Application Of EP Research Articles

Preparation and study on electrical/thermal properties of epoxy/polyacrylate rubber composite dielectric

AbstractWith the development of power systems and electronic devices, epoxy resin (EP) is facing increasingly severe operating environments, and its performance may not meet expectations. In order to broaden the application of EP, the DE/EP composite films were prepared with EP as matrix, polyacrylic rubber dielectric elastomer (DE) as reinforcement materials. The structure of DE/EP composite films was characterized by XRD, SEM, and other methods, and the electrical and thermal properties of the materials were tested and studied. The study found that with appropriate dissolution and stirring treatment, DE can be evenly dispersed in the EP matrix, and the introduction of DE does not significantly affect the structure of the EP molecular chain, also found the introduction of DE improve the electrical and thermal properties of EP. The breakdown strength of the 4% DE/EP composite film surpasses that of the pure EP film by 15.58%. Additionally, the thermal conductivity of the 8% DE/EP composite film is elevated by 41.6% compared to the pure EP film, while its dielectric constant is also enhanced by 8.2%. This work may provide a theoretical basis for studying the application of EP modified system in electrical engineering, integrated circuit packaging and other fields.

Design and Analysis of an SPM Machine for EPS Applications to Reduce Torque Ripple

Design and Analysis of an SPM Machine for EPS Applications to Reduce Torque Ripple

Preparation and Evaluation of Epoxy Based Material for High Performance Electronic Packaging through the Surface Modification of Fillers

The continuous integration and refinement of electronic equipment results in the more stringent requirements for epoxy resin (EP) based materials, such as excellent heat dissipation and low coefficient of thermal expansion (CTE). In order to improve the dispersion of silica powder (SP) in EP and thus expand the application of EP in the field of electronic packaging, our research described in this paper adopted the KH-550 coupling agent to modify the surface of SP (m-SP). The effects of KH-550 coupling agent on the characteristics of the composites were investigated in terms of thermal, rheological, electrical insulation and mechanical properties. The results showed that when the content of KH-550 was 2 wt% of the fillers, the best modification effect was achieved, and the surface properties of the fillers were changed accordingly. In particular, the materials filled with m-SP exhibited lower viscosity end, better mechanical and electrical insulation properties. It was also found that the adding of the KH-550 had different effects on the thermal degradation, dynamic thermo-mechanical properties and the thermal deformation behavior of the materials. According to our study, the thermal conductivity and the CTE of m-SP/EP filled with 70 wt% of modified fillers were 0.787 W/m.K and 28.3 ppm/°C respectively, corresponding to a significant thermal conductivity improvement and low CTE.

Construction of an organic iron phosphate/graphite carbon nitride hybrid system for improved fire safety of epoxy resin

Enhancing the fire safety of epoxy resin (EP) is crucial due to its widespread but inherent flammability, necessitating the integration of additive flame retardants (FRs) that are effective in small quantities and exhibit efficient flame retardancy. This study constructed a novel, efficient FR by synthesizing organic iron phosphate (ATMP-Fe) and loading it on graphitic carbon nitride (g-C3N4). The resulting hybrid flame retardant (ATMP-Fe/g-C3N4) was added to EP in minimal amount to bolster its flame retardancy and safety features. Incorporating a mere 3 wt% of ATMP-Fe/g-C3N4 into EP significantly improved its flame retardancy and thermal stability. This was evidenced by an increase in the limiting oxygen index from 25.5% for EP to 30.1%, achieving a V-1 rating in the UL-94 test, and producing a 22.0 wt% char residue. Moreover, there was a substantial reduction in peak heat release rate, total heat release, and total smoke production by 36.3%, 27.5%, and 39.3%, respectively. The reduction in pyrolysis products, along with the formation of a dense and stable char layer facilitated by the synergistic effects of phosphorus and iron elements, significantly improved the fire safety of EP. Additionally, the enhanced hydrophobicity, mechanical properties, and electrical conductivity of the EP/3ATMP-Fe/g-C3N4 composite suggested potential for wider application of EP in various fields.

Molecular design and properties of P‐N‐B co‐intrinsic flame retardant thermosetting epoxy resin

AbstractCurrently, epoxy resin (EP) is widely used in various fields, but its flammability greatly limits the wider application of EP. In recent years, additive flame retardants have been widely used to enhance the flame retardancy of EPs, but poor resistance to weather and aging is a prevalent issue encountered with additive flame retardants. To improve the weather fastness, researchers have successfully created and synthesized EP molecules that possess a combined effect of P, N, and B. The results demonstrate a significant enhancement in the mechanical properties of materials containing 20% BVN/10% VPD/EP compared with those of pure EP. 20% BVN/20% VPD/EP exhibited a vertical combustion rating of V‐1 with a limiting oxygen index measuring at 29.8%. The flame retardant epoxy thermosets exhibited a notable decrease in both the maximum heat release rate and total heat release. The findings indicate that the inherent flame‐retardant properties of the P‐N‐B coacting EP are not only characterized by exceptional curing and flame retardancy but also by superior resistance to weathering and aging compared with the additive flame retardant.

