Polymer compounds, abbreviated as polymers, also known as polymer polymers, generally refer to compounds with relative molecular weights of several thousand to several million. The vast majority of polymer compounds are mixtures of many homologous compounds with different relative molecular weights. Therefore, the relative molecular weight of polymer compounds is the average relative molecular weight. Polymer compounds are composed of thousands of atoms interconnected by covalent bonds. Although their relative molecular weight is large, they are all connected in simple structural units and repeated ways. The molecules of polymer compounds are much larger than those of low molecular organic compounds. The relative molecular weight of general organic compounds does not exceed 1000, while the relative molecular weight of polymer compounds can reach as high as 104-106. Due to the high relative molecular weight of polymer compounds, there are significant differences in physical, chemical, and mechanical properties compared to low molecular compounds. Although the relative molecular weight of polymer compounds is large, their composition is not complex, and their molecules are often repeatedly connected by specific structural units through covalent bonds. The number of links in the molecular chain of the same polymer compound is not the same, so polymer compounds are essentially a mixture of many compounds with the same link structure but different degrees of polymerization, and their relative molecular weight and degree of polymerization are both average values. Polymer compounds are almost devoid of volatility and often exist in solid or liquid form at room temperature. Solid polymers can be divided into crystalline and amorphous states according to their structural morphology. The former has orderly and orderly molecular arrangement; The latter has an irregular arrangement of molecules. The same polymer compound can have both crystalline and amorphous structures. Most synthetic resins have an amorphous structure. The atoms that make up a polymer chain are bonded by covalent bonds, and polymer chains generally have two different shapes: chain type and body type. The large number of polymer compounds used as materials in the world today are produced from low molecular organic compounds starting from coal, oil, natural gas, etc., and then polymerized to produce them. These low molecular weight compounds are called "monomers", and the polymer compounds generated by their polymerization reaction are also called polymers. Polymerization reactions are usually divided into two categories: addition polymerization and condensation polymerization, abbreviated as addition polymerization and condensation polymerization