Low-dielectric silylbutylene-benzocyclobutene resin with photoactive silacyclobutane groups via acyclic diene metathesis polymerization

UV-curable resins with low dielectric constant can be processed or patterned to form required shapes, making them highly applicable to special fields. In our previous study, UV-curable siloxane-benzocyclobutene resins were synthesized, but their dielectric constants were relatively high. In this work, silylbutylene-benzocyclobutene oligomers (ADM-PBSC) were synthesized by acyclic diene metathesis (ADMET) polymerization of 1,1-dibutenylsilacyclobutane monomers with benzocyclobutene terminated groups. In this way, siloxane moieties were replaced by silylbutylene groups to further reduce dielectric constant while preserving UV curable properties. The UV/thermally cured ADM-PBSC exhibited good mechanical properties and high thermal stability. Furthermore, the cured resins showed low dielectric constants (2.49 at 10 MHz) and low dielectric losses (10(-3) at 10 MHz). Good comprehensive properties of ADM-PBSC may be attributed to its UV/thermally dual cross-linked structure.