Polymer Clay Research Articles

Bond strength of polymer clay with room temperature vulcanizing maxillofacial silicone – An in vitro study

Aim: To assess and analyze the bond strength of polymeric organic clay and heat polymerized PMMA with RTV maxillofacial silicone with and without an adhesive primer. Settings and Design: The use of polymeric clay as a substructure for implant retained maxillofacial silicone prosthesis is suggested. However, the bond strength of polymeric clay with room temperature vulcanizing (RTV) maxillofacial silicone and heat polymerized polymethyl methacrylate(PMMA) with RTV maxillofacial silicone has yet to be studied. Materials and Methods: Fifty two samples were prepared in total. Group 1 (n = 13) silicone and PMMA without primer. Group 2 (n = 13) silicone and PMMA with primer. Group 3 (n = 13) silicone and polymer clay without primer. Group 4 (n = 13) silicone and polymer clay with primer. The samples were of dimensions of 75 mm × 10 mm × 3 mm. For groups 1 and 2, samples were fabricated with PMMA over which RTV silicone was manipulated, packed and vulcanized for 24 h. For Groups 3 and 4, polymer clay was molded to the required dimensions and hardened. RTV maxillofacial silicone was manipulated and packed over it and vulcanized. For Group 2 and 4 samples, primer was applied to the uncovered part of PMMA and polymeric clay respectively. The samples were subjected to a 180° and 90° (t peel test) peel strength test, respectively. Statistical Analysis Used: One way analysis of variance was used to analyze bond strength, which was then followed by a post hoc Tukey’s test. Results: The mean bond strength of silicone and PMMA without primer was 0.35 ± 0.07 mN/m, while silicone and PMMA with primer had a mean bond strength of 0.41 ± 0.04 mN/m. The mean bond strength of silicone and polymer clay without primer and silicone and polymer clay with primer was found to be 0.45 ± 0.13 mN/m and 0.30 ± 0.05 mN/m, respectively. An 80% research power and a 95% confidence interval were used in the statistical analysis. A significance threshold of P < 0.05 was applied. Conclusion: The silicone to heat polymerized PMMA primer bond strength is the same as the silicone to polymer clay primer bond strength. Bond strength of polymer clay and maxillofacial silicone without primer is better than with primer. Therefore, without primer application, polymer clay substitutes PMMA as an interface between maxillofacial silicone material and attachments/keepers.

Utilization of Polymers for the Development of Nanomaterials

AbstractThis study highlights the significance of polymers in the progress of nanoparticles across various areas. The molecules of polymers are highly regarded for their ability to adapt and self‐assemble, making them essential components in the creation of nanomaterials. The variety of polymers include natural polymers such as chitosan, synthetic polymers like polyethylene, and biodegradable polymers like poly(lactic‐co‐glycolic acid) (PLGA). These kinds of polymers possess distinct advantages such as high strength, environmental sustainability, and biocompatibility. Incorporation of nanoscale fillers into polymer matrices, which enhances the mechanical, thermal, and electrical properties of materials, is crucial for the development of nanocomposites. Illustration instances encompass carbon nanotube‐polymer composites and polymer clay hybrids, which find application in the construction, automotive, and aerospace sectors. Composites can employ many synthetic methods to generate nanostructures. Nanofibers have utility in tissue engineering, whereas polymer nanoparticles function as carriers for medical delivery. Also, polymers enhance nanomaterials by modifying their surfaces, a crucial factor for their application in membrane technology, catalysis, and sensing. A collaborative synergy between polymers and nanoparticles fosters a wide range of applications, showcasing the versatility and potential of polymers in altering the characteristics of nanomaterials. The resulting partnership continues to generate pioneering breakthroughs that address complex challenges and unveil unprecedented prospects in the domains of science, technology, and business.

