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Transferred PMN-PT Thick Film on Conductive Silver Epoxy
摘要： Approximately 25 μm Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) thick ?lm was synthesized based on a sol-gel/composite route. The obtained PMN-PT thick ?lm was successfully transferred from the Silicon substrate to the conductive silver epoxy using a novel wet chemical method. The mechanism of this damage free transfer was explored and analyzed. Compared with the ?lm on Silicon substrate, the transferred one exhibited superior dielectric, ferroelectric and piezoelectric properties. These promising results indicate that transferred PMN-PT thick ?lm possesses the capability for piezoelectric device application, especially for ultrasound transducer fabrication. Most importantly, this chemical route opens a new path for transfer of thick ?lm.
关键词： piezoelectric thick ?lm,conductive epoxy,transfer,PMN-PT
更新于2025-09-23 15:21:01
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Development of a composite polymer-dye medium for tunable laser emission
摘要： We demonstrate optically pumped laser medium with emission in the visible spectral range from binary solutions of Rhodamine 6G and Rhodamine B in epoxy resin as matrix without appending additional scattering centers. A frequency doubled Q-switched Nd: YAG laser was used for pumping. The generation’s behavior is similar to random laser (RL) with no external optical resonator. The in?uence of the nanostructured morphology of the medium on the laser properties was investigated by means of SEM, AFM, TEM, SAED, Spectro?uorimetry and Spectrometry. The laser emission is characterized by high intensity – energy per pulse – 300 μJ, threshold pump energy 1.7 mJ, relatively low beam divergence of 70 mrad (for RL) and spectrally narrowed major peak at 597 nm. The new gain medium was also investigated in a conventional tunable resonator. Generation with continuous tuning in the spectral range 590–610 nm was obtained. This new e?ective nanostructured medium, which shows with high optical and energy parameters, can be used in speckle-free laser imaging, time-resolved microscopy, high speed optical converters and others photonics applications.
关键词： Dye laser,Tunable laser,Broadband laser,Random laser,Epoxy resin
更新于2025-09-23 15:19:57
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Fabrication of mechanical controllable, sticky and flexible random lasers based on double-sided tapes
摘要： In this paper, we report on the fabrication of mechanical controllable, sticky and ?exible random lasers based on double-sided tapes that are cheap and commonly available. A double-sided tape is used as the scattering medium. Two di?erent solutions of rhodamine B dye doped with ethylene glycol and SU-8 epoxy based polymer are applied as the gain medium. By investigation of the random laser operating lifetimes for both samples, it is shown that SU-8 epoxy based polymer is the preferred host for dye in practical utilizations. Furthermore, we observe that for the sample fabricated based on the polymeric solution of RhB dye doped SU-8 resin, bending the sample leads to an increase of lasing threshold by 39 MW/cm2. This study can pave the way for manufacturing low cost, simply utilized and mechanical controllable random lasers which can also sticks to di?erent surfaces as the marker.
关键词： Multiple light scattering,SU-8 epoxy based polymer,Random laser,Flexible devices,Double-sided tapes
更新于2025-09-19 17:13:59
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Influence of surface treatment with infrared nanosecond laser on adhesion performance of adhesion-bonded carbon fiber/epoxy composite
摘要： The surface treatment of carbon fiber/epoxy composites with a pulsed infrared (1064 nm wavelength) nanosecond (7 ns pulse duration) laser has been investigated. It is found that single 1064 nm laser pulse can remove the polymer matrix from composite surface to expose the carbon fibers by expansion of the pyrolysis gas resulting from laser-induced polymer degradation. The influences of laser power density and scan strategy on matrix removal process have been studied. The bonding strength of laser processed, adhesion-bonded CFRP (carbon fiber reinforced plastic) increase with lower matrix residues on the fibers and a linear relation is found. The adhesion-bonding strength of CFRP surfaces, tested by lap-joint shear test, exceeds the strength measured for untreated and abrasion treated (SiC paper) samples. The main origin of fiber damage of the laser-treated surface is mechanical fracture rather than thermal damage as found by laser scanning confocal microscope and scanning electron microscope. The characteristic morphologies and failure modes of shear-tested surfaces are analyzed. The obvious improvement of adhesive strength is achieved by the laser-treated surfaces attributed to matrix removal and carbon fibers protruding. A 1 D model is established to describe temperature and internal gas pressure of the irradiated surface. The new laser treatment method needs less laser energy and low pulse numbers and prove the way to an efficient, low-cost surface treatment for preparation of high quality adhesion bonded CFRP components.
