Rheological and Thermal Analysis of Polyborodimethylsiloxane (PBDMS) Gels: Investigating Dynamic Bonding and Energy Dissipation Mechanisms

Polyborodimethylsiloxane (PBDMS) gels, characterized by dynamic SiOB and BOB bonds, exhibit unique vitrimeric behavior, blending mechanical robustness with recyclability. This study investigates how precursor molecular weight influences their rheological, thermal, and energy dissipation properties. Gels were synthesized using PDMS precursors of varying viscosities (150–1000 cSt) and analyzed via FTIR, TGA, DMTA, DSC, and rheometry. Results reveal that lower molecular weight precursors enhance dynamic cross‐link density, yielding superior energy dissipation and stiffness, as evidenced by the glassy region storage modulus (500 MPa for SV150 vs. 99 MPa for SV1000) and terminal zone storage modulus (1.4 MPa for SV150 vs. 0.18 MPa for SV1000). PBDMS exhibits improved thermal stability compared to pure PDMS, enhancing its resistance to thermal degradation (degradation onset: 416°C for SV150 vs. 310°C for pure PDMS). DMTA and DSC analyses confirm dual associative‐dissociative vitrimer mechanisms, with reversible dative bond formation under stress driving rearrangement bond phenomena. These findings advance the design of adaptive materials for impact‐resistant systems, self‐healing applications, and sustainable polymer engineering.