Search

In this article, a hybrid of reduced graphene oxide (rGO) sheets decorated by zinc oxide (ZnO) particles was synthesized by a simple hydrothermal method, and its thermosetting polyimide (TPI) composites were prepared by an in situ polymerization method. The mechanical and tribological properties of the ZnO-rGO/TPI composite under dry sliding conditions were studied. The compression strength and modulus of 0.8 wt% ZnO-rGO/TPI composite reached 120.67 [+ or -] 2 MPa and 1.77 [+ or -] 0.06 GPa, which were 28.1% and 51.3% higher than those of TPI, respectively. The wear rate of 0.8 wt% ZnO-rGO/TPI was also reduced to 1.54 * [10.sup.-8] [mm.sup.3] [N.sup.-1] [m.sup.-1] at 100 N load, which is about two order of magnitude lower than that of TPI. Compared with the addition of GO alone, the results also demonstrate more significant enhancements in mechanical and tribological properties of TPI by ZnO-rGO hybrid. Furthermore, the tribological mechanism exploration indicates that the 'particle-on-plane' structure and chemical bonding between ZnO and rGO lead to the crack suppression and strength increment, contributing to the extraordinary improvement of mechanical and tribological properties. Thus, this ZnO-rGO/TPI composite presents promising potential as high-performance tribological materials under dry-sliding conditions in industrial applications. KEYWORDS mechanical properties, synergistic effect, thermosetting polyimide, tribological properties, ZnO-rGO hybrid, 1 | INTRODUCTION Polymer and its inorganic composites have been applied in various areas due to their outstanding mechanical properties, thermal stability, chemical stability, and wear resistance. [1-4] Polyimide (PI), [...]

The development of environmentally friendly and cost-effective lubricating materials to reduce friction and wear at the macroscale is crucial for reducing fuel consumption and exhaust emissions, thereby enhancing sustainability. Deep eutectic solvents (DESs) have emerged as viable alternatives to traditional lubricants due to their ease of preparation, affordability, reproducibility, and superior tribological properties. Herein, a series of natural ternary DESs (TDESs) are successfully developed by blending eco-friendly and economical D -sorbitol and ethanolamine with quaternary ammonium salts through hydrogen bond interactions that may be regarded as a new and green liquid lubricating system. The synthesized TDESs exhibit exceptional thermal stability, rheological properties, corrosion resistance, and wettability towards metallic substrates. Moreover, the experimental results combined with molecular dynamics simulations indicate that the TDESs can form a robust protective lubricating film on steel surfaces through polar adsorption and tribochemical reactions. Consequently, the synthesized TDESs demonstrate a low friction coefficient (∼0.1) and ultra-low wear rate (as low as 7.8 × 10−10 mm3 N−1 m−1), exhibiting a near-zero wear behavior on steel surfaces under high load (100 N) and multi-environment scenarios. This research not only highlights the potential applications of DESs in tribology but also provides guidance for the future generation of green and high-performance liquid lubricating materials. [ABSTRACT FROM AUTHOR]

A superelastic self–healing eutectogel was designed and prepared using poly (vinyl alcohol) (PVA) as the bulk skeleton material, while silk fibroin (SF) and two–dimensional (2D) MXene (Ti3C2TX) as reinforcing fillers. In brief, the eutectogel possesses a high tensile strength of 7.63 MPa, and its elongation at break reached 1115.2%, higher than most reported polymers (<1000%). In addition, the eutectogel–assembled sensor has a high ionic conductivity of 0.61 S/m and a high strain sensitivity of 5.17 kPa−1. Moreover, eutectogel shows excellent self–healing ability and can achieve self–healing quickly within 10 min, while its tensile strength and elongation at break can be restored to 84.7% and 97.4% of the initial levels. Besides, a stable electrical signal can be transmitted after 200 cycles at 30% strain. Finally, the eutectogel can withstand various environmental conditions, such as atmospheric or even vacuum evaporation and low–temperature freezing, while maintaining good mechanical and sensing performances. The assembled flexible sensors based on the eutectogel demonstrate their significant application prospects in wearable devices, especially human physiological monitoring. [ABSTRACT FROM AUTHOR]