Dark Stool: If your stool is black or bright red in color, it can mean that you are bleeding internally, as a possible result of an ulcer or cancer, and warrants a call to your doctor even if you think it could be hemorrhoids, or tiny tears in the anal tissue, due to constipation and straining.
The chemical reaction in which high molecular mass molecules are formed from monomers is known as polymerization. There are two basic types of polymerization, chain-reaction (or addition) and step-reaction (or condensation) polymerization.
The principle ingredient used in the manufacture of polyester is ethylene, which is derived from petroleum. In this process, ethylene is the polymer, the chemical building block of polyester, and the chemical process that produces the finished polyester is called polymerization.