Fluorinated Epoxy Resin Research Articles

A New Composite Material with Energy Storage, Electro/Photo-Thermal and Robust Super-Hydrophobic Properties for High-Efficiency Anti-Icing/De-Icing.

All weather, high-efficiency, energy-saving anti-icing/de-icing materials are of great importance for solving the problem of ice accumulation on outdoor equipment surfaces. In this study, a composite material with energy storage, active electro-/photo-thermal de-icing and passive super-hydrophobic anti-icing properties is proposed. Fluorinated epoxy resin and MWCNTs/PTFE particles are used to prepare the top multifunctional anti-icing/de-icing layer, which exhibited super-hydrophobicity with water contact angle greater than 155° and conductivity higher than 69Sm-1. The super-hydrophobic durability of the top layer is verified through tape peeling and sandpaper abrasion tests. The surface can be heated by applying on voltage or light illumination, showing efficient electro-/photo-thermal and all-day anti-icing/de-icing performance. The oleogel material at the bottom layer is capable to absorb energy during heating process and release it during cooling process by phase transition, which greatly delayed the freezing time and saved energy. The icing test of single ice droplet, electro-/photo-thermal de-icing and defrosting tests also proved the high efficiency and energy saving of the anti-icing/de-icing strategy. This study provided a new way to manufacture multi-functional materials for practical anti-icing/de-icing applications.

Degradable bio-based fluorinated epoxy resin with excellent flame-retardant, dielectric, hydrophobic, and mechanical properties

Degradable bio-based fluorinated epoxy resin with excellent flame-retardant, dielectric, hydrophobic, and mechanical properties

Preparation of fluorinated epoxy‐phthalonitrile resins with excellent thermal stability and low dielectric constant

AbstractFluoropolymers find applications in heat‐resistant cables, chemical‐resistant linings, electronic components, cladding materials, and weather‐resistant films. Therefore, it is imperative to improve their temperature resistance level and dielectric properties. In this study, a series of new fluorinated epoxy‐phthalonitrile resins with different mass ratios were prepared by adding phthalonitrile to the epoxy resin matrix, followed by a two‐step reaction of the amine with the epoxy resin at low temperature, and then by the reaction of the nitrile with the epoxy resin and the nitrile group at high temperature. The thermal stability and thermal oxidation stability of the cured products were improved; the initial decomposition temperature for 5% weight loss in air was 375.3°C, indicating good heat resistance performance. In addition, the glass transition temperature and storage modulus of the fluorinated epoxy‐phthalonitrile resins cured products increased with an increase in phthalonitrile content. The storage modulus remained above 1500 MPa until 150°C. The glass transition temperature of fluorinated epoxy‐phthalonitrile resins (at a mass ratio of 5:5) was 180°C, much higher than that of the epoxy resin (which was 140°C). Moreover, the dielectric constant of fluorinated phthalonitrile‐epoxy resin (5:5 mass ratio) was 2.01, which was 39.63% lower than that of fluorinated epoxy resin. The thermoset matrix has potential applications in the fabrication of a variety of low dielectric constant composites for electronic device related industries.

Fluorinated epoxy based superhydrophobic coating with robust self-healing and anticorrosive performances

Superhydrophobic surfaces are promising candidates for alleviating notorious corrosion phenomena due to their excellent water repellence. However, superhydrophobic surfaces often possessed with fragile structure stability as well as relatively complex fabrication processes, severely hindering their great potential for broad practical applications in various conditions. Herein, through a facile one-step spray process, a self-healing superhydrophobic coating with excellent anticorrosion performances were developed, by mixing fluorinated epoxy resin (FEP) matrix with polytetrafluoroethylene (PTFE) particles and ceresine wax. The surface maintains robust superhydrophobicity even under harsh conditions (e.g., physical impact, acid, alkali or salt solutions), hence effectively preventing corrosive ions from approaching the surface. Moreover, the superhydrophobic coating also displays remarkable self-healing performances stemming from the introduced ceresine wax, and exhibits excellent recovery of anti-corrosion performance in damaged areas after a rapid heating treatment. The combination of a superhydrophobic performance and self-healing function can significantly enhance the anticorrosion performances of coatings to provide a long-term protection for metals. Therefore, this coating may find promising applications in long-term metal corrosion protection under harsh working conditions.

