Adv Polym Sci (2006) 201: 225–296 DOI 10.1007/12_077  Springer-Verlag Berlin Heidelberg 2006 Published online: 16 February 2006 Polyhedral Oligomeric Silsesquioxanes (POSS)- Containing Nanohybrid Polymers K. Pielichowski 1 (✉) · J. Njuguna 2 · B. Janowski 1 · J. Pielichowski 1 1 Department of Chemistry and Technology of Polymers, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland k.pielich@usk.pk.edu.pl 2 School of Industrial and Manufacturing Science, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK 1 Introduction ................................... 228 2 POSS Cages ................................... 230 3 Methods of POSS Cage Synthesis ....................... 231 3.1 Completely Condensed POSS .......................... 231 3.2 Incompletely Condensed POSS ......................... 232 4 Structure and Reactivity of POSS ....................... 235 5 Synthesis of POSS-Containing Polymers ................... 246 5.1 Free Radical Polymerization .......................... 247 5.2 Polyaddition and Polycondensation ...................... 249 5.3 Ring-Opening Metathesis Polymerization (ROMP) .............. 253 6 Synthesis of POSS-Dendrimer Cores ..................... 256 6.1 Convergent Method ............................... 257 6.2 Divergent Methods ............................... 260 7 Properties of POSS-Containing Nanohybrid Polymers ............ 263 7.1 Mechanical Properties .............................. 264 7.2 Thermal Properties ............................... 265 7.3 Viscoelastic Properties—Rheological Behavior ................ 270 7.4 Morphology of the POSS-Containing Nanohybrid Polymers ......... 272 7.5 Interfacial Interactions, Compatibility and Dispersion Characteristics ... 276 7.6 Catalytic Effects of POSS ............................ 281 7.7 Ion Mobility and Swelling Studies ....................... 282 7.8 Porosity ..................................... 284 8 Applications ................................... 287 9 Concluding Remarks .............................. 289 References ....................................... 290 Abstract Polyhedral oligosilsesquioxane (POSS)-based hybrid polymers have generated much interest recently, both from the academic and industrial points of view. POSS