Property enhancements of common thermoplastics via incorporation of silicon based monomers: Polyhedral oligomeric silsesquioxane macromers and polymers

A catalogue of hybrid plastic building blocks based on Polyhedral Oligomeric Silsesquioxanes (POSS) reagents has been developed. POSS reagents are unique in that they are physically large (approx. 15 angstroms diameter and 1000 amu) and are composed of a robust silicon-oxygen framework that can be easily functionalized with a variety of organic substituents. Appropriate functionalization of POSS cages allows for their incorporation into traditional thermoplastic resins without modification of existing manufacturing processes. The incorporation of POSS segments into linear copolymer systems results in increased glass transition temperatures, oxygen permeability and modified mechanical properties relative to conventional organic systems. A conceptual model for POSS-polymers has been developed based on thermal, rheological and X-ray diffraction studies of POSS-siloxane, POSS-acrylic and POSS-styryl copolymers. Insights into the origins of the above property enhancements will be discussed in light of POSS-polymer chain structure and packing.