Introduction of high polymer
Refers to high molecular weight (usually up to 10 to 106) compounds made up of many identical, simple structural units repeatedly connected by covalent bonds. For example, the polyvinyl chloride molecule is made up of many structural units of vinyl chloride—CH2CHCl—repeatedly connected, so —CH2CHCl— is also called a structural unit or a chain link. A compound composed of small molecules capable of forming structural units is called a monomer and is a raw material for synthesizing polymers. N represents the number of repeating units, also known as the degree of polymerization. The degree of polymerization is an important index for measuring high molecular polymers. Polymers with a low degree of polymerization (1 to 100) are called oligomers, and only when the molecular weight is as high as 10 to 106 (such as plastics, rubber, fibers, etc.) are called high molecular polymers. A polymer polymerized from one monomer is called a homopolymer, such as the aforementioned polyvinyl chloride, polyethylene, and the like. A polymer formed by copolymerizing two or more monomers is called a copolymer, such as a vinyl chloride-vinyl acetate copolymer.