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).