Characterization of HTPBs chemical-, thermal-, mechanical- and radiation-induced degradation

6 Characterization of HTPBs chemical-, thermal-, mechanical- and radiation-induced degradation 

Polymer degradation may be categorized according to the degrading agent as  

Since HTPs are often used under severe conditions (temperature, T, pressure, P, irradiation, Q, stress, a, and their combinations), their structure, MW and MWD, change with the lifetime. The process may lead to the reduction or increase of MW, erosion, etc. Several mechanisms have 

The chemical degradation takes place when a polymer is exposed to reacting fluids, such as gaseous O2,03, CI2, H2S, H2O, etc. In polymers with carbon-carbon backbone, oxidation is the principal chemical degradative mechanism that results in formation of peroxides and/or hydroxy peroxides, chain scission and accompanying it the free radical grafting (which may be absent in high vacuum). Polymers with tertiary carbons (e.g., PP or hnear low density PE, LED PE) oxidize readily for PO the process is autocatalytic.  

A good introduction to this topic is provided by Beyler and Hirschler, with a short introduction to polymers and their properties. Thermal degrada-tion/stabihty has been studied by several methods, namely TGA, differential thermogravimetry (DTG), thermal volatilization analysis (TVA), differential 

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