A robust superhydrophobic anti-icing/de-icing composite coating with electrothermal and auxiliary photothermal performances

Passive anti-icing and active anti-icing/de-icing were two major strategies to suppress icing on surfaces. Combining these two strategies and making full use of various energies can greatly improve anti-icing efficiency. In this study, a multifunctional anti-icing/de-icing coating with superhydrophobic passive anti-icing and electrothermal/photothermal active de-icing properties was proposed. Fluorinated epoxy resin and carbon/PTFE particles were used to prepare the multifunctional anti-icing/de-icing coating, which exhibited superhydrophobicity with water contact angle greater than 155° and conductivity higher than 40 S/m. The robust superhydrophobic property was demonstrated by repeated sandpaper abrasion and tape peeling tests. Moreover, both electricity and solar energy can be adopted for heating the surface and de-icing, showing efficient electrothermal/photothermal and anti-icing/de-icing properties. In addition, the synergistic icephobic mechanism was validated by characterizing the different freezing states of water droplets on surfaces: repelling droplets before freezing occurred, delaying icing during the freezing process and significantly reducing the ice adhesion after freezing via the self-generated micro-scale water film by heating. This study provided a new way to manufacture functional materials for practical anti-icing/de-icing applications.

Methyl-substitution affects dielectric, thermal, mechanical properties, and shrinkage of fluorinated epoxy

Fluorination reduces dielectric constant and dielectric loss of epoxy resins, expanding their applications in high-speed communication. The methyl group (-CH 3 ) is a non-polar and space-occupying group, and it can reduce dielectric constant ( D k ) in some situations. However, it is not well understood how the methyl groups affect dielectric properties, as well as thermal and mechanical properties of fluorinated epoxy resin. To address this question, we specifically select benzene and m-xylene as the reaction monomer for comparison. We synthesize two fluorinated epoxides, diglycidyl ether of 1,3-bis(1,1,1,3,3,3-hexafluoroisopropyl)-benzene (DGE-bHFIP-B) and diglycidyl ether of 4,6-bis(1,1,1,3,3,3-hexafluoroisopropyl)-m-xylene (DGE-bHFIP-MX). We then thermally cure these two epoxides catalyzed with boron trifluoride ethylamine (BF 3 ·MEA) to obtain EP-bHFIP-B and EP-bHFIP-MX. EP-bHFIP-MX with –CH 3 has D k of 2.49–2.51, slightly lower than EP-bHFIP-B with D k of 2.51–2.54 at a high frequency range of 8.2–12.4 GHz. Their D k is much lower than a commercial bisphenol A type epoxy resin (EP-51) with D k of 2.80–2.83. Additionally, EP-bHFIP-MX shrinks less than EP-bHFIP-B after curing, and exhibits higher glass transition temperature with T g − D M A of 181 °C, higher tensile strength of 39.76 ± 5.51 MPa, compared to 129 °C and 34.73 ± 5.10 MPa for EP-bHFIP-B. EP-bHFIP-B and EP-bHFIP-MX both have very low water absorption of 0.134% w/w and 0.147% w/w after being immersed in water for 24 h at 25 °C. Therefore, incorporating –CH 3 groups into phenylene rings of fluorinated epoxies, we can enhance thermal resistance, increase mechanical strength, and reduce shrinkage without compromising dielectric performance. • Two novel fluorinated epoxides with low dielectric constant are synthesized. • Methyl-substitution slightly decreases D k in fluroinated expoxies. • Methyl-substitution improves thermal, mechanical properties and reduces curing shrinkage.

