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Zhao M.,Tianjin University | Feng Y.,Tianjin University | Li Y.,Tianjin University | Li G.,Tianjin University | And 4 more authors.
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry | Year: 2014

1,3,5,7,9,11,13-heptaphenyl-15-vinyl cage half siloxane (Phenyl-Vinyl-POSS) was synthesized via the corner capping reaction of incompletely condensed silsesquioxane, [(C6H5)7Si7O 9(OH)3], with trichlorovinylsilane. The chemical structure of Phenyl-Vinyl-POSS was characterized by FT-IR, 1H-NMR, mass spectrometry and elemental analysis. Phenyl-Vinyl-POSS/ATC silicone rubber organic-inorganic hybrid materials were prepared by hydrosilylation between Phenyl-Vinyl-POSS and addition-type curable (ATC) silicone rubber with karstedt platinum catalyst. These hybrid materials were characterized through SEM, IR, XRD, TGA, DSC and tensile test. The results indicate that Phenyl-Vinyl-POSS is successfully incorporated into silicone rubber matrix by chemical bonding. Both mechanical properties and thermal properties of Phenyl-Vinyl-POSS/ATC silicone rubber hybrid materials have been improved compared to neat silicone rubber. The hardness of Phenyl-Vinyl-POSS/ATC silicone rubber hybrid materials increases from 18A to 28A, tensile strength increases from 0.2 MPa to 0.64 MPa, and the elongation at break increases from 14.12% to 184.39% when Phenyl-Vinyl-POSS content is up to 10 wt%. Meanwhile, temperature with 5% decomposition of modified ATC silicone rubber increases from 344.1°C to 360.4°C. © 2014 Copyright © Taylor & Francis Group, LLC.


Zhao M.,Tianjin University | Feng Y.,Tianjin University | Li Y.,Tianjin University | Li G.,Tianjin University | And 4 more authors.
Journal of Macromolecular Science, Part A: Pure and Applied Chemistry | Year: 2014

A novel inorganic-organic siloxane hybrid material with self-adhesion ability and high refractive index for high-power light emitting diodes (LEDs) encapsulation is introduced. Under the catalysis of an anion exchange resin, the hybrid material was synthesized by a sol-gel condensation process from methacryloxy propyl trimethoxyl silane (MPTS), γ-(2, 3-epoxypropoxy) propytrimethoxysilane (EPTS) and diphenylsilanediol (DPSD). This hybrid material was characterized by Fourier-transform infrared spectroscopy and 1H-NMR. The resin-type encapsulation material was then prepared by hydrosilylation of the newly synthesized inorganic-organic siloxane hybrid material and methylphenyl hydrogen-containing silicone resin. The cured silicone resin-type encapsulation material can be used as a LEDs encapsulant, owing to high refractive index (n = 1.544), high transparency, appropriate hardness, and excellent thermal stability, as well as good adhesive strength between the encapsulating material and the substrate of LED lead frame. © 2014 Copyright © Taylor & Francis Group, LLC.


Zhao M.,Tianjin University | Feng Y.,Tianjin University | Li G.,Tianjin University | Li Y.,Tianjin University | And 4 more authors.
Polymers for Advanced Technologies | Year: 2014

Addition-cure silicone resin is considered as a good choice for light emitting diodes (LEDs); however, it has very poor adhesion to the substrate, which limits its practical application. A novel polysiloxane with self-adhesion ability and higher refractive index for the encapsulating of high-power LEDs is prepared and characterized. This polysiloxane containing vinyl groups, phenyl groups, and epoxy groups was synthesized by a sol-gel condensation process from methacryloxy propyl trimethoxyl silane, γ-(2,3-epoxypropoxy)propytrimethoxysilane, and diphenylsilanediol under the catalysis of an anion exchange resin. Then, the resin-type encapsulation material was prepared by hydrosilylation of methylphenyl hydrogen-containing silicone resin and the newly synthesized polysiloxane material. The novel polysiloxane was characterized by 1H-NMR and Fourier transform infrared spectroscopy. On the basis of higher refractive index, higher transparency, excellent thermal stability, and appropriate hardness, as well as good adhesive strength between the encapsulating material and the LED lead frame (polyphthalamide), the curable silicone resin-type encapsulation material can be used as an encapsulant for LEDs. © 2014 John Wiley & Sons, Ltd.

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