With the gradual deepening of the exploration and development of deep and ultra-deep oil and gas resources, the problem of lost circulation in drilling operations is becoming more and more complex. From field experience, conventional plugging materials cannot fully meet the technical requirements of plugging operations in drilling engineering. In this study, a high-temperature- and salt-resistant polymer HDZ-A was synthesized. A high-temperature and delayed crosslinking polymer gel plugging agent can be prepared by adding a certain concentration of a crosslinking agent and a retarder. In this paper, the optimum synthesis conditions of the HDZ-A were determined with orthogonal experiments using viscoelasticity and viscosity as evaluation criteria for newly developed polymers. The molecular structure, temperature resistance, and relative molecular mass of HDZ-A were determined using infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gel permeation chromatography. In addition, the optimal formula of the gel plugging agent was determined using gel strength as the evaluation standard. The results show that the newly developed gel plugging agent has stable performance after high-temperature crosslinking, and can resist high temperatures of 160 °C during formation. Under conditions of 160 °C, the gelation time can reach 4.5 h, and the plugging efficiency can reach more than 97%. Finally, the field test of the newly developed high-temperature-resistant delayed crosslinking polymer gel plugging agent was carried out in the direct exploration well KT-14X in the Ordos Basin. The field test showed that the plugging effect of the HDZ-A gel plugging agent was remarkable.

Hydrogel dressings traditionally promote wound healing by maintaining moisture and preventing infection rather than by actively stimulating the skin to regulate cell behavior. Electrical stimulation (ES) is known to modulate skin cell behavior and to promote wound healing. This study describes the first multifunctional conductive hydrogel for wound healing and health monitoring based on a deep eutectic solvent (DES). Sodium hyaluronate and polydopamine constituted the hydrogel skeleton, and tea tree oil and Panax notoginseng extract were used as the active ingredients to induce adhesion, promote antioxidant and antibacterial activity, and support biocompatibility of the hydrogel. The inclusion of DES increases the temperature resistance of the hydrogel and improves its environmental adaptability. We used a small, portable coin battery-powered to provide electrical stimulation. Treatment with both the hydrogel and ES resulted in a stronger therapeutic effect than that provided by the commercial DuoDERM dressing. The hydrogel detected movement and strain when applied as a sensor. Overall, this study reports the development of a multifunctional conductive hydrogel dressing based on DES as a wound healing and health monitor.

Biomass-based hydrogel is a promising flame-retardant material and has a high potential for applications in transportation, aerospace, building and electrical engineering, and electronics. However, rapid vat photopolymerization (VP) 3D printing of biomass-based hydrogels, especially that of all-natural ones, is still rare. Herein, a new class of VP 3D-printed hydrogels with strong covalent networks, fabricating using fully biomass materials and a commercial liquid crystal display (LCD) printer assembled with low-intensity visible light is presented. Encouragingly, the highly ordered layer-by-layer packing structures provided by VP 3D printing technology endow these hydrogels with remarkable flame retardancy, exceptional temperature resistance, advantageous combustion behaviors, and favorable mechanical strength, in particular, giving them a better limit oxygen index (83.5%) than various biomass-based hydrogels. The proposed approach enables the green design as well as the precise and efficient preparation for flame-retardant materials, paving the way for the future flame-retardant materials toward attaining green sustainability.

The temperature resistance of glued timber, which is crucial for glued wood construction, represents a significant assessment criterion. To gain insights into this aspect, this study utilized methods such as a shear strength test in accordance with EN 302-1:2013-06 under thermal loading (from 20 °C to 200 °C), and Differential Scanning Calorimetry (DSC) to determine the glass transition temperature (Tg). An increase in thermal load resulted in a decrease in shear strength and an increase in wood breakage. A hierarchy of adhesive groups was established based on strength performance and wood failure percentage (WFP) at 200 °C. Thermoset adhesives (MF: Melamine Formaldehyde, PRF: Phenol Resorcinol Formaldehyde) led the ranking, followed by elastomer adhesives (1C-PUR: One-Component Polyurethane, EPI: Emulsion Polymer Isocyanate), with thermoplastic adhesive (PVAc: Polyvinyl Acetate) last. Thermoset adhesives further cured under heat. PUR adhesives exhibited higher strength performance at 150 °C and lower temperatures.

