Conductive Powder Research Articles

Closed-Loop Recycling of Wearable Electronic Textiles.

Wearable electronic textiles (e-textiles) are transforming personalized healthcare through innovative applications. However, integrating electronics into textiles for e-textile manufacturing exacerbates the rapidly growing issues of electronic waste (e-waste) and textile recycling due to the complicated recycling and disposal processes needed for mixed materials, including textile fibers, electronic materials, and components. Here, first closed-loop recycling for wearable e-textiles is reported by incorporating the thermal-pyrolysis of graphene-based e-textiles to convert them into graphene-like electrically conductive recycled powders. A scalable pad-dry coating technique is then used to reproduce graphene-based wearable e-textiles and demonstrate their potential healthcare applications as wearable electrodes for capturing electrocardiogram (ECG) signals and temperature sensors. Additionally, recycled graphene-based textile supercapacitor highlights their potential as sustainable energy storage devices, maintaining notable durability and retaining ≈94% capacitance after 1000 cycles with an areal capacitance of 4.92 mF cm⁻2. Such sustainable closed-loop recycling of e-textiles showcases the potential for their repurposing into multifunctional applications, promoting a circular approach that potentially prevents negative environmental impact and reduces landfill disposal.

Synergistic effect of nickel and graphite powders on the thermoelectric properties of ultra-high-performance concrete containing steel fibers and MWCNTs

The study investigates the influence of multi-walled carbon nanotubes (MWCNTs) and conductive powders, namely nickel powder (NP) and graphite powder (GP), on the mechanical and thermoelectric properties of ultra-high-performance concrete (UHPC). Flowability tests indicate that the addition of MWCNTs and conductive powders affects the flow diameter, with higher concentrations resulting in decreased flowability. Thermalgravimetric analysis and Fourier transform infrared spectroscopy reveal that the enhancement of the hydration reaction by 0.1 % MWCNTs in UHPC reaches saturation at this concentration. Pore structure analysis demonstrates a reduction in porosity and a denser structure upon the addition of 0.1 % MWCNTs. Mechanical tests indicate that the incorporation of 0.1 % MWCNTs enhances compressive and tensile strengths, whereas the introduction of 0.3 % MWCNTs diminishes the mechanical performance. Moreover, the electrical conductivity and thermoelectric effect are enhanced with the addition of MWCNTs and conductive powders. However, a decline in thermoelectric effect is observed when 0.3 % MWCNTs are added, although the conductivity remained high. The optimal thermoelectric performance is achieved with the combination of 0.3 % MWCNTs and 5 % NP, yielding a maximum power factor (PF) of 2148.2 μW/m·K2 and a figure of merit (ZT) of 4.9 × 10⁻7.

Preparation and Properties of Conductive Aluminum Powder (Al@Si@C) for Water-Borne Heavy-Duty Anticorrosive Coatings

Preparation and Properties of Conductive Aluminum Powder (Al@Si@C) for Water-Borne Heavy-Duty Anticorrosive Coatings

Improved thermal conductivity of high‐density polyethylene by incorporating hybrid fillers of copper powders and silicon carbide whiskers

AbstractIn this paper, highly electrically and thermally conductive copper powders (Cu) and electrically insulative yet thermally conductive silicon carbide whiskers (SiCw) were selected as functional fillers and high‐density polyethylene (HDPE) was used as the matrix to prepare thermal conductive composites. By controlling the amount of Cu at 30 vol% which is below percolation threshold, the volume resistivity of the composites is maintained above 1014 Ω cm. The results showed that SiCws entered the area which was not occupied by Cu particles and they played a bridging effect among Cu particles, thereby promoting the formation of intact thermal conductive pathways that contributed to improving the thermal conductivity of corresponding composites. The combination of SiCw:Cu = 3:1 at a filler content of 30 vol% resulted in a thermal conductivity as high as 1.921 W/mK, which is 380% higher than pure HDPE.

