Degradation phenomena plasticity

It is easier to dissolve a stabilizer than to evaporate it [27]. The physical loss of stabilizers due to the leaching from polymer surfa< layers into liquids which come into contact is therefore more serious than volatilization. Problems arise mainly in systems where the degradation process has been concentrated at the surface layer and therefore an efficient surface protection of a polymer is mandatory. This phenomenon takes place mainly in photostabilization of plastics or antiozonant protection of rubbers. The surface loss of stabilizers is extremely serious in very thin profiles or products having a very high surface/mass ratio. 

The phenomenon of rigidification can be interpreted both as the result of degradation of the PC and as a consequence of the loss of additives designed to plasticize the macromolecules. In both cases, any outdoor use of parts made of recycled PC must be preceded by a stage of reformulation to compensate for the loss of the stabilizing and plasticizing additives present in virgin PC. 

Environmental stress cracking (ESC) is the premature cracking of a polymer due to the combined action of a stress and a fluid. It is associated with the phenomenon of crazing and solvent plasticization of the polymer. The embrittlement by oxidative or other chemical degradation is not included under ESC, but is classed as corrosion stress cracking (CSC). 

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