Improving performance oftwo‐stagephotopolymers for volume holographic recording by fluorinatedepoxy‐amine cross‐linkedmatrices

AbstractHost matrices play an important role in the volume holographic gratings formation of photopolymers. In this study, a series of fluorinated epoxy resin (FTGE) with low refractive index (1.44–1.46) are synthesized and characterized by nuclear magnetic resonance spectra (1H NMR,19F NMR) and fourier transform infrared spectra (FTIR). Fluorinated epoxy‐amine cross‐linked matrices are formed at room temperature and their thermal polymerization properties are investigated through real‐time FTIR and thermogravimetric analyses (TGA). Using the fluorinated epoxy‐amine as host matrices, holographic photopolymers are fabricated. The influence of different kinds (Prop‐FTGE, Buta‐FTGE, and Penta‐FTGE) and weight ratios (0%, 8%, 16%, and 23%) of FTGEs on holographic performances of the photopolymers are explored. The results show that the sample with 23% Prop‐FTGE has the most excellent holographic optical characteristics. 0.5 mm thick sample with 23% Prop‐FTGE reaches 91% diffraction efficiency within 80 mJ/cm2exposure dosage, and gets a 2000 lp/mm Bragg volume grating with 0.24° angular selectivity. Meanwhile, under a single pulse exposure mode (150–200 ps pulse width, 25 mJ/cm2exposure dosage), a grating with 4.4% diffraction efficiency is obtained, which proves the ultrafast response and recording capability of the sample.

Spraying pressure-tuning for the fabrication of the tunable adhesion superhydrophobic coatings between Lotus effect and Petal effect and their anti-icing performance

The tunable adhesion behavior of superhydrophobic surfaces has received much attention due to its unique properties to control the wetting state of water droplets. Herein, we report a facile and scalable spraying pressure-tuning method to control surface morphology by adjusting the spraying pressure to fabricate the tunable adhesion superhydrophobic coating (TASC). The superhydrophobic suspension prepared by fluorinated epoxy resin and polytetrafluoroethylene particles is sprayed on the glass substrate by altering the spraying pressure between 0.25 bar and 2.0 bar to control surface morphology, line profile, and surface roughness of TASCs. The water contact angles of TASCs are greater than 150°, while the water sliding angles of these surfaces are found from 2.6° (Lotus effect) to 180° (Petal effect) with the decrease of spraying pressure, which are attributed to the transformation of the wetting state on their surface from Cassie-Baxter state to Cassie impregnating state caused by the change of line profile and the decrease of surface roughness. We have proved that TASCs with different spraying pressure can be used in the droplet transportation, selection, and microreaction platform. Furthermore, the anti-icing performance of TASCs with different surface morphology and roughness was investigated by the freezing time and the ice adhesion strength. TASC-2.0 exhibited excellent anti-icing performance with freezing time at 392 s and the ice adhesion strength at 51 kPa than TASC-0.25 exhibited relatively flat surface, which is attributed to the air pocket captured by rough structure to reduce the solid/liquid contact area and has great potential for anti-icing applications.

Preparation and properties of a fluorinated epoxy resin with low dielectric constant

AbstractDemand for electronic materials with improved dielectric properties are increasing. One of the ways to reduce the dielectric constant is to incorporate fluorine atoms. In this article, a novel fluorinated epoxy resin (diglycidol ether of 2,4‐bis (1,1,1,3,3,3‐hexafluoroisopropyl) fluorobenzene (FB‐EP)) with 45.7 wt% fluorine content was synthesized from fluorobenzene, epichlorohydrin and hexafluoroacetone. The structures of desired monomers were characterized by NMR and FTIR. The epoxy resin FB‐EP was cured by copolymerization with hexahydrophthalic anhydride (HHPA) and by homopolymerization catalyzed with boron trifluoride ethylamine (BF3MEA), respectively. The curing reaction kinetics of the fluorinated epoxy and the properties of the cured materials were studied in comparison with those of common diglycidol ether epoxy resin (BADGE). The results of curing activation energy indicate that FB‐EP is reactive as the BADGE, and the four‐trifluoromethyl groups on FB‐EP do not negatively affect the cationic polymerization reactivity of the epoxy groups. The cured FB‐EP materials had lower moisture absorption, and especially lower dielectric constant (Dk, 2.23) and lower dielectric loss (Df, 0.011) in the frequency range of 8.2–12.4 GHz. This article provides a base for further study of fluorinated epoxy resin as advanced electronic materials.

