The Silicone Materials Modified With POSS For LED Packaging

Compared with tradition lighting device, light-emitting diode(LED) exhibits various advantages, such as higher luminosity at low currents and voltages, longer service life, and environmental friendliness. Because of these favorable characteristics, LED is becoming more and more widespreadly. LED device made up with chips, wires, brackets, conductive adhesives and packaging materials. The function of the packaging materials is to protect the chips. The packaging materials have become one of the most important factors for LED device. The packaging materials should have high transparency and good antiultraviolet ability.At present, packaging materials of common LED device are mainly of epoxy resins. But the epoxy resins have several disadvantages. At first, epoxy resins will turn yellow after using a content of time, which will decrease the transmittance. Secondly, the higher thermal resistance of epoxy resin leads to the rapid rise of the chip’s temperature and accelerates the decay of the LED devices. What is worse, the rapid thermal expansion will make the device open circuit.Silicone materials are ideal packaging materials for LED because of their outstanding performances. In this thesis, the octavinylpolyhedral oligomeric silsesquioxane (OVPOSS) and eight poly four methyl ammonium silicate were prepared to modified the vinyl silicone oil via ring opening polymerization. Then the vinyl silicone oil mixed with a certain proportion of hydrogen silicone oil, platinum catalyst and cured. The results are as follows:(1)Ring-opening copolymerization of OVPOSS with D3to prepare the POSS modified vinyl silicone oil. The features of the copolymerization were investigated symatically. Then the modified vinyl silicone oil、hydrogen-contained silicone oil and platinum catalyst were mixtured to prepared silicone materials for LED packaging. The hardness of the material is in the range of0-30Shore A.(2)The TMAOH is the catalyst for the ring-opening copolymerization of D4and DnMe,Ph for preparing high refractive modified vinyl silicone oil. The copolymerization was investigated in detail. Then the vinyl silicone oil, hydrogen-contained silicone oil and platinum catalyst were mixtured together to prepare silicone materials for LED packaging. The hardness of the material is from20Shore A to40Shore A.(3)The tetramethylammonium silicate octamer is the catalyst to initiate ring-opening polymerization of D4to prepare the vinyl silicone oil like star. The ring-opeing polymerization were studied in details. Then vinyl silicone oil produced, hydrogen-contained silicone oil and platinum catalyst were mixtured to prepare materials for LED packaging. The hardness of the material is too low to use. MQ resin was added as reinforcement agents, then a kind of packaging materials with good mechanical properties, good toughness, high transmittance for LED packaging were produced.(4)The ring-opening copolymerization of D4and DnMe,Ph were initiated by the tetramethylammonium silicate octamer to prepare the high refractive vinyl silicone oil like star. Then vinyl silicone oil, hydrogen-contained silicone oil and platinum catalyst were mixtured to prepare silicone materials for LED packaging. The materials obtained were with the good toughness but low hardness. Therefore, high refractive MQ resin was added as reinforcement agent, and silicone materials with good mechanical properties, good toughness and high transmittance were obtained for LED packaging.