The black part in plastics is due to the addition of cheap carbon black to recycled plastic which is usually pale and unappealing grey, it is a form of 'soot p

The black part in plastics is due to the addition of cheap carbon black to recycled plastic which is usually pale and unappealing grey, it is a form of 'soot produced by the incomplete combustion of coal, petroleum or vegetable matter. It is added to plastics as a reinforcing substance, the same reason for which it finds widespread use in tires' .https://www.mcgill.ca/oss/article/environment-did-you-know/dark-side-black-plastics https://www.mcgill.ca/oss/article/environment-did-you-know/d...