Qingli Cheng

A continuous-flow microfluidic strategy was developed for the synthesis of nitrogen-containing bio-based polyols via cyclohexylamine aminolysis of epoxidized soybean oil (ESO). The effects of temperature, residence time, catalyst loading, flow rate, and channel diameter on epoxy and hydroxyl values were systematically investigated. Under optimal conditions (100 °C, 60 min, 5 wt% catalyst), a hydroxyl value of 259 mg_KOH/g and a residual epoxy value of 0.11% were achieved. Compared to a conventional batch process requiring 12 h, the microfluidic method shortened the reaction time to minutes while delivering significantly higher hydroxyl values and narrower molecular weight distribution. FTIR, GPC, DSC, and TGA analyses confirmed more complete conversion, suppressed etherification side reactions, and superior structural uniformity in the microreactor-derived products. Based on the experimental results, microfluidic processing showed the potential for efficient and sustainable production of nitrogen-containing bio-based polyols.

Polyurea (PUR) has been widely used as a protective coating in recent years. In order to complete the understanding of the relationship between PUR microstructure and its energy absorption capabilities, the mechanical and dynamic performance of PURs containing various macrodiol structural units were compared using material characterization techniques and molecular dynamic simulation. The results showed that the PUR polycarbonate diols formed as energy absorbing materials showed high tensile strength, high toughness, and excellent loss factor distribution based on the comparison of stress–strain tensile curves, glass transition temperatures, phase images, and dynamic storage loss modulus. External energy from simple shear deformation was absorbed to convert non-bond energy, in particular, based on fractional free volume, interaction energy, and total energy and hydrogen bond number change from the molecular dynamic simulation. Hydrogen bonds formed between soft segments and hard segments in the PURs have been proven to play a significant role in determining their mechanical and dynamic performance. The mechanical and dynamic properties of PURs characterized and tested using experimental techniques were quantified effectively using molecular dynamic simulation. This is believed to be an innovative theoretical guidance for the structural design of PURs at the molecular level for the optimization of energy absorption capabilities.

WO₃ and silicone rubber (SR)-based gasochromic composites were fabricated to detect hydrogen leaks at room temperature. WO₃ rod-like nanostructures were uniformly distributed in the SR matrix, with a particle size of 60–100 nm. The hydrogen permeability of these composites reached 1.77 cm³·cm/cm²·s·cm_Hg. At a 10% hydrogen concentration, the visible light reflectance of the composite decreased 49% during about 40 s, with a color change rate of 6.4% s⁻¹. Moreover, the composite detected hydrogen concentrations as low as 0.1%. And a color scale was obtained for easily assessing hydrogen concentrations in the environment based on the color of composites. Finally, the composite materials as disposable sensors underwent testing at several Sinopec hydrogen refueling stations.

The risk of fire in the chemical industry’s production process is fatal. Gel foam has been widely employed in petroleum storage tanks, oil pools, and other petrochemical equipment for fire extinguishing and thermal protection. Recently, nanoparticles have been doped into gel foam to enhance thermal stability and insulation. However, heat transfer behaviors of the gel foam layer containing nanoparticles are still missing. In this study, a numerical heat transfer model of a gel foam layer containing silica nanoparticles under a radiative heat flux was established. Through simulation, the changes in foam thickness and temperature distribution were analyzed. The effects of the maximum heating temperature, initial gas content, nanoparticle size, and concentration on the thermal insulation behavior of the gel foam layer were systematically studied. The results showed that the thermal stability and insulation performance of the three-phase gel foam layer decreased with the increase in the initial gas content and particle size. Increasing the nanoparticle concentration could enhance the foam’s thermal stability and insulation performance. The results provide guidance for a designing gel foam with high thermal protection performance.