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Polymers are naturally occurring and synthetic substances composed of long chains of atoms linked together to form 'giant molecules' or ______.
Polymers are naturally occurring and synthetic substances composed of long chains of atoms linked together to form 'giant molecules' or ______.
macromolecules
The high polymers are complex compounds of very large molecules usually with molecular weights of over ______.
The high polymers are complex compounds of very large molecules usually with molecular weights of over ______.
10,000
Natural polymers such as starch, cellulose, wool, various proteins etc. have always been part of our normal environment and have been used ______.
Natural polymers such as starch, cellulose, wool, various proteins etc. have always been part of our normal environment and have been used ______.
extensively
The basic structural units of high polymers are called ______.
The basic structural units of high polymers are called ______.
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It is possible to classify polymers in three groups, based on their reactions to stress and ______.
It is possible to classify polymers in three groups, based on their reactions to stress and ______.
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Thermoplasts or Thermoplasting Materials are essentially long chain macromolecules with a limited number of ______.
Thermoplasts or Thermoplasting Materials are essentially long chain macromolecules with a limited number of ______.
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The important examples of thermoplastic polymers are polyethylene, polystyrene. -1- of thermoplastic polymers are HIGH POLYMERS (MSU POLYTECHNIC)
The important examples of thermoplastic polymers are polyethylene, polystyrene. -1- of thermoplastic polymers are HIGH POLYMERS (MSU POLYTECHNIC)
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Polyethylene is produced by the addition polymerization of ethylene monomers under the influence of pressure, heat and a suitable catalyst: -2- HIGH POLYMERS (MSU POLYTECHNIC)
Polyethylene is produced by the addition polymerization of ethylene monomers under the influence of pressure, heat and a suitable catalyst: -2- HIGH POLYMERS (MSU POLYTECHNIC)
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The most important examples of thermosetting polymers are phenolic and urea formaldehydes, polyesters etc. 3. Elastomers: The third group of polymers called elastomers is composed of large molecules which tend to form spiral threads, somewhat like a coiled spring. These coils yield to a small stress but exert increasing resistance to further deformation. The group of elastomers is typified by rubber, which stretches under a slight stress but shows progressively greater resistance to distortion. The most important examples of elastomers are thiokols, Neoprene, Buna-S, Buna-N etc. SYNTHESIS OF HIGH POLYMERS: Synthetic high polymers can be made by two main processes: (a) -3- polymerisation (b) condensation polymerisation.
The most important examples of thermosetting polymers are phenolic and urea formaldehydes, polyesters etc. 3. Elastomers: The third group of polymers called elastomers is composed of large molecules which tend to form spiral threads, somewhat like a coiled spring. These coils yield to a small stress but exert increasing resistance to further deformation. The group of elastomers is typified by rubber, which stretches under a slight stress but shows progressively greater resistance to distortion. The most important examples of elastomers are thiokols, Neoprene, Buna-S, Buna-N etc. SYNTHESIS OF HIGH POLYMERS: Synthetic high polymers can be made by two main processes: (a) -3- polymerisation (b) condensation polymerisation.
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The above reaction thus occurs via double bond, and a chain reaction is propagated. To set the process going on an initiator is added. The process is terminated by either combining (coupling) two chains or by a reaction called -4-.
The above reaction thus occurs via double bond, and a chain reaction is propagated. To set the process going on an initiator is added. The process is terminated by either combining (coupling) two chains or by a reaction called -4-.
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The addition polymerization of the following compounds also takes place via double bonds to give polymers as mentioned against their names: -5- Polymerization: Polymerization may also take place via so called organic condensation reactions.
The addition polymerization of the following compounds also takes place via double bonds to give polymers as mentioned against their names: -5- Polymerization: Polymerization may also take place via so called organic condensation reactions.
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Condensation Polymerization occurs when two similar or dissimilar molecules react under the action of heat or initiation to form one larger molecule accompanied by the elimination of some simple molecules such as -6-.
Condensation Polymerization occurs when two similar or dissimilar molecules react under the action of heat or initiation to form one larger molecule accompanied by the elimination of some simple molecules such as -6-.
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The most important examples of elastomers are thiokols, Neoprene, Buna-S, Buna-N etc. SYNTHESIS OF HIGH POLYMERS: Synthetic high polymers can be made by two main processes: (a) addition polymerisation (b) -7- polymerisation.
The most important examples of elastomers are thiokols, Neoprene, Buna-S, Buna-N etc. SYNTHESIS OF HIGH POLYMERS: Synthetic high polymers can be made by two main processes: (a) addition polymerisation (b) -7- polymerisation.
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The most important examples of thermosetting polymers are phenolic and urea formaldehydes, polyesters etc. 3. Elastomers: The third group of polymers called elastomers is composed of large molecules which tend to form spiral threads, somewhat like a coiled spring. These coils yield to a small stress but exert increasing resistance to further deformation. The group of elastomers is typified by rubber, which stretches under a slight stress but shows progressively greater resistance to -8-.
The most important examples of thermosetting polymers are phenolic and urea formaldehydes, polyesters etc. 3. Elastomers: The third group of polymers called elastomers is composed of large molecules which tend to form spiral threads, somewhat like a coiled spring. These coils yield to a small stress but exert increasing resistance to further deformation. The group of elastomers is typified by rubber, which stretches under a slight stress but shows progressively greater resistance to -8-.
