperature resistance and shear resistance, drag reduction, anti‐expansion, and core damage. The fracturing fluid showed good temperature and shear resistance, with a viscosity retention of 58.4% at 120°C and 170 s−1 shear for 1 h. At a loading of 0.1%, the drag reduction rate reaches 72.3%, the anti‐expansion rate of the gel‐breaking fluid is 86.04%, and the damage rate to the tight sandstone core is 16.25%. The results show that the fracturing fluid has good heat resistance and shear stability, as well as low damage and good resistance reduction and anti‐expansion properties. This work can provide new strategies for designing polymeric fracturing fluids with low damage, good heat resistance and shear stability.

We targeted high-temperature and highly saline old oil fields, whose environmental conditions could be attributed to the significantly high heterogeneity cause by long-term water flooding. The Huabei Oilfield was chosen as the research object. We developed a hydrophobic functional monomer–polymer with temperature and salt resistance by introducing the temperature-resistant and salt-resistant monomer NVP and a hydrophobic functional monomer into the main chain for copolymerization. We used a crosslinking agent with phenolic resin to prepare a weak gel system that showed temperature and salt resistance and investigated its temperature and salt resistance, infective property, plugging performance, liquid flow ability, micropore throat migration, and plugging characteristics. The results obtained using the infrared spectroscopy technique revealed the successful preparation of the phenolic resin crosslinker. The weak gel exhibited good temperature and salt resistance when the polymer concentration was 2000 mg/L, the cohesion ratio was 1:1.5, the additive concentration was 2000 mg/L, the reservoir temperature was 120 °C, and the injected water salinity was 40,300.86 mg/L. The average viscosity retention rate of the 90-day weak gel reached more than 80% and its microstructure was examined. The coreflow experiment results revealed that the weak gel system was characterized by good infectivity. After plugging the weak gel, the effect on the direction of the liquid flow was evident and the flow rate of the low permeability layer increased to a maximum of 48.63% under conditions of varying permeability levels. A significant improvement in the water absorption profile was achieved. The plugging was carried out through a sand-filling pipe under varying permeability conditions and the pressure measuring points in the sand-filling pipe were sucessfully pressurized. The migration ability of the weak gel was good and the blocking rate was >85%.

Bromhexine a mucolytic agent was studied to explore for dermal route of administration. The formulations were based on commercial eudragit polymers and polyvinyl pyrrolidone.Two systems i.e., Matrix and Pseudolatex were studied for their comparative performance evaluation in in vitro. The various combinations of hydrophobic (Eudragit RL-100) and hydrophilic (PVP 40,000) polymers were used to prepare the both matrix and pseudolatex topical systems. The prepared systems were studied for in vitro diffusion using a Franz diffusion cell. Study revealed that the relative concentration of hydrophobic to hydrophilic polymers determines the drug diffusion and across the skin permeation of the drug. Both the systems were noted to be stable, however, the drug release and across the skin permeability of drug from pseudolatex system recorded to be better and uniform. Preliminary studies on bromhexine are indicative of its potentiality for transdermal preparation and establish the need for in vivo evaluation.

Preparation and performance evaluation of non-chemically crosslinked four-tailed hydrophobic associative polymer thickeners

Synthesis and properties of hydrophobically associating polymer fracturing fluid

The channeling resistance of cement slurry is one of the critical factors related to cementing quality, especially in the cementing of adjustment well. Due to the complex pressure layer and large pressure fluctuation, the annular channeling problem is easily caused by water invasion. Using 2‐acrylamide‐2‐methyl propane sulfonic acid (AMPS), acrylamide (AM), maleic anhydride (MA), acrylic ester 18(St) as raw materials, we prepared a hydrophobic associative polymer (SMAL) by free radical micellar polymerization. The synthetic products were characterized by IR, NMR, and SEM, and the evaluated engineering application performance. The results showed that SMAL achieved the expected synthesis purpose. Compared with the water channeling pressure of 0.1 Mpa for blank cement slurry, the water channeling pressure of SMAL cement slurry reaches 5.3 Mpa, which significantly improves the anti‐water channeling ability of cement slurry. After adding SMAL, the 14d flexural strength of cement stone was also increased from 7.7 to 8.3 MPa, which had no adverse effect on cement slurry's rheological property.

This study introduces a novel blocking agent composed of polymerized hydrophobic particles to address the challenge of sealing formations with heterogeneous permeability. These particles display high viscosity and adsorption capabilities, essential for sealing highly permeable formations effectively. Hydrophobic associative polymers (AMSN) were prepared using free radical micellar polymerization, grounded in hydrophobic association principles and molecular design. Optimal monomer ratios and synthesis procedures were identified through the observation of the polymers’ apparent viscosity in aqueous solutions. Characterization of the polymers involved Fourier transform infrared spectroscopy, thermogravimetric analysis, and fluorescence analysis to assess their temperature and salt resistance, reduction in filtrate loss, and blocking abilities. The polymers, containing hydrophobic groups at 300 mg/L concentrations, demonstrated excellent temperature resistance, maintaining 50% of their original viscosity at 95 °C, and sustained effectiveness in 50 g/L salt solutions, surpassing conventional polymers like HPAM. The sealing effect of this hydrophobic conjugated polymer on cracks with different openings can effectively solve the leakage problem. It addresses the need for effective plugging in heterogeneous formation with uncertain leak channel dimensions. Therefore, this study is of great significance for solving cementing leakage, especially for oil and gas reservoir protection in non-homogeneous reservoirs.

