Synthesis and properties of LED-packaging epoxy resin toughened by a novel polysiloxane from hydrolysis and condensation

Abstract

A novel polysiloxane (G x D y ) containing a large number of epoxide groups and flexible segments was synthesized by hydrolysis and condensation of 3-glycidoxypropyl trimethoxysilane (GPTMS) and dimethyldiethoxylsilane (DMDES) to toughen the 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ERL-4221). The chemical structures of G x D y (molar ratio of GPTMS to DMDES is x/y) were confirmed by Fourier transform infrared spectroscopy (FTIR), 29 Si nuclear magnetic resonance spectroscopy (NMR), and gel permeation chromatography (GPC), and G 4 D 6 have the highest degree of branching. The thermal and mechanical properties, morphologies and transmittance of the cured epoxy resins were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile testing, fracture testing, SEM, and UV-vis spectroscopy. The T g of the G x D y modified epoxy depends on the structure and addition content of G x D y . The TGA results under a N 2 demonstrate that the thermal stability of the epoxy resin was improved by G x D y and the Si-(O-) 3 from the GPTMS part forms silica more easily than the Si-(O-) 2 from the DMDES part. The addition of 10 phr G 4 D 6 resulted in greatly improved toughness, but maintained the transmittance of the epoxy resin. In addition the morphology of the fracture surfaces showed that G x D y can be dispersed homogeneously in the epoxy resin, and the toughening follows the pinning and crack tip bifurcation mechanism. In conclusion, G x D y can increase the toughness and thermal properties of the ERL-4221 system simultaneously, and maintain its transmittance. Therefore, G x D y can be used as a toughening agent for light emitting diode (LED)-packaging epoxy resins.

Triphenylphosphine‐containing microcapsules fabricated from Pickering emulsions as a thermal latent curing accelerator for an epoxy/anhydride system

“…Thermosetting epoxy resins have been widely utilized in various industrial applications, such as adhesives, 1 coatings, 2 automobiles, 3 electronics, 4 architecture 5 and aerospace, 6 owing to their remarkable mechanical and chemical properties. In electronic packaging, an acid anhydride is commonly used as a curing agent, 7 and epoxy resin cured with an acid anhydride exhibits better thermal and dielectric performance than that cured with amines and imidazole.…”

Thermal latent curing agent for epoxy resins from neutralization of 2‐methylimidazole with a phosphazene‐containing polyfunctional carboxylic acid

“…Epoxy resin (EP) is one of the most important thermosetting resins globally, which is now broadly applied in various fields, such as coatings, adhesives, and flip chip encapsulation, for its excellent mechanical and thermal properties, as well as chemical resistance after being crosslinked into three‐dimensional networks . Curing agents are vital in the curing process, which greatly determine the final network architecture as well as the properties of the thermosets .…”

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

“…Epoxy resins have typically been used as packaging materials owing to their characteristics of excellent sealing, high insulation resistance, and good mechanical properties. However, with the increase of LED device power, the respective shortcomings of epoxy resins such as low thermal stability against yellowing were revealed gradually, which is unable to meet the requirement of the high‐power white LED encapsulants . Owing to the high transmittance as well as excellent thermal resistance, silicone resins have currently been considered to be an outstanding packaging material.…”