Doped Epoxy Resin Research Articles

Strong nonlinear optical limiting of resin composed by carbon nanotubes

The development of solid-state nonlinear optical limiting (NOL) materials is crucial for advancing the practicality in the field of optical limiting. In this paper, we innovatively prepare a new solid NOL material which is spiral carbon nanotubes doped epoxy resin (SCNTs-doped ER, SER) with a simple physical mixing method, and achieve an excellent nonlinear optical limiting performance. We experimentally measured optical limiting of SER with different SCNTs concentrations (0.14, 0.28, and 0.43 mg/mL) and obtained the nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility at the wavelength 1064 nm. Z-scan experiment results show that the SER exhibits a large nonlinear absorption coefficient (5.07 ± 0.38) × 10−9 m/W. We also measure the transmittance of the SER to evaluate its nonlinear optical limiting performance. For the SER with 0.43 mg/mL concentration, the linear transmittance and minimum transmittance with NOL effects at 1064 nm are 54.8% and 26.2%, respectively. In addition, the SER also has prominent features such as a high damage threshold and easy fabrication, indicating that the SER is a promising solid material for nonlinear optical limiting.

Mitigation of electrical treeing at high temperature in nano‐SiO2 doped epoxy resin

AbstractIn this work, electrical tree inception and ageing experiments were conducted to investigate the initiation, growth characteristics and structural characteristics of electrical trees of nano‐SiO2 doped epoxy resin at different temperatures. Electrical tree inception and ageing experiments were conducted using power frequency voltage of 15 kV at 20, 40, 60, 80 and 100°C. Electrical breakdown properties of epoxy resin were investigated by applying AC and DC voltages at 20, 40, 80 and 120°C. There are two major observations based on the experimental results. With the increase of temperature, the morphological structure of the electrical trees changes from dendritic to plexiform, the tree inception voltage decreases and the growth rate of the electrical trees increases obviously. Either under DC or AC voltage, the breakdown strength of the nano‐SiO2 doped epoxy resin decreases as the temperature increases. Finally, based on the space charge and the trap level measurement, the mechanism of the electrical tree propagation and breakdown in nano‐SiO2 doped epoxy resin was analysed.

Fe3O4-Nanoparticle-Doped Epoxy Resin as a Detachable Adhesive by Electromagnetic Heating for GFRP Single-Lap Joints.

An adhesive based on a Fe3O4-nanoparticle (MNP)-doped epoxy resin was proposed for the development of detachable adhesive joints with GFRP substrates. The analysis of cryofractures showed that the increasing MNP content promotes a higher presence of larger aggregates and a lower sedimentation of nanoparticles due to the higher viscosity of the mixture. In this regard, the inclusion of expandable microspheres (MS) induces a more uniform dispersion of MNPs, reducing their sedimentation. The capability of the proposed adhesives for electromagnetic (EM) heating was also evaluated, with increases in temperature of around 100 °C at 750 A, enough to reach the Tg of the polymer required to facilitate the adhesive detachment, which is around 80 °C. Finally, the lap shear strength (LSS) of 14 and 20 wt.% MNP samples was evaluated in a single-lap shear joint with simultaneous EM heating. The LSS values were reduced by 60-80% at 750 A, thus promoting successful adhesive joint detachment under EM heating.

Spectral Properties of Hybrid of Rhodamine (6G) Dyes Doped Epoxy Resin Dissolved in Chloroform

The research is dealing with the absorption and fluorescence spectra for the hybrid of an Epoxy Resin doped with organic dye Rhodamine (R6G) of different concentrations (5*10-6, 5*10-5, 1*10-5, 1*10-4, 5*10-4) Mol/ℓ at room temperature. The Quantum efficiency Qfm, the rate of fluorescence emission Kfm (s-1), the non-radiative lifetime τfm (s), fluorescence lifetime τf and the Stokes shift were calculated. Also the energy gap (Eg) for each dye concentration was evaluated. The results showed that the maximum quantum efficiency 62 % and maximum stokes shift 96 nm was obtained in dye concentration 5*10-6 and 1*10-4. The energy gap ranges between 1.066 eV to 1.128 eV depending proportionally on the dye concentrations.

