Polyhedral Oligomeric Silsesquioxanes in Plastics

Polyhedral oligomeric silsesquioxanes (POS or POSS

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) were fi rst synthesized as long ago as the 1960s. Since that time, global interest has grown considerably as indicated by the many articles and patents in the fi eld [1,2,3,4,5]. The reason being that POS, with a unique three dimensional cage structure composed of silicon and oxygen (Fig. 5.1), is an unusual type of molecule with correspondingly unusual properties. The discovery of the cage form of carbon, called buckminsterfullerene (Fig. 5.1), was awarded the 1996 Nobel Prize for Chemistry, and other cage structure hydrocarbons such as adamantane and other diamondoids have attracted considerable interest. However, time has shown that POS is far more commercially important for several reasons. Firstly, POS is extremely versatile.