The synthesis of biphenyl ether/vanillin‐based flame retardants for enhancing both the flame retardant properties and mechanical performance of epoxy resin

AbstractImparting good flame retardancy and mechanical properties to epoxy resin (EP), while pursuing the sustainable and safe application of EP, we synthesized a novel reactive phosphorus/nitrogen flame retardant for biomass through nucleophilic addition reaction, which contains flexible ether bonds and rigid aromatic ring structure (DVD). Owing to the cooperative effect of aryl ether diamine, phosphorus phenanthrene, and biomass vanillin, the DVD exhibited excellent flame retardancy. EP/DVD‐1 (0.4 wt% phosphorus content) achieved UL‐94 V‐0 rating, with an improvement in limiting oxygen index value from 26.5% (pure EP) to 32.5%. In the CCT, the modified DVD EP showed a 44.5% reduction in peak peak of heat release rate (PHRR) and a 38.0% reduction in total heat release compared to pure EPs. And flame retardant epoxy resin (FREP) still had good transparency after the addition of DVD, which indicated the nice compatibility between DVD andEP. What was noteworthiness was that at high levels of addition, the mechanical properties of modified EP for DVD was still improved compared to pure EP. These results demonstrate that DVD is an excellent and multifunctional bio‐based flame retardant with broad application prospects in the field of EP material modification.

Exploration of Application of Essential Principles of Safety and Performance of Medical Devices and IVD Medical Devices: Take Artificial Joint Products as Example

Through the effective application of Essential Principles of Safety and Performance of Medical Devices and IVD Medical Devices (EP), to continuously improve the corresponding management tools to ensure the safety and effectiveness of medical device in the quality management system, risk management system, evaluation of safety and effectiveness for the supervision departments and manufacturers. The current status of the application of EP and the application issues are analyzed in the study. Take artificial joint products for example, the idea of using EP in quality management system, risk management system and evaluation of safety and effectiveness is investigated, and several thoughts are proposed. Supervision departments should strengthen the unified understanding of EP, develop requirements according to the classification of medical device，and refine specific execution requirements.

Epoxy resin for solidification/stabilization of soil contaminated with copper (II): Leaching, mechanical, and microstructural characterization

Among different types of heavy metal-contaminated soil, copper (Cu)-contaminated soil is very serious, and the Cu concentration in it is usually very high. It is common to solidify/stabilize Cu-contaminated soil using alkaline cementitious material. However, the remediated Cu-contaminated soil fails to meet the requirements of environmental safety and load-bearing capacity. This dilemma in the remediation of Cu-contaminated soil hinders the effective utilization of land resources. In this study, epoxy resin (EP) was utilized to solidify/stabilize Cu-contaminated soil due to its stable and rapid curing performance and excellent resistance to acid, alkali, and salt erosion. The mechanical properties, environmental effects, and curing mechanism of EP-cured Cu-contaminated soil were investigated. The results showed that the application of EP significantly enhanced the unconfined compressive strength (UCS), cohesion and internal friction angle of Cu-contaminated soil. All specimens met the UCS criterion specified by the United States Environmental Protection Agency (USPEA), namely no less than 0.35 MPa, which indicated that those EP-cured Cu-contaminated soil were qualified for practical engineering applications. According to the toxicity characteristic leaching procedure (TCLP), the application of EP enhanced the stability of Cu in Cu-contaminated soil. The leaching index of Cu ranged from 11 to 14. A high leaching index showed that the S/S treatment was safe and effective and the remediated Cu-contaminated soil satisfied the environmental requirement for heavy metals. This study confirmed the feasibility of utilizing EP in the solidification/stabilization (S/S) technology to convert high-concentration Cu-contaminated soil into secure and stable engineering materials. The remediation of Cu-contaminated soil by EP lays a solid foundation for the safe treatment and reuse of heavy metal-contaminated land resources.

Application of EPS to Mitigate Ground Movements Caused by Mechanized Tunneling

Application of EPS to Mitigate Ground Movements Caused by Mechanized Tunneling

A Rigid-Flexible and Multi-Siloxane Bridge Strategy for Toughening Epoxy Resin with Promising Flame Retardancy, Mechanical, and Dielectric Properties.

