Effect of cross-link density on optoelectronic properties of thermally cured 1,2-epoxy-5-hexene incorporated polysiloxane

摘要

The synergesic effect from copolymerising polysiloxane and epoxy functionality offer a viable encapsu-lant material for use in electronic devices. A series of epoxy group-containing organopolysiloxane without ether bond spacer was prepared. The cross-link density was progressively monitored by controlling the mole ratio of the epoxy monomer. Thermal, optical, dielectric and hardness properties were measured and related to the cross-link density. The crosslink density affect an increase in refractive indices in the range 1.4359-1.4655 and dielectric constants in the range 2.78-3.34 at 500 MHz. Transparency were in the range 60-80% in visible region. A higher crosslink structure displays an improved transparency in the UV-visible region. These observations were related to changes in free volume and group polarizability and discussed within the scope of Lorentz-Lorenz relationship.