PREPARATION OF IONICALLY CROSS-LINKED POLYPHOSPHAZENE MICROSPHERES BY COACERVATION

摘要

A method of preparing polyphosphazene microspheres wherein the polyphosphazene microspheres are produced by coacervation. In one embodiment, a solution containing a polyphosphazene is admixed with a dehydration agent, such as a solution containing a salt of a monovalent ion such as a salt of a Group I element (such as, for example, NaCl) to form a dispersion containing polyphosphazene coacervate microdroplets. The dispersion then is admixed with a solution containing a salt of a multivalent ion, such as a salt of a Group II element (such as, for example, CaCl2) to form a suspension of polyphosphazene microspheres. The polyphosphazene microspheres then are recovered from the suspension. Such method enables one to obtain high yields of microspheres having a controlled size distribution.