Mechanical properties and morphological characteristics of ARALL reinforced with TRGO doped epoxy resin

ABSTRACT Mechanical properties in tension, bending, fatigue and lap-shear in two different proportions (0.5%wt and 1%wt) of TRGO (Thermally Reduced Graphite Oxide) doped ARALL (Aramid Aluminium Laminate) were examined. The materials and their failure modes were characterized morphologically by examination through SEM (Scanning Electron Microscopy). Some mechanical properties of ARALL were improved when doped with 0.5% of TRGO, showing a significant increase of fatigue properties, as well as a change in fracture surface morphology. Tension andbending properties showed variable results and further studies should be carried out to arrive to definitive conclusions, while lap-shear testing showed lower shear values. The results were statistically validated through mono-factorial variance analysis. Comparing the present results with previous work on CNT (Carbon Nanotubes) doped ARALL, it can be stated that: (a) TRGO doped ARALL showed improved fatigue properties when compared with non-doped ARALL, but in a less effective way than doping with CNT, (b) TRGO doped ARALL tension properties showed no significant variation as compared with ARALL alone, showing no deleterious influence as in the CNT doping case, (c) TRGO doped ARALL bending properties resulted better than non-doped ARALL, but similar than those obtained when doping with CNT and (d) TRGO decreased the adherence between aramid fiber impregnated L20 epoxy resin and aluminium. These last results are sustained based on observed improvements as a percentage value, without a statistical variance analysis made on CNT doped ARALL.

Mechanical properties and morphological characteristics of ARALL reinforced with TRGO doped epoxy resin

ABSTRACT Mechanical properties in tension, bending, fatigue and lap-shear in two different proportions (0.5%wt and 1%wt) of TRGO (Thermally Reduced Graphite Oxide) doped ARALL (Aramid Aluminium Laminate) were examined. The materials and their failure modes were characterized morphologically by examination through SEM (Scanning Electron Microscopy). Some mechanical properties of ARALL were improved when doped with 0.5% of TRGO, showing a significant increase of fatigue properties, as well as a change in fracture surface morphology. Tension andbending properties showed variable results and further studies should be carried out to arrive to definitive conclusions, while lap-shear testing showed lower shear values. The results were statistically validated through mono-factorial variance analysis. Comparing the present results with previous work on CNT (Carbon Nanotubes) doped ARALL, it can be stated that: (a) TRGO doped ARALL showed improved fatigue properties when compared with non-doped ARALL, but in a less effective way than doping with CNT, (b) TRGO doped ARALL tension properties showed no significant variation as compared with ARALL alone, showing no deleterious influence as in the CNT doping case, (c) TRGO doped ARALL bending properties resulted better than non-doped ARALL, but similar than those obtained when doping with CNT and (d) TRGO decreased the adherence between aramid fiber impregnated L20 epoxy resin and aluminium. These last results are sustained based on observed improvements as a percentage value, without a statistical variance analysis made on CNT doped ARALL.

Study of dielectric and insulation properties of nano-additives doped epoxy resin

This paper aims to reveal the high voltage insulation and dielectric properties of epoxy resin samples with various nano-particle of Al2O3 and SiO2. In addition, experimental results were measured for dielectric properties (permittivity and tanδ at 1 kHz and 10 kHz), breakdown voltage and dielectric strength. The dielectric and high voltage insulation properties of nano-composites are analyzed in detail with respect to different experimental parameters such as frequency, particle size of additives, additive contents, additive permittivity and thickness of the samples. The results show the effects of nano-additives in permittivity, dissipation factor, breakdown strength and voltage for nano-composites.

Graphite Nanoplatelet Modified Epoxy Resin for Carbon Fibre Reinforced Plastics with Enhanced Properties

A simple approach to deliver graphene or graphite nanoplatelets (GNPs) into carbon fibre reinforced plastic (CFRPs) to enhance the multifunctional properties of carbon/epoxy laminates was demonstrated. GNPs improved the typically low interlaminar mechanical, thermal, and electrical properties of CFRPs after direct vacuum infusion of GNP doped resin obtained via in situ exfoliation by three-roll milling (TRM). Compared to high shear mixing or probe ultrasonication, TRM produces higher shear rates and stresses to exfoliate and finely disperse GNP particles within an epoxy matrix. This environmentally friendly and industrial scalable process does not require the use of solvents, additives, or chemical treatments. The flexural modulus and interlaminar shear strength (ILSS) of CFRPs was increased by 15% and by 18%, respectively, with the addition of 5 wt.% in situ exfoliated GNP in the doped epoxy resin. Out-of-plane electrical and thermal conductivity, at the same filler content, were, respectively, improved by nearly two orders of magnitude and 50%.

