Grafting reactions onto poly(organophosphazenes). I. The case of poly[bis(4-isopropylphenoxy) phosphazene-g-polystyrene copolymers

In this paper we propose a method for grafting organic polymers onto polyphosphazene matrices, which is of general applicability for carbon-backboned polymers that are synthesized via radical initiation. As an example, we describe the grafting reaction of polystyrene onto poly[ bis(4isopropylphenoxy)phosphazene] to obtain poly[bis(4isopropylphenoxy)phosphazene]-g-polystyrenec opolymers. Gel permeation chromatography, fractional precipitation, thermal analysis, and X-ray diffraction studies performed on these materials indicated that the grafting reaction was successful, yielding comblike grafted Copolymers attached to organic substituents on the polyphosphazene skeleton. Moreover, thermogravimetric analysis of the poly[bis(4-isopropylphenoxy) phosphazene]-g-polystyrene copolymers indicated that the thermal properties of these materials are different from those of the constituent homopolymers and blends and imply that they are considerably more thermally stable than pure polystyrene.