Kingfa (China)

Pioneering the next generation of robotics and reusable devices demands innovative metal adhesives with exceptional durability and sterile performance. However, the integration of robust adhesion, high energy dissipation, and inherent antibacterial activity into a recyclable adhesive remains a challenge, particularly in balancing complex performance with synthetic simplicity. Herein, a histamine-functionalized lipoic acid (LA-His)-based elastomer is reported to address the multifaceted needs within a minimalist design. Leveraging the imidazole group in histamine, which offers strong metal coordination, abundant hydrogen bonding, and inherent bactericidal efficacy, a dynamic network is constructed via a solvent-free melt polymerization of LA-His and a polyethylene glycol cross-linker. This approach results in a versatile polymer with a broadly tunable Young's modulus (2.8-194.1 MPa). The optimized elastomer exhibits exceptional metal adhesion (∼12 MPa), rivaling that of commercial cyanoacrylate adhesives, while also demonstrating superior energy dissipation. Reversible disulfide bonds impart self-healing properties and closed-loop chemical recyclability to the material. Notably, the material exhibits low cytotoxicity but exceptional antibacterial efficacy, achieving greater than 99.8% inhibition against E. coli and effectively inhibiting S. aureus biofilm formation by more than 99.3%.

To meet the underwater drag reduction needs in engineering applications, one can draw on the drag reduction strategies of marine animals such as sharks, utilizing their surface groove structures and the secretion of viscoelastic drag-reducing mucus to achieve drag reduction effects. However, in the field of engineering research, efficient and accurate simulation methods for viscoelastic fluid flow are relatively scarce. There is an urgent need to develop efficient numerical simulation methods for viscoelastic fluids, and to analyse the drag reduction characteristics of the coupling between surface grooves and drag-reducing agents. Through large eddy simulation and re-development of the ANSYS Fluent platform, efficient and accurate simulation of viscoelastic fluid flow as well as wall infiltration method has been successfully realized. Quantitative analysis of drag reduction characteristics of surface structures and viscoelastic fluid additives within the Reynolds number range of 4×104 to 4×105 has been conducted. Moreover, the synergistic effect of micro-grooves and drag reducer infiltration on drag reduction has been deeply explored. It is found that the maximum drag reduction by the groove surface solely is below 20%, whilst the maximum drag reduction by viscoelastic drag-reducing agent infiltration on the smooth flat plate is up to 28.9%. Notably, when combining the groove structure with drag-reducing agent infiltration, the maximum drag reduction reaches up to approximately 70%. The mechanism for the drag reducing effect is analysed from the aspects of vortex structure evolution on the wall, velocity profile and drag-reducing agent diffusion. This establishes an efficient and accurate simulation method for viscoelastic fluid flow suitable for engineering research, providing an important reference and foundation for underwater drag reduction studies.

It has been commonly accepted that Frank-Kasper spherical phases are stabilized over the classical phases in AB-type block copolymers by expanding the spherical region toward a large volume fraction of the A-block (f). Qiang et al. drastically expand the spherical region to f > 0.5 and find multiple reentrant transitions between Frank-Kasper and classical phases, the mechanisms of which have not yet been fully understood. In this work, we probe into the mechanisms by quantitatively analyzing the geometrical deformation of domains as well as its relationship with the chain architecture. As f increases, domains undergo convex deformation, followed by concave deformation to release the nonuniformity of stretching of short B-blocks filling the matrix. When convex deformation solely occurs, Frank-Kasper phases are favorable due to their milder deformation. As concave deformation starts to appear, the classical phases become more stable because their more convex deformation at the vertices of the Voronoi cell can alleviate the concave deformation on the faces. Moreover, it is revealed that the geometrical deformation is closely related with the dendritic architecture.

The chlorinated polyvinyl chloride (CPVC)/acrylonitrile–butadiene–styrene (ABS) composite represents an important class of engineering thermoplastics, offering a strong balance of flame retardancy, chemical resistance, mechanical properties, processability, and cost efficiency. Despite its widespread application, the flame-retardant mechanism in the CPVC/ABS system remains poorly understood. This work systematically investigated the non-monotonic flame-retardant behavior of CPVC/ABS composites through comprehensive characterization. The combustion performance, as determined by limiting oxygen index (LOI), UL-94 vertical burning tests, and cone calorimeter tests (CCTs), showed an unexpected pattern of flame retardancy initially improving then decreasing with reduced ABS content, which contradicted conventional expectations. The optimal composition at a CPVC/ABS ratio of 2:3 demonstrated good performance, achieving a UL-94 5VA rating and 47.3% reduction in total heat release (THR) relative to CPVC. A more stable and compact structure was observed from the morphology analysis of the residual char, and the thermogravimetric analysis further revealed a synergistic effect in carbonization behavior. The above flame-retardant mechanism could be interpreted by the combined effects of accelerated char formation during the early decomposition stage and significantly enhanced char crosslinking degree. These findings provided fundamental insights for designing high-performance flame-retardant polymer composites and facilitating their industrial implementation.

Although poly(vinyl alcohol) (PVA) is commonly used to reinforce starch-based materials, the significant difference in melting behavior between starch and PVA makes it difficult to simultaneously achieve effective plasticization of PVA and preservation of high molecular weight starch during conventional melt processing. Even with plasticizers, traditional methods often result in molecular degradation and phase incompatibility, which limits the final performance. In this study, we employed a novel biaxial eccentric rotor extruder (BERE) for plasticization and transportation, dominated by volumetric elongational flow, which minimizes shear-induced degradation and facilitates PVA plasticization through periodic compression and release. This process improves the interfacial compatibility between starch and PVA. Morphological and structural characterizations confirm the formation of a cocontinuous phase morphology in blends with a starch content of 60–90%. The composites prepared via BERE exhibit reduced crystallinity, higher molecular weight retention, and enhanced mechanical strength compared with those prepared using conventional twin-screw extrusion. This work demonstrates the potential of elongational flow processing in fabricating high-performance biodegradable starch/PVA composites without the need for chemical compatibilizers.