An Investigation of the Factors Influencing the High Temperature Rheology of Polymers

Introduction: Nowadays, polymers, as an important application material in drilling engineering, have obvious advantages in solving the rock-carrying problem at the bottom of deep wells, and improving the drilling speed due to their excellent viscosity enhancement effect. Method: In this study, the effects of polymer type, concentration, shear time, electrolyte, and clay on the rheological properties of polymer solutions at high temperature and high pressure were investigated using a Fann 50SL rheometer. The experimental results showed that, except for the polymer additive amount and clay, the increase in shear time and the amount of salt both led to a decrease in the viscosity of the polymer solution, with 190°C as the critical temperature above which the viscosity decreased significantly. Results: The polymer solution containing formate showed higher viscosity retention during heating and then cooling compared to chlorides. The presence of clay enhances the reticulation of polymer molecules in the blend, which facilitates the carrying of rock cuttings at high temperatures. In addition, regression analyses showed that the increase in temperature resulted in an enhanced tendency for the polymer solution to evolve from a pseudoplastic to a Newtonian type. Conclusion: This research provides theoretical basis and data support for developing high-temperature polymers and formulating high-temperature drilling fluid systems.

Phosphorus Availability and Adsorption Kinetics of Novel DAP Encapsulated Nano Clay Polymer Composites (NCPCs)

Phosphorus Availability and Adsorption Kinetics of Novel DAP Encapsulated Nano Clay Polymer Composites (NCPCs)

Augmenting barrier efficiency in clay‐based starch composite films for enhanced packaging sustainability

AbstractThe pervasive utilization of plastic as a cost‐effective packaging material for food has led to environmental concerns, primarily due to its non‐biodegradable nature and the ensuing release of carbon dioxide gas that contributes to global warming. In response to these challenges, researchers have shifted their focus toward biopolymers to develop eco‐friendly packaging solutions. The present study introduces a novel approach to study the release of micronutrient (Fe) from clay free starch‐glycerol film and clay‐starch‐glycerol composite film. The structural composition and characteristics of the synthesized film are meticulously examined using x‐ray diffraction (XRD), ATR, scanning electron microscopy and transmission electron microscopy analytical techniques. Notably, XRD analysis reveals a significant interaction between the starch chains and Mt through hydrogen bonding, indicative of starch and glycerol intercalation within the nanoclay gallery—a phenomenon further corroborated by IR spectra analysis. The nanoclay‐infused starch/glycerol composite film exhibits a noteworthy 2.22‐fold increase in water vapor permeability compared to clay free film, attributed to the formation of a convoluted diffusion path indicating the enhancement of the barrier performance of starch‐based films. Comparative evaluations against earlier studies are undertaken to elucidate the advancements in barrier properties, subsequently elucidating the underlying mechanisms through analytical interpretations. From the release study, the release of Fe2+ from the film with clay was observed to be more prolonged compared to a film without clay. As a result, the Montmorillonite clay–polymer composite film was selected for coating rice seeds using the dip‐coating method.

Optimization of batch process parameters for chromium (VI) removal from synthetic wastewater using eggshell–clay composite

In this study, a biodegradable spherical adsorbent bead was developed from eggshell (ES) and Bijoypur clay (BC) for the removal of hexavalent chromium from synthetic tannery wastewater. This Eggshell–Clay polymer composite (ES–BC) was made by incorporating them with PVA and alginate. To analyze the morphology and chemical composition of the adsorbent before and after the chromium adsorption, SEM, FTIR, XRD, and EDX were used. The impact of adsorption parameters such as adsorbent dosage (0.67–2.23 g/L), pH of the solution (1.5–9), contact time (10–240 min), initial Cr (VI) concentration (25–100 ppm), and solution temperature (25–65 °C), percentage clay in ES-BC adsorbent (0–40%) for Cr (VI) adsorption were investigated. The optimum value for adsorbent dosage, pH, contact time, initial Cr concentration, temperature, and clay to eggshell ratio was found 1.17 g/L, 1.5, 150 min, 58.2 ppm, 25 °C, and 80/20% respectively. The isotherm model was well-fitted to the Freundlich isotherm suggesting heterogeneous adsorption in multilayer on surface. The adsorption kinetics followed pseudo-second-order kinetics supporting the chemisorption process. Moreover, a decrease in enthalpy (H°) and negative Gibbs free energy (G°) with increased temperature indicated exothermic and spontaneous reaction. Therefore, this research investigated that the composite may serve as a viable option for treating Cr (VI) containing tannery effluent.