关键词： matrix removal,adhesion strength,1064 nm laser,Carbon fiber/epoxy composite
更新于2025-09-19 17:13:59
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Preparation and Characterization of UV-LED Curable Acrylic Films Containing Biochar and/or Multiwalled Carbon Nanotubes: Effect of the Filler Loading on the Rheological, Thermal and Optical Properties
摘要： UV-LED curable coatings represent an up-to-date attractive field due to the high curing efficiency even in the presence of high filler loadings, as well as to the absence of infrared wavelengths that may negatively impact on heat-sensitive substrates. The addition of carbonaceous materials, such as biochar (BC) and/or multiwalled carbon nanotubes (MWCNTs) could positively improve both the rheological and thermal properties. In this study we report on the synthesis and characterization of carbon-reinforced films containing nanometric (MWCNTs) and micrometric (BC) carbon-based materials. We analyze the rheological properties of the UV-LED curable dispersions, as well as the thermal and optical properties of the resulting films, establishing some correlations between filler dispersion/loading with the main observed properties.
关键词： composites,epoxy-acrylate resin,biochar,multiwalled carbon nanotubes,UV-LED curing
更新于2025-09-19 17:13:59
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Transparent Cellulose Nanofibrils Composites with Two-layer Delignified Rotary-cutting Poplar Veneers (0?°-layer and 90?°-layer) for Light Acquisition of Solar Cell
摘要： Our transparent cellulose nanofibrils composites (TCNC) directly from rotary-cutting poplar veneer (RPV) whose lignin can be easily stripped by our treatment. This TCNC is prepared by stripping lignin of original RPV and infiltrating epoxy resin (ER) into delignified RPV. This TCNC with two-layer delignified RPVs whose grains perpendicular (0/90°) to each other, which were solidified on solar cell while infiltrating ER. This TCNC with high transmittance (~90%), high haze (~90%), and equal refractive index fluctuation. Comparing with epoxy resin (ER), this TCNC can enhance open circuit voltage (VOC) from 1.16 to ~1.36 and short circuit density (JSC) from 30 to ~34 for the solar cell, and can enhance test fore from 0.155 kN to ~0.185 kN and displacement from 43.6 mm to ~52.5 mm.
关键词： light acquisition,rotary-cutting poplar veneer,delignification,epoxy resin,solar cell,transparent cellulose nanofibrils composites
更新于2025-09-19 17:13:59
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Novel Siloxane-Modified Epoxy Resins as Promising Encapsulant for LEDs
摘要： This study investigated a new category of transparent encapsulant materials for light-emitting diodes (LEDs). It comprised a phenyl group that contained siloxane-modified epoxy (SEP-Ph) hybridized with a cyclic tetrafunctional siloxane-modified epoxy (SEP-D4) with methylhexahydrophthalic anhydride (MHHPA) as a curing agent. The SEP-Ph/SEP-D4 = 0.5/0.5 (sample 3) and SEP-D4 (sample 4) could provide notably high optical transmittance (over 90% in the visible region), high-temperature discoloration resistance, low stress, and more crucially, noteworthy sulfurization resistance. The lumen flux retention of the SEP encapsulated surface mounted device LEDs remained between approximately 97% and 99% after a sulfurization test for 240 h. The obtained comprehensive optical, mechanical, and sulfurization resistance proved the validity and uniqueness of the present design concept with complementary physical and chemical characteristics.
