Wuhan modern plasticizer
DATE：2020/12/15 9:42:12 / READ： / SOURCE：This station
Wuhan modern plasticizer
1、 Definition and requirement of plasticizer
1. Plasticizer and plasticizer
A substance added to a polymer system to increase its plasticity (the property of a polymer to undergo permanent deformation under stress) is called a plasticizer.
Plasticization is divided into internal and external plasticization. In fact, the internal plasticizer is the second monomer introduced in the polymerization process, which can reduce the regularity (i.e. crystallinity) of macromolecular chain, or promote the introduction of branched chain on the macromolecular chain to reduce the intermolecular force. With the increase of branch chain length, the plasticizing effect also increases. Some chemicals containing reactive gene can react with polymer under certain conditions, graft onto polymer molecular chain or form network structure between molecular chains, so as to make the flexibility, strength and hardness of plastics. The latter is actually the crosslinking agent for plasticizing. These compounds are called reactive plasticizers. Allyl ester, acrylate, epoxy compound, unsaturated polyester, etc. The internal plasticizer does not belong to the category of additives. The commonly referred plasticizer is actually the external plasticizer, but the reactive plasticizer is also included. In addition, there is a family of compounds that act opposite to plasticizers when added to plastics. Such substances are called anti plasticizers. They are usually compounds rich in polar and cyclic structures, such as chlorinated biphenyls, nitrated biphenyls (phenylethylene glycol) and rosin acid derivatives. They can be used as anti plasticizers for polycarbonate to improve their tensile strength and reduce their elongation. www.handern.com Hollow plate equipment
Plasticizer is a kind of liquid or solid substance with high boiling point, low molecular weight and low melting point. Most of them are ester organic compounds. They do not react with polymers but swell at higher temperature to form a solid solution. Crystalline polymers are difficult to plasticize. Only PA, PVA and ptcfe can be plasticized significantly. Other crystalline polymers will reject plasticizers.
The main function of plasticizer is to weaken the secondary valence bond (i.e. van der Waals force) between polymer molecules, so as to increase the mobility of polymer molecular chain, reduce the crystallization tendency of molecular chain, and show that the hardness, modulus, softening temperature and embrittlement temperature of plastic decrease, while elongation, flexibility, flexibility and elasticity increase. Plasticizers can reduce the melt viscosity, melting temperature and flow temperature of the polymer, making it easy to be molded. Plasticizers can also affect or improve their physical, mechanical, chemical and dielectric properties.
2. Requirements of plasticizer
An ideal plasticizer should meet the following requirements.
(1) Compatibility with resin refers to the amount of plasticizer absorbed by resin and no precipitation after plasticizing. It is the basic property of plasticization. It is generally measured by solubility parameters, interaction parameters, viscosity, cloud point, etc. The solubility parameter is the square root of evaporation energy per unit volume of solvent (i.e. cohesive energy density CFD), which is closely related to the dielectric constant of solvent, dipole moment of solvent itself and hydrogen bond. Generally, the solubility parameter ranges from 8.4 to 11.4. When the dielectric constant is between 3 and 8, it has good compatibility with PVC. www.handern.com Hollow plate equipment
(2) Processability the processability of the mixture prepared with plasticizer with good compatibility is good. The influence of lubricants and stabilizers with poor compatibility should be considered in extrusion molding. When they are used in large quantities, plasticizers such as fatty acid esters and chlorinated paraffin should be paid attention to.
(3) Plasticizing efficiency refers to the amount of plasticizer used to make the resin reach a certain degree of softness. 1、 The plasticizing efficiency is generally expressed by the decrease of glass transition temperature and modulus. It is the most important method to measure chain mobility.
(4) In a certain range, the addition of a small amount of plasticizer will lead to the decrease of elongation, impact strength and embrittlement, which is called reverse plasticizing. The appropriate dosage should be selected when mixing.
(5) The cold resistance of plasticizers with good cold resistance compatibility is poor, especially the plasticizer with ring structure. On the contrary, the aliphatic esters with straight chain methylene (- CH2 -) as the main body have good cold resistance, and the longer the carbon chain, the better the cold resistance. However, when the number of carbon atoms exceeds 12 or the alkyl branch chain increases, they can not be selected because of their poor compatibility and plasticizing efficiency. At present, fatty acid esters are mainly used as cold resistant plasticizers.
(6) The aging resistance of aging resistant plastics mainly depends on heat stabilizer, antioxidant and light stabilizer, but the plasticizer should be able to withstand the molding temperature to prevent its thermal decomposition. The straight chain alkyl group is stable, but the plasticizer with more alkyl branch chain is less stable. Epoxy plasticizers can also be used as stabilizers and have synergistic effect when used with metal stabilizers. www.handern.com Hollow plate equipment
(7) Durability includes volatility resistance, extraction resistance and migration resistance.
① The ability of volatile plasticizers to convert into gases and evaporate from the surface after heating. Plasticizers with molecular weight above 350 are required because of their small molecular weight and high volatility. The plasticizer with good compatibility with PVC has higher volatility, while the polymer plasticizer with larger molecular weight and larger molecular weight has smaller volatility.
② Extraction resistance mainly refers to chemical extraction, which usually includes oil resistance, solvent resistance, water resistance and soap water resistance. This depends on the structure, polarity and molecular weight of plastics and plasticizers, as well as the physical and chemical properties of the media in contact with the plastics. For example, plasticizers with a relatively large proportion of alkyl groups in the molecular structure are resistant to gasoline or oil solvent sextraction, but good water and soap water resistance.
