The plasticization process of plasticizers in plastics can be regarded as a process in which resin and plasticizer low-molecular compounds dissolve each other, but plasticizers are different from general solvents. The solvents will volatilize during processing, while plasticizers are required to stay in the polymer for a long time and do not chemically react with the resin, forming a solid with the resin. After the plasticizer is added, it can increase the plastic's flexibility, flexibility, cold resistance, and elongation. Reduce the plastic's hardness, modulus, glass transition temperature, melting point, softening temperature, or low temperature, so that the viscosity of the plastic becomes smaller and the fluidity increases, thereby improving the processing performance.
The plasticizing mechanism of plasticizers is generally considered to have the following two types:
1) When the plasticizer and the resin melt together, the small molecules of the plasticizer will be inserted between the polymer molecular chains, weakening the attraction between the polymer molecular chains and increasing the distance between them, as a result, It increases the mobility of polymer molecular chains and reduces the entanglement between polymer molecular chains so that the resin can undergo glass transition at a lower temperature, thereby increasing the plasticity of the plastic. It can be seen that the gravitational force and entanglement between polymer molecular chains are a major cause of anti-plasticization.
2) The polymer's molecular structure also affects the attraction between the polymer molecular chains, especially the properties of the groups on the polymer molecular chain. The interaction between the molecular chains with strong polar groups is large, and there are non-polar groups. The force between the molecular chains is small. To make the polymer with strong polar groups easy to shape, a plasticizer can be added. The polar groups of the plasticizer will interact with the polar groups of the polymer, thereby weakening With the attraction between the polymers, the purpose of plasticization is achieved.
It can be seen from the above that the key to the plasticizer's plasticizing effect is to weaken the force between the polymers.