Linear and Star-Shaped POSS Hybrid Materials Containing Crystalline Isotactic Polystyrene Chains
Maximilian Vielhauer, Pierre J. Lutz, Günter Reiter und Rolf Mülhaupt. Journal of Polymer Science, Polymer Chemistry 51, 947–953 (2013)
Abstract
New crystalline nanostructured inorganic–organic hybrid materials containing isotactic polystyrene (iPS) are prepared by means of hydrosilylation coupling of vinyl-terminated iPS with octakis(dimethylsilyloxy)silsesquioxane (Q8M8H). The number average molar mass of the iPS chains varies between 2000 and 6000 g/mol. As a function of the iPS/Q8M8H ratio, using excess reagent, the formation of linear or star-shaped hybrid architectures is achieved. Via fractionation, it is possible to isolate well-defined linear hybrids containing one iPS chain and seven ethyl groups per silica core (iPS-Q8M8E7) as well as star-shaped hybrids containing up to eight iPS side chains (iPS6-8-Q8M8). These new iPS/polyhedral oligomeric silsesquioxane hybrid materials crystallize when the number average molar mass of iPS side chain exceeds 5500 g mol1. The hydrosilylation coupling reaction and the resulting linear iPS-Q8M8E7 and starshaped iPS6-8-Q8M8 are characterized by NMR spectroscopy, size exclusion chromatography (gel permeation chromatography), and polarized light microscopy.