Highly Thermally Stable, Reversible, and Flexible Main Chain Type Benzoxazine Hybrid Incorporating Both Polydimethylsiloxane and Double‐Decker Shaped Polyhedral Silsesquioxane Units through Diels–Alder Reaction

Abstract

AbstractThis work synthesizes a new bifunctional furan derivative (PDMS‐FBZ) through a sequence of hydrosilylation of nadic anhydride (ND) with polydimethylsiloxane (PDMS), reaction of the product with p‐aminophenol to form PDMS‐ND‐OH, and its subsequent Mannich reaction with furfurylamine and CH2O. Then, the main chain‐type copolymer PDMS‐DABZ‐DDSQ is prepared through a Diels–Alder (DA) cycloaddition of PDMS‐FBZ with the bismaleimide‐functionalized double‐decker silsesquioxane derivative DDSQ‐BMI. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirm the structure of this PDMS‐DABZ‐DDSQ copolymer; differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) reveal it to have high flexibility and high thermal stability (Tg = 177 °C; Td10 = 441 °C; char yield = 60.1 wt%); contact angle measurements reveal a low surface free energy (18.18 mJ m−2) after thermal ring‐opening polymerization, because the inorganic PDMS and DDSQ units are dispersed well, as revealed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). This PDMS‐DABZ‐DDSQ copolymer possesses reversible properties arising from the DA and retro‐DA reactions, suggesting its possible application as a functional high‐performance material.