Optical properties of modified epoxy resin with various oxime derivatives in the UV-VIS spectral region (original) (raw)
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Two polymers were prepared from diglycidyl ether of bisphenol A (DGEBA) and triglycidyl p-aminophenol (TGAP) epoxy resins, using the same hardener diethylenetriamine (DETA). The obtained polymers were compared in terms of structural, optical, mechanical, thermal and dielectric properties. Dielectric spectroscopy and dynamic mechanical analysis indicated the presence of dipolar dielectric relaxations in both polymers, and interfacial one only for TGAP/DETA, which is consistent with XRD findings. Different approaches were considered to fit electrical modulus and conductivity and to estimate the relaxation times and activation energies according to temperature. For optical measures, a novel result processing approach is proposed for an accurate determination of the polymers bandgap and for highlighting the existence of additional energy transition level for TGAP. Results indicate that this polymer could be a potential candidate for use as a protective film and as UV/ blue-light filter for screens and windows.
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Polymer Photochemistry, 1982
The spectroscopic properties of various commercial epoxy resins are examined using infra-red, fluorescence~phosphorescence and ultraviolet visible derivative techniques. Infra-red studies on the uncured resins and hardeners show the presence of impurity carbonyl chromophores but their chemical nature appears to be very dependent upon the resin/hardener type. All the hardeners examined exhibit very weak fluorescence, the origin of which is unknown and those hardeners containing an alkyl phenol accelerator give strong phosphorescence. All the uncured resins examined exhibit very intense phosphorescence, due to the Bisphenol A component, while the cured resins gave emission due to a triplet eximer. Ultraviolet visible derivative absorption spectroscopy showed the presence of impurity chromophores, probably quinone in type, which absorb light wavelengths > 300 nm. The results are discussed in relation to the known light stabilities of the resins and their ability to sensitise the photofading of dyestuffs.
Journal of Sol-Gel Science and Technology, 2006
A hybrid material system consisting of (3glycidyloxypropyl)trimethoxysilane, dimethyldimethoxysilane and zirconium(IV) n-propoxide was prepared. The influence of processing parameters including Zr content, UV irradiation and sol ageing on the properties of the resultant thin films was discussed. Refractive index, at 633 nm, and reflectance measurements were performed and near-field waveguide images of the samples were taken. Optical propagation loss measurements, at 633 nm, were studied. Film thickness and cross-sectional scanning electron microscopy images were obtained as a function of process conditions. FT-IR spectroscopy was used to monitor chemical reaction pathways in the system during processing. It was demonstrated that the crosslinking of epoxy groups in the structure, along with inorganic network formation as a result of sol-gel reactions, was the primary reason for the changes in the optical and physical properties of the system. As Zr containing species and/or UV irradiation may be employed to crosslink the epoxy groups in the structure, the optical and physical properties of the system can be tuned by optimal combination of these two crosslinking methods, as well as sol ageing process.
Optical Properties of Dy3+ Doped Epoxy Novolak Resin
Proceedings of SPIE, …, 2008
We report about properties of epoxy novolak resin polymer doped with dysprosium ions. The polymer layers were fabricated by spin-coating onto silicon substrates, or pouring epoxy novolak resin solution into bottomless molds placed on a quartz substrate and leaving them to dry. Rather strong bands around 3366 cm-1 in the infrared spectra indicated presence of the O-H groups. Absorption measurements were done in the spectral range from 300 nm to 3000 nm and showed six strong bands at 758 nm (6 F 3/2), 807 nm (6 F 5/2), 906 nm (6 F 7/2), 1100 nm (6 F 9/2), 1280 nm (6 F 11/2) and 1685 nm (6 H 11/2) corresponding to Dy 3+ ions. Optical band gap E g was determined from the absorption coefficient values using Tauc's procedure, i.e., from the relationship αhv = A(hv − E g) 2 and the obtained values varied from 3.489 eV to 3.539 eV depending on the amount of dysprosium ions involved in the samples. Photoluminescence spectra around 1300 nm were investigated by using excitation of He-Ne laser (632.8 nm) and two semiconductor lasers (980 nm and 827 nm).
Materials (Basel, Switzerland), 2017
Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV) damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR) analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM) imaging. Additionally, the glass transition tempera...
