Effects of Temperature and Water Vapor Content on Microstructure, Mechanical Properties and Corrosion Behavior of C/C-SiC Composites.

Carbon-fiber-reinforced carbon and silicon carbide (C/C-SiC) composites were prepared using chemical vapor infiltration (CVI) combined with reactive melt infiltration (RMI). The microstructure and flexural properties of C/C-SiC composites after oxidation in different temperature water vapor environments were studied. The results indicate that the difficulty of oxidation in water vapor can be ranked from easy to difficult in the following order: carbon fiber (CF), pyrolytic carbon (PyC), and ceramic phase.

Strategy for Fabricating Degradable Low-Surface-Energy Cross-Linked Networks with Excellent Anti-Fouling Properties.

Marine biofouling negatively impacts marine industries and ship navigation. However, current coatings are based on a single antifouling mechanism, which is insufficient to cope with the complex and ever-changing marine environment. Herein, multifunctional antifouling coatings were developed using a material system containing perfluoropolyether and caprolactone chains.

Saturate Acts as Both a "Lubricant" and an "Activator" during the Conversion Process of Mesophase in Fluid Catalytic Cracking Slurry Oil.

Saturate (Sa), the lightest component in fluid catalytic cracking (FCC) slurry oil, exhibits a poorly understood influence on the formation and development of mesophase, thereby constraining the production of premium-quality mesophase pitch. To address this issue, Sa is isolated from FCC slurry oil, and its concentration is modulated to investigate its impact on the formation and development of mesophase. The results indicate that Sa contains a high concentration of long alkane side chains and naphthenic structures, which render it an effective "lubricant" and "activator" within the reaction system.

A Photoelectric Synergistic Flexible Solid Slippery Surface for All-Day Anti-Icing/Frosting.

The accumulation of ice on surface has caused great harm to lots of fields such as transportation or aerospace. Nowadays, various equipment or tools used in low-temperature environments, which face the risk of interface icing, usually have irregular shapes. Traditional rigid anti-icing materials are difficult to meet practical application requirements.

Preparation and Properties of Flexible Phenolic Silicone Hybrid Aerogels for Thermal Insulation.

In order to prepare flexible thermal protection aerogel materials, using dimethyldimethoxysilane (DMDMS) and methyltrimethoxysilane (MTMS) as co-precursors, isocyanate-propyltrimethoxysilane (CFS-006) was added to the co-precursor as a coupling agent, and resorcinol and formaldehyde were added to the sol solution to prepare a phenolic silicone hybrid aerogel (FAS) by the sol-gel method. The prepared FAS aerogel had no phase separation problem, the density was only 0.118 g/cm, the hydrophobic angle reached 155.

Preparation of Mesophase Pitch with Fine-Flow Texture from Ethylene Tar/Naphthalene by Catalytic Synthesis for High-Thermal-Conductivity Carbon Fibers.

Mesophase pitch is usually prepared by radical polymerization or catalytic polymerization from coal tar, petroleum, and aromatic compounds, and the catalytic synthesis of mesophase pitch from pure aromatic compounds is more controllable in the preparation of high-quality mesophase pitch. However, the corrosive and highly toxic nature of the catalyst has limited the further development of this method. In this study, mesophase pitch was synthetized using ethylene tar and naphthalene as raw materials and boron trifluoride diethyl etherate as a catalyst.

Noncontact Microfluidics of Highly Viscous Liquids for Accurate Self-Splitting and Pipetting.

Accurate dosing for various liquids, especially for highly viscous liquids, is fundamental in wide-ranging from molecular crosslinking to material processing. Despite droppers or pipettes being widely used as pipetting devices, they are powerless for quantificationally splitting and dosing highly viscous liquids (>100 mPa s) like polymer liquids due to the intertwined macromolecular chains and strong cohesion energy. Here, a highly transparent photopyroelectric slippery (PS) platform is provided to achieve noncontact self-splitting for liquids with viscosity as high as 15 000 mPa s, just with the assistance of sunlight and a cooling source to provide a local temperature difference (ΔT).

Effect of scanning speeds on mechanical properties of CoCrNi medium entropy alloy prepared by laser additive manufacturing.

Medium entropy alloy (MEA) is a hot spot in the field of material research in recent years. At present, the most widely used processing method of MEAs is "casting-rolling-heat treatment", and the preparation of CoCrNi MEA by laser additive manufacturing (LAM) is still in primary stage. In this study, CoCrNi MEAs were fabricated with different scanning speeds by laser additive manufacturing, and the influence of scanning speed on its mechanical properties was investigated.

Molecular Dynamics Simulation on the Heat Transfer in the Cross-Linked Poly(dimethylsiloxane).

In this work, the effect of cross-linking degree and stretching on the thermal conductivity of poly(dimethylsiloxane) (PDMS) is explored by performing a molecular dynamics simulation. Our results demonstrate that the thermal conductivity of PDMS exhibits a monotonous rise with an increase in the cross-linking degree. By decomposing the total heat flux into three microscopic heat transfer modes, the high cross-linking degree improves the contribution from bonding interactions to the heat transfer more than that from the nonbonding interactions.