Enhanced resistance to desiccation cracking of polymer–bentonite mixtures: an experimental investigation of underlying mechanisms

Polymers have been shown to enhance the resistance of swelling clay soils to desiccation cracking, a critical property in engineering applications, particularly in waste containment facilities. However, the microscopic and macroscopic mechanisms driving this improvement remain poorly understood. Additionally, the influence of different mixing methods on these mechanisms is not well-established. While dry mixing (DM) is more convenient for onsite implementation, wet mixing (WM) offers intercalation between clay and polymer, resulting in potentially more durable stabilization outcomes. In this paper, key properties related to desiccation cracking of a polymer–clay mixture were measured. The mixture was synthesized by amending Na-bentonite with sodium carboxymethyl cellulose (Na-CMC) using DM and WM. Soil water-retention characteristics curves (SWCC), swelling and shrinkage potential, tensile strength, and pore-size distribution by mercury intrusion porosimetry (MIP) were measured for both mixtures and untreated bentonite. Compared to pure bentonite, mixtures were found to have slightly reduced air-entry values, significantly lower swelling and shrinkage potentials, and higher tensile strengths. In all experiments, DM exhibited superior performance compared to WM. MIP analysis of the amended mixtures revealed a more porous structure compared to untreated bentonite.

Novel fibrous Ag(NP) decorated clay-polymer composite: Implications in water purification contaminated with predominant micro-pollutants and bacteria

Due to the potential harm caused by emerging micro-pollutants to living organisms, contaminating water supplies by micro-pollutants like EDCs, pharmaceuticals, and microorganisms has become a concern in many countries. Considering both microbiological and micro-pollutant exposure risks associated with water use for agricultural/or household purposes, it is imperative to create a strategy for improving pollutant removal from treated wastewater that is both effective and affordable. Natural clay minerals efficiently remove contaminants from wastewater, though the pristine clay has less affinity to several organic pollutants. Hydrophilic polymers, viz., poly(ethylene glycol) (PEG), improve the dispersion of particles, flocculation processes, and surface properties. In this study, PEG grafted with attapulgite, thereby providing a high-specific surface-area, mesoporous materials for the adsorption of micro-pollutants like ciprofloxacin (CIP) and 17α-ethinylestradiol (EE2) at high rates. A gentle washing process regenerates the clay-polymer material several times with no performance loss, and the natural water implications show fair applicability of solid in decontaminating the CIP and EE2 in an aqueous medium. Further, greenly synthesized silver nanoparticles in situ disperse with the clay polymer efficiently remove the gram-positive and gram-negative bacterium viz., Bacillus subtilis, and Pseudomonas aeruginosa, which are commonly persistent in aquatic environments. The clay polymer outperformed a modified clay composite to eliminate microorganisms and organic micro-pollutants in significant quantities quickly. These results clearly show the importance of fibrous clay-polymer composite for water purification technologies.

Purification of Iranian bentonite for organoclay synthesis for use in clay–polymer composites

Abstract Polymer-based composites modified with organoclay are economically beneficial candidates for a variety of applications. Different types of impurities accompany montmorillonite phases in various bentonites, which impact the quality and cost of organoclays and final composites. To obtain organoclays for clay composite applications, eight Iranian raw bentonites from different geographical locations were selected as the candidates and characterized by X-ray diffraction (XRD). Sample IB was chosen due to its high purity and lower cristobalite content than the other samples. It was purified by centrifugation or sedimentation methods using a sodium hexametaphosphate (NaHMP) dispersant. The cation-exchange capacity (CEC) was measured for bentonite before and after purification by sedimentation, and it showed a significant increase from 6.944 to 12.128 eq g–1, confirming successful purification. Organoclays were prepared using purified bentonite (sedimentation method) with two surfactants (cetyltrimethylammonium bromide and octadecylamine), and the amount of octadecylamine was optimized. Purified bentonite and organoclay were characterized by XRD, scanning electron microscopy (SEM) and X-ray fluorescence. The results indicate that most of the impurities were removed after purification, and the interlayer space of organoclays increased to 35 Å in the optimized sample prepared with an amount of octadecylamine that was twice the CEC in purified bentonite. The prepared organoclay was used to improve low-density polyethylene (LDPE) polymer properties. The clay–polymer composite properties were studied by field emission SEM, thermogravimetric analysis and tensile strength tests. The organoclay was fully dispersed in the LDPE matrix and in the sample with 5 wt.% of organoclay, where Ti (the temperature at which 10% of the sample is decomposed) and T50% (the midpoint of degradation) were 17°C and 13°C greater than those of polyethylene, respectively. Additionally, the sample residue with 5 wt.% of organoclay at 600°C was 43.4%. The tensile strength of polyethylene increased from 8.67 to 9.03 MPa in the sample with 4 wt.% of organoclay.