Aqueous zinc-ion hybrid capacitors (ZHCs) are considered ideal energy-storage devices. However, the common aqueous Zn2+ -containing electrolytes used in ZHCs often cause parasitic reactions during charging-discharging owing to free water molecules. Hydrated eutectic electrolytes (HEEs) that bind water molecules through solvation shells and hydrogen bonds can be applied at high temperatures and within a wide potential window. This study reports a novel bimetallic HEE (ZnK-HEE), consisting of zinc chloride, potassium chloride, ethylene glycol, and water, which enhances the capacity and electrochemical reaction kinetics of ZHCs. The bimetallic solvation shell in ZnK-HEE is studied by molecular dynamics and density functional theory, confirming its low step-by-step desolvation energy. A Zn//activated carbon ZHC in ZnK-HEE shows a high operating voltage of 2.1 V, along with an ultrahigh capacity of 326.9 mAh g-1 , power density of 2099.7 W kg-1 , and energy density of 343.2 Wh kg-1 at 100 °C. The reaction mechanisms of charging-discharging process are investigated by ex situ X-ray diffraction. This study reports a promising electrolyte for high-performance ZHCs, which exhibits high-temperature resistance and is operable within a wide potential window.

OBJECTIVE: Worm-like micelles are susceptible to heating owing to the fast dynamic exchange of molecules between micelles. Inhibition of such exchange could afford robust worm-like micelles, which is expected to largely improve rheology properties at high temperatures.
METHODS: A cationic surfactant docosyl(trimethyl)azanium chloride (DCTAC) and a strongly hydrophobic organic counterion 3-hydroxy naphthalene-2-carboxylate (SHNC) were used for the worm-like micelles fabrication. The microstructure was characterized using cryogenic transmission electron microscopy and small-angle neutron scattering, and the interactions between DCTAC and SHNC were characterized using nuclear magnetic resonance spectroscopy. Rheometer was employed to measure the rheological properties of the solution.
RESULTS: SHNC/DCTAC at the molar ration of 1:2 forms ultra-stable worm-like micelles, whose viscosity remain stable at temperature up to 130 °C. SHNC is found to strongly adsorbs on DCTAC micelle with the orientation on the surface of micelle, keeping the naphthalene backbone entire penetration into the palisade layer while both carboxylic and hydroxyl groups protrude out of the micelle. With temperature increasing, this adsorption further strengthens, resulting in the growth contour length and accompanying the enhancement of rheological properties. One SHNC molecule and two DCTAC molecules are speculated to form a stable complex via multiple interactions including hydrophobic, cationic-π, and π-π interactions, which decreases the dynamic exchange of them between micelles. These findings are helpful to understand surfactant aggregates stability and assist the development of novel stable supramolecular nanostructures. Additionally, the excellent thermal stability of this worm-like micellar fluid makes it a potential high-temperature resistant clean fracturing fluid for deep oil reservoirs.

In view of the problems of polymer cross-linked elastic particle plugging agents commonly used in oilfields, including easy shear, poor temperature resistance, and weak plugging strength for large pores, the introduction of particles with certain rigidity and network structure, and cross-linking with a polymer monomer can improve the structural stability, temperature resistance, and plugging effect, and the preparation method is simple and low-cost. An interpenetrating polymer network (IPN) gel was prepared in a stepwise manner. The conditions of IPN synthesis were optimized. The IPN gel micromorphology was analyzed by SEM and the viscoelasticity, temperature resistance, and plugging performance were also evaluated. The optimal polymerization conditions included a temperature of 60 °C, a monomer concentration of 10.0-15.0%, a cross-linker concentration of 1.0-2.0% of monomer content, and a first network concentration of 20%. The IPN showed good fusion degree with no phase separation, which was the prerequisite for the formation of high-strength IPN, whereas particle aggregates reduced the strength. The IPN had better cross-linking strength and structural stability, with a 20-70% increase in the elastic modulus and a 25% increase in temperature resistance. It showed better plugging ability and erosion resistance, with the plugging rate reaching 98.9%. The stability of the plugging pressure after erosion was 3.8 times that of a conventional PAM-gel plugging agent. The IPN plugging agent improved the structural stability, temperature resistance, and plugging effect of the plugging agent. This paper provides a new method for improving the performance of a plugging agent in an oilfield.