关键词： crosslinking density,surface mounted device LEDs,encapsulant,sulfurization resistance,siloxane-modified epoxy
更新于2025-09-16 10:30:52
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Study on light aging of anhydride-cured epoxy resin used for RGB LED packaging material
摘要： RGB LED is widely used in white light illumination and display fields due to its high luminous efficiency and full color display. However, the color drift will occur when RGB LED is used for a long time. In this paper, the luminous performance of RGB LED encapsulated by epoxy materials during longtime lighting and the aging mechanism of methyl hexahydrophthalic anhydride (MHHPA) cured diglycidyl ether of bisphenol-A (DGEBA) were studied by Array spectrometer, ATR-FTIR, XPS and quantum-chemistry calculation. Firstly, the analysis of the lumen maintenance and forward voltage of RGB LED lamps showed, the color drift might be attributed to the degradation of its epoxy materials caused by blue light. FTIR Spectroscopy showed that the aging of packaging materials mainly occurred on the surface of blue LED lamps, where active hydrogen of secondary and tertiary carbon might be oxidized to carbonyl groups due to O2 or peroxy groups in the air. And the aging of epoxy materials also might include the chain scission or the rearrangement reactions of C-O-Ph. XPS results further manifested the decrease of C-C group and increase of C-O and C=O group were mainly caused by the chain scission of C-C, C-O-Ph or the ester groups and the oxidation of active hydrogen. And several possible aging reactions were given from the analysis of ATR-FTIR and XPS characterization. The results of quantum-chemistry calculation indicated that C-O bond in C-O-Ph of DGEBA/MHHPA epoxy system was more easily to be broken down during blue light aging, which further verified the results of IR and XPS characterization.
关键词： quantum-chemistry calculation,epoxy resin,light aging,RGB LED
更新于2025-09-16 10:30:52
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Research on epoxy-based nanocomposites with high energy density and charge-discharge efficiency filled with Ti0 <sub/>2</sub> nanofibers
摘要： Capacitor films with high energy density are critical to energy storage. However, the energy density of state-of-the-art commercial capacitor films are limited by their low dielectric permittivity. In this study, epoxy-based nanocomposite films are prepared by filling with TiO2 nanofibers. Results show that nanocomposite films have larger discharge energy density because of the significant increase in dielectric permittivity, which caused by the additional interface polarization and space charge polarization. And a superior charge-discharge efficiency is achieved in the composite films at the same time due to the low dielectric loss. In addition, the composites also keep a high breakdown strength because of the dispersion of the nanofibers. The discharge energy density of 5.19 J/cm3 with the efficiency of 80% is achieved at 470 MV/m in the nanocomposites containing 2wt% nanofibers. The excellent energy density and charge-discharge efficiency of epoxy-based nanocomposites offer a promising opportunity for future researches and industrial application.
关键词： dielectric permittivity,energy density,epoxy-based nanocomposites,charge-discharge efficiency,TiO2 nanofibers
更新于2025-09-16 10:30:52
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Finite element modeling of effective permittivity in nanoporous epoxy composite filled with hollow nanosilica
摘要： The relative permittivity of nanoporous epoxy composites (NPCs) filled with hollow nanosilica is lower than that of unfilled epoxy resin. The low permittivity is considered to arise from the existence of cavity volume, but the effects of nanosilica particle shape, particle size distribution and agglomeration are not clear. In this study, the relative permittivity of an NPC filled with hollow nanosilica is modeled by using finite-element method including the above-mentioned factors. The proposed model successfully reproduces the experimentally-obtained low permittivity of NPCs. The effect of cavities is significant, while particle corner shape, particle size distribution or particle agglomeration is not dominant.
关键词： epoxy,permittivity,nanoporous composite,hollow nanosilica
更新于2025-09-16 10:30:52