On the Contributions to the Materials Science Aspects of Phosphazene Chemistry by Professor Christopher W. Allen: The One-Pot Synthesis of Linear Polyphosphazenes

Summary The wide range of applications for the phosphazene compounds has stimulated a major research effort involving several industrial, academic, and national laboratories over the past 40 years. One of Professor Allen’s research areas was to establish fundamental synthetic methods for the commercial preparation of phosphazene polymers, investigate their properties, and develop useful products. In this paper we review some of the materials science aspects of Professor Allen’s research including recent advances on the preparation and polymerization of Cl₃PNP(O)Cl₂. This work, in particular, has led to a route for the “one-pot” synthesis of stable linear poly(organophosphazenes) as demonstrated through the formation of polybis-(2-methoxyethoxyethoxy)phosphazene] (MEEP) and a phosphazene heteropolymer (HPP) containing a balance of hydrophilic and hydrophobic components that allow for control and molecular affinities. The authors would like to dedicate this paper to Professor Christopher W. Allen in honor of his significant contributions to phosphazene chemistry. Furthermore, the authors thank him for his counsel and friendship in the development of the “one pot” phosphazene synthesis discussed in this paper.