FUNCTIONALIZATION OF POLYPROPYLENE BY A MICROWAVE (433 MHZ) COLD-PLASMA OF CARBON-DIOXIDE - SURFACE MODIFICATION OR SURFACE DEGRADATION

The surface modification of isotactic polypropylene (PP) in a microwave plasma of CO2 is described. The modified PP is characterized in bulk and also at its surface. The mechanism of plasma modification is discussed in terms of degradation and oxidation. The degradation leads to volatile products and to the formation of a layer of oxidized oligomers of PP. The oxidation leads to ketone, acid or ester groups. The degradation and oxidation rates depend on plasma parameters (duration, discharge power, gas flow, pressure, discharge or post-discharge treatment). The oxidation rates vs the various plasma parameters show a maximum. The crosslinking of PP (Crosslinking Activated Species of INert Gases) seems to be negligible. © 1990.