Developing highly efficient and multifunctional epoxy resins (EPs) that overcome the shortcomings of flammability and brittleness is crucial for pursuing sustainable and safe application but remains a huge challenge. In this paper, a novel biomass-containing intumescent flame retardant containing a rigid-flexible and multi-siloxane bridge structure (DPB) was synthesized using siloxane; 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO); and biomass vanillin. DPB could facilitate the formation of a carbon residual with an intumescent structure, which effectively blocked the propagation of heat and oxygen. As a result, the peak heat release rate (pHRR) and total heat release (THR) of DPB/EP-7.5 decreased by 38.8% and 45.0%, respectively. In terms of mechanical properties, the tensile and flexural elongations at break of DPB/EP-7.5 increased by 77.2% and 105.3%, respectively. Impressively, DPB/EP-7.5 had excellent dielectric properties, with a dielectric constant of 2.5-2.9. This was due to the Si-O bonds (multi-siloxane bridges) contained in DPB/EP, which can quench the polarization behavior of the hydroxyl group. This paper provides a facile strategy for the preparation of multifunctional EP, which will pave the way for the promotion and application of EP in the high-end field.

Zinc hydroxystannate dripped on magnesium hydroxide flower for enhancing smoke suppression and toxicity reduction properties of epoxy resin

AbstractIn order to reduce the emission of smoke and toxic gases during the combustion of epoxy resin (EP), inspired by the structure of “flowers after rain,” a novel low‐cost flame retardant (FMH@ZHS) was prepared by using flower‐like magnesium hydroxide (FMH) as the flower and zinc hydroxystannate (ZHS) as the raindrop. The tensile strength of EP/3FMH@ZHS increased by 13.7% compared with EP/3FMH. Moreover, the 3 wt% FMH@ZHS hybrid material increased the limited oxygen index value of the EP composite to 27.6% while suppressing the dripping phenomenon during combustion, achieving self‐extinguishing characteristic. Meanwhile, compared with pure EP, peak heat release rate, peak smoke production rate, total smoke production, and peak carbon monoxide production rate of EP/3FMH@ZHS decreased by 34.6%, 55.6%, 41.8%, and 50.0%, respectively. The flame retardant mechanism showed that during the combustion process, the catalytic char formation of magnesium oxide, zinc oxide, and stannic oxide generated from FMH@ZSH can promote the formation of a denser and continuous char layer, inhibiting the transport of flammable gases, toxic gases and heat and improving the fire safety of EP composites. In conclusion, this biomimetic material provided a good approach for the industrial application of EP.

A Novel Impedimetric Sensor Based on Cyanobacterial Extracellular Polymeric Substances for Microplastics Detection.

Cyanobacterial extracellular polymeric substances “EPS” have attracted intensive concern in biomedicine and food. Nevertheless, the use of those polymers as a sensor coating material has not yet been investigated mainly for microplastic detection. This study focuses on the application of EPS as a sensitive membrane deposited on a gold electrode and investigated with electrochemical impedance spectroscopy to detect four types of microplastics with a size range of 0.1 µm to 1 mm. The surface properties of this impedimetric sensor were investigated by Scanning electron microscopy, Fourier transforms infrared spectroscopy, and X-ray spectroscopy and, showed a high homogenous structure with the presence of several functional groups. The measurements showed a high homogenous structure with the presence of several functional groups. The EPS-based sensor could detect the four tested microplastics with a low limit of detection of 10–11 M. It is the first report focusing on EPS extracted from cyanobacteria that could be a new quantification method for low concentrations of microplastics.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10924-022-02555-6.

Synthesis of Nitrogen‐Rich Black Phosphorus via a Diazotization Strategy for Efficient Flame Retardancy and Mechanical Properties of Epoxy Resins

AbstractSevere flame retardancy and poor impact resistance of epoxy resins (EPs) have become key factors limiting their industrial application. Herein, a strategy is developed to integrate nitrogen‐rich black phosphorus (BP) loaded with cerium oxide via aryl diazonium chemistry to reduce the flame risk of the EPs. Cone test results exhibit that the fire hazard of EPs containing 2 wt.% BP‐NHH‐Ce is suppressed effectively, such as that total heat release rate (THR) is reduced by 46.9%, the peak heat release rate (pHRR) is reduced by 56.2%, and the total smoke production (TSP) is reduced by 48.9%. With only 1.0 wt.% of the BP‐NHH‐Ce added, the nanocomposite can reach up to 30.5 of LOI value and simultaneously upgrade the UL‐94 rate to V‐0. In addition, the nano‐structure is beneficial to stress transfer and homogenization, which leads to significant elevation (28.2%) for the impact strength of EPs. This developed new EP/BP‐NHH‐Ce nanocomposite merits the high‐end field application of EPs.

