Applications of Polymers Containing Cyclophosphazene Pendant Groups

4 Applications of Polymers Containing Cyclophosphazene Pendant Groups 

One of the important applications of cyclophosphazene pendant polymers appears to be in the field of thermally stable and flame-retardant materials. Thus, polymers such as 19, 20 and 26 have been shown to be selfextinguishing [19-21]. Polymer 26 has shown exceptional thermal stabilities and has char yields as high as 60-65% even at high temperatures such as 800 °C [23, 24]. Also it has been shown that incorporation of N3P3Cl5(0-C6H4-/7-C6H4-p-CH=CH2) in styrene and acrylate polymers 

Many other applications of these polymers depend upon their design. Analogous to the polyphosphazene family discussed in Chap. 3 these polymers also can be modified considerably by careful design of the monomers. Two types of applications that emanate from such designs are illustrated below. 

Similar to polymers 36 and 37, polynorbomenes containing cyclophosphazene pendant groups (x = 2, 3) (34) also form complexes with lithium salts. These show ionic conductivities of the order of 10 Scm . The polymer-Li salt complex formed with polymer 34 (x = 1) with a shorter oligoetiheroxy substituent does not show appreciable ambient temperature ionic conductivity. 

The ionic conductivity studies carried out on the lithium salt complexes of 34, 36 and 37 reveals that the backbone flexibility is not the only criterion for mediating ion transport. Facile pathways for allowing ion-transport can exist in stiff backbone polymers also provided the side-chains are sufficiently flexible. 

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