The Scrutiny of the Insulation Breakdown Strength for the Nanocomposite Oxide Doped Epoxy Resin Insulator with Different Electrodes by Using Positive Impulse Voltage

This research presents the ratio of doping nanocomposite oxides in dielectric materials for increasing the efficiency strength and endurance voltage. Tests were conducted and analyzed the characteristics of epoxy nanozinc oxides. By using positive standard impulse voltage abilities of nanocomposite oxides were used as electrical insulators-epoxy resin doped with zinc oxides nanocomposite in ratios of 0, 5, 10, 15, and 20% by weight. And the design of electrodes embeds in the specimens with 4 types of electrode, as needle electrode, point electrode, spherical electrode and the partial spherical electrode. When adjusted the impulse voltage level of 75kV to the specimen immersed in transformer oil. The experiment aforementioned to investigate the ratios damages on insulator surfaces and the number of breakdowns. The microscopes with magnification levels of 20-800X were used to view the damages on insulator surfaces. Results, it was found that regarding specimens used for doping an epoxy resin with zinc oxides nanocomposite in a ratio of 5% had high withstand insulator with electrode types. The partial spherical electrode tested with positive impulse standard voltage has destructive distance lower damage than other electrode types.

The Investigation of Insulation Breakdown Strength for the Nano-composite Oxide Doped Epoxy Resin Insulator by Using Positive Impulse Voltage in Comparison with Negative Impulse Voltage

This article presents the nano-composite oxides in dielectric materials which are suitable for increasing the efficiency of the destruction of strength and durability against voltage. Tests were conducted to compare the characteristics and details of epoxy resin materials doped with nano zinc oxides by using positive and negative impulse standard voltage to test the destruction of specimen in order to make insulators more efficient and durable against the positive and the negative impulse voltage. This research also studied the abilities of nano-composite oxides to be used as electrical insulators - epoxy resin doped with zinc oxides nano-composite in ratios of 0, 5, 10, 15 and 20% by weight. After that, there were destruction tests by using impulse voltage at levels of 75, 90, 98, and 115 kV connected to the specimen's electrodes immersed in oil transformer by using each voltage level against specimen usage in each of the aforementioned ratios to investigate the damages on insulator surfaces and the number of breakdowns. In viewing damages on insulator surfaces, microscopes with magnification levels of 20-800X were used. From experimental results, it was found that regarding specimens used to doped an epoxy resin with zinc oxides nano-composite and each level of standard positive impulse voltage, in the first round of voltage feeding it was observed that the period of specimens surface destruction was higher than when negative impulse voltage were used, and the breakdown occurrences were also faster increasing than that the of standard negative impulse voltage were used. In conclusion, a 5% doped epoxy resin with nano-composite zinc oxides tested with negative impulse voltage has better properties as an insulator than other samples in ratios of 0, 10, 15, and 20%, respectively, as the 5% ratio has a breakdown occurrences also happened later with smaller periods of insulator surface destruction in the first round of voltage feeding than the other cases.

Polythiophene–graphene oxide doped epoxy resin nanocomposites with enhanced electrical, mechanical and thermal properties

Polythiophene–graphene oxide nanoparticle hybrids as high performance multifunctional reinforcement for epoxy resin.

Polypyrrole doped epoxy resin nanocomposites with enhanced mechanical properties and reduced flammability

As well as limiting the crack propagation, polypyrrole nanofibers further initiated shear bands in epoxy to give a higher tensile strength than polypyrrole nanospheres.

Investigation into the Influence of Carbon Contamination on the Corrosion Behavior of Aluminum Microelectrodes and AA2024-T3

The effect of electron beam induced carbon contamination on the corrosion behavior of aluminum alloy 2024-T3 (AA2024-T3) has been investigated using immersion and polarization-type corrosion tests. For the immersion test, carbon was deposited on a polished surface of AA2024‑T3 in the form of concentric squares increasing in thickness toward the center. The sample was then corroded in 0.1 M NaCl for 80 hrs at room temperature and subsequently examined in a scanning electron microscope (SEM) to determine how the matrix and intermetallic phases behaved under the contamination layer. Results indicated that only the longest contamination time (16 hours) produced significant corrosion inhibition. Within this region corrosion was largely limited to pitting of some intermetallics. Outside this region inhomogeneous corrosion, significant pitting and variable matrix etching were observed.For the polarization test, a multi electrode sample was prepared containing 20 electrodes of pure aluminum wire embedded in carbon doped epoxy resin and polished to 0.25 μm finish. The electrodes were given electron beam exposure times of up to 64 hours and then given a standard polarization test. Results indicated that corrosion inhibition increased with increasing electron beam exposure time, although even the shorter electron beam exposures resulted in significant inhibition.

