The Entanglements of Macromolecules and Their Influence on the Properties of Polymers

Abstract Macromolecules form entanglements, the presence of which determines many of the polymer's properties; in solution, melt, and solid state. In this review, how the properties of polymers (rheological, thermal, and mechanical), depend on the concentration of the entanglements, is discussed. Although a typical polymer is characterized by the equilibrium density of entanglements, there are methods that can be applied for the reduction of this density. The methods used most often include dissolving a polymer and rapid freezing, crystallization during polymerization, and crystallization from a cooled dilute solution. The properties of disentangled polymers are significantly different from the properties of fully entangled polymers. These properties are discussed in relation to their dependence on the density of the entanglements. The disentangled material can be re‐entangled by the annealing of the polymer; however, reaching the equilibrium density of the entanglements is usually a slow process. It means that a polymer may be processed without losing its disentanglements. The properties of the re‐entangled polymer are usually close to the properties of the initial polymer.