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The above reaction thus occurs via double bond, and a chain reaction is propagated. To set the process going on an initiator is added. The process is terminated by either combining (coupling) two chains or by a reaction called -9-.
The above reaction thus occurs via double bond, and a chain reaction is propagated. To set the process going on an initiator is added. The process is terminated by either combining (coupling) two chains or by a reaction called -9-.
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The most important examples of thermoplastic polymers are polyethylene, polystyrene. -10- of thermoplastic polymers are HIGH POLYMERS (MSU POLYTECHNIC)
The most important examples of thermoplastic polymers are polyethylene, polystyrene. -10- of thermoplastic polymers are HIGH POLYMERS (MSU POLYTECHNIC)
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Metals with the exception of the noble metals Ag, Au, and Pt, are usually found in nature combined with non-metals as oxides, sulphides, sulphates, carbonates, silicates etc. in the form of compounds known as ______
Metals with the exception of the noble metals Ag, Au, and Pt, are usually found in nature combined with non-metals as oxides, sulphides, sulphates, carbonates, silicates etc. in the form of compounds known as ______
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The natural combined form of the metal (i.e. mineral form) is more stable than the metal. That is why the metal after extraction from the mineral tends to revert to the stable natural combined to form when it comes in contact with the elements in the ______
The natural combined form of the metal (i.e. mineral form) is more stable than the metal. That is why the metal after extraction from the mineral tends to revert to the stable natural combined to form when it comes in contact with the elements in the ______
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The surfaces of almost all metals begin to decay more or less rapidly when exposed to gaseous atmosphere, water or any other reactive liquid medium. If the process is allowed to continue to completion, the metals are chemically converted to form the new products which are usually in form of oxides, hydrated oxides, carbonate, sulphides, sulphates etc. which have the same composition and crystal structure as the ______
The surfaces of almost all metals begin to decay more or less rapidly when exposed to gaseous atmosphere, water or any other reactive liquid medium. If the process is allowed to continue to completion, the metals are chemically converted to form the new products which are usually in form of oxides, hydrated oxides, carbonate, sulphides, sulphates etc. which have the same composition and crystal structure as the ______
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Such a process of chemical decay of metals due to the action of the surroundings medium is called ______
Such a process of chemical decay of metals due to the action of the surroundings medium is called ______
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Corrosion can be defined as the chemical attack on metals by the surrounding medium which tends to convert the metal into metallic ______
Corrosion can be defined as the chemical attack on metals by the surrounding medium which tends to convert the metal into metallic ______
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For example, when iron is exposed to an aqueous environment containing dissolved oxygen it tends to revert to its oxide ______
For example, when iron is exposed to an aqueous environment containing dissolved oxygen it tends to revert to its oxide ______
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Corrosion is a naturally occurring process of chemical conversion of a metal into its compound by the action of the surrounding ______
Corrosion is a naturally occurring process of chemical conversion of a metal into its compound by the action of the surrounding ______
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The simplest case of corrosion is that which occurs when metals come in contact directly with the gases like chlorine, hydrogen sulphide, sulphur ______, etc.
The simplest case of corrosion is that which occurs when metals come in contact directly with the gases like chlorine, hydrogen sulphide, sulphur ______, etc.
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The nature of the oxide film thus formed depends such upon the nature of ______
The nature of the oxide film thus formed depends such upon the nature of ______
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In the case of alkali and alkaline earth metals as Na, Mg (except Al), oxide film produced is smaller in volume than that of the metal from which it is formed. In such cases the oxide film formed over the surfaces of the metals is ______ in nature and thus does not prevent further action of oxygen.
In the case of alkali and alkaline earth metals as Na, Mg (except Al), oxide film produced is smaller in volume than that of the metal from which it is formed. In such cases the oxide film formed over the surfaces of the metals is ______ in nature and thus does not prevent further action of oxygen.
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The system involves the formation of several type of electrolytic cells mainly ______
The system involves the formation of several type of electrolytic cells mainly ______
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This type of corrosion occurs at a solid-liquid interface when the metals are in contact with the moist air or any liquid medium. It is also known as immersed or wet ______.
This type of corrosion occurs at a solid-liquid interface when the metals are in contact with the moist air or any liquid medium. It is also known as immersed or wet ______.
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Synthetic high polymers can be made by two main processes: (a) addition polymerisation (b) ______ polymerisation.
Synthetic high polymers can be made by two main processes: (a) addition polymerisation (b) ______ polymerisation.
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Polyethylene is produced by the addition polymerization of ethylene monomers under the influence of pressure, heat and a suitable catalyst: ______ HIGH POLYMERS (MSU POLYTECHNIC)
Polyethylene is produced by the addition polymerization of ethylene monomers under the influence of pressure, heat and a suitable catalyst: ______ HIGH POLYMERS (MSU POLYTECHNIC)
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Polymers are naturally occurring and synthetic substances composed of long chains of atoms linked together to form 'giant molecules' or ______.
Polymers are naturally occurring and synthetic substances composed of long chains of atoms linked together to form 'giant molecules' or ______.
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The high polymers are complex compounds of very large molecules usually with molecular weights of over ______.
The high polymers are complex compounds of very large molecules usually with molecular weights of over ______.
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