Poly heterophosphazene s

We will first examine polymers that contain P-N-C, P-N-S and P-N-M linkages. These are also called poly(heterophosphazene)s since they are prepared from the corresponding heterocyclophosphazenes. 

Poly(heterophosphazene)s are a recently emerging polymer family that contain a heteroatom such as carbon or sulfur or a transition metal as part 

How are these polymers assembled and what are their properties How are they different from polyphosphazenes These aspects will be addressed in the following sections. 

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Fig. 5.2. Examples of poly(heterophosphazene)s. Poly(dichlorophosphazene) is also shown for comparison...

Poly(heterophosphazene)s whose backbones comprise phosphoms, nitrogen, and another element - carbon or sulfur -were also synthesized. " In poly(carbophosphazene)s (poly-114), every third phosphoms atom is replaced by carbon. Poly-114 obtained in the thermal polymerization of a cyclic carbophosphazene was further transformed into white, solid, hydrolytically stable poly((aryloxy)carbophosphazene) (stmcture 115 Af -lO ). The polymer backbone in stmcture 115 was less flexible than in classical polyphosphazenes. The reaction of poly-114 with alkylamines was also studied. Poly (carbophosphazene) s have higher glass transition temperatures than their classical polyphosphazene counterparts with the same side groups. The increased stiffness of the carbophosphazene backbone is attributed to the high torsional barrier of the organic C = N n-bonds compared to the low barrier of the P = N n-bonds. ... 

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