Microwave Susceptor Research Articles

Formation of polypropylene nanocomposite joint using silicon carbide nanowhiskers as novel susceptor for microwave welding

Up to present, no study has reported on the use of silicon carbide nanomaterials (SiCNMs) as susceptor for microwave welding of thermoplastics. Therefore, in this study, silicon carbide nanowhiskers (SiCNWs) was attempted as the microwave susceptor for the microwave welding of polypropylene (PP). It was observed that SiCNWs are capable of absorbing microwave and converting them into heat, leading to a sharp increase in temperature until it reaches the melting point of PP substrates. The microwave welded joint is formed after the molten PP at the interface between PP substrates is cooled under pressure. The effect of microwave heating duration and solid loading of SiCNWs suspension was studied and reported. The formation mechanism of SiCNWs reinforced PP welded joint was proposed in this study. With these remarkable advantages of microwave welding and enhanced mechanical properties of the welded joint, it is believed that this study can provide a new insight into welding of thermoplastic and material processing through short-term microwave heating.

Effect of Microwave Power and Clamping Pressure on the Microwave Welding of Polypropylene Using Silicon Carbide Nanowhiskers as Microwave Susceptor

Effect of Microwave Power and Clamping Pressure on the Microwave Welding of Polypropylene Using Silicon Carbide Nanowhiskers as Microwave Susceptor

Doping of Al/CuO with microwave absorbing Ti3C2 MXene for improved ignition and combustion performance

Nanothermites have a wide application in many civil and defense applications, including propulsion and detonations systems, micro-electromechanical (MEMs) and other systems that require fast energy release rate and low ignition temperature. Traditional ignition methods are commonly based on surface excitation (spot ignition), possessing a risk of undesired ignition. Safe and selective microwave (MW)-based igniting systems can interact with an ignitable material (typically a thermite) over its full volume at once. Unfortunately, thermites have low susceptibility to MW due to the presence of Al2O3 oxide shell on Al particles, which would commonly require a high ignition power of MW radiation and long ignition delay times. In this work, Ti3C2 MXene was introduced as a MW susceptor into Al/CuO energetic nanocomposites. The samples were ignited using a MW probe, showing that the introduction of MXene into Al/CuO/MXene could significantly reduce the power required for its MW ignition, as well as shorten the ignition delay time versus the parent Al/CuO nanothermite. Besides, presence of MXene could modulate and control a heat release, gas production and combustion performance of the Al/CuO/MXene composites, substantially extending safety, flexibility and adaptability of new nanothermites to various operational requirements.

High-efficient microwave plasma discharging initiated conversion of waste plastics into hydrogen and carbon nanotubes

Large-scale manufacture and discard of plastics cause ever serious white pollution. Chemical recycling has been identified as a promising method to convert waste plastics into fuels and chemical products. In this work, a simple and high-efficient method initiated by microwave plasma discharging is proposed to decompose plastics into hydrogen and carbon nanotubes, wherein iron-based catalysts are used as the microwave susceptor and metal tips are utilized to induce plasma discharging. Iron-based catalysts supported on activated carbons calcinated at 400 °C have displayed the best catalytic activity due to the excellent physicochemical properties. Massive H2 rapidly evolves out in the 25 s with a hydrogen efficiency of over 85%. The yield of H2 with plasma discharging by using Fe/AC-400 catalyst is near 300 mmol·g-1Hplastic, which exhibits a 6 times improvement compared to 41 mmol·g-1Hplastic without plasma discharging by using AC catalyst. Little other gases including CH4, CO and CO2 are detected while high-value carbon nanotubes are fabricated. The continuity test over Fe/AC-400 catalyst with microwave plasma discharging presents the distinct ability to generate CNTs continuously. The decomposition for three kinds of plastics has demonstrated the extremely high universal and potential in practical application for real-world plastic wastes.