Biomechanically tunable scaffolds for bone tissue regeneration and testbeds of cancer bone metastasis

Current challenges in bone regeneration and design of humanoid 3D bone metastases cancer testbeds can be overcome by designing bone-mimetic tissue engineering scaffolds with tunable mechanical and biological properties. This study employs three unnatural amino acids to modify montmorillonite clay (MMT), producing polymer clay nanocomposites (PCNs) to construct 3D bone-mimetic scaffolds. The modification of MMT clay with 5-aminovaleric acid, (±)-2-aminopimelic acid, and 4-(4-Aminophenyl) butyric acid is analyzed through x-ray diffraction (XRD) and fourier-transform infrared spectroscopy (FTIR), revealing changes in the interlayer spacing and functional groups. Molecular modeling elucidates the interaction energies in the amino acid intercalated nanoclays that influence the mechanical properties of the scaffolds. 4-(4-Aminophenyl) butyric acid-modified scaffolds exhibited the highest compressive strength, highlighting the critical influence of molecular interactions on the mechanical properties of the PCN. Despite being a small fraction of the scaffold, the presence and type of amino acids significantly affect the scaffold mechanical properties. Cell viability assays affirm biocompatibility of scaffolds. The amino acids within the nanoclays also impact mineralization on scaffolds seeded with human mesenchymal stem cells (hMSCs). Amino acid type also influences the amount of mineralization in the scaffolds. A sequential culture involving hMSCs and breast cancer cells (MCF-7) on the scaffold mimics breast cancer metastasis to bone. Enhanced mineralization by bone cells in the presence of MCF-7 cells is observed, emphasizing their osteoblastic characteristics. Hence, 3D scaffolds for bone regeneration and bone metastasis cancer testbeds can exhibit tunable mechanical properties and biological responses though a simulation guided choice of unnatural amino acids.

Preparation of Polyethylene Clay Composites via Melt Intercalation Using Hydrophobic and Superhydrophobic Organoclays and Comparison of Their Textural, Mechanical and Thermal Properties.

Polymer clay nanocomposites, which can exhibit many superior properties compared to virgin polymers, have gained increasing interest and importance in recent years. This study aimed to prepare composites of two organoclays with unusual ratios and different degrees of lyophilicity with low-density polyethylene and compare their textural structures and thermal and mechanical properties with those of virgin polymer. For this purpose, firstly, organoclays, hydrophobic and superhydrophobic organoclays (OC and SOC), were prepared by solution intercalation method using cetyltrimethylammonium bromide with and without addition of a hydrocarbon substance. Then, using both organoclays, polyethylene organoclay composites were prepared and characterized using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Additionally, tensile and hardness tests were performed to determine the mechanical properties of the composites, and differential scanning calorimetry (DSC) thermograms were taken to examine their thermal behavior. XRD patterns and HRTEM images of hydrophobic and superhydrophobic organoclays and the composites show that the characteristic smectite peak of the clay shifts to the left and expands, that is, the interlayer space widens and, in the composites, it deforms immediately at low clay ratios. HRTEM images of the composites prepared especially with low clay ratios indicate that a heterogeneous dispersion of clay platelets occurs, indicating that nanocomposite formation has been achieved. On the contrary, in the composites prepared with high clay ratios, this dispersion behavior partially turns into aggregation. In the composites prepared using up to 20% by weight of superhydrophobic organoclay, extremely stable and continuous improvements in all mechanical properties were observed compared to those of the composites prepared using hydrophobic organoclay. This indicates that by using superhydrophobic organoclay, a ductile nanocomposite of polyethylene containing inorganic components in much higher than usual proportions can be prepared.