Degradable Bio-Based Fluorinated Epoxy Resin with Excellent Flame-Retardant Properties, Dielectric Properties, Hydrophobic Properties and Mechanical Properties

Degradable Bio-Based Fluorinated Epoxy Resin with Excellent Flame-Retardant Properties, Dielectric Properties, Hydrophobic Properties and Mechanical Properties

Preparation of durable superhydrophobic composite coatings with photothermal conversion precisely targeted configuration self-healability and great degradability

Rapid self-healing of micro-configurations is an effective strategy to enhance the durability of superhydrophobic surfaces, however, this property is challenging to achieve. Here, a durable superhydrophobic coating with a precisely targeted self-healing ability to repair its’ dual structure was developed by spray-coating a polyimine film with a mixture of novel fluorinated epoxy resin and Fe3O4@SiO2–NH2 nanoparticles. The superhydrophobic surface can heal both the broken morphology and wettability through a short irradiation process on account of its local photothermal conversion ability and dynamic imine bond, and can maintain the static water contact angle at a value higher than 159° even after six damage/healing cycles. Furthermore, superhydrophobic coatings can be controllably degraded in three ways. Additionally, because of the robust epoxy resin protection, the surface can withstand sixteen times the dynamic impact and still maintain a WCA greater than 150°. This preparation strategy may aid the fabrication of durable superhydrophobic surfaces for various practical applications.

Plasma dielectric barrier discharge fluorination modified epoxy resin and its ageing behavior

The modification effect of plasma on the material will be weakened with the storage time, that is, it shows a certain timeliness, which limits further development of plasma modification technology. To explore ageing behavior of plasma dielectric barrier discharge (DBD) fluorinated epoxy resin, the surface fluorination of epoxy resin was realized by plasma dielectric barrier discharge. Scanning electron microscopy (SEM), surface profilometer, X-ray photoelectron spectroscopy (XPS), contact angle tester, high resistance meter, flashover voltage and surface potential testing system were used to characterize the physical morphology, chemical composition and electrical properties of epoxy resin surface before modification as well as being placed in 25 ℃ aging box for 0−30 d after modification. The experimental results show that fluoride grafting on the surface of epoxy resin is realized by DBD fluorination modification, which reduces the surface energy, surface resistivity and trap level of epoxy resin, thus speeds up the surface potential decay rate and increases the flashover voltage along the surface. After storage of 30 d, the fluorine content decreased, the surface energy increased, the attenuation rate of surface potential slowed down slightly, and the flashover voltage also decreased, but it is still higher than that of the untreated sample.

Molecular Dynamics Simulation for the Effect of Fluorinated Graphene Oxide Layer Spacing on the Thermal and Mechanical Properties of Fluorinated Epoxy Resin.

Traditional epoxy resin (EP) materials have difficulty to meet the performance requirements in the increasingly complex operating environment of the electrical and electronic industry. Therefore, it is necessary to study the design and development of new epoxy composites. At present, fluorinated epoxy resin (F-EP) is widely used, but its thermal and mechanical properties cannot meet the demand. In this paper, fluorinated epoxy resin was modified by ordered filling of fluorinated graphene oxide (FGO). The effect of FGO interlayer spacing on the thermal and mechanical properties of the composite was studied by molecular dynamics (MD) simulation. It is found that FGO with ordered filling can significantly improve the thermal and mechanical properties of F-EP, and the modification effect is better than that of FGO with disordered filling. When the interlayer spacing of FGO is about 9 Å, the elastic modulus, glass transition temperature, thermal expansion coefficient, and thermal conductivity of FGO are improved with best effect. Furthermore, we calculated the micro parameters of different systems, and analyzed the influencing mechanism of ordered filling and FGO layer spacing on the properties of F-EP. It is considered that FGO can bind the F-EP molecules on both sides of the nanosheets, reducing the movement ability of the molecular segments of the materials, so as to achieve the enhancement effect. The results can provide new ideas for the development of high-performance epoxy nanocomposites.