Realization of Phase and Microstructure Control in Fe/Fe2SiO4-FeAl2O4 Metal–Ceramic by Alternative Microwave Susceptors

This study provides a novel method to prepare metal–ceramic composites from magnetically selected iron ore using microwave heating. By introducing three different microwave susceptors (activated carbon, SiC, and a mixture of activated carbon and SiC) during the microwave process, effective control of the ratio of metallic and ceramic phases was achieved easily. The effects of the three susceptors on the microstructure of the metal–ceramics and the related reaction mechanisms were also investigated in detail. The results show that the metal phase (Fe) and ceramic phase (Fe2SiO4, FeAl2O4) can be maintained, but the metal phase to ceramic phase changed significantly. In particular, the microstructures appeared as well-distributed nanosheet structures with diameters of ~400 nm and thicknesses of ~20 nm when SiC was used as the microwave susceptor.

Biochar from microwave co-pyrolysis of food waste and polyethylene using different microwave susceptors – Production, modification and application for metformin removal

Biochar (BC) production by microwave (MW) co-pyrolysis of food waste (FW) with polyethylene (PE) (mixed in a ratio of 8:1) was performed in the present study using different MW susceptors, i.e. granular activated carbon (G), silica gel (S), cement (C) and flyash (F). BC yield varied from 37 wt% to 45 wt%. The highest yield of 45 wt% was obtained with flyash as MW susceptor. All BC exhibited increased carbon content (57.1–69.0 wt%), fixed carbon (76.0–85.3 wt%), and porous structure with improved thermal stability than the feedstock. The inferential plot exhibited an inverse relationship between yield and carbon of BC with loss tangent (tan δ) and specific surface area (SSA) of the MW susceptor. Alkali (potassium phosphate) modified F-BC (K-F-BC) showed further improvement in porous structures with a good cavity and presence of carbonyl group (CO) and hydroxide group (O–H) on its surface, which showed good adsorptive removal of metformin (MET). Alkali modification of F-BC improved the adsorption capacity by ∼8 times; thus, resulting in ∼62% MET removal within 5 min. Kinetic models suggested the MET adsorption on BC predominantly controlled by intra-particle diffusion (R2 = 0.72–0.98). Adsorption of MET with S-BC and F-BC followed Langmuir isotherm (R2 = 0.99). On the other hand, G-BC, C-BC and K-F-BC followed Freundlich isotherm (R2 = 0.99). Maximum MET adsorption of 0.17 mg/g, 0.23 mg/g, 0.26 mg/g and 0.27 mg/g were observed with F-BC, G-BC, S-BC and C-BC respectively. Alkali modification of F-BC (K-F-BC) improved its adsorption capacity up to 0.34 mg/g. The Surface deposition, pore filling, π-π interaction and chemical bonding of functional groups with K-F-BC were the predominant mechanisms of MET removal by K-F-BC.

Packaging technology for home meal replacement: Innovations and future prospective

The global demand for home meal replacement (HMR) products has been increasing because of changing consumer behavior toward convenience foods. Although the quality of food products is the most important factor in the decision to purchase, packaging also has a decisive influence on customer choice. Therefore, the importance of packaging technology in the HMR industry has increased significantly. Depending on the packed food requirements, appropriate packaging technology can provide significant benefits to both producers and consumers. Active packaging technology, such as modified atmosphere and antimicrobial packaging, has received considerable attention because of its potential to prolong the product shelf-life, while intelligent packaging technology such as colorimetric indicators and radio-frequency identification labels can monitor the real-time condition of the packed food and communicate with consumers. Packaging technology keeps evolving in response to the growing challenges from industry and society. This review aims to provide information about innovative and commercialized packaging technologies applied to HMR products. Recognized packaging technologies have been discussed, including easy-peel adhesive, microwave susceptor, and intelligent packaging. In addition, the influence of external factors, such as modern consumer behavior, recent global issues such as circular economy and pandemics, and emerging technology on packaging trends, are evaluated and discussed for future development. • Shifts in consumer preferences for convenience foods have increased global demand for HMR products. •Packaging is critical for quality control of HMR products. •Consumers benefit from advanced materials and functional packaging. •Intelligent packaging is becoming more prevalent in chilled and frozen foods. •Greener and safer food packaging is being considered due to global issues.

