News Details
Polypropylene plastic antioxidant
2018-1-2 20:55:56
Polypropylene plastic antioxidant
The molecular structure of polypropylene contains a large number of tertiary carbon atoms, so polypropylene is very sensitive to oxidation. To this end, stabilizing treatment must be adopted before processing, at least in the polymerization stage to add a proper amount of polypropylene plastic antioxidant. A proper amount of polypropylene plastic antioxidant is added to the granulation.
The processing temperature of PP is generally 220~280 C. If the antioxidant is not added, the thermal degradation will be produced at the processing temperature, which makes the melt index increase. A commonly used industrial polypropylene plastics antioxidant system, mainly 2,6- butylated hydroxytoluene (BHT), phosphite and phosphonic acid ester.
The antioxidant system of PP often uses phosphorus containing compounds and hindered phenolic antioxidants to achieve good synergy. But for the processing stability is not high, the use of high molecular weight of phenolic antioxidants can be. Phosphorus containing compounds have good pumping resistance and also have the function of inhibiting color pollution.
The mechanism of action of polypropylene antioxidant:
1, chain initiation
Under the action of oxygen, light or heat, polypropylene (RH) can easily generate free radicals in its tertiary carbon atom.
RH light and heat R+HRH+O2 R+HOO
2. Chain transfer
The free radicals automatically catalyze the generation of free radicals and macromolecules, the decomposition of peroxide produces free radicals, and the free radicals can react with the polymer.
The free radical is continuously transmitted and the reaction continues:
R+O2ROO
ROO+RHROOH+R
ROOHRO+HO
ROOH+RH RO+R+H2O
RO+RHROH+R
HO+RHH2O+R
2ROOHRO+ROO+H2O1.3
Triphenyl phosphite (antioxidant, stabilizer TPPi)
Packing method: net weight of 200KG/galvanized iron bucket (a small cabinet to hold 16 tons), 1000KG/IB (a small container with 18 tons) or 23 tons of it.
Port of shipment: Shanghai port
Price quotation validity: 15 days
Warehouse time: within 15 days (customs clearance)
Export rights: our own right to import and export.
Triphenyl phosphite (TPPi antioxidants, stabilizer) is mainly used in PVC, polyethylene, polypropylene, polystyrene, polyester, abs resin, epoxy resin, synthetic rubber antioxidant stabilizer, used in polyvinyl chloride (PVC) products as a chelating agent.
3. Chain termination
The free radicals combine to produce stable products and terminate the chain reaction.
R+RR - R
R+ROOROOR
ROO+ROOROOR+O2
ROO+ROROR+O2
R+OH ROH
During the oxidation process, when the large molecular chain breaks down, the molecular weight decreases, the melt viscosity decreases, and the strength of polypropylene decreases or pulverized. When the macromolecule has crosslinking reaction, the molecular weight increases, the melt fluidity decreases, and the embrittlement and hardening occur. Oxidation structures such as carbonyl and peroxide generated during the oxidation process reduce the electrical properties of polypropylene, and increase the sensitivity to light induced degradation. The further reaction of this oxidation structure makes macromolecules break or cross link.
The role of antioxidants is to prevent the process of automatic oxidation chain reaction of polypropylene, that is to supply hydrogen to make the free radicals R and ROO generated in the oxidation process become RH and ROOH, or to turn ROOH into ROH, thereby improving the ability of oxidation and pyrolysis of polypropylene in processing and application.
Polypropylene, a thermoplastic resin made from polymerization of propylene, is a kind of thermoplastic resin. According to the position of methyl arrangement, it can be divided into three kinds: isotactic polypropylene (isotactic polypropylene), atactic polypropylene (atactic polypropylene) and syndiotactic polypropylene (syndiotactic polypropylene).
The methyl arrangement is called the isotactic polypropylene on the same side of the main chain. If methyl is arranged in disorder on both sides of the main chain, it is called atactic polypropylene. When methyl is alternately arranged on both sides of the molecular backbone, it is called syndiotactic polypropylene. In the general industrial polypropylene resin, the isotactic structure content is about 95%, and the rest are random or gauge polypropylene. Industrial products are mainly composed of isotactic materials. Polypropylene also includes copolymers of propylene and a small amount of ethylene. It is usually semitransparent and colorless solid, odorless and nontoxic. Because of the high crystallization of the structure, the melting point can be as high as 167 degrees C. Heat resistant, corrosion resistant, and steam disinfection of products are its outstanding advantages. Small density, the lightest general plastic.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
The molecular structure of polypropylene contains a large number of tertiary carbon atoms, so polypropylene is very sensitive to oxidation. To this end, stabilizing treatment must be adopted before processing, at least in the polymerization stage to add a proper amount of polypropylene plastic antioxidant. A proper amount of polypropylene plastic antioxidant is added to the granulation.