A superhydrophobic coating harvesting mechanical robustness, passive anti-icing and active de-icing performances

HypothesisIce accretion is a challenging issue for various residential activities and industrial facilities. However, most of the current anti/de-icing coatings fail to maintain their properties when subject to frequent mechanical wear, and their limited functionality (either anti-icing or de-icing individually) cannot meet the requirement of all-weather utilization. ExperimentsHerein, a multifunctional superhydrophobic coating is prepared by compositing ferroferric oxide nanoparticles (Fe3O4 NPs) with fluorinated epoxy resin via an inverse infiltration process. The surface composition, morphology and wettability are systematically characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), laser scanning microscopy and contact angle tensiometer. The anti-icing and de-icing performances are evaluated by investigating the freezing delay and photothermal effect, respectively. FindingsThis coating shows outstanding water repellency (water contact angle up to 161.0°, sliding angle down to 1.4°) and can maintain superhydrophobicity within 400 cycles of tape peeling, 260 cycles of sandpaper abrasion or 25 cycles of sand impact. Besides, because the hydrophobic nano/micro hierarchical structures tremendously retard the heat transfer, the freezing process of water droplet on this coating can be apparently delayed by up to 35 min as compared to the uncoated substrate. Moreover, owing to the photothermal effect of the Fe3O4 NPs, the coating’s surface temperature can be rapidly increased above 0 °C under infrared irradiation, which facilitates the ice melting on cold surfaces. Our work offers a versatile approach to address the icing problems in diverse weather conditions, which exhibits great prospects in various engineering applications.

Molecular Structure Modulated Trap Distribution and Carrier Migration in Fluorinated Epoxy Resin.

Surface charge accumulation on epoxy insulators is one of the most serious problems threatening the operation safety of the direct current gas-insulated transmission line (GIL), and can be efficiently inhibited by the surface modification technology. This paper investigated the mechanisms of fluorination modulated surface charge behaviors of epoxy resin through quantum chemical calculation (QCC) analysis of the molecular structure. The results show that after fluorination, the surface charge dissipation process of the epoxy sample is accelerated by the introduced shallow trap sites, which is further clarified by the carrier mobility model. The electron distribution probability of the highest occupied molecular orbitals (HOMO) under positive charging and the lowest unoccupied molecular orbitals (LUMO) under negative charging shows distinctive patterns. It is illustrated that electrons are likely to aggregate locally around benzenes for the positively charged molecular structure, while electrons tend to distribute all along the epoxy chain under negatively charging. The calculated results verify that fluorination can modulate surface charge behaviors of epoxy resin through redesigning its molecular structure, trap distribution and charging patterns.

Metal-Printing Defined Thermo-Optic Tunable Sampled Apodized Waveguide Grating Wavelength Filter Based on Low Loss Fluorinated Polymer Material

In this work, thermo-optic (TO) lateral shift apodized sampled waveguide grating for 1550 nm wavelength is designed and fabricated by the metal-printing technique based on fluorinated epoxy-terminated polycarbonates (FBPA-PC EP) and fluorinated epoxy resin (FSU-8) materials. The optical characteristics and thermal stability of the FBPA-PC EP and FSU-8 materials are analyzed. To realize periodic wide-spectrum filtering and suppress the side-lobes of grating, a lateral shift apodized sampled waveguide grating is proposed. The 3 dB bandwidth and wavelength spacing can reach 4.8 nm and 9.7 nm. The side-lobe suppression ratio of proposed device can reach 22.6 dB, which is much better than traditional Bragg grating (6.1 dB). Driving electrical powers of 42.4 mW and 87.2 mW can produce blueshifts of 1.8 nm and 3.5 nm in the measured reflection spectrum, respectively. This device realizes the aim of multiple functions, including periodic filtering, wide-spectrum filtering, and high side-lobe suppression. The device is applicable of realizing signal processing and wavelength division multiplexing (WDM )systems.

