Synthesis and characterization of mixed-substituent poly(organophosphazenes)

This thesis focuses on the synthesis and characterization of mixed-substituent poly(organophosphazenes).; In chapter 2, several poly(alkoxyphosphazenes) and poly(fluoroalkoxyphosphazenes) were synthesized and allowed to react with various organic nucleophiles. The possible use of single-substituent polymers as hydrolytically stable macromolecular intermediates for mixed-substituent polyphosphazene synthesis is discussed and factors that influence side group replacement in poly(organophosphazenes) are examined. In addition, evidence for a random, irreversible SN2-like mechanism of side group replacement is presented. The work in chapter 3 is complementary to chapter 2 and examines the equilibrium exchange reactions of fluoroalkoxy substituents and fluoroalkoxy nucleophiles.; In chapter 4, a series of poly(fluoroalkoxyphosphazenes) containing a mixture of 2,2,3,3,4,4,5,5-octafluoropentoxy and 2,2,2-trifluoroethoxy substituents was synthesized. The series included polymers with 25--94% incorporation of the trifluoroethoxy substituent, as well as single-substituent polymers with 100% octafluoropentoxy or trifluoroethoxy side groups. The variation in thermal and mechanical properties as a function of the side group ratios is discussed and polymers that may be suitable for fabrication into low temperature elastomer materials are identified.; The use and evaluation of mixed-substituent polyphosphazenes as single ion conductors is described in chapter 5. Polyphosphazenes with both 2-(2-methoxyethoxy)ethoxy and lithiated sulfonimide functionalized side groups were synthesized and characterized. The polymers were examined for their behavior as single ion conductors using impedence analysis.{09}The dependence of the conductivity on the macromolecular motion of the polymers and on the amount of sulfonimide functionalized side group is discussed. (Abstract shortened by UMI.)...