Double organic groups‐containing polyhedral oligomeric silsesquioxane filled epoxy with enhanced fire safety

Abstract To simultaneously improve the flame retardancy, smoke suppression, mechanical properties, and dielectric properties of epoxy resin (EP), a series of polyhedral oligomeric silsesquioxane containing vinyl and epoxy groups (EV‐POSSs) was designed and successfully synthesized. The results of Fourier transform infrared (FT‐IR), Nuclear Magnetic Resonance (NMR) and mass spectra indicated that the EV‐POSSs possessed two main cage structures, T 10 and T 12 . The epoxy groups attaching to POSS connected the polymer main chains, forming higher crosslinking‐density networks. The self‐polymerization of vinyl groups under high temperatures improved the mechanical property and the quality of char residues. Based on our study, the introduction of EV‐POSSs can enhance the flame retardancy, smoke suppression, mechanical and dielectric properties. Compared with pure EP, the dielectric constant of EP containing 2 wt% EV‐POSS dropped from 3.9 to 3.6 at 10 6 Hz. In addition, with the 10 wt% EV‐POSSs, the peak of heat release rate and total smoke production also reduced by 50.7% and 36.7%, respectively. Most notably, the maximum smoke density declined by 44.8% due to the EV‐POSSs simultaneously containing epoxy and vinyl groups show comprehensive enhancement and occupy spacious applications.