Fabrication of two multifunctional phosphorus–nitrogen flame retardants toward improving the fire safety of epoxy resin

Abstract To improve the fire safety of epoxy resin (EP), two novel phosphorus–nitrogen flame retardants, which named as diphenyl allylphosphoramidate (DPCA) and N-allyl-P, P-diphenylphosphinic amide (DCA), were synthesized by acyl chloride reaction and introduced into EP for fabricating EP composites. The combustion tests showed that incorporation of 5 wt% DPCA or 5 wt% DCA into EP led to the exceptional limited oxygen index (LOI) value (27.1% or 31.6%). Besides, the peak of heat release rate of EP-5 wt% DPCA and EP-5 wt% DCA was reduced by 40.69% and 36.69%, respectively, compared to pure EP. The enhanced fire resistance of EP was ascribed to the trapping effect of fillers in the gas phase and the charring effect in the condensed phase. Furthermore, ultraviolet-visible spectra revealed that both EP-5 wt% DPCA and EP-5 wt% DCA have considerable transparency. This study is expected to broaden the application of EP in the industrial area.

A new highly sensitive micro-sensor for the ultra-traces analysis of paracetamol directly in water

In the present work, a simple, inexpensive and highly sensitive electrochemical micro-sensor was developed for trace detection of paracetamol (PAR) directly in water, using electrochemical preconcentration technique (EP) on a cavity microelectrode modified with carbon black nanoparticles (nCB/ CME). The results demonstrate that with an EP of PAR on nCB/ CME at 0 V for 900 s in BRS 0.04 M at pH = 7, the new proposed micro-sensor show two large linear response in ranges of 5 × 10-10 to 9 × 10-8 mol.L-1 and from 1 × 10-7 to 1 × 10-6 mol.L-1. The detection and quantification limits are estimated to be 1.4 × 10-10 and 4.3 × 10-10 mol.L-1, respectively. The performances of the new proposed nCB/ CME for the determination of PAR were compared to its performances without EP and the results reveal the importance of the application of EP in improving the electroanalytical characteristics. The applicability of the designed micro-sensor was successfully applied for the direct analysis of local tap water and treated wastewater samples spiked with trace PAR compounds with a satisfactory recovery (less than 4 %) and a relation standard deviation less than 5 %. It indicates that the electrochemical micro-sensors are an effective device for monitoring PAR concentrations directly in water without any pretreatment.

Facile construction of lamellar-like phosphorus-based triazole-zinc complex for high-performance epoxy resins

Epoxy resins (EP) possessing superior flame retardancy, mechanical properties and glass transition temperature are urgently needed to meet the ever-increasing requirement of high performance for the practical application of EP. Herein, lamellar-like phosphorus-based triazole-zinc complex (Zn-PT) was firstly constructed through coordination reaction in a facile condition to address the above issue. The results revealed that Zn-PT was well dispersed in epoxy matrix, and with 3 wt% Zn-PT, the tensile strength, flexural strength and modulus of epoxy composites were remarkably increased from 71, 112 and 2982 MPa of neat epoxy resin (EP) to 80, 162 and 3482 MPa respectively. The glass transition temperature was higher than EP. Besides, the limiting oxygen index (LOI) increased to 28.3%, and UL-94V-1 level was available. Meanwhile, the cone calorimeter test (CCT) results showed that epoxy composites displayed less heat release and smoke production. Generally, this work provides a feasible strategy to prepare high-performance epoxy composites, which has the potential to satisfy the requirement of epoxy in the practical application.

Induced systemic resistance (ISR) as a mechanism of biocontrol in maize (Zea mays)

