Polyphosphazene , semicrystalline

The side chain substituents can affect the properties of the polyphosphazenes in yet another way. Whereas (NP CH.CH ), is amorphous, increasing the side chain length by using long chain alcohols can result in polymers which are semicrystalline (13). Presumably these polymers assume more of the character of poly(ethylene oxide), as the side chain length increases. 

The morphology of the semicrystalline polyphosphazenes is complex. Table I provides examples of phosphazenes with two first order transitions denoted by T(l) and Tm. The T(l) is an intermediate transition to a partially ordered state. Between T(l)... 

Crystallinity. Polyphosphazenes with a single substituent that is either small or rigid are semicrystalline. Their melting behavior consists of two first-order transitions, T(l) and Tm, separated by a 150-200°C gap. Optical microscopy showed that the crystalline structure was not lost at T(l), but rather existed as a mesophase until Tm was reached (2). Most fluoroalkoxy and aryloxy derivatives exhibited very high thermal stability with decomposition temperatures of 300-400°C. 

Chemical and solvent resistance PMMA, PS, PC, PA, PPE, PEST Semicrystalline pol5miers (e.g., PO), polysiloxanes, polyphosphazenes,... 

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