The permeability of tight gas reservoirs is usually lower than 1 md. When the external fluids from drilling and completion processes invade such reservoirs, formation damage occurs and causes serious damage to oil and gas production. Fluorocarbon surfactants are most often recommended for removing such damage because they have extremely low surface tension, which means that they can change the reservoir wettability from water wet to gas or oil wet. However, they are not normally applied in the field because they are not cost-effective. Besides, some environmental concerns also restrict their application. In this work, we studied the effects of an oligomeric organosilicon surfactant (OSSF) on wettability modification, surface tension reduction, invasion of different fluids, and fluid flow back. It was found that the amount of spontaneous imbibition and remaining water could be reduced by the surfactant as a result of surface tension reduction and wettability alteration. Compared to the distilled water, the concentration of 0.20 wt% OSSF could decrease water saturation of cores by about 4%. At a flow-back pressure of 0.06 and 0.03 MPa after 20 PV displacement, permeability recovery could increase from 8 to 7–93% and 86%, respectively. We also found that the mechanism of OSSF includes the physical obstruction effect, surface tension reduction of external fluids, and wettability alteration of the reservoir generated. Meanwhile, quantum chemical calculations indicated that adsorbent layer of polydimethylsiloxane could decrease the affinity and adhesion of CH4 and H2O on the pore surface.

Wetting conditions specified for conventional porcelain and glass insulators are not severe enough for the evaluation of contamination flashover voltage performance of hydrophobic polymer insulators. They give lower flashover voltages under heavier fog conditions but a detailed comparison of their contamination performance under varied fog densities hasn't been made. In this paper we investigate contamination flashover performance of polymer insulators under varied fog densities.

Contamination withstand voltage performance of hydrophobic polymer insulators is influenced largely by wetting conditions. Heavier wetting, such as heavy fog and rain could give lower contamination withstand voltages compared with the light fog conditions specified for conventional ceramic insulators. Using the newly installed power source stiff enough for contamination tests, systematic investigation has been conducted on vertically and horizontally installed specimens under different precipitation and water droplet conditions. Simulated rain test is proposed to be included for evaluation of insulation performance of contaminated hydrophobic polymer insulators.

Aiming to solve the problems of the large particle size, high expansion rate of polymer microspheres currently used in anatomical water-plugging technology. In this study, acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and 4-acrylamido-morpholine (ACMO) were used as the raw materials, and the hydrophobic monomer, hexadecyl dimethyl allyl ammonium chloride (DMAAC-C16), and the cross-linking agent poly(ethylene glycol) 200 diacrylate (PEG200DA). A slow-expanding temperature- and salt-resistant polymer nanomicrospheres (PHM) were prepared by reverse-phase microemulsion polymerization. The PHM structure was characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy, and scanning electron microscopy, and their properties were analyzed nano-laser particle sizing, and rheometry and employing the filtration factor. Results showed that the average particle size of PHM was 68.69 nm. The swelling multiplicity of PHM microspheres was 4.34 times after four days of dissolution in water at 80°C. The swelling multiplicity after four days of dissolution in mineralized water with a mineralization level of 80,000 mg/L at 25°C was 2.34 times, and the blocking rate was more than 85%. The slow expansion of the synthesized PHM under the high-temperature and high-salt conditions confirmed their good expansion performance. Viscoelasticity test showed that the synthesized PHM had good elasticity and injection properties.

In the last decades, many surface modification technologies have been developed in an attempt to improve the function of medical device surfaces by adding or enhancing surface characteristics. These value-added processes included treatment to affect lubricity, hemocompatibility and drug delivery. A unique hydrophilic, lubricious coating was developed to treat hydrophobic polymer surfaces. The coating platforms described are composed of a polyelectrolyte molecular film containing hydrophilic, lubricant molecules. The molecular film is then further cross-linked with di-functional aldehyde molecules to form an interpenetrating network (IPN). The IPN entraps lubricant molecules in the matrix and provides for prolonged stability of the lubricity. This coating was applied to cartridges which were used to deliver intraocular lenses (IOLs) that replaced the cataractous crystalline lenses in patients In order to determine the safety and effectiveness of the coating, a rabbit in vivo study was designed to evaluate the ease of implantation and postoperative response to implantation of the foldable acrylic IOLs. The performance evaluation of the lubricious treated cartridges focused on the ease of insertion and post-IOL implantation response. It was found that the UNFOLDER™ Emerald Insertion System (Advanced Medical Optics) with lubricious treated cartridges generally required lower insertion forces than the standard UNFOLDER™ Emerald cartridges. The postoperative inflammatory response following lens extraction and posterior chamber implantation of low (6D), medium (20D) and high (30D) diopter foldable acrylic IOLs with both treated and standard cartridges was mild. Inflammation generally resolved by 3 weeks. Thus, in this animal study, the coating was shown to be effective in assisting the delivery of IOLs through cartridges, without causing any adverse effects.