Preparation of self-assembled graphene materials with assisted multi-structured TiO2: Internal three-phase heterojunction built by doping with Al3+

Conductive coatings provide electromagnetic shielding against interference and radiation from electromagnetic waves. This is critical for electronic devices, communications equipment, medical instruments, and other industries. In this paper, XRD and Raman proved that Al3+ doped anatase, rutile, and brookite coexisting mixed crystalline phase TiO2, which evolved into highly conductive powder materials after ultrasonically compounding graphene, are prepared by simply controlling the calcination temperature. Tauc spectra proved the three-phase heterojunction shortens the distance between the conduction and valence bands, and electron jumping becomes easy. XPS proves that with low-price Al3+, the high-price Ti4+ in the lattice will be replaced, forming oxygen vacancies. A fast charge transfer pathway (Al–O–C) is established between Al3+ and graphene, and the synergistic effect of the two greatly reduces the resistivity. Four-probe test material resistance learned the resistivity of TAl-G is 57 % lower than that of T-G. At the same time, the excellent electrical conductivity of the TAl-G composite makes it suitable for practical applications in antistatic coatings, while the significantly shorter bandgap gives it great potential for photoelectrocatalysis.

Investigation on characteristic of vanadium trioxide insulation mixed with metal powder for rare-earth barium copper oxide coils

This study examined the turn-to-turn contact resistance (R ct) between rare-earth barium copper oxide (REBCO) tapes and layers of vanadium trioxide (V2O3) and V2O3 mixed with metal powder mixture. V2O3 in single crystal structure was electrically characterised to exhibit resistivity with negative temperature dependence, allowing the turn-to-turn insulation to self-regulate the current bypass between REBCO tapes. To facilitate effective quench protection of V2O3-insulated REBCO magnets above the metal-insulator transition temperature (T rt), R ct must be further reduced to a level similar to those of non- and metal as insulated (NI and MI) REBCO magnets. Thus, we explored the mixing of conductive metal powders such as molybdenum (Mo) with V2O3 paste and investigated the transition properties of R ct. The resistance versus temperature characteristics, microscopic morphologies of the V2O3 layers, and thermal conductivity (k v) were appropriately assessed to determine the effects of mixing the metal powder with V2O3. The R ct of virgin V2O3 exhibited variations of 107–105 μΩ cm2 under 77–293 K. As the mixing concentration of the metal powder was increased, the reduction magnitude on R ct increased for > T rt (approximately 150 K). Furthermore, the transition slope became gentler for a wider temperature range of < T rt. For metal powder concentrations exceeding 50 wt%, R ct decreased by approximately 2 orders of magnitude (∼103 μΩ cm2) for > 150 K compared with that for virgin V2O3 paste. Moreover, compared to that of pure V2O3, k v demonstrated a remarkable increase of approximately 352% at 91 K for Mo powder mixed at a concentration of 60 wt%. The improved electrical and thermal properties of the V2O3 insulation layer owing to the mixing of metal powders can help REBCO magnets operate in an insulated state under normal conditions and effectively convert to a non-insulated state under quenching.

Effect of Conductive Metal Powder Incorporation on Vanadium Trioxide Insulation Between REBCO Tapes

Effect of Conductive Metal Powder Incorporation on Vanadium Trioxide Insulation Between REBCO Tapes

Unravelling the intricacies of micro-nonuniform heating in field-assisted sintering of multiphase metallic microstructures

Micro-nonuniform heating in the field-assisted sintering (FAST) of electrically conductive powders has been a topic of discussion in the materials science community. Microstructural specifics, such as neck formation at low consolidation temperatures and density variations, have previously been ascribed to local overheating at the particle-particle contacts due to the Joule effect. However, recent theoretical modelling studies suggest that the very fast diffusion of heat within the micron-sized particles prevents the overheating, thereby challenging the conventional understanding of FAST-related heating effects. To provide a new experimental perspective on the local overheating and underscore its pivotal role in controlling the microstructure formation, we have studied the phase transformations in a Nd-Fe-B-type multiphase metallic powder during FAST. The formation of the α-Fe phase, following the peritectic decomposition of the Nd2Fe14B matrix phase expected at ≈1180 °C (TPER), was observed for FAST temperatures (TFAST) below TPER. A correlation between the electric current and the final phase composition, which can only be explained by considering the local overheating effect, was established. We showed that the formation of the α-Fe phase at TFAST <TPER can be mitigated by (i) decreasing the electric current through the sample, which is achieved by lowering the heating rate from 100 to 10 °C/min or by using electrically highly conductive pressing tools (WC) and a non-conductive coating (BN), or by (ii) interparticle necking achieved through a thermal pre-treatment of the powder compact that decreases the overall resistance. Our findings emphasize the criticality of the electric current modulation to minimize any undesired phase transformation, paving the way for future developments in rapid, FAST-based strategies aimed at refining the microstructures and tailoring the properties of multiphase metallic materials.