An irgacure 784 doped photopolymers for display holograms recording at 532 nm

This paper presents an investigation on the preparation and characterization of thick photopolymers for display holograms recording at 532 nm. Based on our previous research on fabrication and characterization of the doped photopolymer for volume holographic data storage, we develop a new large size Irgacure 784 doped epoxy resin photopolymer plate for display holograms recording in this research. The material system consists of two sub-systems. The first one is the epoxy resin polymer matrix, which provides a strong material structure so that the optical induced shrinkage during hologram recording can be minimized. The second part consists of photosensitive elements, which are uniformly dispersed in the epoxy resin to provide a mechanism for holograms recording. Material fabrication technique and the characteristics including absorption spectra, dynamic range and recording sensitivity are reported in this paper. Successful recording and reconstruction of a Fresnel hologram of the transmission type in a photopolymer plate of size 20 cm × 30 cm demonstrates the feasibility of display holograms recording in this material.

Preparation and characterization of Irgacure 784 doped photopolymers for holographic data storage at 532 nm

This paper presents the development of a thick photopolymer for holographic data storage at a wavelength of 532 nm. Irgacure 784, one kind of the titanocene photoinitiators, has been selected and doped to synthesize the photopolymers in this research. Using a two-step thermo-polymerization procedure two photopolymer samples have been fabricated, Irgacure 784 doped poly(methyl methacrylate) (PMMA) and Irgacure 784 doped epoxy resin. Samples of 2 mm thick have been fabricated. Holographic measurements show that Irgacure 784 doped epoxy resin is very sensitive at 532 nm and that it is capable of supporting holographic data storage at a ultra-fast recording rate of 760 Mb s−1. Mass spectrum measurement, solid state 1H-NMR spectrum measurement, and thermogravity analyses (TGA) have been performed. The results reveal the physical mechanism of holographic recording in these samples, providing a guideline for a design strategy and fabrication technique to produce a low-shrinkage recording material for holographic data storage in the tera-byte information age.

Piezoresistive Performance of Long-Fiber Composites with Carbon Nanotube Doped Matrix

The electrical and mechanical properties of carbon nanotube (CNT) doped epoxy resin and composites based on this matrix were studied. The investigation was carried out on neat nanocomposites and on structural composites i.e., when the nanocomposite is used as matrix in composite materials reinforced with long continuous fibers. Tensile tests showed that CNT doped epoxy exhibited clear piezoresistive behavior. It was, however, also shown that geometrical changes of the specimen also contribute significantly to resistance changes during tensile loading. Particular effort was made to establish the relations between transverse cracking in glass fiber cross-ply laminates with nanotube doped matrix and changes of electrical resistance. It was shown that changes of electrical resistance during tensile loading of composites containing CNT doped matrix gives highly relevant information about the damage state of the material. In an unloaded state the resistance change is proportional to the relative change of stiffness. This work demonstrates that there are three different mechanisms, which contribute to changes of electrical resistance of a composite specimen subjected to tensile strain. These three mechanisms are: (a) geometrical changes of the specimen (b) piezoresistive material response, and (c) accumulation of micro-damage.

A high-sensitivity laser microprobe mass analyzer

A laser microprobe mass analyzer has been developed. It is intended for application in biomedical and physiological research. A frequency-doubled ruby laser is focussed through an incident light microscope to a spot of minimally 0.5 μm in diameter on a thin section specimen of 0.1–1.5 μm thickness. The microplasma generated from the irradiated volume is analyzed in a time-of-flight mass spectrometer recording the complete spectrum for each shot. From lithium doped epoxy resin (5 ppm by weight), used as an organic standard, 1.4×10−19g or 1.4×104 atoms of the6Li isotope have been detected. This sensitivity corresponds to that of ion microprobes but is at least an order of magnitude higher than obtained with electron probe X-ray microanalyzers.