Disentangelment in Polymer/POSS Nanocomposite Blends

In the melt state of nanocomposites, rheological behavior is dictated by complex and often non-intuitive interactions between components. Many nanocomposites with relatively large and hard fillers show rheological jamming, which prevents terminal flow on long timescales and makes processing these advanced materials challenging. In contrast, polymers loaded with a much smaller filler, polyhedral oligomeric silsesquioxane (POSS), readily exhibit terminal flow on timescales comparable to neat polymers. Furthermore, the phenomenon of polymer disentanglement at high POSS loadings has been widely reported, but a molecular perspective of this phenomenon is elusive. Here, we study these disentanglement effects in the model poly(2-vinylpyridine) (P2VP)/octa(aminophenyl) silsesquioxane (OAPS) nanocomposite system. In this presentation, we discuss the effects of OAPS loading and P2VP molecular weight on the disentanglement to elucidate a detailed picture of the molecular-level processes taking place. We anticipate that an understanding of disentanglement mechanisms will prove vital for precisely tailoring and predicting the rheological behavior of complex materials used in fields such as additive manufacturing, where both high performance and facile processing are essential.