Branched Silicone Acrylates Enhanced Photocurable Epoxy Resins with High Strength, Toughness, and Low Dielectric Constant for SLA 3D Printing

High strength and low dielectric constant materials are highly desirable in the areas of electronics and communication. In this work, two kinds of multifunctional branched silicone acrylates (DQEA and QSIEA) were designed and synthesized from 2,4,6,8-tetramethylcyclotetrasiloxane and tetrakis (dimethylsiloxy)silane in a concise synthetic route. Owing to the enhanced flexibility and cross-linking networks provided by the branched organosilicone, the elongation at break and impact strength of modified epoxy resins significantly increased by more than 20% with the introduction of 7.5 wt % DQEA or QSIEA, whereas no visible loss of the tensile strength was observed. The resultant photocurable materials also displayed good thermal stability with a nearly 50 °C increase of the initial thermal decomposition temperature (Td5%) according to the thermogravimetric analysis. Furthermore, benefiting from the intrinsic properties of silicone, the DQEA contained epoxy resins that exhibited high hydrophobic properties (contact angle >90 °C) and great dielectric properties (dielectric loss by 40% at the frequency of 10 MHz). This facile preparation strategy is finally applicable for the 3D printing of PCB circuit boards in high fabrication resolution and precision, displaying considerable potential applications in electronics and other related fields.