Factors Accelerating or Slowing Down Fading of Composites

Having said this, it is not surprising to see that there is no clear correlation indeed between the amount of antioxidants in a WPC boards and the degree of its fading (Fig. 16.4). 

However, this correlation does not have much of a sense. The OIT first of all depends on antioxidants present in the material. Some commercial additives or fillers, such as wood flour, can play a role of these antioxidants. Fading (rather, a lack of it) depends mainly on added pigments. There is no meaningful correlation between pigments and their antioxidant properties. Here is why  

At the same time, when a WPC contains a systematically increased amount of an ingredient, which increases the OIT of the material (that is, possesses an antioxidant properties) and concurrently increases its fading, one would observe a certain correlation between the two properties (Fig. 16.5). 

FACTORS ACCELERATING OR SLOWING DOWN FADING OF COMPOSITES 

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