Chemical changes in irradiated polymers

The main chemical changes induced by ionizing radiation are (a) main-chain scission, (b) crosslinking formation, (c) volatile products formation, (d) formation and decay of unsaturation, and (e) cyclization. The yields strongly depend on the chemical structure of the polymer. 

Volatiles formed are mainly hydrogen and products arising from side-chain decomposition. Their yield also depends on the temperature and physical state of the polymer, and their formation often partly results in double bond formation. Vinyl and vinylidene double bonds, either initially present or formed during irradiation, often decay with a large yield owing to their high reactivity towards free radicals. 

The presence of additives can deeply affect the course of radiation-induced reactions. Some additives exhibit a protective effect while others sensitize the radiolysis or even completely modify the behaviour of the polymers during irradiation. 

---

Table 1. Classification of chemical changes in irradiated polymers.

---