Nafion based semi-interpenetrating polymer network membranes from a cross-linkable SPAEK and a fluorinated epoxy resin for DMFCs

A Nafion based blending PEM with a thinner thickness but enhanced methanol resistance was prepared by introducing a semi-interpenetrating polymer network (semi-IPN) between Nafion matrix and blender. A side-chain-type sulfonated poly(arylene ether ketone) (SNF-PAEK) blender with hydroxyl groups was designed to be cross-linked by a fluorinated epoxy resin monomer (fEO) to form the semi-IPN in blending membranes (S@N/fEO). The S@N/fEO-6 exhibits enhanced proton conductivity (0.198 S cm−1) due to the aggregated ionic clusters in SNF-PAEK. Besides, the blenders caused a rearrangement in microstructure, leading to a shorter ionic clusters distance and facilitating the proton conduction, proved by TEM and SAXS. Furthermore, all S@N/fEO membranes show satisfactory dimensional stability and suppressed methanol crossover (methanol permeability of 1.34 × 10−6 cm2 s−1) because the semi-IPN restricts the molecular segments movement and hinders methanol passing through. Compared with Nafion 212, S@N/fEO-6 membrane performs superior single cell efficiency of 180.9 mW cm−2, almost 29% increase. Electrochemical impedance spectroscopy was used to further study the behavior of membranes, and S@N/fEO-6 was found to possess the lowest mass transfer resistance contributing to the best single cell performance. Thus, Nafion-based semi-IPN membrane is proved to improve properties significantly and have potential to be applied in DMFC.

Preparation and Performance of Hybrid Superhydrophobic Materials from Fluorinated Epoxy Resin and Silica Nanoparticles

Preparation and Performance of Hybrid Superhydrophobic Materials from Fluorinated Epoxy Resin and Silica Nanoparticles

DC breakdown and flashover characteristics of direct fluorinated epoxy/Al2O3 nanocomposites

The effect of direct fluorination on DC breakdown and flashover characteristics of epoxy/Al 2 O 3 nanocomposites was investigated. Pure epoxy resin and epoxy/Al 2 O 3 nanocomposites with 1, 3 and 5 wt% mass fractions were synthesized, and direct fluorination of the samples was carried out at 55 °C for 30 min using a F 2 /N 2 mixture with 20 vol% F 2 at 0.05 MPa. Fourier transform infrared spectroscopy and atomic force microscopy show that molecular chain scission occur during direct fluorination, which may significantly suppress surface charge accumulation while incorporating Al 2 O 3 nanoparticles into epoxy may restrict surface potential decay of fluorinated epoxy resin. The trap characteristics obtained by isothermal surface potential decay show that 1 wt. % sample has deeper traps and higher trap density. DC breakdown and flashover of samples were measured to evaluate the influence of nano filling and direct fluorination on electrical performance of epoxy resin. The results show that epoxy resin with higher DC breakdown and flashover strength can be obtained by simultaneous application of nano filling and direct fluorination. Compared to un-fluorinated epoxy resin, the DC breakdown and flashover voltage of fluorinated epoxy/Al 2 O 3 nanocomposites with mass fraction of 1 wt% improved 17 and 23%, respectively.

Influence of the chemical composition and formulation of fluorinated epoxy resin on its surface characteristics

The incorporation of perfluorononanoic acid into epoxy resins was investigated in order to prepare a material with low adhesion properties (low free surface energies comprised between 15 and 26 mJ m−2). A laboratory-grade tetrafunctional epoxy resin was fluorinated by direct reaction with the perfluorinated carboxylic acid. A bifunctional epoxy resin fluorinated beforehand was also added to the tetrafunctional epoxy resin. The fluorinated resins were analyzed by FTIR spectroscopy. Dynamic DSC experiments were performed for the resins in presence of a stoichiometric quantity of the curing agent. Results were compared with those obtained with a commercial grade of the fluorinated tetrafunctional resin. Finally, the influence of the curing cycle was studied and optimized. The surface properties of the cured resins were then characterized in terms of free surface energy with contact angle measurements.