Microwave Susceptor Positional Configuration for Palm Empty Fruit Bunch and Waste Tire Co-Pyrolytic Oil Yield and Selectivity of Value-Added Chemicals

Microwave Susceptor Positional Configuration for Palm Empty Fruit Bunch and Waste Tire Co-Pyrolytic Oil Yield and Selectivity of Value-Added Chemicals

Microwave Sintering Rapid Synthesis of Nano/Micron β-SiC from Waste Lithium Battery Graphite and Photovoltaic Silicon to Achieve Carbon Reduction

The paper describes one promising method and approach for the recycling, reuse, and co-resource treatment of waste photovoltaic silicon and lithium battery anode graphite. Specifically, this work considers the preparation of nano/micron silicon carbide (SiC) from waste resources. Using activated carbon as a microwave susceptor over a very short timeframe, this research paper shows that nano/micron β-SiC can be successfully synthesized using microwave sintering technology. The used sintering temperature is significantly faster and more energy-efficient than traditional processes. The research results show that the β-SiC particle growth morphology greatly affected by the microwave sintering time. In a short microwave sintering time, the morphology of the β-SiC product is in the form of nano/micron clusters. The clusters tended to be regenerated into β-SiC nanorods after appropriately extending the microwave sintering time. In the context of heat conversion and resource saving, the comprehensive CO2 emission reduction is significantly higher than that of the traditional SiC production method.

Analysis of thermal and structural properties of clinoptilolite zeolite and its possible application as a microwave radiation susceptor

The need for heating systems, increasingly efficient and specific, makes us always think of systems aided by microwave radiation, and in the search for materials that interact with this radiation, although zeolites have stood out as materials of construction, as catalysts, as filtration systems, but they can also be used to heat by microwave action, the following work evaluates the action as a microwave susceptor of a synthetic zeolite, and analyses its thermal behavior, as the basis of a system of specific heating based on said zeolite.

Catalytic Activity of Various Carbons during the Microwave-Initiated Deep Dehydrogenation of Hexadecane.

Carbon materials have been widely used as microwave susceptors in many chemical processes because they are highly effective at transforming incoming electromagnetic energy for local (hot spot) heating. This property raises the intriguing possibility of using the all-pervasive carbonaceous deposits in operating heterogeneous catalytic processes to augment the catalytic performance of microwave-initiated reactions. Here, the catalytic activities of a range of carbon materials, together with carbon residues produced from a “test” reaction—the dehydrogenation of hexadecane under microwave-initiated heterogeneous catalytic processes, have been investigated. Despite the excellent microwave absorption properties observed among these various carbons, only activated carbons and graphene nanoplatelets were found to be highly effective for the microwave-initiated dehydrogenation of hexadecane. During the dehydrogenation of hexadecane on a Fe/SiC catalyst, active carbon species were formed at the early stage of the reactions but were subsequently transformed into filamentous but catalytically inert carbons that ultimately deactivated the operating catalyst.

Toward an energy-efficient synthesis method to improve persistent luminescence of Sr2MgSi2O7:Eu2+,Dy3+ materials

The synthesis of persistent luminescent materials usually requires a multi-step long time annealing at high temperatures (>1200°C) in a resistive oven, causing a huge energy consumption. Also, to achieve reduced oxidation states of emitter ions (e.g., Eu3+ → Eu2+ ), the H2(g) atmosphere is often used, which can be dangerous and increase the costs of the process. Therefore, the development of a quick and new single-step green strategy, using in-situ low-risk atmosphere (e.g., CO(g)) and a microwave-assisted solid-state (MASS) method has been encouraged. In this work, we present a single-step method to synthesize the compound Sr2MgSi2O7:Eu2+,Dy3+ using the MASS method and the results were compared with those prepared by a conventional ceramic method. The luminescent material was prepared in 25 min of synthesis using carbon as a microwave susceptor and CO(g) atmosphere source at the same time. A higher concentration of Eu2+ emitter was identified by XANES in the MASS method product, which has a significant effect on the luminescence efficiency, as well as an improvement in the optical properties, leading to an emission 100 times more intense. Furthermore, to understand the Eu3+ reduction process under CO(g) atmosphere, we present here the innovative results of in-situ XANES analysis for the Sr2MgSi2O7:Eu2+,Dy3+ material. Finally, the MASS method makes it possible to prepare the materials with less than 5% of the ceramic method's duration in time. The energy-saving and better-quality persistent luminescent properties obtained in the MASS method provide viable applications on anti-counterfeiting markers, solar cell sensitizers, and other luminescent technologies.