A high performance fireproof quasi-solid-state electrolyte enabled by multi-phase synergistic mechanism

Composite quasi-solid electrolytes usually suffer from reduced safety performance due to the presence of liquid plasticizers and an inherently unsafe polymer matrix. Adding inorganic fillers is an effective strategy to improve the safety performance of quasi-solid electrolytes, but excessive content may block ion transport channels, leading to a decrease in electrochemical performance. Therefore, it is proposed to construct a multi-phase synergistic non-flammable composite quasi-solid electrolyte (MS-NCQE) by combining an intrinsically safe porous composite framework with a Li+ conductive polymer through in-situ solidification technique. Thanks to multi-phase synergistic mechanism, a porous composite framework consisting of ceramic powder as well as a non-flammable polymer matrix enables MS-NCQE to exhibit significantly improved safety properties. At the same time, due to the interaction between the third-phase Li+ conductive polymer and ceramic powder, MS-NCQE presents excellent lithium ion transport performance (6.59×10−4 S cm−1 at 25 °C) and dendrite resistance (0.1 mA cm−2; 3000 h). Further, the as-prepared LiFePO4|Li and LiNi0.83Co0.12Mn0.05O2|Li batteries display outstanding cycling performance. In particular, the capacity retention rate of the LiFePO4|Li battery is approximately 98 % after 300 cycles at 0.5 C, and its average Coulombic efficiency is higher than 99.8 %. In addition, the pouch cell can work normally and safely under different abuse conditions. This work provides new insights into the design of composite quasi-solid electrolytes with high safety and excellent electrochemical properties.

Effect of gamma irradiation on the electrical and optical properties of PEVA composite membrane embedded with conductive copper fluoroborate glass powder

Effect of gamma irradiation on optical bandgap of PEVA/glass-powder membranes.

Ex-Situ Studies of Hydraulic Pressure Effect on the Electrochemical, Structural and Morphological Properties of Nickel-Rich NMC

The development of industry and technology, as well as the Earth's growing population, is forcing an ever-increasing demand for energy and raw materials. In tandem with this demand, efficient energy storage is also necessary and equally important. One of the most attractive forms of energy storage, has proven to be electrochemical cells, which allow the conversion of chemical reaction energy into electricity. The most promising cell type turned out to be lithium-ion batteries, and this was due to the attractive properties of lithium, which have the high negative standard potential (about -3 V) and high specific capacity (3860 Ah kg-1) 1. The majority of commercial lithium-ion batteries (LIB) are manufactured using roll-to-roll (R2R) wet processing technology (i.e., the slurry method), where active battery powder, conductive carbon powder and inactive binding agent are mixed in a organic solvent , cast onto metallic current collectors and then dried 2. Up next, the electrode layers undergo a calendaring process in which they are compressed. It is important to clarify the effect of hydraulic pressure on the properties of electrode materials and correlate this relationship to its type and characteristics. An inadequate selection of hydraulic pressure conditions can adversely affect the properties of the active battery material, leading to grain cracking and thus the capacity drop. The phenomenon of cracking of nickel-rich NMC secondary particles is considered to be the one of the critical causes that deteriorate the long-term cyclic stability of the NMC cathode in lithium-ion batteries 2,3.In this study various methods are applied to observe and understand the electrode properties that accompany grain fracture and electrode preparation conditions. Morphological changes that occur before and after the electrode calendaring and further the cell’s operation can be examined by scanning electron microscopy (SEM). This technique can be used as a tool to gather information about the composition of cathode materials while tracking a realistically operating battery 3. Another analysis technique is the ex-situ Raman spectroscopy, which allows us to gather detailed information on the local properties of the electrode material. It provides details on phase transitions and the causes of capacity loss over successive battery cycles 4. The information about grain size, crystallographic parameters and the phases present in the sample, can be gathered by X-ray diffraction (XRD). In this research all these methods will be employed to identify possible defects present in electrode materials before and after cycling with regard to applied hydraulic pressure during electrode preparation. We will determine the most suitable hydraulic pressure conditions and correlate our results with initial material morphology and crystallographic structure as well as the electrochemical response. A detailed data analysis will be reported at the conference. Funding for this work was provided by the National Science Center in Poland under the Sonata BIS 11 program (No. UMO-2021/42/E/ST5/00390). A. Czerwiński. Akumulatory, baterie, ogniwa. (2005). Kirsch, D. J. et al. Scalable Dry Processing of Binder-Free Lithium-Ion Battery Electrodes Enabled by Holey Graphene. ACS Appl Energy Mater 2, 2990–2997 (2019). Cheng, X. et al. Real-Time Observation of Chemomechanical Breakdown in a Layered Nickel-Rich Oxide Cathode Realized by in Situ Scanning Electron Microscopy. ACS Energy Lett 6, 1703–1710 (2021). Flores, E., Novák, P. & Berg, E. J. In situ and Operando Raman spectroscopy of layered transition metal oxides for Li-ion battery cathodes. Front Energy Res 6, (2018).