PREPARATION AND FLAME RETARDANT APPLICATION OF CLAY POLYURETHANE NANOCOMPOSITES

In recent years, clay-based organic thermosetting polyurethane polymer nanocomposites have more attracted attention in academia and industries because they exhibit different properties from conventional materials. In this study, we investigated novel thermoplastic Polyurethane (TPU) by adding nanoparticles of clay as a fire-retardant property. By employing an in-situ polymerization technique with a 2:1 ratio of tolylene 2,4-diisocyanate (TPI) and polyethylene glycol (PEG2000), the NCO terminated TPU prepolymer was created. Cloisite 25A (C25A), an organo-modified montmorillonite clay, was utilized to provide sufficient compatibility with the PEG/TPI matrix. The synthesized nanocomposite was examined using thermogravimetric analysis (TGA), SEM analysis, and X-ray diffraction (XRD). FTIR analysis provides information on functional groups. Compared to pure polyurethane, the nanocomposites showed superior thermal stabilities, as determined by thermogravimetric analysis (TGA). The results from X-ray diffraction and Scanning Electron Microscopy confirm the successful formation of an exfoliated polymer clay nanocomposite under all conditions, evidenced by the absence of the distinct peak (2θ = 4.79º) corresponding to the d-spacing of the organoclay. The relationship between clay loading and TPU matrix type and the mechanical characteristics of nanocomposites was examined. As the amount of clay in the Young's TPU/Cl25A nanocomposites grew, so did their tensile strength and modulus. The fire-retardant experiment was studied by a cone colorimeter. There have been notable advancements in the fire-retardant qualities, including smoke, CO output, and heat release rate. Comparing polyurethane integrated with 5-weight percent organoclay to ordinary polyurethane polymer, a noteworthy 53% reduction was observed.

Preparation of Melamine Formaldehyde Foam and a Melamine-Formaldehyde-Organo-Clay Nanocomposite and Hybrid Composites

Mineral fillers can be added to thermoset polymers to improve thermal conductivity and deformation behavior, shrinkage, impact strength, dimensional stability and molding cycle time. This study aims to prepare various hybrid composites (MFHCs) using melamine formaldehyde foam (MF), a melamine formaldehyde organo-clay nanocomposite (MFNC) and also pumice as primary filler, and gypsum, kaolinite and a hollow glass sphere as secondary filler. It also focuses on the study of some mechanical properties and thermal conductivities, as well as their microscopic and spectroscopic characterization. For this, firstly, organo-clay was prepared with the solution intercalation method using montmorillonite, a cationic surfactant and long-chain hydrocarbon material, and then was produced using a melamine formaldehyde nanocomposite with in situ synthesis using a melamine formaldehyde pre-polymer and organo-clay. Finally, hybrid composites were prepared by blending various minerals and the produced nanocomposite. For morphological and textural characterization, both FTIR spectroscopy and XRD spectra, as well as SEM and HRTEM images of the raw montmorillonite (MMT), organo-montmorillonite (OMMT), pure polymer (MF) and prepared hybrid composites, were used. Spectroscopic and microscopic analyses have shown that materials with different textural arrangements and properties are obtained depending on effective adhesion interactions between polymer–clay nanocomposite particles and filler grains. Mechanical and thermal conductivity test results showed that melamine-formaldehyde-organo-clay nanocomposite foam (MFCNC) exhibited a very good thermal insulation performance despite its weak mechanical strength (λ: 0.0640 W/m K). On the other hand, among hybrid composites, it has been determined that the hybrid composite containing hollow glass beads (MFCPHHC) is a material with superior properties in terms of thermal insulation and mechanical strength (λ: 0.642 W/m K, bulk density: 0.36 g/cm3, bending strength: 228.41 Mpa, modulus of elasticity: 2.22 Mpa and screw holding resistance: 3.59 N/mm2).

Synthesis of a novel polysiloxane as an inhibitor in water-based drilling fluids and an assessment of the inhibition mechanism