Photochemical changes in absorption and fluorescence of DDM-containing epoxies
Polymer, 2018
Photochemical changes in the optical characteristics of solid polymers form the basis for many important technologies, but few examples are demonstrated in diamine-cured epoxy, one of the most important structural polymer systems. We have observed that diamine-cured epoxies containing the 4,4 0-diaminodiphenyl methane (DDM) framework display changes in both absorption and fluorescence in response to UV light. The change from original "blue" to photo-activated "red" emission can be accomplished by illuminating samples of DDM-containing epoxy with photons of 254 nm or 370 nm wavelengths, followed by excitation of the newly-generated red-emitting fluorophore with 350e400 nm light. Studies of the monomer constituents and of many formulations of diamine-cured epoxy identify the DDM structure as the responsive moiety, both from the epoxy or diamine monomer. The fluorescence change is accompanied by the formation of orange and green chromophores; the orange chromophore is the fluorophore, with a broad 410 nm excitation and 607 nm emission. Our work shows the "blue-to-red" transition to be irreversible and independent of atmospheric oxygen; the fluorophore's impermanence with time and its radical spectral signature identify it as a reactive intermediate rather than a photooxidation product. The central methylene radical of the benzoidal DDM structure is proposed as a redemitting fluorophore/orange chromophore, with the green chromophore being a quinoidal methine resulting from the DDM radical.
Study the optical properties of Rhodamine C doped in epoxy resin prepared with casting method
THE 9TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2021)
We prepared solid-laser-medium samples by mixing Rhodamine C dye dissolved in chloroform at different concentrations (1 × 10 −4 , 7 × 10 −5 , 5 × 10 −5 , 3 × 10 −5 and 1 × 10 −5 mol/l) with epoxy resin as a polymer matrix at an appropriate volume ratio. The samples' photophysical properties were examined by obtaining absorption and fluorescence spectra and calculating the fluorescence quantum yield, optical energy gap (Eg), absorption coefficient (α) and extinction coefficient (K). The relationships amongst these parameters were also determined. Results showed a red shift in the peaks of the samples with increased concentration of doped RC dye, and their absorption and fluorescence intensities increased. This result agreed with Beer-Lambert's Law. Moreover, Eg values decreased with increased concentration of doped dye, i.e., 3.42, 3.43 and 3.44 eV for the concentrations of 1 × 10 −4 , 7 × 10 −5 and 5×10 −5 mol/l, as well as 3.38 and 3.39 eV for the concentrations of 3 × 10 −5 and 1 × 10−5 mol/l, respectively. However, α and K increased and red shifted with increased concentration of doped RC dye.
Optical properties of bi‐doped epoxy novolak resin containing Ce, Dy, and Y ions
Journal of Applied Polymer Science, 2012
In this article, we report on the optical properties of Bismuth doped Epoxy Novolak Resin (ENR) co‐doped with Dysprosium, Cerium, and Yttrium ions. The polymer layers containing 1.0 to 20.0 at % of Bismuth were fabricated by spin‐coating onto silicon or quartz substrates. The properties of the material were studied using several methods with special regards to its potential utilization in photonics devices. Transmission spectra were taken in the range from 350 to 1600 nm, while photoluminescence spectra around 1300 nm were recorded by using excitation of semiconductor lasers operating at 808 nm and at 980 nm (Ex = 250 mW). Optical properties of the samples were evaluated on the bases of the concentration of the Bismuth ions as well as on the concentrations of the co‐doping ions and showed close relations between concentration of the dopants and intensity of the luminescence band at 1300 nm. Our results proved that the Bismuth doped ENR has a strong potential for application in activ...
Thermo-mechanical and Light Transmittance of Silica Diffusant Filled Epoxy Composites
Epoxy ternary blends (DCN) were prepared by mixing diglycidyl ether bisphenol A (DGEBA), cycloaliphatic epoxy, and novolac epoxy. The silica diffusants were prepared by the addition of spherical silica (SS) into epoxy blends. The thermal properties of the epoxy composites were characterised using a thermo-mechanical analyser (TMA), a differential scanning calorimeter (DSC), and a dynamic mechanical analyser (DMA). It was found that the storage modulus of the epoxy was increased in the presence of SS diffusants. However, the coefficient of thermal expansion (CTE) and the glass transition temperature (Tg) of the epoxy ternary blends was reduced by the addition of SS diffusants, which was because the expansion of the epoxy matrix was constrained in the presence of silica fillers. The UV/Vis spectroscopy results demonstrated that the percentage of transmittance of epoxy was decreased by the incorporation of the silica diffusant.
Photopolymerization of an Epoxy Resin: Conversion and Temperature Dependence of its Refractive Index
Macromolecular Chemistry and Physics, 2016
Obtaining photocomposite materials with predefi ned optical properties requires a good knowledge of the refractive index evolution of the photopolymerizable media. In this aim, relationships between refractive index and conversion in the course of an epoxy resin photopolymerization are fi rst established due to real time refractometric and infrared spectroscopic techniques. Refractive index value increases with conversion as long as the photocured material is not in glassy state. A shift of the relationship toward lowest refractive index values is observed when the reaction temperature increases. Second, the fi nal photocured materials previously obtained are characterized. It is highlighted that the higher the photocuring temperature, the higher the epoxy conversion but the lower the material density at room temperature. This unusual result can be explained by the evolution of the material thermo-optic coeffi cient, d n /d T. Indeed, the higher the conversion, the lower this coeffi cient.