Guiqiang Fei

Conventional starch and polyvinyl alcohol sizing agents rely on hydrogen bonding, but are susceptible to temperature and humidity, limiting their use in specialty papers such as banknotes. To address this, we synthesized a fluorine–silicon modified acrylate via radical copolymerization of hexafluorobutyl methacrylate (HFBMA) and silane coupling agents (KH570 and KH560) with common acrylate monomers, using ethanol as solvent. HFBMA lowers surface energy through C–F bond surface segregation, while the silane components form Si–O–Si networks and silanol groups that strengthen hydrogen bonding with cellulose fibers. Upon drying, the fluorinated and siloxane segments migrate to the paper surface and assemble into a hydrophobic barrier. Among three systems (F3, Si ₅₇₀ -F3, and Si ₅₆₀ -F3), the optimized Si ₅₆₀ -F3 at 5% dosage increased tensile strength from 28.1 to 47.8 MPa (+70.1%), reduced water absorption from 29.1% to 5.5% (−81.1%), and raised water contact angle from 85° to 122°. These results confirm that this sizing agent effectively enhances both mechanical strength and water resistance for specialty paper.

Food packaging materials require both antibacterial activity and mechanical strength to ensure food safety. However, conventional synthesis of silver nanoparticles (AgNPs) often involves toxic reagents or leads to particle agglomeration, and composite films usually exhibit insufficient mechanical properties. In this study, carboxymethyl chitosan (CMCS) was used as both a reducing and stabilizing agent to in situ reduce Ag⁺ under atmospheric-pressure oil-bath heating, yielding CMCS-Ag composites, which were then impregnated into carboxymethyl cellulose (CMC) films to prepare CMC-CMCS-Ag ternary composite packaging films. Under optimal conditions (102 °C, 6 h, 10 mM AgNO₃, 0.05% CMCS), AgNPs were uniformly dispersed without aggregation. The tensile strength reached 125.45 MPa, and the inhibition zone diameters against E. coli and S. aureus were 14.1 mm and 14.7 mm, respectively. This work provides a facile strategy for high-performance antibacterial food packaging films.

Solar-driven interfacial seawater evaporation is a pivotal technology for relieving global freshwater shortage. Although two-dimensional photothermal evaporators feature low cost and high flexibility, they are plagued by insufficient mechanical robustness, poor thermal localization and low stability, hindering practical applications. Herein, we use a continuous dynamic electrostatic cladding yarn strategy to build core–shell structured yarns, with a high-modulus stainless steel wire as the core and a transition metal-modified carbon-based photothermal polymer as the shell. The PM-1.35 yarn exhibits an ultrahigh tensile strength of 3692 MPa, a water evaporation rate of 2.18 kg·m^-2 h^-1 and an efficiency of 89.6% under 1 sun illumination. The integrated system delivers a maximum open-circuit voltage of 150.3 mV and stably generates 40.3 mV by waste heat recovery. This work integrates robust mechanical properties and outstanding photothermal activity, providing a new technical route for practical seawater desalination and thermoelectric cogeneration.

Long-term water flooding development has exacerbated reservoir heterogeneity, and traditional polymer gels are unable to simultaneously meet the requirements of high injectability and strong plugging strength. If the viscosity of the polymer is high, its injectability will be poor; on the contrary the viscosity is low, the plugging strength will be poor, which severely restricts the oil recovery effect. This study synthesized an NBAP through free radical polymerization followed by a substitution reaction, and a plugging system (NBAP-B1) was subsequently formed by combining the polymer with a Cr³⁺ crosslinking agent. Rheological experiments demonstrated that the system exhibited significant shear thinning behavior, as well as excellent temperature and salt resistance. Gelation experiments indicated that the NBAP-B1 system featured controllable gelation time (20~150 h) and high gelation strength (J grade), along with excellent resistance to both high temperature and high salinity. Microscopic analysis revealed that the gel formed by NBAP-B1 possessed a dense and uniform three-dimensional network structure. Injection and plugging experiments demonstrated that NBAP-B1 exhibited optimal injectability and outstanding plugging performance. Additionally, profile control and displacement tests revealed a 18.37% enhancement in oil recovery efficiency by water flooding after the application of NBAP-B1 for conformance control. Collectively, these results demonstrate that the NBAP exhibits significantly superior performance compared to single component systems. It combines excellent injectability with high strength plugging capability, offering an effective approach for enhancing oil recovery in low permeability reservoirs.

