Effect of Chain Flexibility of Epoxy Encapsulants on the Performance and Reliability of Light-Emitting Diodes
writer：Zhuo Chen, Zhuoyu Liu, Gebin Shen, Ruiheng Wen, Jie Lv, Jizhen Huo, Yingfeng Yu*
keywords：Chain flexibility, Epoxy packaging materials, LED devices, Reliability.
source：期刊
specific source：Ind Eng Chem Res 2016, 55 (28), 7635-7645
Issue time：2016年
In this work, cycloaliphatic epoxy resin (3-4-epoxycyclohexane) methyl 3-4-epoxycyclohexyl-carboxylate (ECC) was formulated with flexible hydrogenated bisphenol A diglycidyl ether (HBADGE) to investigate the effect of chain flexibility on the performance and reliability of epoxy packaged Light-emitting Diode (LED) devices. The properties of epoxy packaging materials were characterized by using differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), dynamic mechanical analysis (DMA), thermomechanical analyzer (TMA), ultraviolet visible spectrophotometer (UV?vis), scanning acoustic microscopy (SAM), and scanning electron microscopy (SEM). With the incorporation of flexible HBADGE, favorable properties were obtained, such as decreased coefficient of thermal expansion (CTE), lowered storage modulus at reflow temperature, and depressed equilibrium water uptake of the epoxy resins. The light transmittance of epoxy packaging materials varied after thermal and UV aging. Compared with Neat ECC and Neat HBADGE, the HBADGE-modified materials endowed LED devices with good performance in both reliability test and aging test.