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The polymerization of styrene monomer
by：CSSSLD
2021-02-03
Due to the volume effect weakens the injection molding processing factory PS force between molecules, in under the action of heat, prone to slip between macromolecules so it melt in the molding processing has good liquidity.
Because benzene radiant energy can be evenly distributed on the benzene ring, and thus to minimize damage to the polymer itself, so the PS has high radiation resistance.
Only under the effect of large dose of radiation energy, the performance will change significantly.
styrene bulk polymerization is by heat or initiator type caused by free radical polymerization. On poly styrene polymerization when first in 95 - in the kettle 115 ℃ for pre - polymerization, after waiting for the conversion of 30% Again, after a 35% into continuous tower reactor, increasing reaction temperature from 100 ℃ segmented to about 180 ℃, maintain reaction rate up to 95%. The final reaction products in a vacuum tank degassing processing, remove not after the reaction of volatiles, from the bottom, after extruding get PS granular material.
PS bulk polymerization and suspension polymerization are following radical polymerization mechanism, macromolecular chain basic random configuration, which makes the PS for typical amorphous thermoplastic polymer, has the good transparency; PS is basically linear macromolecular chain, chain transfer and termination of polymerization reaction will produce a small amount of branched chain and unsaturated structure. Unsaturated structure will form the sensitive when aging. PS macromolecular chain on the presence of benzene ring to make the space steric effect is larger, the PS of macromolecular chain is relatively rigid, just and brittle nature of the macro. As a result, its products will be in the case of improper molding process conditions to produce internal stress, resulting in products to produce silver lines, and even cracking.
basic does not need to add auxiliary material by bulk polymerization, and the high purity product, has the good transparency and electric properties. But owing to the high polymer viscosity, heat dissipation is difficult, not easy to control temperature, cause the product the low relative molecular mass, At the same time, stirring difficulty, easy to cause local temperature is too high, causes the relative molecular mass distribution, make the product mechanical properties was given a certain influence.
the suspension polymerization of styrene in water as medium, according to the reaction temperature is different, can be divided into the polymerization temperature and polymerization at low temperature. Low temperature polymerization with pva as dispersant, with two benzoyl peroxide as initiator, under 85 ℃ by strong mixing suspension aggregated; High temperature polymerization without using initiator to magnesium carbonate or calcium carbonate as dispersant, with styrene - Sodium salt of maleic anhydride to dispersant and aggregated under 150 ℃ high temperature.
the manufacturing methods of styrene are many, in industry is given priority to with ethylbenzene catalytic dehydrogenation method. Ethylene mainly ethylene and benzene as raw materials by means of into. Styrene monomer by bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, ionic polymerization methods such as synthesis of PS, more in industrial application is bulk polymerization and suspension polymerization. Bulk polymerization and suspension polymerization process there is a big difference.
get pulp after suspension polymerization of styrene polymers, with nitrogen to expel unreacted styrene monomer, then after wash, centrifugal separation, drying PS resin bead granular molding processing. Suspension polymerization temperature easy to control, heat of reaction is easy to send out, the product has a relatively uniform molecular weight distribution, the characteristics of excellent comprehensive performance. But in the products will remain a small amount of dispersant, has certain influence to the product transparency, also had a bulk polymerization and complex process. At present, the styrene polymerization is given priority to with bulk polymerization, suspension polymerization is used to produce hair PS bead.
more excellent articles: polyolefin elastomer, click directly.
http://www。 csssld。 cn//html/2017/Info_0930/687。 HTML
changshu smoothly da plastic products factory website: http://www. csssld。 Cn /
more wonderful articles, immediately search: changshu da plastic products factory smoothly
styrene bulk polymerization is by heat or initiator type caused by free radical polymerization. On poly styrene polymerization when first in 95 - in the kettle 115 ℃ for pre - polymerization, after waiting for the conversion of 30% Again, after a 35% into continuous tower reactor, increasing reaction temperature from 100 ℃ segmented to about 180 ℃, maintain reaction rate up to 95%. The final reaction products in a vacuum tank degassing processing, remove not after the reaction of volatiles, from the bottom, after extruding get PS granular material.
PS bulk polymerization and suspension polymerization are following radical polymerization mechanism, macromolecular chain basic random configuration, which makes the PS for typical amorphous thermoplastic polymer, has the good transparency; PS is basically linear macromolecular chain, chain transfer and termination of polymerization reaction will produce a small amount of branched chain and unsaturated structure. Unsaturated structure will form the sensitive when aging. PS macromolecular chain on the presence of benzene ring to make the space steric effect is larger, the PS of macromolecular chain is relatively rigid, just and brittle nature of the macro. As a result, its products will be in the case of improper molding process conditions to produce internal stress, resulting in products to produce silver lines, and even cracking.
basic does not need to add auxiliary material by bulk polymerization, and the high purity product, has the good transparency and electric properties. But owing to the high polymer viscosity, heat dissipation is difficult, not easy to control temperature, cause the product the low relative molecular mass, At the same time, stirring difficulty, easy to cause local temperature is too high, causes the relative molecular mass distribution, make the product mechanical properties was given a certain influence.
the suspension polymerization of styrene in water as medium, according to the reaction temperature is different, can be divided into the polymerization temperature and polymerization at low temperature. Low temperature polymerization with pva as dispersant, with two benzoyl peroxide as initiator, under 85 ℃ by strong mixing suspension aggregated; High temperature polymerization without using initiator to magnesium carbonate or calcium carbonate as dispersant, with styrene - Sodium salt of maleic anhydride to dispersant and aggregated under 150 ℃ high temperature.
the manufacturing methods of styrene are many, in industry is given priority to with ethylbenzene catalytic dehydrogenation method. Ethylene mainly ethylene and benzene as raw materials by means of into. Styrene monomer by bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, ionic polymerization methods such as synthesis of PS, more in industrial application is bulk polymerization and suspension polymerization. Bulk polymerization and suspension polymerization process there is a big difference.
get pulp after suspension polymerization of styrene polymers, with nitrogen to expel unreacted styrene monomer, then after wash, centrifugal separation, drying PS resin bead granular molding processing. Suspension polymerization temperature easy to control, heat of reaction is easy to send out, the product has a relatively uniform molecular weight distribution, the characteristics of excellent comprehensive performance. But in the products will remain a small amount of dispersant, has certain influence to the product transparency, also had a bulk polymerization and complex process. At present, the styrene polymerization is given priority to with bulk polymerization, suspension polymerization is used to produce hair PS bead.
more excellent articles: polyolefin elastomer, click directly.
http://www。 csssld。 cn//html/2017/Info_0930/687。 HTML
changshu smoothly da plastic products factory website: http://www. csssld。 Cn /
more wonderful articles, immediately search: changshu da plastic products factory smoothly
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