Study of phenolic resin and their tendency for carbon graphitization

Achieving stable zinc metal anodes by regulating ion transfer and desolvation behavior

Aqueous Zn ion batteries (AZIBs) are considered to be highly promising rechargeable secondary batteries. However, the growth of zinc dendrites and irreversible side reactions hinder its further application. In this paper, an artificial interfacial protective layer of phenol-formaldehyde resin (PF) was constructed to achieve high-performance zinc anode. There is a strong interaction between hydroxyl groups in PF and Zn ions. This interaction modulates the solvation sheath of Zn ions and promotes the desolvation of [Zn(H2O)6]2+, which reduces the side reactions induced by reactive H2O. Furthermore, the pore structure of PF provides ion-confinement effect to regulate the Zn ions flux, thus reducing the growth of dendrites caused by inhomogeneous deposition. Thus, the PF coating has the dual effect of fast desolvation and ion confinement, which is beneficial to the uniform Zn ions deposition and achieves highly stable zinc anodes. Consequently, the Zn@PF||MnO2 full cell can be stably cycled for 1500 cycles at 1.5 A/g and the capacity retention remains 82.4 %. This method provides a convenient and practical approach to tackle the problems of zinc anodes, and establishes the foundation for their further application.

Tribological Behavior of Cotton Fabric/Phenolic Resin Laminated Composites Reinforced with Two-Dimensional Materials

In this study, cotton fabric-reinforced phenolic resin (CPF) composites were modified by adding four two-dimensional fillers: graphitic carbon nitride (g-C3N4), graphite (Gr), molybdenum disulfide (MoS2), and hexagonal boron nitride (h-BN). The tribological properties of these modified materials were investigated under dry friction and water lubrication conditions. The CPF/Gr composite exhibits significantly better tribological performance than the other three filler-modified CPF composites under dry friction, with a 24% reduction in friction coefficient and a 78% reduction in wear rate compared to the unmodified CPF composite. Under water lubrication conditions, all four fillers did not significantly alter the friction coefficient of the CPF composites. However, except for an excessive amount of Gr, the other three fillers can reduce the wear rate. Particularly in the case of 10% MoS2 content, the wear rate decreased by 56%. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed for the analysis of the morphology and composition of the transfer films. Additionally, molecular dynamics (MD) simulations were conducted to investigate the adsorption effects of CPF/Gr and CPF/MoS2 composites on the counterpart surface under both dry friction and water lubrication conditions. The difference in the adsorption capacity of CPF/Gr and CPF/MoS2 composites on the counterpart, as well as the resulting formation of transfer films, accounts for the variation in tribological behavior between CPF/Gr and CPF/MoS2 composites. By combining the lubrication properties of MoS2 and Gr under dry friction and water lubrication conditions and using them as co-fillers, we can achieve a synergistic lubrication effect.

Dynamic Impact Properties of Carbon-Fiber-Reinforced Phenolic Composites Containing Microfillers

The addition of nano- and microfillers to carbon-fiber-reinforced polymers (CFRPs) to improve their static mechanical properties is attracting growing research interest because their introduction does not increase the weight of parts made from CFRPs. However, the current understanding of the high strain rate deformation behaviour of CFRPs containing nanofillers/microfillers is limited. The present study investigated the dynamic impact properties of carbon-fiber-reinforced phenolic composites (CFRPCs) modified with microfillers. The CFRPCs were fabricated using 2D woven carbon fibers, two phenolic resole resins (HRJ-15881 and SP-6877), and two microfillers (colloidal silica and silicon carbide (SiC)). The amount of microfillers incorporated into the CFRPCs varied from 0.0 wt.% to 2.0 wt.%. A split-Hopkinson pressure bar (SHPB), operated at momentums of 15 kg m/s and 28 kg m/s, was used to determine the impact properties of the composites. The evolution of damage in the impacted specimens was studied using optical stereomicroscope and scanning electron microscope. It was found that, at an impact momentum of 15 kg m/s, the impact properties of HRJ-15881-based CFRPCs increased with SiC addition up to 1.5 wt.%, while those of SP-6877-based composites increased only up to 0.5 wt.%. At 28 kg m/s, the impact properties of the composites increased up to 0.5 wt.% SiC addition for both SP-6877 and HRJ-15881 based composites. However, the addition of colloidal silica did not improve the dynamic impact properties of composites based on both phenolic resins at both impact momentums. The improvement in the impact properties of composites made with SiC microfiller can be attributed to improvement in crystallinity offered by the α-SiC type microfiller used in this study. No fracture was observed in specimens impacted at an impact momentum of 15 kg m/s. However, at 28 kg m/s, edge chip-off and cracks extending through the surface were observed at lower microfiller addition (≤1 wt.%), which became more pronounced at higher microfiller loading (≥1.5 wt.%).

Evaluation of a graphitic porous carbon modified with iron oxides for atrazine environmental remediation in water by adsorption

In the last decades, the growth of world agricultural activity has significantly contributed to the increased presence of emerging pollutants such as atrazine (ATZ) in aquatic ecosystems. Due to its high stability to the natural or artificial degradation processes, the ATZ environmental remediation by adsorption has been investigated. In this study, a graphitic-porous-carbon- (GPC) based material with magnetic domains was applied to remove ATZ from aqueous solution. ATZ high adsorption efficiency in a reduced time was achieved in the presence of the GPC adsorbent, leading to a detailed investigation of the mechanisms involved in the adsorption processes. Pseudo-first-order (PFO), pseudo-second-order (PSO), Ritchie, Elovich, and Weber-Morris models were applied to calculate the kinetic process efficiency. Likewise, adsorption isotherms based on Langmuir, Freundlich, Temkin, and Redlich-Peterson models were applied for a detailed understanding of the adsorption mechanisms. GPC was successfully applied for ATZ remediation in natural waters, confirming its high potential for treating natural waters contaminated by ATZ using adsorption process. The material can also be recovered and reused for up to 4 application cycles due to its magnetic properties, showing that in addition to ATZ adsorption efficiency, its sustainable use can be achieved.

Formation of Fe Nanoparticles by Ion Implantation Technique for Catalytic Graphitization of a Phenolic Resin

Ion implantation technique was employed to introduce iron nanoparticles (Fe NPs) into a carbon precursor polymer with the aim of forming of a graphitic nanostructure through catalytic graphitization by the introduced Fe NPs. A phenolic resin was implanted by 100 keV Fe+ ions with ion fluence of 1 × 1014–1 × 1016 ions/cm2 at ambient temperature under vacuum, and subsequently heat-treated at 800 °C in a nitrogen gas atmosphere. It was found that the particle size of Fe NPs could be controlled in the range of 5–30 nm by the Fe+ ion fluence. Additionally, it was found that a nanosized turbostratic graphite structure with mean interlayer distance of 0.3531 nm, which is consisted of shell-like carbon layers and intricately distorted carbon layers, was formed around the Fe NPs. The ion implantation technique is one of the advantageous ways to introduce size-controlled fine metal NPs which are effective for the formation of graphitic nanostructure from a carbon precursor polymer.