Effect on Oxidation and Degradation

The effect of density of WPC on its durability in terms of oxidative depolymerization of its plastic matrix is described in detail in Chapter 15. Briefly, porosity in WPC, which is directly related to the decrease of density (specific gravity) of the material, provides a chemically reactive area for oxygen. Oxygen flows into pores and attacks WPC from inside, particularly at elevated temperatures. An increase in temperature by every 10°C accelerates the oxidative destruction of WPC by about 

TABLE 6.2 The effect of density (specific gravity) of GeoDeck composite deck boards on their flexural modulus. Center point load, support span 14 inches 

DENSITY (SPECIFIC GRAVITY) OF WOOD-PLASTIC COMPOSITES 

TABLE 6.3 Thermo-oxidation of GeoDeck composite boards in an airflow oven at 107°C (225°F) after 87 h, measured by residual load at failure (flex and shear strength) after boards conditioning. No antioxidants were added to the composite materials 

Speciflc gravity (g/cm ) Residual load at failure compared to control (no heating) (%) 

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