To stimulate the progress of clean fracturing fluid systems, an innovative erucyl ultra-long-chain gemini surfactant (EUCGS) was devised and manufactured during the course of this study. The target product was successfully prepared via a two-step reaction involving erucyl primary amine, 3-bromopropionyl chloride, and 1,3-bis(dimethylamino)propanediol, with an overall yield of 78.6%. FT-IR and ¹H NMR characterization confirmed the presence of C₂₂ ultra-long chains, cis double bonds, amide bonds, and quaternary ammonium headgroups in the product structure. Performance tests showed that EUCGS exhibited an extremely low critical micelle concentration (CMC = 0.018 mmol/L) and excellent ability to reduce surface tension (γCMC = 30.0 mN/m). Rheological property studies indicated that EUCGS solutions gradually exhibited significant non-Newtonian fluid characteristics with increasing concentration, and wormlike micelles with a network structure could self-assemble at a concentration of 1.0 mmol/L. Dynamic rheological tests revealed that the solutions showed typical Maxwell fluid behavior and significant shear-thinning properties, which originated from the orientation and disruption of the wormlike micelle network structure under shear stress. In the presence of 225 mmol/L NaCl, the apparent viscosity of a 20 mmol/L EUCGS solution increased from 86 mPa·s to 256 mPa·s. A temperature resistance evaluation showed that EUCGS solutions had a good temperature resistance at high shear rates and 100 °C. The performance evaluation of fracturing fluids indicates that the proppant settling rate (0.25 cm/min) of the EUCGS-FFS system at 90 °C is significantly superior to that of the conventional system. It features the low dosage and high efficiency of the breaker, with the final core damage rate being only 0.9%. The results demonstrate that the EUCGS achieves a synergistic optimization of high-efficiency interfacial activity, controllable rheological properties, and excellent thermal–salt stability through precise molecular structure design, providing a new material choice for the development of intelligent responsive clean fracturing fluids.

To address critical technical challenges in coalbed methane fracturing, including the uncontrollable release rate of conventional breaker agents and incomplete gel breaking, this study designs and fabricates an intelligent controlled-release breaker system based on paraffin-coated mesoporous silica nanoparticle carriers. Three types of mesoporous silica (MSN) carriers with distinct pore sizes are synthesized via the sol-gel method using CTAB, P123, and F127 as structure-directing agents, respectively. Following hydrophobic modification with octyltriethoxysilane, n-butanol breaker agents are loaded into the carriers, and a temperature-responsive controlled-release system is constructed via paraffin coating technology. The pore size distribution was analyzed by the BJH model, confirming that the average pore diameters of CTAB-MSNs, P123-MSNs, and F127-MSNs were 5.18 nm, 6.36 nm, and 6.40 nm, respectively. The BET specific surface areas were 686.08, 853.17, and 946.89 m²/g, exhibiting an increasing trend with the increase in pore size. Drug-loading performance studies reveal that at the optimal loading concentration of 30 mg/mL, the loading efficiencies of n-butanol on the three carriers reach 28.6%, 35.2%, and 38.9%, respectively. The release behavior study under simulated reservoir temperature conditions (85 °C) reveals that the paraffin-coated system exhibits a distinct three-stage release pattern: a lag phase (0–1 h) caused by paraffin encapsulation, a rapid release phase (1–8 h) induced by high-temperature concentration diffusion, and a sustained release phase (8–30 h) attributed to nano-mesoporous characteristics. This intelligent controlled-release breaker demonstrates excellent temporal compatibility with coalbed methane fracturing processes, providing a novel technical solution for the efficient and clean development of coalbed methane.

The catalyst derived from Prussian blue precursor, using the “internal and external cultivation” strategy, fully exploits the potential of each step of photogenerated carriers in photocatalytic CO ₂ hydrogenation, effectively promoting CO production.