In oil and gas well engineering, shale wellbore stability poses significant challenges. Developing shale inhibitors with high inhibition and resistance to elevated temperatures is crucial to address wellbore stability in deep wells. In this study, an amphoteric polysiloxane known as SC-POTD was synthesized as a heat-resistant shale inhibitor for water-based drilling fluid. The inhibition properties were evaluated using linear swelling, rolling recovery, and rheological tests, and the results were compared with the properties of potassium chloride and commercial polyamines. Various analysis methods were conducted to understand the interaction mechanism between the clay particles and polymer molecules, including X-ray diffraction test, Zeta potential determination, particle size analysis, contact angle measurement, and scanning electron microscope observation. SC-POTD with an amphoteric structure can effectively adsorb on the clay surface through electrostatic force, compressing the electric double layer of clay and forming a hydrophobic layer. Furthermore, SC-POTD can embed in the crystal interlayer, exchange cations and discharge interlayer water, effectively inhibiting hydration. With the flexibility of the Si-O backbone and the small steric hindrance of methyl side groups, SC-POTD may have a better affinity with bentonite containing siloxane tetrahedrons, and cooperate with the quaternary ammonium group to enhance clay interlayer interaction. In addition, the temperature resistance of SC-POTD can be improved by the siloxane backbone with larger bond energy. The results indicated that modified polysiloxane may find a promising application as heat-resistant drilling fluid additives.

Effect of Nitrogen Fertilizers Applied through Nano Clay Polymer Composites on Nitrogen Use Efficiency of Rice

Nitrogen (N) is an essential nutrient for crop growth. However, excessive nitrogen fertilizer application leads to environmental losses. In this study, an attempt was made to reduce the nitrogen losses by loading of urea and urea ammonium nitrate (UAN) into Nano clay polymer composites (NCPCs) to act as slow release N fertilizers. To achieve the objectives of the present study, five N fertilizer treatments (T1-control, T2- N applied through urea, T3- N applied through UAN, T4- N applied through NCPC loaded with urea and T5- N applied through NCPC loaded with UAN) were assessed using three rice genotypes namely IR-64, Nagina 22 and MTU 1010. Results of the greenhouse study indicated that the UAN loaded NCPC treatment was more effective in terms of increasing the grain yield, nitrogen uptake, agronomic use efficiency and apparent nitrogen recovery by 36.9%, 51.0%, 64.2%, and 92.0% over urea, respectively. Amongst the genotypes, MTU 1010 was recorded with highest gran yield followed by IR-64 and Nagina-22.

Synthesizing Conducting Poly(Aniline-co-Aminoacetophenone) Nanocomposites based on Polyhydroxy Iron Cation–modified Clay

Abstract: Conductive clay–polymer nanocomposites were prepared via the in situ polymerization of aminoacetophenone and/or aniline monomers (at initial “aminoacetophenone:aniline”) in the presence of polyhydroxy iron cation–modified montmorillonite (MMT-PIC). Fourier transform infrared spectroscopy analysis demonstrated the characteristic bands of the MMT-PIC polymers/copolymers. The morphological properties analyzed and imaged through X-ray diffraction and scanning electron microscopy, respectively, displayed an increasing interlayer distance with the mass loading of PIC and poly(aminoacetophenone-co-aniline) (poly(AAP-co-ANI)), affording intercalated nanocomposites. Energy-dispersive X-ray spectroscopy measurements revealed that the clay experienced a cation exchange of sodium by the PIC, and poly(AAP-co-ANI) was present in large amounts on the nanocomposite surface. The electrical conductivity of the obtained nanocomposites was 5.760 × 10−5 S⋅cm−1. Moreover, the electrochemical behavior of the polymers extracted from the nanocomposites was studied via cyclic voltammetry; the redox processes indicated that the polymerization into activated carbon produced electroactive polymers.

Research on strength improvement and stabilization mechanism of organic polymer stabilizer for clay soil of subgrade

Soil stabilizer can improve the physical and chemical properties of clay and improve the bearing capacity of subgrade soil. A kind of liquid polymer soil stabilizer of vinyl acetate-ethylene was used in this paper. First of all, the effects of stabilizer content and curing time on the unconfined compressive strength (UCS) and the water stability were studied to clarify the strength evolution of stabilized soil. Furthermore, the pH test, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-Ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were performed to study mineralogy, morphology, and chemistry of clay minerals and polymer stabilizer, as well as the potential interaction of the both. The results show that the stabilized soil has a quick strength growth before 14d that reaches about 89% of the final strength, then followed by a decreasing growth rate. Extending the curing time and increasing stabilizer content contribute to the dense agglomeration structure and homogenous skeleton structure. When immersed in the water, the strength has the largest reduction amplitude within the first day. The pore-filling effect, physicochemical bonds, and surface wrapping for clay particles are dominating roles of the polymer stabilizer. The formed fine colloidal particles could fill micro-pores distributed in the matrix. In addition, the polar functional group of carbonyl could create a strong electrostatic attraction and hydrogen bond with the clay minerals, further improving the adhesion, while there are no other new function groups generated. The polymers containing hydrophobic groups are recommended in consideration of water stability.

