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What is the difference between bleeding and blooming of polymer additives?
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Michelle Gibson
What is the difference between bleeding and blooming of polymer additives?
It is common for polymeric compounds to form surface regions with compositions different from the bulk of the material, by selective diffusion of components. This process is called blooming when the surface component is solid, and bleeding if it is liquid. Blooming is a phenomenon shown by compounds with low solubility and high diffusion rate. It involves the migration of the additive out of the polymer matrix onto the surface as a very thin film. Soluble Sulphur shows Blooming, and therefore affects cross link density and hence vulcanizate properties. Therefore we use Insoluble Sulphur. Blooming can occur when large amounts of soluble sulfur are used, because at high mixing temperatures, the solubility of S8 is high, enabling large amounts to dissolve, but upon cooling the solubility decreases. When the solubility limit is reached, excess sulfur blooms to the surface. Sulfur bloom reduces the "tack" of a rubber compound, a necessary property if layers of rubber are to be plied up to make a composite structure, such as a tire. Insoluble sulfur does not bloom because it disperses in rubber as discrete particles, which cannot readily diffuse through the rubber. However, above 120°C, insoluble sulfur transforms into soluble sulfur. Thus, mixing temperatures must be kept below 120°C to take advantage of the bloom resistance of insoluble sulfur.
Also note that Insoluble sulphur is also called Amorphous Sulphur as it looks more like a Polymer chain. And soluble sulphur is called Rhombic Sulphur (s8).
It is common for polymeric compounds to form surface regions with compositions different from the bulk of the material, by selective diffusion of components. This process is called blooming when the surface component is solid, and bleeding if it is liquid. Blooming is a phenomenon shown by compounds with low solubility and high diffusion rate. It involves the migration of the additive out of the polymer matrix onto the surface as a very thin film. Soluble Sulphur shows Blooming, and therefore affects cross link density and hence vulcanizate properties. Therefore we use Insoluble Sulphur. Blooming can occur when large amounts of soluble sulfur are used, because at high mixing temperatures, the solubility of S8 is high, enabling large amounts to dissolve, but upon cooling the solubility decreases. When the solubility limit is reached, excess sulfur blooms to the surface. Sulfur bloom reduces the "tack" of a rubber compound, a necessary property if layers of rubber are to be plied up to make a composite structure, such as a tire. Insoluble sulfur does not bloom because it disperses in rubber as discrete particles, which cannot readily diffuse through the rubber. However, above 120°C, insoluble sulfur transforms into soluble sulfur. Thus, mixing temperatures must be kept below 120°C to take advantage of the bloom resistance of insoluble sulfur.
Also note that Insoluble sulphur is also called Amorphous Sulphur as it looks more like a Polymer chain. And soluble sulphur is called Rhombic Sulphur (s8).
Bleeding and blooming phenomena are most common in polymers which uses additives.
Bleeding
Whenever an additive is added to a polymer first its compatibility (solubility) with the polymer should be studied. If the additive added have some solubility with polymer as well as the adjacent material in which the polymer is in contact during service the added additive bleed on the surface of adjacent material. The adjacent material can get colored or contaminated due to bleeding
Blooming
Whenever an additive added to the polymer is soluble in processing temperature but insoluble in service temperature then the insoluble additive comes out of the bulk of the polymer and gets deposited on the surface of the polymer.
This phenomena is used to coat the surface of the polymer and protect the polymer. Initially the additive which is soluble in polymer in processing temperature but insoluble in service temperature is added and as the polymer cools the additive behaves as incompatible member and blooms to the surface making a coating over the surface of the article
Bleeding and blooming phenomena are most common in polymers which uses additives.
Bleeding
Whenever an additive is added to a polymer first its compatibility (solubility) with the polymer should be studied. If the additive added have some solubility with polymer as well as the adjacent material in which the polymer is in contact during service the added additive bleed on the surface of adjacent material. The adjacent material can get colored or contaminated due to bleeding
Blooming
Whenever an additive added to the polymer is soluble in processing temperature but insoluble in service temperature then the insoluble additive comes out of the bulk of the polymer and gets deposited on the surface of the polymer.