Highly Conductive Ultrafine N-Doped Silicon Powders Prepared by High-Frequency Thermal Plasma and Their Application as Anodes for Lithium-Ion Batteries

Highly Conductive Ultrafine N-Doped Silicon Powders Prepared by High-Frequency Thermal Plasma and Their Application as Anodes for Lithium-Ion Batteries

Nanoparticle Incorporation to Enhance Titanium Alloy Electric Discharge Machining Capabilities

The primary objective of this study was to examine the effects of the Powder-blended Micro Electric Discharge Machining (PMEDM) technique on micromachining applications, specifically when sea water is employed as the dielectric medium. Tiny apertures with a width of 200µm were punctured over Ti-6Al-4V plates. In the initial round of experimentation, the machining performance was evaluated by subjecting sea water to various process variables without the inclusion of any other ingredients. The effects of input variables, including electrode material, hole voltage, current, Pulse-on-time, and Duty factor, on the Material Removal Rate (MRR), Tool Wear Rate (TWR), Overcut (OC), Circularity Error (CE), and Taper Ratio (TR) were analysed by conducting tests in accordance with Taguchi's L18 plan design. The method employed to ascertain the optimal parametric configuration for multi-objective enhancement involved utilising the strategy of soliciting inclination based on similarity to an ideal arrangement. The present study aimed to investigate the effects of foreign materials on the dielectric-based miniature electrical discharge machining (EDM) process in sea water. This was achieved by utilising powders with varying weight concentrations and molecule sizes, including non-conductive (Al2O3), semi-conductive (SiC), and conductive (Al) powders. The experimental setup ensured that the variable boundaries were maintained at their ideal settings. The results indicate that the choice of tool has a notable influence on the functioning of micro EDM when sea water is employed as the dielectric, without the inclusion of extraneous particles. The performance metric of multi-objective execution in PMEDM is influenced by the conductivity of supplementary compounds. An 83.18 percent increase in Material Removal Rate (MRR) was observed when SiC added compounds were utilised in Powder Mixed Electrical Discharge Machining (PMEDM). Conversely, there was a drop in Tool Wear Rate (TWR) by 36.42 percent, Open Circuit voltage (OC) by 21.48 percent, Current Efficiency (CE) by 45.15 percent, and Tool Roughness (TR) by 22.87 percent.

Optimization of PMEDM process parameters for B4C and B4C+SiC reinforced AA7075 composites