Halloysite for clay–polymer nanocomposites: effects of nanofillers on the anti-corrosion, mechanical, microstructure, and flame-retardant properties—a review

Halloysite for clay–polymer nanocomposites: effects of nanofillers on the anti-corrosion, mechanical, microstructure, and flame-retardant properties—a review

Visualization-based experimental investigation of microscopic sand production characteristics and mechanisms in weakly consolidated sandstone reservoirs

Sand production is a troublesome problem in the petroleum industry, especially in relation to weakly consolidated formations. In this work, a visual experimental apparatus, which allows sand particles to be observed, has been constructed to simulate sand production in weakly consolidated sandstone core. The experimental apparatus can accommodate sandstone core flakes as a reactor. The experiment aims to investigate the microscopic sand production mechanism of the weakly consolidated sandstone reservoir under the influence of high water cut, high clay content and polymer aging blockage. Core flakes were produced using simulated formation sands with median particle sizes of 160 μm and uniformity coefficients of 2.5, 4.6, 7.3 and 12.6, as well as clay (content 5%, 10%, 20%, 30%, respectively) and aged polymers in the wells. A total of 17 sets of experimental tests were carried out with water injection. The visual experimental results show that sand morphology presents complex wormhole. Morphology is particularly affected by core strength and heterogeneity. Based on dynamic differential pressure of experimental results, most sand production process is divided into two obvious stages, that is, the cavities formation stage of sharp sand production and the stable sand production stage. Analysis of sensitive factors revealed that the sand production rate is strongly influenced by the core strength and related to clay content, formation heterogeneity and production program. The volumetric sand production ratio decreases with the increase of core strength, with the volumetric sand production ratio (VSPR) reaching up to 0.24%. It is found that about 38% clay (1–3.91 μm) was produced in the initial stage of low flow, which is particularly evident in cores with high clay content. Moreover, for weakly consolidated reservoir, the particle competition peeling mechanism of wormhole front is proposed, and the strengthening bonding effect of aging polymer and the pore blockage effect of fine clay are clarified. The findings could contribute to better understanding of the mechanisms underlying sand production in weakly consolidated sandstone reservoirs, which also provide a solid evidence base for accurate sand production prediction and more targeted sand control.

DEVICE AND TECHNOLOGY OF CONTINUOUS WELL FLUSHING

Link for citation: Tretyak A.Ya., Litkevich Yu.F., Kruglova T.N. Device and technology of continuous well flushing. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.181-188. In Rus. The relevance research is due to the fact that at present a large number of accidents occur due to the stoppage of the rotation of the drill string and the cessation of flushing during the build-up of the drill string. Staying the wellbore for some time at rest, and then creating flushing fluid pressure pulses accompanying the start and stop of mud pumps, can lead to undesirable phenomena and complications in the form of sticking. Sticking can be mechanical, due to the complex geometry of the wellbore, falls into the rocks from the walls of the well, the formation of cuttings at the bottom of the well due to insufficient flushing of the well. The percentage of such accidents can reach 20. Up to 80 % of differential sticking is due to the pressure difference – hydrostatic, formed in the wellbore due to the density of the drilling fluid, and reservoir, formed in the well formation. Due to these processes, water infiltration from the drilling fluid into the formation occurs, and a thick polymer clay cake is formed on the well walls, which contributes to the formation of differential sticking, that is, the sticking of the drill string to the well walls. The purpose: to develop a device and technology for continuous flushing of wells when building a drilling tool. Objects: device and technology for continuous well flushing. Methods. A device for continuous flushing of the well, consisting of synchronously overlapping on-off valves that provide continuous flushing of the well when building up the drilling tool is proposed for manufacturing. A mobile crane switching synchronizer is described, its design and principle of operation are given. Technological methods are proposed that realize the possibility of the device operation. Results. The solution of the task set made it possible to develop the design of the device and the technology of continuous flushing of wells.