Study of thermal and optical properties of epoxy/organically modified silicate hybrids

Abstract

Three epoxy resins were examined in this study: Eporite-901 (474 g/eq), Eporite-904 (807 g/eq) and Eporite-909 (1915 g/eq), which are bisphenol-A-type epoxy resins. In this study, we used an amine terminated organically modified silicate (Ormosil) that was compatible with the diglycidyl ether of bisphenol-A epoxy to partially replace the epoxy resin at various ratios, cured by hexahydrophthalic anhydride (HHPA). The thermal and optical properties of the Ormosil-modified epoxy resins (Epoxy/Ormosil) were studied. The M n and M w of the resulting hybrids were in the range of 10668-31450 and 30617-120422, respectively, with a polydispersity index range of 2.870-3.829. The thermogravimetric analysis (TGA) results implied that Ormosil can raise the crosslink density and enhance the thermal properties. The optical properties were measured after curing and thermal aging of the polymer films with thickness around 8-10 mm. The refractive indexes of the Epoxy/Ormosil hybrids were 1.62-1.68, and the transmittances of the cured composites were above 85% in the visible wavelength.The key attributes of Epoxy/Ormosil hybrids that make them attractive materials for LEDs including their high transparency in the UV-visible region, controlled refractive index (RI), and excellent thermal resistance.

Preparation of polyoxometalate-doped aminosilane-modified silicate hybrid as a new barrier of chem-bio toxicant

“…So, if a chemical warfare agent (CWA) with an oxidizable group, such as the sulfur atom in sulfur mustard (HD), was to come into contact with the POM solution, the POM would be reduced (and the HD oxidized). In the literature survey, Ormosil materials have already been found to have many promising applications in the fields of optics, electronics, mechanics, energy, environment, biology and medicine [32][33][34]. Recent reports have described the immobilization of POMs and transition metal-substituted POMs on various supports, including porous silica [23], carbon [24,25], metal-organic frameworks [26], titania [27], polymers [28,29] and organic-inorganic hybrid materials [30,31], through an organic linker, and explored their use in various organic transformations.…”

High refractive index adamantane‐based silicone resins for the encapsulation of light‐emitting diodes

“…In general, the transmittance of LED encapsulation materials is related to realization of high‐luminescence efficiency and the reliability of semiconductor devices . Figure shows the transmittances of the encapsulants measured by a spectrophotometer from 400 to 800 nm.…”

Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses

“…Polyurethane (PU) materials are also candidates for the encapsulation of LEDs and organic LEDs (OLEDs) in particular due to their excellent properties for lens formation by evaporative polymer droplet deposition and imprint processes [13,14]. Furthermore, silicone [4,15,16] and silicone hybrid materials, like epoxy-silicone resins [17][18][19][20] and sol-gel based siloxane [21][22][23][24] are widely used. The disadvantages of most conventional polymers are that they are hard and brittle because they have rigid cross-linked networks and decompose under the influence of radiation and high temperature, which leads to chain splitting and discoloration [6][7][8]10,17].…”

“…Furthermore, silicone [4,15,16] and silicone hybrid materials, like epoxy-silicone resins [17][18][19][20] and sol-gel based siloxane [21][22][23][24] are widely used. The disadvantages of most conventional polymers are that they are hard and brittle because they have rigid cross-linked networks and decompose under the influence of radiation and high temperature, which leads to chain splitting and discoloration [6][7][8]10,17]. Silicone resins, on the other hand, have a high thermal stability, UV resistance and are highly transparent in the UV spectral range, but they are relatively soft and have poor adhesion properties [15,16,17].…”

“…The disadvantages of most conventional polymers are that they are hard and brittle because they have rigid cross-linked networks and decompose under the influence of radiation and high temperature, which leads to chain splitting and discoloration [6][7][8]10,17]. Silicone resins, on the other hand, have a high thermal stability, UV resistance and are highly transparent in the UV spectral range, but they are relatively soft and have poor adhesion properties [15,16,17]. A further drawback of silicone resins is the refractive index matching of the silicone with respect to the LED material.…”