Induced systemic resistance is an alternative mechanism to antagonism for achieving biological control of plant diseases. Induced Systemic Resistance (ISR) involves the activation of latent resistance mechanisms that are expressed upon subsequentsocalled “challenge’ inoculation with a pathogen. Induced resistance occurs naturally as a result of limited infection by the pathogen, particularly when the plant develops a hypersensitive reaction. Therefore, ISR as a mechanism of biocontrol against leaf blight disease (Helminthosporium turcicum) in maize, cv. CO 1 was investigated. The application effect of different formulations of Azospirillum and Paenibacillus cells viz., single strain inoculation, co-inoculation and co-aggregates (natural and artificial) on the enhancement of growth and reduction in leaf blight disease incidence of maize was studied under in vivo conditions. It was observed that the application of each formulation of Azospirillum and Paenibacillus cells augmented the growth parameters and reduction in the incidence of leaf blight disease of maize to a higher level when compared to un-inoculated control. However, the application of Azospirillum and Paenibacillus cells, as, natural co-aggregates, exhibited the highest performance followed by artificial co-aggregates of Azospirillum and Paenibacillus cells co-inoculation and single strain inoculation of PGPR cells. The comparative study of rhizobacterial EPS viz., Azospirillum and Paenibacillus and some ISR inducing chemicals viz., salicylic acid (SA), Jasmonic acid (JA) and Azibenzolar on the enhancement of growth and reduction in leaf blight disease incidence in maize plant revealed incidence to a higher level than rhizobacterial EPS but they couldn't augment the growth of the maize plant as in the case of rhizobacterial EPS. The application of rhizobacterial EPS had both phytostimulatory and biocontrol effect whereas the use of ISR inducing chemicals exert only biocontrol activity against Helminthosporium turcicum.

Construction of multifunctional linear polyphosphazene and molybdenum diselenide hybrids for efficient fire retardant and toughening epoxy resins

Epoxy resins (EP) are deemed as one kind of most commonly used thermosets, but immanently suffer from inflammability and brittleness. Herein, we report a newly designed hierarchical molybdenum diselenide (MoSe2) nanotubes assembled from several-layered nanosheets, and then merged with linear polyphosphazene (LPP) for constructing LPP-MoSe2 hybrids. LPP-MoSe2 possesses great advantages in improving the properties of EP for their typical nanotube structure and the combination effect of transition metal, phosphorous and nitrogenous compounds. The developed EP/LPP-MoSe2 composites present obvious reduction in flammability, obtaining a high LOI value of 29% and reaching V-0 rating in UL-94 test. They also exhibit obvious reduction in the heat hazards of EP, such as peak heat release rate (39.0%) and total heat release (24.8%), as well as the toxicity hazards including total smoke production (31.3%) and the yields of CO and CO2. Gas-phase and condensed-phase mechanism are elucidated to explain the contribution of LPP-MoSe2 to the fire retardation of EP. Moreover, the addition of LPP-MoSe2 can also obviously enhance the mechanical properties of EP. The impact strength of EP is only 9 kJ/m2, while EP/LPP-MoSe2 3.0 can reach up to 14.2 kJ/m2. Based on tensile test, the well-dispersed LPP-MoSe2 also leads to significant elevation in tensile strength (74.6%) and elongation at break (100%) of EP. Our data demonstrate that LPP-MoSe2 shows impressive performance in developing high-performance EP composites, thereby broadening the practical application of EP.

Multichannel ratiometric fluorescence sensor arrays for rapid visual monitoring of epinephrine, norepinephrine, and levodopa

Catecholamines (CAs), as the important signal mediators in normal physiological processes, regulate many basic physiological functions in the body. However, it is hardly to rapidly distinguish different CAs molecules, such as dopamine, epinephrine (Ep), and norepinephrine (NE), because of their extremely similar molecular structures. Here, we, for the first time, propose a simple and fast fluorescence turn-on strategy to distinguish different CAs and their precursor levodopa (L-DOPA). Specifically, novel ratiometric fluorescent probes with high sensitivity and selectivity were constructed for the quantitative detection of Ep, NE, and L-DOPA, with the detection limits of 18.9, 85.5, and 9.7 nM, respectively. In addition, the suitability of these ratiometric fluorescent probes was validated by detection application of Ep, NE, and L-DOPA in real human serum and urine samples. Furthermore, a portable ratiometric fluorescent hydrogel sensing platform was prepared, with agarose chosen as the carrier for semi-quantitative on-site detection of Ep, NE and L-DOPA based on visual inspection with the naked eye. These results indicate that the developed detection strategy opens up a novel and exciting avenue for the rapid identification and clinical diagnosis of CAs.

IMDRF Essential Principles of Safety and Performance of Medical Devices and IVD Medical Devices Introduction and Consideration

IMDRF revised the Essential Principles of Safety and Performance of Medical Devices and IVD Medical Devices (hereinafter referred to as "EP"), which further promoted the unification of medical device safety and effectiveness internationally. In order to strengthen the scientific review of medical device and deepen the understanding of EP, we introduce EP, focus on the role of EP and the connection with the construction of quality management systems, risk and benefit determination, and registration, analyze the problems and reasons in the process of medical device registration, and give suggestions to promote the application of EP.