Inorganic High Polymers

Abstract

Since the development and commercialization of the polysiloxanes, a number of linear, inorganic‐backbone polymers have been reported. Most prominent among these are the polyphosphazenes and the polysilanes. Some, like poly(sulfur nitride) and the polycarborane–siloxanes, have manufacturing or stability problems. The heterophosphazenes, the alkyl/arylphosphazenes, and the polyoxothiazenes are relatively new and awaiting development and breakthrough in manufacturing technology for a number of potential applications. The polyphosphazenes with PO and PN‐bonded substituents (synthesized by a ring‐opening polymerization–substitution route) are the most mature and have seen limited manufacturing and commercialization in the area of specialized rubber markets. These polymers are extremely versatile in terms of potential applications in the areas of biomedical technology, elastomers, solid‐state batteries (via ionic conduction), catalysis, etc. The poly(alkyl/arylphosphazenes), synthesized by a polycondensation route, possess many of the properties of the PO‐ and PN‐substituted polymers and appear to be suitable for application as wide temperature‐range elastomers, thermoplastic polymers, and biomaterials. The polysilanes, which can be prepared by a number of methods are a unique class of polymers in exhibiting σ‐conjugation along the backbone. The majority of the developing applications for these polymers are based on this phenomenon, which leads to near‐uv photoabsorption, thermo‐ and piezochromism, and photodegradation. For many of the existing and developing inorganic‐backbone polymers with potential for commercial applications, a pivotal aspect for manufacture is relative ease of industrial scale‐up. This translates into readily accessible and relatively inexpensive starting materials, in addition to a process that allows flexibility with equipment and is environmentally friendly.