S1.4. General characterizations
The fourier transform infrared spectra (FT-IR) were recorded on a Nicolet Is50 spectrometer (U.S.A) equipped with an attenuated total reflectance (ATR) model. The nuclear magnetic resonance spectroscopy of 1H,13C and 31P (1H-NMR, 13C-NMR,31P-NMR) was performed using a Bruker Avance 400 MHz spectrometer. The concentration of hydroxyl groups was determined by a titration experiment in accordance with GB/T 7383-2007 (Chinese standard). XRD patterns of the cured thermoset samples was acquired on a Bruker XRD machine (D8 DISCOVER A25). The transmission electron microscope (TEM, FEI Talos F200X) equipped with an energy dispersive spectrometer (EDS, Thermo NS7) microanalyzer was used to observe the distribution and aggregate state of HBPSi-R within the resin, with the cured sample cut by LEICA UC7 freezing microtome at room temperature first, then staining by a phosphotungstic acid (1 wt.% aqueous solution, 2 h).
The mechanical properties were performed on an electro-mechanical tester (CMT 6303) in accordance with GB/T 2567-2008 (Chinese standard), with the sample dimension of 80 mm × 15 mm × 4 mm for flexural test and 80 mm × 10 mm × 4 mm for impact test. Dynamic thermomechanical analysis (DMA) was conducted using a three-point bending model on a NETZSCH DMA 242E machine at the frequency of 1 Hz. Differential scanning calorimetry was performed under nitrogen (N2) atmosphere using a Mettler-Toledo DSC3 at a heating rate of 15 K·min-1. Thermogravimetric analysis (TGA) was performed under N2atmosphere using a STA 449F3 thermal analyzer with a heating rate of 15 °C·min-1. The morphology of impact fracture surface was observed by a Scanning Electron Microscope equipped with a tungsten filament gun (TESCAN VEGA 3 LMH).