Effects of Organic Side Group Structures on the Properties of Poly (organophosphazenes)

Methods are reported for the synthesis of three new classes of poly(organophosphazenes) via the substitution reactions of poly(dichlorophosphazene). The first class consists of single-substituent polymers with aromatic rings separated from the main chain by methvleneoxy-spacer groups. The second and third classes comprise mixed-substituent polymers that contain aryloxy and aryl ester or aryl Schiffs base side groups. The variations in glass transition temperature with changes in side groups are discussed and are compared with the values for various alkoxy and alkoxy ether side group systems. The absence of liquid crystallinity for most of the derivatives was ascribed to the restricted rotational freedom of the side groups and, for the mixed-substituent polymers, to a lack of stereoregularity.