Effect of Crosslinking Conditions on the Transport of Protons and Methanol in Crosslinked Polyvinyl Alcohol Membranes Containing the Phosphoric Acid Group.

In this investigation, we systematically explored the intricate relationship between the structural attributes of polyvinyl alcohol (PVA) membranes and their multifaceted properties relevant to fuel cell applications, encompassing diverse crosslinking conditions. Employing the solution casting technique, we fabricated crosslinked PVA membranes by utilizing phosphoric acid (PA) as the crosslinking agent, modulating the crosslinking temperature across a range of values. This comprehensive approach aimed to optimize the selection of crosslinking parameters for the advancement of crosslinked polymer materials tailored for fuel cell contexts.

A design method of high-compatibility horn for broad-bandwidth transducer.

Broad-bandwidth transducers are one of the main areas of focus for the development of power ultrasonic systems, which address the issues that the contactless transformer system cannot track transducer frequency and narrowband transducers are not compatible with different tools. This paper aims to investigate the potential capabilities of broad-bandwidth transducers in terms of compatibility with different horns and to propose a design method for highly compatible tools. The frequency equation of horn is nondimensionalized to calculate relative frequency errors δ.

Microstructure and Ablation Behavior of C/C-SiC-(ZrHf)C Composites Prepared by Reactive Melt Infiltration Method.

C/C-SiC-(ZrHf)C composites were prepared by the reactive melt infiltration method. The microstructure of the porous C/C skeleton and the C/C-SiC-(ZrHf)C composites, as well as the structural evolution and ablation behavior of the C/C-SiC-(ZrHf)C composites, were systematically investigated. The results show that the C/C-SiC-(ZrHf)C composites were mainly composed of carbon fiber, carbon matrix, SiC ceramic, (ZrHf)C and (ZrHf)Si solid solutions.

Electrochemical Impedance Spectroscopy (EIS) Explanation of Single Crystal Cu(100)/Cu(111) in Different Corrosion Stages.

Copper and its alloys are used widely in marine environments, and anisotropic corrosion influences the corrosion kinetics of copper. Corrosion of copper in an electrolyte containing Cl- is described as a dissolution-deposition process, which is a prolonged process. Therefore, it is laborious to clarify the corrosion anisotropy in different stages.

Phase Change Energy Storage Material with Photocuring, Photothermal Conversion, and Self-Cleaning Performance via a Two-Layer Structure.

Compared with the thermal curing process, the photocuring process has advantages such as high efficiency and less energy consumption. However, the preparation of photocurable phase change materials (PCMs) with photothermal conversion and self-cleaning properties is challenging due to the conflict between the transparency required by the photocurable resin system and the opacity deduced by the large number of fillers required by photothermal conversion and the negative effect of filler steric hindrance on the reaction rate and crystallinity. In this work, a "thiol-ene" click chemical reaction induced using UV was used to prepare photocurable PCMs, followed by spraying a carboxylated multiwalled carbon nanotube (CCNT) suspension (with ethyl acetate) onto the surface to achieve an effective two-layer composite of the PCM and CCNTs, by which the rough surface of the PCM and the interaction offered by the hydrogen bonds on the interface of the PCM and the CCNTs provide sufficient adhesion for the two phases.

Enhancing Interfacial and Electromagnetic Interference Shielding Properties of Carbon Fiber Composites via the Hierarchical Assembly of the MWNT/MOF Interphase.

A metal-organic framework (MOF) based on a conjugated organic ligand and a transition-metal ion was designed and used to construct a novel multiwalled carbon nanotube (MWNT)/MOF interphase via hierarchical assembly on the carbon fiber (CF) surface and was compared to various interphases established by MWNT and MOF. An intertwined MWNT and MOF "jujube core" was randomly dispersed on MWNT@CF and MOF@CF surfaces, while interpenetrating structures with the MWNT network and MOF jujube core were simultaneously observed on MWNT/MOF@CF due to coordination bonds and π-π conjugation effects, which were derived from the MWNT template with carboxyl groups and sp-hybridized domains as well as the secondary growth of MOF to promote self-assembly and the connection of MOF. The transverse fiber bundle test (TFBT) strength and interfacial shear strength (IFSS) of the MWNT/MOF@CF composite were 36.

Manipulation of Rashba splitting and thermoelectric performance of MTe (M = Ge, Sn, Pb) Te off-centering distortion.

The Rashba effect is an essential phenomenon in asymmetrical ferroelectric materials with local dipole fields. Rashba spin splitting due to spin-orbit coupling in the asymmetrical 2D ferroelectricity MTe (M = Ge, Sn, Pb) has provided a promising arena for achieving an ultra-high power factor to improve their thermoelectric performance. Herein, we show that the hidden Rashba effect may exist in centrosymmetric rock-salt MTe because of the emerging macroscopic electric dipoles caused by the local Te off-centering distortion.

