What Are The Properties And Functions Of Commonly Used Plasticizers?
Plasticizers refer to a class of substances that can improve the rationality of polymers. Plasticizers are mainly used for PVC resins, and their amount can account for more than 98% of the total amount of plasticizers. The addition of plasticizers can reduce the force between PVC molecular chains and reduce the glass transition temperature, flow temperature and melting point of the contained microcrystals of PVC plastics. Plasticizers can increase the plasticity of the resin and make the product soft and resistant. Good low temperature performance.
Adding a plasticizer to the resin can change the plasticity of the material, make it soft, reduce the melt viscosity, and improve the molding processing characteristics. So, what are the properties and functions of commonly used plasticizers? You must understand these 5 plasticizers!
The plasticizing ability or plasticizing effect of the plasticizer on the polymer is good or bad, and the plasticizing efficiency of different plasticizers is a relative concept. Plasticization efficiency is generally evaluated by the amount of plasticizer required to change the quantitative flexibility index. The less plasticizer is added, the higher the plasticization efficiency. General molecular weight plasticizers. Higher molecular weight plasticizers have high plasticizing efficiency for PVC. As the polarity of the plasticizer molecule increases, the degree of alkyl branching and the increase in aromatic ring structure reduce the plasticization efficiency.
The order of plasticizing efficiency of commonly used plasticizers is:
The compatibility of plasticizers with polymers, the same plasticizer has different compatibility with polymers of different polarities.
The compatibility sequence of commonly used plasticizers and PVC is:
The low temperature resistance of plasticizer plasticized products. The cold resistance of plasticizers is related to its structure. Aliphatic dibasic acid esters with methylene (—CH2—) as the main body have the best cold resistance and are one of the most commonly used cold-resistant plasticizers, and contain cyclic and The branched plasticizer has excellent cold resistance due to its difficulty in moving in the polymer at low temperatures.
The order of cold resistance of commonly used plasticizers is:
▶Five common plasticizers
Dibutyl phthalate (DBP)
Colorless and transparent liquid, soluble in most organic solvents, ignition point 202℃. It is used in PVC products to make the products have better flexibility.
Dioctyl Adipate (DOA)
Colorless, odorless liquid, boiling point 210℃ (655Pa), ignition point 235℃, insoluble in water, soluble in most organic solvents. It is a kind of cold-resistant plasticizer in polyvinyl chloride products. The products still have good flexibility in low-temperature environments. At the same time, they also have stability and water resistance. It can be used as a molding aid for food packaging materials, but it is volatile and electrical. Insufficient insulation.
Dibutyl Sebacate (DBS)
Colorless liquid, ignition point 218℃, explosion limit in air 0.44% (volume fraction, lower limit at 243℃), water solubility 0.40g/L (20℃). Compatible with most resins, has a good solvent effect, and can be used as the main plasticizer for cold resistance; it is often used in combination with phthalates to reduce its volatility and is easily extracted by water, soapy water and washing solutions Possibility.
Dioctyl Sebacate (DOS)
Colorless oily liquid, ignition point 263℃, soluble in organic solvents such as alcohol, benzene, ether, but insoluble in water. It is a kind of cold plasticizer with good low temperature performance and low volatility commonly used in cable materials. It can also be used in high temperature environments with good weather resistance and electrical insulation; but it is easy to be extracted by hydrocarbon solvents and easy to migrate.
Di-n-butyl adipate (DBA)
Transparent and clear liquid, no visible mechanical impurities, boiling point 168°C (10mmHg), melting point -37.5°C, freezing point -20°C, viscosity 6 centipoise (20°C), refractive index 1.4330~1.4350. Used in high-grade plastic products, it can be used as a plasticizer for vinyl resin, cellulose resin, PVC and synthetic rubber. Can be used as nitrocellulose coating.
Light yellow to colorless transparent viscous liquid. It is a solvent intermediate and can be miscible with water and alcohol. It can be used to make some important drugs, such as ezetimibe and rovastatin. It can also be used as a wetting agent, solvent, medicine, and intermediate; tobacco additives, reducing the harm of tar components, and a component of photographic developer , Increase color and adhesion, anti-drying agent for advanced ink, surface treatment agent for advanced clothing, ceramic processing aid, crosslinking agent for polymer materials.