The processing temperature of PP is generally 220~280 C. If the antioxidant is not added, the thermal degradation will be produced at the processing temperature, which makes the melt index increase. A commonly used industrial polypropylene plastics antioxidant system, mainly 2,6- butylated hydroxytoluene (BHT), phosphite and phosphonic acid ester.
The antioxidant system of PP often uses phosphorus containing compounds and hindered phenolic antioxidants to achieve good synergy. But for the processing stability is not high, the use of high molecular weight of phenolic antioxidants can be. Phosphorus containing compounds have good pumping resistance and also have the function of inhibiting color pollution.
The mechanism of action of polypropylene antioxidant:
1, chain initiation
Under the action of oxygen, light or heat, polypropylene (RH) can easily generate free radicals in its tertiary carbon atom.
RH light and heat R+HRH+O2 R+HOO
2. Chain transfer
The free radicals automatically catalyze the generation of free radicals and macromolecules, the decomposition of peroxide produces free radicals, and the free radicals can react with the polymer.
The free radical is continuously transmitted and the reaction continues:
R+O2ROO
ROO+RHROOH+R
ROOHRO+HO
ROOH+RH RO+R+H2O
RO+RHROH+R
HO+RHH2O+R
2ROOHRO+ROO+H2O1.3
Triphenyl phosphite (antioxidant, stabilizer TPPi)
Packing method: net weight of 200KG/galvanized iron bucket (a small cabinet to hold 16 tons), 1000KG/IB (a small container with 18 tons) or 23 tons of it.
Port of shipment: Shanghai port
Price quotation validity: 15 days
Warehouse time: within 15 days (customs clearance)
Export rights: our own right to import and export.
Triphenyl phosphite (TPPi antioxidants, stabilizer) is mainly used in PVC, polyethylene, polypropylene, polystyrene, polyester, abs resin, epoxy resin, synthetic rubber antioxidant stabilizer, used in polyvinyl chloride (PVC) products as a chelating agent.
3. Chain termination
The free radicals combine to produce stable products and terminate the chain reaction.
R+RR - R
R+ROOROOR
ROO+ROOROOR+O2
ROO+ROROR+O2
R+OH ROH
During the oxidation process, when the large molecular chain breaks down, the molecular weight decreases, the melt viscosity decreases, and the strength of polypropylene decreases or pulverized. When the macromolecule has crosslinking reaction, the molecular weight increases, the melt fluidity decreases, and the embrittlement and hardening occur. Oxidation structures such as carbonyl and peroxide generated during the oxidation process reduce the electrical properties of polypropylene, and increase the sensitivity to light induced degradation. The further reaction of this oxidation structure makes macromolecules break or cross link.
The role of antioxidants is to prevent the process of automatic oxidation chain reaction of polypropylene, that is to supply hydrogen to make the free radicals R and ROO generated in the oxidation process become RH and ROOH, or to turn ROOH into ROH, thereby improving the ability of oxidation and pyrolysis of polypropylene in processing and application.
Polypropylene, a thermoplastic resin made from polymerization of propylene, is a kind of thermoplastic resin. According to the position of methyl arrangement, it can be divided into three kinds: isotactic polypropylene (isotactic polypropylene), atactic polypropylene (atactic polypropylene) and syndiotactic polypropylene (syndiotactic polypropylene).
The methyl arrangement is called the isotactic polypropylene on the same side of the main chain. If methyl is arranged in disorder on both sides of the main chain, it is called atactic polypropylene. When methyl is alternately arranged on both sides of the molecular backbone, it is called syndiotactic polypropylene. In the general industrial polypropylene resin, the isotactic structure content is about 95%, and the rest are random or gauge polypropylene. Industrial products are mainly composed of isotactic materials. Polypropylene also includes copolymers of propylene and a small amount of ethylene. It is usually semitransparent and colorless solid, odorless and nontoxic. Because of the high crystallization of the structure, the melting point can be as high as 167 degrees C. Heat resistant, corrosion resistant, and steam disinfection of products are its outstanding advantages. Small density, the lightest general plastic.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
http://www.yaruichem.com
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