Preparation of polyborosiloxanes with systematically changed mechanical properties and correlation of their structure/property relationship

Abstract Polyborosiloxanes (PBSs) are an important class of polymer as they serve as the platform for developing dynamic networks with versatile viscoelastic properties. However, an effective and systematic way to tuning the properties of these polymers is still lacking. Here in this work, we report a new method to preparing PBSs with versatile properties. By increasing the degree of polymerization of boronic acid end‐functionalized polydimethylsiloxane, a series of well‐defined PBSs with different mechanical properties were obtained. Various instruments such as Fourier transform infrared (FT‐IR) spectrometer, nuclear magnetic resonance (NMR) spectrometer and rheometer have been used to characterize the obtained products. By looking into the results we found rheological behaviors of these samples were closely related to their specific microstructures, shear stiffening of these polymers were directly related to the dynamics of hydrogen bonds rather than dative BO bonds. These new findings provide important insights for the development of PBSs with desired properties.