This phenomena is used to coat the surface of the polymer and protect the polymer. Initially the additive which is soluble in polymer in processing temperature but insoluble in service temperature is added and as the polymer cools the additive behaves as incompatible member and blooms to the surface making a coating over the surface of the article
It is common for polymeric compounds to form surface regions with compositions different from the bulk of the material, by selective diffusion of components. This process is called blooming when the surface component is solid, and bleeding if it is liquid.
Blooming is a phenomenon shown by compounds with low solubility and high diffusion rate. It involves the migration of the additive out of the polymer matrix onto the surface as a very thin film. Soluble Sulphur shows Blooming, and therefore affects cross link density and hence vulcanizate properties. Therefore we use Insoluble Sulphur. Blooming can occur when large amounts of soluble sulfur are used, because at high mixing temperatures, the solubility of S8 is high, enabling large amounts to dissolve, but upon cooling the solubility decreases. When the solubility limit is reached, excess sulfur blooms to the surface. Sulfur bloom reduces the "tack" of a rubber compound, a necessary property if layers of rubber are to be plied up to make a composite structure, such as a tire. Insoluble sulfur does not bloom because it disperses in rubber as discrete particles, which cannot readily diffuse through the rubber. However, above 120°C, insoluble sulfur transforms into soluble sulfur. Thus, mixing temperatures must be kept below 120°C to take advantage of the bloom resistance of insoluble sulfur.
Also note that Insoluble sulphur is also called Amorphous Sulphur as it looks more like a Polymer chain. And soluble sulphur is called Rhombic Sulphur (s8).
It is common for polymeric compounds to form surface regions with compositions different from the bulk of the material, by selective diffusion of components. This process is called blooming when the surface component is solid, and bleeding if it is liquid.
Blooming is a phenomenon shown by compounds with low solubility and high diffusion rate. It involves the migration of the additive out of the polymer matrix onto the surface as a very thin film. Soluble Sulphur shows Blooming, and therefore affects cross link density and hence vulcanizate properties. Therefore we use Insoluble Sulphur. Blooming can occur when large amounts of soluble sulfur are used, because at high mixing temperatures, the solubility of S8 is high, enabling large amounts to dissolve, but upon cooling the solubility decreases. When the solubility limit is reached, excess sulfur blooms to the surface. Sulfur bloom reduces the "tack" of a rubber compound, a necessary property if layers of rubber are to be plied up to make a composite structure, such as a tire. Insoluble sulfur does not bloom because it disperses in rubber as discrete particles, which cannot readily diffuse through the rubber. However, above 120°C, insoluble sulfur transforms into soluble sulfur. Thus, mixing temperatures must be kept below 120°C to take advantage of the bloom resistance of insoluble sulfur.
Also note that Insoluble sulphur is also called Amorphous Sulphur as it looks more like a Polymer chain. And soluble sulphur is called Rhombic Sulphur (s8).
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Bleeding and blooming phenomena are most common in polymers which uses additives.
Bleeding
Whenever an additive is added to a polymer first its compatibility (solubility) with the polymer should be studied. If the additive added have some solubility with polymer as well as the adjacent material in which the polymer is in contact during service the added additive bleed on the surface of adjacent material. The adjacent material can get colored or contaminated due to bleeding
Blooming
Whenever an additive added to the polymer is soluble in processing temperature but insoluble in service temperature then the insoluble additive comes out of the bulk of the polymer and gets deposited on the surface of the polymer.
This phenomena is used to coat the surface of the polymer and protect the polymer. Initially the additive which is soluble in polymer in processing temperature but insoluble in service temperature is added and as the polymer cools the additive behaves as incompatible member and blooms to the surface making a coating over the surface of the article
Bleeding and blooming phenomena are most common in polymers which uses additives.
Bleeding
Whenever an additive is added to a polymer first its compatibility (solubility) with the polymer should be studied. If the additive added have some solubility with polymer as well as the adjacent material in which the polymer is in contact during service the added additive bleed on the surface of adjacent material. The adjacent material can get colored or contaminated due to bleeding
Blooming
Whenever an additive added to the polymer is soluble in processing temperature but insoluble in service temperature then the insoluble additive comes out of the bulk of the polymer and gets deposited on the surface of the polymer.
This phenomena is used to coat the surface of the polymer and protect the polymer. Initially the additive which is soluble in polymer in processing temperature but insoluble in service temperature is added and as the polymer cools the additive behaves as incompatible member and blooms to the surface making a coating over the surface of the article
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