③ Migration refers to the diffusion of plasticizer to the contact layer of products, including internal diffusion and diffusion to the contact layer. Migration often causes softening, stickiness, even surface fragmentation or contamination of products
1、 Definition and requirement of plasticizer
1. Plasticizer and plasticizer
A substance added to a polymer system to increase its plasticity (the property of a polymer to undergo permanent deformation under stress) is called a plasticizer.
Plasticization is divided into internal and external plasticization. In fact, the internal plasticizer is the second monomer introduced in the polymerization process, which can reduce the regularity (i.e. crystallinity) of macromolecular chain, or promote the introduction of branched chain on the macromolecular chain to reduce the intermolecular force. With the increase of branch chain length, the plasticizing effect also increases. Some chemicals containing reactive gene can react with polymer under certain conditions, graft onto polymer molecular chain or form network structure between molecular chains, so as to make the flexibility, strength and hardness of plastics. The latter is actually the crosslinking agent for plasticizing. These compounds are called reactive plasticizers. Allyl ester, acrylate, epoxy compound, unsaturated polyester, etc. The internal plasticizer does not belong to the category of additives. The commonly referred plasticizer is actually the external plasticizer, but the reactive plasticizer is also included. In addition, there is a family of compounds that act opposite to plasticizers when added to plastics. Such substances are called anti plasticizers. They are usually compounds rich in polar and cyclic structures, such as chlorinated biphenyls, nitrated biphenyls (phenylethylene glycol) and rosin acid derivatives. They can be used as anti plasticizers for polycarbonate to improve their tensile strength and reduce their elongation. www.handern.com Hollow plate equipment
Plasticizer is a kind of liquid or solid substance with high boiling point, low molecular weight and low melting point. Most of them are ester organic compounds. They do not react with polymers but swell at higher temperature to form a solid solution. Crystalline polymers are difficult to plasticize. Only PA, PVA and ptcfe can be plasticized significantly. Other crystalline polymers will reject plasticizers.
The main function of plasticizer is to weaken the secondary valence bond (i.e. van der Waals force) between polymer molecules, so as to increase the mobility of polymer molecular chain, reduce the crystallization tendency of molecular chain, and show that the hardness, modulus, softening temperature and embrittlement temperature of plastic decrease, while elongation, flexibility, flexibility and elasticity increase. Plasticizers can reduce the melt viscosity, melting temperature and flow temperature of the polymer, making it easy to be molded. Plasticizers can also affect or improve their physical, mechanical, chemical and dielectric properties.
2. Requirements of plasticizer
An ideal plasticizer should meet the following requirements.
(1) Compatibility with resin refers to the amount of plasticizer absorbed by resin and no precipitation after plasticizing. It is the basic property of plasticization. It is generally measured by solubility parameters, interaction parameters, viscosity, cloud point, etc. The solubility parameter is the square root of evaporation energy per unit volume of solvent (i.e. cohesive energy density CFD), which is closely related to the dielectric constant of solvent, dipole moment of solvent itself and hydrogen bond. Generally, the solubility parameter ranges from 8.4 to 11.4. When the dielectric constant is between 3 and 8, it has good compatibility with PVC. www.handern.com Hollow plate equipment
(2) Processability the processability of the mixture prepared with plasticizer with good compatibility is good. The influence of lubricants and stabilizers with poor compatibility should be considered in extrusion molding. When they are used in large quantities, plasticizers such as fatty acid esters and chlorinated paraffin should be paid attention to.
(3) Plasticizing efficiency refers to the amount of plasticizer used to make the resin reach a certain degree of softness. 1、 The plasticizing efficiency is generally expressed by the decrease of glass transition temperature and modulus. It is the most important method to measure chain mobility.
(4) In a certain range, the addition of a small amount of plasticizer will lead to the decrease of elongation, impact strength and embrittlement, which is called reverse plasticizing. The appropriate dosage should be selected when mixing.
(5) The cold resistance of plasticizers with good cold resistance compatibility is poor, especially the plasticizer with ring structure. On the contrary, the aliphatic esters with straight chain methylene (- CH2 -) as the main body have good cold resistance, and the longer the carbon chain, the better the cold resistance. However, when the number of carbon atoms exceeds 12 or the alkyl branch chain increases, they can not be selected because of their poor compatibility and plasticizing efficiency. At present, fatty acid esters are mainly used as cold resistant plasticizers.
(6) The aging resistance of aging resistant plastics mainly depends on heat stabilizer, antioxidant and light stabilizer, but the plasticizer should be able to withstand the molding temperature to prevent its thermal decomposition. The straight chain alkyl group is stable, but the plasticizer with more alkyl branch chain is less stable. Epoxy plasticizers can also be used as stabilizers and have synergistic effect when used with metal stabilizers. www.handern.com Hollow plate equipment
(7) Durability includes volatility resistance, extraction resistance and migration resistance.
① The ability of volatile plasticizers to convert into gases and evaporate from the surface after heating. Plasticizers with molecular weight above 350 are required because of their small molecular weight and high volatility. The plasticizer with good compatibility with PVC has higher volatility, while the polymer plasticizer with larger molecular weight and larger molecular weight has smaller volatility.
② Extraction resistance mainly refers to chemical extraction, which usually includes oil resistance, solvent resistance, water resistance and soap water resistance. This depends on the structure, polarity and molecular weight of plastics and plasticizers, as well as the physical and chemical properties of the media in contact with the plastics. For example, plasticizers with a relatively large proportion of alkyl groups in the molecular structure are resistant to gasoline or oil solvent sextraction, but good water and soap water resistance.
③ Migration refers to the diffusion of plasticizer to the contact layer of products, including internal diffusion and diffusion to the contact layer. Migration often causes softening, stickiness, even surface fragmentation or contamination of products
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