Fast Degradable and Thermally Conductive Silicone Rubber Vitrimer with Low Dielectric and UV-Shielding Properties

Silicone rubbers are widely employed in various fields such as electronics, electrical engineering, mobile communications, aerospace, and automotive industries. However, silicone rubbers are typically challenging to reprocess and degrade. Moreover, with the advancement of technology, higher demands are placed on its thermal conductivity and dielectric properties. In this study, diglycidyl ether terminated polydimethylsiloxane is cured by 4,4′-dithiodibutyric acid which contains dual dynamic covalent disulfide and ester bonds with triazobicyclodecene as the ester exchange catalyst to prepare silicone rubber vitrimers (SRVs) through a casting method. The SRVs demonstrate a relatively higher intrinsic thermal conductivity of 0.26 W (m⁻¹ K⁻¹) compared to ≈0.20 W (m⁻¹ K⁻¹) of conventional silicone rubber. Besides, the SRVs exhibit very low and stable dielectric constant and dielectric loss at both low and high frequencies (X-band). The lowest dielectric constant and dielectric loss tangent at 10 GHz are 2.75 and 0.0650, respectively. Besides, the dual dynamic covalent bonds enable the SRVs to have excellent reprocessability and fast degradability. Moreover, the SRVs reveal UV-shielding capability, as the transmittance of the SRVs is 0% from 200 to 400 nm of UV light.