MaterialsWith sufficient electrical conductivity can be successfully processed by applying the electrical discharge machining (EDM) method; however, due to the presence of non-conductive particles in composites, which have been produced by adding ceramics particles, problems such as unstable machining, low material removal rate, and high tool wear are observed during the EDM. This study employed powder-mixed electrical discharge machining (PMEDM) by adding electrically conductive nano-size graphite powder into the dielectric liquid to minimize these problems. Moreover, the machinability of AA7075/ B4C and AA7075/ B4C+SiC composites was evaluated using the Taguchi method. The experimental study used L18 orthogonal array (OA) (21 ×32). ANOVA was employed to obtain significant parameters and percent contributions of variable parameters on the material removal rate (MRR). Reinforcement ratio, current and sintering time applied to the workpiece were chosen as variable parameters. The optimum parameters for MRR were obtained at A1B3C3 (reinforcement ratio= 10%, current= 8 A, sintering time=150 min). According to S/N ratio graphs, increasing the reinforcement ratio leads to a decreased MRR. On the contrary, when the applied current increases, MRR increases. Additionally, analysis results show that the discharge current is the most important parameter affecting MRR. In the morphological examinations, it was understood that the amounts of B4C and SiC particles in the composite structure affect the quality of the machined surfaces. It was determined that the surface quality deteriorated with the increase in the amount of SiC and B4C in the composite structure and the increase in the discharge current.

Coupled Lead Halide Perovskite Photoelectrode for Unbiased Photoelectrochemical Water Splitting

In search for new technology to preserve global warming caused by fossil fuel, solar energy driven devices have been high in demand. For instance, photovoltaics (PV) are a promising technology that can produce high power conversion efficiency (PCE). In addition, photoelectrochemical (PEC) water splitting, a promising artificial photosynthesis method, is a potential alternative technique to generate renewable fuel. PEC devices can generate renewable energy sources such as hydrogen, which can alleviate CO2 emission from fossil fuels. However, most readily employed PEC devices require external bias to function as a hydrogen producer. Thus, utilizing PV active layer as a photo absorber, PEC system is a suitable approach to the breakthrough of efficient hydrogen production.In the past decade of PV technology advances, organic-inorganic lead halide perovskite (LHP) can be arguably the most progressive research because of its tunable bandgap, fast charge separation, broad light absorption spectra, low cost, facile fabrication, and high efficiency. These advantageous properties led LHPs to be used as an active layer of water splitting devices. However, LHP-based PECs have flaws to be addressed to be viable material for PEC. LHP are known for their fragile nature from exposure to water. Hence, LHP-based PECs are commonly protected with metal foil encapsulation while covering the edges with epoxy resins. However, the metal foil provides poor contact with the LHP leading to poor charge transfer for water splitting. To solve this problem, we applied carbon conductive powder (CCP) as the interlayer to successfully facilitate charge transfer.With the proposed device modeling, monolithic PEC device that is capable of generating hydrogen in presence of low external applied bias is fabricated. Nonetheless, single monolithic PEC devices still need external applied bias to function as water splitting device which seek for further research. Therefore, adding another photoelectrode will eliminate the necessity of external bias resulting in an only solar powered water splitting device. Herein, we report unassisted solar to hydrogen conversion by using inverted and planar type LHP solar cells as photocathode and photoanode, respectively. With the integration of catalyst, 3D Ni.NiFe and NiPCoP, LHP-based PEC with exceptional performance was attained. We demonstrated unbiased PEC water splitting using a coupled LHP-based photoelectrode under alkaline conditions. Each LHP-based photoelectrode exhibited a outstanding performance of 22.42 mA cm-2 at 1.23 VRHE and 21.96 mA cm-2 at 0 VRHE for the photoanode and photocathode, respectively. Thus, we achieved solar to hydrogen (STH) of 10.64% and unassisted photo-current density of 8.65 mA/cm2. In addition, unbiased catalytic reactivity over 20 h retaining about 60% of photo-current density was attained.

Development of 3D Printable Highly Flexible Siloxane Elastomers for Direct Ink Writing (DIW) of Soft Robotic Actuators for Space Applications

