3. Degradation of silicones in the environment

Until a few years ago, silicones were considered non-degradable in the environment and inert to living organisms. This was seen as a positive commercial and societal argument. Today, their degradation has been demonstrated, but the fact remains that they are polymers that are highly resistant to different environmental biophysical and chemical contexts. Degradation is generally described in two successive phases:

• the first is chemical hydrolysis (an abiotic process);

• the second may be UV degradation (abiotic process) or biodegradation (biotic process). The intermediate degradation products are siloxanols and silanols (including mainly DMSD) and the final products, CO ₂ and inorganic silicates.

The general mechanism for PDMS is...