Mask-Point: Automatic 3D Surface Defects Detection Network for Fiber-Reinforced Resin Matrix Composites.

Surface defects of fiber-reinforced resin matrix composites (FRRMCs) adversely affect their appearance and performance. To accurately and efficiently detect the three-dimensional (3D) surface defects of FRRMCs, a novel lightweight and two-stage semantic segmentation network, i.e.

Preparation of NaF Microcapsules for High-Temperature Thermal Storage.

A novel NaF phase change microcapsule with a carbon shell (NaF@C microcapsule) was prepared by a simple approach. The carbon shell was synthesized by carbonization of a resole-type phenolic resin shell, which was encapsulated onto the surface of NaF particles by a simple phase separation process induced by tetraethoxysilane. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis were used to characterize the morphology, composition, crystal phase, and thermal properties of the microcapsules.

Constructing a Rigid-and-Flexible Twin-Stage Gradient Interphase through Starlike Copolymer Coating on Carbon Fibers: A Route for Enhancing Interfacial Properties of Composites.

A rigid-and-flexible interphase was established by a starlike copolymer (Pc-PGMA/Pc) consisting of one tetraaminophthalocyanine (TAPc) core with four TAPc-difunctionalized poly(glycidyl methacrylate) (PGMA) arms through the surface modification of carbon fibers (CFs) and compared with various interphases constructed by TAPc and TAPc-connected PGMA (Pc-PGMA). The increase in the content of N-C═O showed that PGMA/Pc branches were successfully attached onto the CF-(Pc-PGMA/Pc) surface, exhibiting concavo-convex microstructures with the highest roughness. Through adhesive force spectroscopy by atomic force microscopy (AFM) with peak force quantitative nanomechanical mapping (PF-QNM) mode and visualization of the relative distribution of TAPc/PGMA via a Raman spectrometer, a rigid interphase with highly cross-linked TAPc and a flexible layer from PGMA arms as the soft segment were separately detected in CF-TAPc/EP and CF-(Pc-PGMA)/EP composites.

Exploring the Effects of MXene on Nonisothermal Crystallization and Melting Behavior of β-Nucleated Isotactic Polypropylene.

In this study, one of the commonly used MXene (TiCT) and β nucleated isotactic polypropylene (β-iPP)/MXene composites of different compositions were fabricated. The effects of MXene on non-isothermal crystallization and polymorphic behavior of β-iPP/MXene composites were comparatively studied. The non-isothermal crystallization kinetics indicates that for all samples, the lower cooling rates promote composites to crystallize at higher temperatures.

Self-diffusion mechanisms based defect complexes in MoSi.

MoSiis widely concerned due to excellent electrical conductivity, oxidation resistance as a typical transition metal silicide. The high-temperature diffusion behavior is one of the important factors for the degradation of MoSicoatings. However, the diffusion mechanism in MoSiis still unclear.

High-Temperature-Aging Induced Sequential Recovery of Shape Memory Nitrile Butadiene Rubber Composites.

The sacrificial bonds in natural materials have inspired the preparation of shape memory polymer (SMP), which can be prepared through the construction of dual cross-linking networks in a polymer matrix. With the rise of 4D printing technology, fine control over the shape recovery of SMPs, especially control over the recovery time, is urgently needed. In this study, the high-temperature aging method is adopted to tune the shape recovery time of dual cross-linked SMPs.

The synthesis of monodispersed M-CeO/SiO nanoparticles and formation of UV absorption coatings with them.

CeO/polymer nanoparticles have drawn considerable attention for their excellent UV absorption properties. However, many challenges still exist in the successful incorporation of ceria into the polymer matrix for the easy agglomeration and photocatalytic activity of CeO nanoparticles. Herein, we address these issues by constructing three-layer structured nanoparticles (M-CeO@SiO) and incorporating them into a polymer matrix through a mini-emulsion polymerization process.

Preparation and Characterization of Microencapsulated Ethylenediamine with Epoxy Resin for Self-healing Composites.

Healing agent microcapsules have been used to realize self-healing for polymeric composites. In this work a novel kind of microcapsules encapsulating ethylenediamine (EDA) with epoxy resin as shell material were prepared by interfacial polymerization technology. The oil phase was epoxy resin prepolymer and carbon tetrachloride, and the water phase was EDA and deionized water.

Percolation analysis of the electrical conductive network in a polymer nanocomposite by nanorod functionalization.

Chemical functionalization of nanofillers is an effective strategy to benefit the formation of the conductive network in the matrix which can enhance the electrical conductivity of polymer nanocomposites (PNCs). In this work, we adopted a coarse-grained molecular dynamics simulation to investigate the effect of the nanorod (NR) functionalization on the conductive probability of PNCs under the quiescent state or under a shear field. It is found that the direct aggregation structure of NRs is gradually broken down with increasing the NR functionalization degree , which improves their dispersion state.