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.
Patents. A process for preparing low molecular weight, highly reactive polyisobutylene having an average molecular weight Mn of from 500 to 5000 Dalton and a terminal double bond content of more than 80 mol % by polymerization in the liquid phase of isobutene or hydrocarbon streams comprising isobutane [sic]...ccording to stage (c) the enriched and/or separated catalyst complex is then recycled, usually without further purification, to the polymerization, in the case of a multi-stage polymerization generally into the first stage. It is generally possible to recycle from 70 to 90% of the catalyst complex.