There is an interest in soft robotics for various space applications within low gravity and tight space environments to navigate, observe and even service various components within space assets, spacecraft and planetary stations. As an example, in an emergency, such as a pipe system failure occurring in a spacecraft, a soft robot may be able to assist in navigating the structure to detect the location and means of failure. The manufacturing of soft robotic actuators in space can be crucial. In addition, the fabrication of soft robotic tooling in a single step plays a critical role in space. 3D printing systems allow the manufacturing of soft robotic actuator parts in a single step. Stereolithography (SLA) and digital light processing (DLP) systems are not convenient because of the space environment. However, direct ink writing (DIW) which is the most commonly available and affordable system compared to SLA or DLP can be utilized to produce 3D objects, in addition, the DIW process permits the ability to in situ produce composite structures during the printing process. Various inorganic particles can be inserted within the elastomer print to control the mechanical, electrical and magnetic properties on-demand to produce smart or multi-functional soft robotic actuators and structures.The current work focuses on the development of a highly flexible and low (or nearly no) cytotoxicity silicone-based elastomer via thiol-ene click reaction that allows rapid polymerization of an elastomer to prevent the collapse of the structure during the printing. The work also demonstrates the use of this novel UV-durable elastomer to produce structures with embedded electrical interconnects and sensors for in-situ measurement of temperature and strain. In this study Poly(mercaptopropylmethylsiloxane-co-dimethylsiloxane) (M-MPS) was first prepared through the cohydrolysis-condensation reaction of 3-Mercaptopropylmethyltrimethoxysilane (MPS) and dimethyldimethoxylsilane (DMDES) with water and hydrochloric acid. Then M-MPS was compounded with various molecular weight vinyl-terminated polydimethylsiloxane (VPS) (MW~800-25000) and different dosage (0.1- 4.0 wt%) of a photoinitiator (1:1 weight ratio of 2-Hydroxy-2-methyl-phenyl-propane-1-one (PI 1173) and phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide (PI819)). For example, Figure 1 depicts the change in the viscosity of (M-MPS)-VPS 6000 2 wt% when it exposes to UV light irradiation. When (M-MPS)-VPS 6000 2 wt% was exposed to UV light irradiation, it polymerized at ~2 sec which is enough time to retain the structure during printing. To elucidate the properties of synthesized elastomer, FTIR, NMR, SEM, and tensile test measurements were performed. Furthermore, the synthesized elastomer was loaded with conductive inorganic particles so as to utilize the printed material as a temperature and tactile sensor (and sensor array). In addition, other printing variables were evaluated to produce 2D/3D structures of the pure and composite elastomers, such as the effect of the power and wavelength of UV light source, loading different types of conductive powders, and thiol-ene ratio. Acknowledgments: Work supported by a subcontract under the NASA-EPSCOR program (project number is 80NSSC20M0218). The authors would like to thank our NASA technical monitor Mr. Curtis Hill and project manager Dr. Melanie Page due to their contributions. Material characterization and imaging work were made possible with the support of the West Virginia University Shared Research Facilities (SRF). Figure 1

Analysis of electrical resistance measurements as a potential determination method for coating thickness on powders

The electrical resistance of conductive and non-conductive coatings on non-conductive and conductive powders, respectively, is investigated under increasing external load. A specially designed equipment was used to deposit coatings on small and light as well as heavy powdery substances by DC magnetron sputtering. Several reference methods to predict or measure the absolute film thickness on powders are discussed.When measuring the electrical resistance of insulating powders coated with a metal, in this case hollow glass microspheres (HGMs) coated with copper, under increasing load, a typical resistance curve is found. This resistance curve is discussed in terms of percolation theory and the Heckel equation for powder compaction. The influence of coating thickness of the conductive coating is then evaluated and other factors like inhomogeneity of the coating are discussed. To reduce the influence of measurement parameters, selected experiments are interpreted under the concept of a force per grain, which is introduced and explained.To further substantiate the typical electrical resistance curve, stabilized and non-stabilized NMC811 powder is coated with aluminium and zirconium oxides of different thicknesses, corresponding to a conductive powder with an insulating coating. When comparing measurements for stabilized and non-stabilized powder, the perspective for electrical resistance measurements under increasing load becomes apparent, as it is possible to even detect surface modifications which are not known a priori.

