Polymers surface radicals containing

As has been discussed, a polymer exposed to a reactive plasma will be undergoing simultaneous surface modification reactions and surface removal reactions. If the removal rates dominate or if a non-reactive plasma is used, the polymer surface will contain a large number of free radicals when the plasma is turned off. These radicals may react with themselves to form cross-linking or unsaturation, they may react with the plasma gas as it decays after the power is turned off or, they will react with... 

There is a special kind of particulate matter so called "black smoke" that cover polymer surfaces very tightly and is difficult to remove. Black smoke may contain stable unpaired electrons (free radicals) which may play a specific role in photostabilization of polymeric materials by scavenging free radicals formed from photolysis of polymers. 

Class III consists of halogen-containing polymeric materials. Some of them form a small char residue, others form none at all. These polymers are inherently flame retardant because halogen radicals act as radical scavengers in the vapor phase and, therefore, inhibit combustion, as described earlier. Also the splitting-off of noncombustible gases such as HCl, Hf, and CnF, seals the polymer surface from the combustion air and is thereby partly responsible for the flame retardancy. All these factors thus influence the interaction between pyrolysis and ignition. 

When the plasma gas contains oxygen, the free organic radical R generated by non-thermal plasma treatment on polymer surfaces (9-80) very effectively attaches molecular oxygen from the gas phase, forming active organic peroxide radicals ... 

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