ABSTRACT
Commercially significant polymers may be conveniently grouped in two broad classes: those with backbones containing only aliphatic carbon and those with backbones containing ring structures or additional atoms such as oxygen, nitrogen, sulfur, or silicon. Polymers in the first class usually are made by addition reactions at the double bond (or 1,4-polymerization at a conjugated double bond system). Polymers in the second class can be made by a variety of reactions, including condensation and ring scission.