Optimization of process conditions of Powder Mixed Electric Discharge Machining of Nickel based Superalloy using Grey Wolf Optimizer algorithm

The Powder-Mixed Electric Discharge Machining (PMEDM) process has been drawing the attention of researchers since it could successfully overcome some of the limitations of the conventional Electric Discharge Machining (EDM) process. There was extensive research carried out on the PMEDM process to explore various possibilities for enhancing the process output. In the present work, an experimental study has been undertaken to investigate the influence of three conductive powders: zinc, cobalt, and molybdenum, while machining Nimonic 75, a nickel-based superalloy, by the EDM process. The work material considered in the study has been widely used in the aerospace industries and in applications involving higher temperatures. The experiments were carried out based on the Response Surface Methodology using the Box–Behnken design. Using the experimental data, regression equations were formed to predict the outcome of the process, which are Material Removal Rate (MRR), Electrode Wear Ratio (EWR), and Surface Roughness (SR). This work attempted to optimize the EDM machining parameters using the Grey Wolf Optimizer (GWO) algorithm combined with the Utility concept. The optimum conditions obtained by the GWO algorithm were: Powder – Molybdenum; Concentration of powder – 5.4 g/L; Discharge current – 4 A; Duty factor – 0.8.

The Effect of Conductive Polyaniline on the Anti-Fouling and Electromagnetic Properties of Polydimethylsiloxane Coatings.

In this paper, four conductive polyaniline powders doped in hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid were selected and blended with polydimethylsiloxane to prepare coatings with an electromagnetic absorption effect and fouling desorption effect, respectively. A UV spectrophotometer was used to evaluate the settling rate of the powders. Fourier transform infrared spectrometry, laser confocal microscopy, and scanning electron microscopy were used to observe the morphology and structure of the powder and the coating. The interface properties of the coatings were characterized using a contact angle measurement, the mechanical properties of the coatings using a tensile test, and the electromagnetic properties of the powders and microwave absorption properties of the coatings using vector network analyzers. Meanwhile, the antifouling performance of the coatings was evaluated via the marine bacteria adhesion test and benthic diatom adhesion test, and the effect of conductive polyaniline on the antifouling performance of the coating was analyzed. The results show that adding polyaniline reduced the surface energy of the coating and increased the roughness, mechanical properties and anti-fouling properties of the coating. Moreover, adding appropriate polyaniline powder can enhance the electromagnetic wave loss of the coating. The followings values were recorded for a hydrochloric-acid-doped polyaniline coating: lowest surface energy of 17.17 mJ/m2, maximum fracture strength of 0.95 MPa, maximum elongation of 155%, maximum bandwidth of 3.81 GHz, and peak of reflection loss of -23.15 dB. The bacterial detachment rate of the polydimethylsiloxane (PDMS) samples was only 30.37%. The bacterial adhesion rates of the composite coating containing hydrochloric-acid-doped polyaniline were 4.95% and 2.72% after rinsing and washing, respectively, and the desorption rate was 45.35%. The chlorophyll concentration values were 0.0057 mg/L and 0.0028 mg/L, respectively, and the desorption rate was 54.62%.

Preliminary Study on the Preparation of Conductive Nanosized Calcium Carbonate Utilizing Biogas Slurry by a Synchronous Double Decomposition Coating Method.

Nanosized calcium carbonate (NCC) plays a vital role in the rubber and plastic fields as a filler, but it cannot resolve the electrostatic problem. Humic-acid-based NCC (HA-NCC) was accidentally discovered in the reaction between biogas slurry and calcium chloride (CaCl2), based on nutrient recovery and gradient treatment technology to solve the biogas slurry problem. A preliminary study on the preparation of conductive nanosized calcium carbonate (CNCC) from the HA-NCC was implemented. Meanwhile, a synchronous double decomposition coating method was proposed to properly explain the formation of HA-NCC in the biogas slurry. The CNCC was further obtained through drying and carbonizing the HA-NCC sample. The morphology of CNCC was a square shape with aggregation, and its crystals were calcite. The C content of CNCC was 5% higher than that of the normal CaCO3, implying a synchronous coating effect of soluble HA in biogas slurry on NCC. The weight loss of CNCC was about 2.5% at 630 °C, explaining why the HA-NCC remained black at 550 °C for 4 h. The CNCC was partly ordered and graphitized. The resistivity of the CNCC reached 2.62 × 106 Ω·cm. It could be used as a conductive powder. In view of the favorable characteristics described above, CNCC would be expected to be a filler and antistatic agent for plastics and rubbers to enhance the tensile and bending resistance of polymer materials, while eliminating electrostatic hazards. The results are also of great significance for developing high-end products to realize resource utilization of biogas slurry.