Organic–Inorganic Hybrid Ladder-like Polysilsesquioxanes as Compatibilized Nanofiller for Nanocomposite Materials

Nanocomposite materials composed of an organic matrix and an inorganic nanofiller have been the subject of intense research in recent years. Indeed, the synergy between these two phases confers improved properties thanks to an increased surface-volume ratio, which reinforces the interactions between the particles and the polymer matrix. These interactions depend on many factors such as the shape, size and dispersion of the nanoobjects. Polysilsesquioxanes (PSQs) are a silicon polymer family that offers different sizes, shapes and structures and possesses ceramics properties (i.e., high thermal and/or oxidative resistance and high chain rigidity), thanks to the siloxane backbone. In this article, we propose to incorporate polymer-grafted ladder polysilsesquioxanes (LPSQs) as nanofillers in thermoplastic matrices. Chloride-functionalized LPSQs were synthesized from two different precursors and thoroughly characterized by ¹H, ¹³C and ²⁹Si NMR, as well as by SEC and WAXS. The well-defined LPSQ was then converted into an azide analog. The resulting hybrid material was functionalized with poly(ethylene glycol) (PEG) chains and incorporated into poly(ethylene oxide) or poly(methyl methacrylate) matrices. We found that the viscoelastic properties of the nanocomposite materials were impacted by plasticizing or the reinforcement effect depending on the grafted PEG chain length.