Polymers are naturally colored, greyish or yellowish and so on, and are somewhat unappealing. The situation is even more disastrous with compounds incorporating additives leading to other undesired colors going up to the black color of numerous rubber goods. To obviate these drawbacks it is necessary to carefully choose the polymer grade and additives (To know more about fillers and pigments, see the second part, Appealing Plastics and Rubbers: White is Beautiful Part II - Toward a Nice Whiteness) and it is possible to use white fillers, and other optically active additives. Generally, that is not sufficient and it is necessary to carefully process the materials and to preserve the obtained colors by carefully stabilizing the compound during all the service life.
Outdoor exposure is, perhaps the most severe ageing condition but heat, neon light or exposition to the north in cold climates can also be aggressive. For example, PVC compounds can turn to:
1. Mat and possibly yellow by outdoor exposure