Polyphosphazenes degradation mechanisms

For the hydrolytic degradation of polyphosphazenes several mechanisms have been proposed (Allcock et al, 1977-1994 Goedemoed et al., 1988). Ffowever, analysis of the degradation products revealed that the main hydrolysis pathway involves release of the amino acid ester side group, followed by hydrolysis of the ester with formation of the amino acid and the alcohol (Crommen et al, 1992) (Fiigpre 12). 

Tlie results represent the first tliermal degradation study that has been conducted on well-defined polyphosphazenes. Tliey also provide an unambiguous answer to the actual mechanism of degradation in tlrese polymers. 

Although the poor mechanical properties limit their applications to repair load-bearing defects, the inherited buffering capacity of polyphosphazenes to neutralize the acidic degradation of PLA makes this a unique system. 

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