Microwave-assisted preparation of carbon coating layer on raspberry-shaped iron oxide particles for lithium-ion battery anodes

• Raspberry-shaped iron oxide nanostructure(RSIN) shows super-paramagnetic properties. • The RSIN generates heat via microwave irradiation to carbonize polydopamine coating. • The resulting conformal carbon coating has intimate contact with the RSINs. • The capacity retention of resulting material is 87.5% after 1000 cycles at 2 A g −1 . Carbon coating is one of the important methods to suppress volumetric changes of iron oxide particle when it is used as an anode for lithium-ion batteries. Herein, we report a rapid and facile preparation of carbon coating on raspberry-shaped iron oxide nanostructure (RSIN) via microwave irradiation. The RSIN is a hollow secondary particle, which is consisted of superparamagnetic iron oxide nanoparticles. For this reason, the RSIN is used as an effective microwave initiator and generates heat to carbonize polydopamine coating on its surface. As a result, the RSIN plays a dual role as a microwave susceptor and anode material. When microwave irradiated pRSIN (MW-pRSIN) was tested as an anode material for lithium-ion batteries, a high initial reversible capacity of 893 mAh g −1 at 0.1 A g −1 is delivered. The MW-pRSIN exhibits stable capacity retention of 87.5% after 1000 cycles at 2.0 A g −1 . Furthermore, the MW-pRSIN showed a reversible capacity of 415 mAh g −1 at the first step of 8.0 A g −1 in rate performance. The outstanding electrochemical performance is attributed to an effective carbon coating, which is a result of localized heating of microwave irradiation.

Process intensification on co-pyrolysis of polyethylene terephthalate wastes and biomass via microwave energy: Synergetic effect and roles of microwave susceptor

The present study employs microwave (MW) energy to enhance the co-pyrolysis of polyethylene terephthalate (PET) wastes and biomass. Based on the characterization of raw materials as well as gas and liquid products, we propose a pyrolysis mechanism of PET and biomass during microwave-assisted pyrolysis (MAP). The MAP of PET-biomass blends shows a synergetic effect that the interaction between PET and biomass promotes the yields of value-added products (e.g. aromatic acids and phenols) and suppresses the generation of biphenyls and polycyclic aromatic hydrocarbons, compared to the MAP of individual biomass or plastics. Besides, the blending ratio of PET-biomass has significant effect on the formation of major liquid products. The liquid product from the MAP of PET-biomass 4:1 blends contains above 30 wt.% chain hydrocarbon that can be used as gasoline and kerosene. Moreover, we evaluate the roles of three typical MW absorbing materials during MAP, including carbon powder, ferroferric oxide (Fe3O4) and calcium oxide (CaO). Carbon powder can enlarge the yield of main products from plastics pyrolysis due to its significant dielectric loss. Apart from the MW-absorbing ability, Fe3O4 can accelerate the esterification and decarboxylation reaction; CaO can convert acids into ketones and hydrocarbons through neutralization and catalytic cracking reactions.

New process to obtain unslaked lime through microwave hybrid heating and its fluid dynamics computational modeling

This study aimed to analyze the advantages of limestone calcination through a conventional microwave heating technique. For such a purpose, the microwave was merged by hybrid heating and a refractory ceramic internally coated with copper oxide was used with a conventional muffle furnace. It has also been analyzed the behavior of calcining limestone with different masses and variations in retention time using a muffle furnace and microwaves, both with and without using the refractory ceramic. Afterwards, the process has been modeled so as to analyze temperature versus retention time. As a result, calcination using a microwave susceptor with the refractory ceramic substance proved to be a process that takes 35% less time than conventional methods. Furthermore, there has been a reduction in 66.1% of energy expenditure. It was also observed that the new procedure offers advantages in reduced greenhouse gases emissions on account of the release of only a single substance, ease of air treatment in industrial environments and being a more economically viable process for limestone calcination, which can be further utilized by companies belonging to such a sector. Its patent deposit number BR 202018073002-4 U2 in INPI.

