The Force Of Plasticizer
We have already talked about the plasticizer on the relevant knowledge, I believe we have a deep understanding of plasticizers, Plasticizer but the mechanism of action of plasticizers, we did not elaborate, today plasticizer manufacturers Sen Di Chemical to lead you Learn together.
The lubrication theory suggests that the resin can resist deformation (rigidity) because of the intermolecular friction. Plasticizers can act as lubricants to promote movement between macromolecules or between molecules. The plasticizer only reduces the force between molecules, Plasticizer so it can only cause partial plasticization.
2. Gel theory
Gel theory suggests that polymer resistance to deformation due to the presence of a three-dimensional honeycomb structure or gel. This gel is formed by more or less adhesion between the molecular chains of the polymer. As the molecular point of absorption is often concentrated in one piece, so the soft plastic or hard plastic honeycomb is very small. This honeycomb is extremely small and difficult to deform by moving inside the object. The plasticizer enters the resin, Plasticizer producing a lot of absorption points along the polymer chain, relaxing by the new suction and destroying the original attraction, and replacing the gravitational centers within the polymer molecules, making the molecules easy to move.
3. Solvation theory
Based on colloid chemistry. The solvating and swelling properties of the plasticizer depend on three intermolecular forces. Plasticizer / plasticizer, plasticizer
/ Polymer, polymer / polymer. The plasticizer should be a small molecule and should have a certain attraction to the polymer molecule, which is less than the force between the polymer and the polymer. The lower the force between the plasticizer and the plasticizer, Plasticizer the more effective the plasticizer is. Plasticizers should not be too small, otherwise easy to volatilize.
4. Polarity theory
The polarity theory suggests that there must be a good balance between the plasticizer molecules, the polymer molecules and the plasticizer / polymer molecules to ensure that the gel is stable. The plasticizer must therefore contain one or more polar or non-polar groups that match the polarity of the particular polymer. That is, Plasticizer the crystallinity of the polymer mentioned above.
Mechanism of Plasticizer
It is generally believed that the plasticizing process is divided into the following steps:
1. wetting, the surface of the suction
The plasticizer molecules enter the pores of the resin resin and fill their pores.
2. Dissolution on the surface
The rate at which the plasticizer penetrates into the resin particles is very slow, especially at low temperatures. It is generally believed that the plasticizer dissolves the molecules of the swollen polymer surface, which can prolong the phase of the polymer when the polymer has a colloidal polymer.
3. Absorb effect
The resin particles are slowly swollen internally from the outside, Plasticizer resulting in a strong internal stress, exhibiting a decrease in the total volume of the resin and the plasticizer.
4. Polar free radicals
The plasticizer is incorporated into the resin and partially changes its internal structure, dissolving a number of special functional groups, the reaction is that the plasticizer is absorbed, the dielectric constant is higher than the starting mixture. This process is affected by the temperature and activation energy.
5. Structural damage
The plasticizer in the dry mix is present in the form of molecular beam between the polymer or the segment. When the system is subject to higher energy such as heating to 160 ---- 180oC, or roll it. The structure of the polymer will be destroyed and the plasticizer will penetrate into the molecular beam of the polymer.
6. Structural reconstruction
The mixture of the plasticizer and the polymer is heated to the flow state and then plasticized, and then cooled, will form a structure different from the original polymer. Plasticizer This structure exhibits a high toughness, but the structure often takes some time. For example, when DOP is used as a plasticizer, the maximum hardness can be achieved after one day, and a medium molecular weight polyester is used for a week.
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