Artificial ecosystems with high biological complexity are generally considered to be efficient in metabolizing substances and resistant to temperature shock. In this study, a novel near-natural system (BCT system), which consisted of simple biofilter, constructed wetland and trophic biology pond, was conducted to treat rural sewage in situ for irrigation into farmland. Water quality related to carbon and nutrients and microbial community were analyzed along the system to reveal the effect of each unit. The annual average removals of BCT system for TN, NH4+-N, TP and COD could reach 46.53%, 52.18%, 41.48%, and 53.21%, respectively. There was no significant decrease for removal efficiencies from high temperature period (HTP, ≥15 °C) to low temperature period (LTP, <15 °C). In LTP, the trophic pond (TRP) removed 34.85% of TN, 33.93% of NH4+-N, 13.71% of TP and 18.77% of COD, while the removal efficiencies of constructed wetland fluctuated greatly. The TRP facilitated the BCT system to maintain the removal capability during low temperature period. The relative abundance of denitrification functional genes in TRP increased nearly tenfold from HTP to LTP. The effluent quality from the system can meet the agricultural irrigation standards, demonstrating the effect of BCT system on sewage treatment and agricultural irrigation in rural area.

With the exploration and development of high-temperature and high-salt deep oil and gas, more rigorous requirements are warranted for the performance of water-based drilling fluids (WBDFs). In this study, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, diallyl dimethyl ammonium chloride, and N-vinylpyrrolidone were synthesized by free radical copolymerization in an aqueous solution to form a temperature and salt-resistant zwitterionic polymer gel filtration loss reducer (AADN). The zwitterionic polymer had excellent adsorption and hydration groups, which could effectively combine with bentonite through hydrogen bonds and electrostatic attraction, strengthening the hydration film thickness on the surface of bentonite, and promoting the stable dispersion of drilling fluid. In addition, the reverse polyelectrolyte effect of zwitterionic polymers strengthened the drilling fluid’s ability to resist high-temperature and high-salt. The AADN-based drilling fluid showed excellent rheological and filtration control properties (FLAPI < 8 mL, FLHTHP < 29.6 mL) even after aging at high-temperature (200 °C) and high-salt (20 wt% NaCl) conditions. This study provides a new strategy for simultaneously improving the high-temperature and high-salt tolerance of WBDFs, presenting the potential for application in drilling in high-temperature and high-salt deep formations.

Innovative dielectric materials with high-temperature resistance and outstanding dielectric properties have attracted tremendous attention in advanced electronical fields. Polyimide(PI) is considered a promising candidate for the modern electronic industry due to its excellent dielectric properties and comprehensive properties. However, the limited-adjustable range of dielectric constant and the difficulty to obtain a high dielectric constant restrict the application of PI as high dielectric materials. Herein, a novel diamine monomer (2,2\'-bis((methylsulfonyl)methyl)-[1,1\'-biphenyl]-4,4\'-diamine (BSBPA)) containing a rigid biphenyl structure and high dipolar sulfonyl pendant groups is designed for high dielectric polyimides. The rigid biphenyl and polar sulfonyl pendant groups can reasonably optimize the molecular structure and orientational polarization of polyimides to improve their dielectric properties and thermal properties. Moreover, the effect of different bridge linkages on the dielectric properties is studied by using the different dianhydrides. Thus, the PI-BSBPA films especially the DSDA-BSBPA film (DSDA: 3,3\',4,4\'-diphenylsulfonetetracarboxylic dianhydride) achieve great thermal properties (T5%d of 377 °C and Tg of 358 °C) and excellent dielectric properties (6.95 at 1 kHz) along with high discharged energy density of 5.25 J cm-3 and charge-discharge efficiency of 90%. The collaborative control of main-chain and side-chain engineering is effective to endow the polyimides with high-temperature tolerance and high dielectric performance.