The use of microwaves in the process of obtaining nanopowders

We present a new approach to the study of microwave efficiency (MW) and microwave susceptors in the process of obtaining high quality nanopowders. Susceptors accelerate the processing of various poorly absorbent materials in the microwave field, reduce processing time and energy consumption. We calculated the electric field by a three-dimensional modelling of a microwave applicator designed to obtain nanopowders. The main objective is to optimize the technology of nanopowder production, by using raw materials and catalysts to ensure low processing temperatures. The performance of nanopowders was evaluated by physical-chemical, morphological, phase methods.

A Study on the Dewaxing Behavior of Carbon-Black-Modified LDPE–Paraffin Wax Composites for Investment Casting Applications

Dewaxing is an intermediate step in investment casting which can determine the properties of final metallic product and is strongly dependent on the properties of pattern wax. Processing of pattern wax composites with the conventionally available heating processes is energy intensive and requires high processing time, thus resulting in the lower processing rate at larger scale. Use of microwave technology for the dewaxing study is highly attractive alternative owing to the advantage of energy-efficient processing. The processing time of pattern wax composite of paraffin wax, bitumen, polyethylene and EVA in microwaves oven as a function of susceptor has been investigated. Carbon black was used as microwave susceptor in wax composites at several weight percentages. The efficient processing and melting behavior of pattern wax composite utilizing microwave dewaxing, thanks to the creation of heat sensitive sites within the pattern wax composite by the susceptor material, were analyzed in this study. FTIR-ATR, rheometer, TGA, DSC, UTM, SEM and OM were used to study the behavior of the wax composite. With the increase in the susceptor (CB) loading from 0.15 to 0.75%, an increase in the thermal stability of 6.86% was observed as depicted by the increase in the on-set temperature of the specimens. 71.9% decrease in the melt flow time of pattern wax composite was observed with the incorporation of 1.5% of CB as compared to reference specimen which manifested an inverse relationship between susceptor loading and processing time in the presence of microwave.

Mechanism of microwave-initiated ignition of sensitized energetic nanocomposites

One of the challenges in propellant formulation is the inability to moderate the burn rate dynamically. Here, we consider spatially localized remote ignition of additively manufactured composites via microwave absorption. Previous studies demonstrated that a passivating shell on Ti nanoparticles (nTi) enhances microwave absorption. Incorporated within a polyvinylidene fluoride (PVDF) matrix, Ti/PVDF films ignite under microwave irradiation in air. To gain more comprehensive insight into pre-ignition behavior, the ignition delay was studied as a function of applied power and the microwave susceptor loading. Infrared (IR) camera studies were further used to investigate the heating behavior of the films under variable power. We found that ignition delay decreases with increasing power to an apparent heating saturation region, where the ignition sensitivity is limited by the combustion reaction kinetics. Thermogravimetric analysis coupled with differential scanning calorimetry (TGA-DSC) showed that nTi oxidizes with O2 at lower temperatures than fluorination with PVDF and drives combustion. Findings in this work build a pathway for remote and controlled ignition of solid propellants via microwave radiation.

전자레인지 서셉터 패키징 기술개발 현황

전자레인지 서셉터 패키징 기술개발 현황

Phenol-rich bio-oil derivation via microwave-induced fast pyrolysis of oil palm empty fruit bunch with activated carbon

Abstract In the present study, oil palm empty fruit bunch (EFB) was subjected to microwave-induced fast pyrolysis. It has been demonstrated that EFB pyrolysis with activated carbon (AC) as microwave susceptor significantly increases the bio-oil yield (38.26 wt%) at an optimized temperature of 500 °C as compared to the EFB pyrolysis without AC (1.89 wt%). The EFB bio-oil produced at 500 °C (EPO500) was characterized to be enriched with oxygenated compounds (92%) and high nitrogenous compounds (8%) with an overall low carbon to hydrogen ratio (0.1) that prohibits its direct usage as a transportation fuel. The EPO500 was also determined to have a higher selectivity of phenol compound at 42.95% with total phenolic derivatives up to 67.5%. The high phenolic content of EPO500 achieved at the highest possible yield indicates its potential to be used for the production of renewable phenolic resins. Hence, the present work of microwave-induced pyrolysis of EFB presents itself as a promising method to produce highly selective mono-phenol rich bio-oil from biowaste.