Cross-Linking Behavior and Effect on Dielectric Characteristics of Benzocyclobutene-Based Polycarbosiloxanes

The cross-linked low-dielectric-constant material has garnered much attention in the rapid development of advanced electronics packaging. However, few studies have systematically explored the effects of cross-linking density and cross-linking degree on dielectric properties of benzocyclobutene (BCB)-based polymeric materials. Herein, a series of BCB-based polycarbosiloxanes with varying cross-linking densities were synthesized through Piers–Rubinsztajn polycondensation and post-Heck modification. The relationship between cross-linking behavior and the dielectric characteristics of cured materials was systematically explored using both molecular dynamics (MD) simulation and experimental verification. The results revealed that higher cross-linking density and cross-linking degree resulted in more microbranched structures, which effectively reduced the dielectric constant and dielectric loss of the materials. Moreover, high cross-linking density enhanced the thermal and dimensional stability and enabled a facile tuning of the mechanical property of the materials. Overall, our work offered a facile route to realize cross-linking process of BCB-based polymeric materials by MD simulation and to investigate the relationship between cross-linking and comprehensive performances, providing a valuable theoretical and experimental basis for the study of cross-linked low-dielectric-constant material.