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UNIT IIIADVANCED MATERIALS Q1) Give a brief idea about the polymer and its properties.A1) Polymer chemists study large, complex molecules that are built up from many smaller units. They study about the smaller building blocks combine, and create useful materials with specific characteristics by manipulating the molecular structure of the monomers/polymers used, the composition of the monomer/polymer combinations, and applying chemical and processing techniques that can to a large extent, affect the properties of the final product. Polymer chemists are unique within the chemistry community because their understanding of the relationship between structure and property spans from the molecular scale to the macroscopic scale. It is a long molecule formed by joining together of thousands of small molecular units by chemical bonds. Polymers are giant molecules also called macromolecules that are essential to our existence. They are important chemicals in our bodies in plants (starch, cellulose) and in our everyday lives (fibers, plastics, elastomers). Polymers are made by transforming small molecules into molecules with very large molecular weights. Although the chemical properties of polymers are similar to those of analogous small molecules, their physical properties are quite different. Every polymer has its own characteristics, but most polymers have the following general properties: Polymers can be very resistant to chemicals.Polymers can be both thermal and electrical insulators.Generally, polymers are light in weight with varying degrees of strength.Polymers can be processed in various ways to produce thin fibers or intricate parts. Q2) What are thermoplastic polymer?A2) A thermoplastic is a resin that is solid at room temperature but becomes plastic and soft upon heating, flowing due to crystal melting or by virtue of crossing the glass transition temperature (Tg). Upon processing, usually via injection-moulding or blow-moulding-like processes, thermoplastics take the shape of the mould within which they are poured as melt, and cool to solidify into the desired shape. The significant aspect of thermoplastics is their reversibility, the ability to undergo reheating, melt again, and change shape. This allows for additional processing of the same material, even after being prepared as a solid. Processes such as extrusion, thermoforming, and injection moulding rely on such resin behaviour. Some common thermoplastic materials include polyethylene (PE), polycarbonate (PC), and polyvinyl chloride (PVC). Q3) What is thermosetting polymer?A3) A thermosetting resin, or thermosetting polymer, is generally a liquid material at room temperature which hardens irreversibly upon heating or chemical addition. When it is placed in a mould and heated, the most solidifies into the specified shape, but this solidification process includes the formation of certain bonds, called cross links, that hold the molecules in place and change the basic nature of the material, preventing it from melting. As a result, a there most, as opposed to a thermoplastic, cannot return to its initial phase, rendering the process irreversible. There most, upon heating, become set, fixed in a specific form. During overheating, there most tend to degrade without entering a fluid phase. Processes such as compression molding, resin transfer molding, pultrusion, hand lay-up, and filament winding depend on thermosetting polymer behavior. Some common there most include epoxy, polyimide, and phenolic, many of which are significant in composites. Q4) Explain phenol formaldehyde with its structure.A4) Phenol formaldehyde is the synthetic high polymers. They are formed by the reaction of phenol and substitute of phenol with formaldehyde. Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignin’s in thermo setting materials. They are formed by the step growth polymerization reaction.
Q5) Explain the applications of phenol formaldehyde.A5)1) Phenolic resins are mainly used in the circuit board production that is for making circuit board like PCB.2) It is also used in Laminated Material like Laminated sheets, rods and tubes.3) Phenolic resin is used as a binder in loudspeaker driver suspension components which are made of cloth.4) Phenolic resins are used in making of Duroplast, used in the Trabant automobiles. Q6) What is Urea formaldehyde?A6) Urea-formaldehyde is also known as urea-methanal. It is a non-transparent thermosetting resin which is made from urea and formaldehyde when they are heated in the presence of a mild base such as ammonia or pyridine. These resins are commonly used in adhesives, finishes and molded objects.A class of synthetic resins called Urea-formaldehyde resin is obtained by chemical combination of urea (a solid crystal obtained from ammonia) and formaldehyde (a highly reactive gas obtained from methane). Urea-formaldehyde resins are used mostly as adhesives for the bonding of plywood, particle board and other structured wood products.
Q7) Explain the synthesis of Urea Formaldehyde.A7)
Q8) Mention the applications of Urea formaldehyde.A8)
Q10) Mention the applications of epoxy resins.A10)
Q13) Explain Glass reinforced plastics.A13) GRP is an acronym for Glass Reinforced Plastic is also often referred to as fibreglass (fibre glass in the US) or glass fibre composite and belongs to a family of products known as FRP or Fibre Reinforced Plastics. These are composed on fibres embedded in the matrix material. These can be further divided into 3 categories – continuous aligned, discontinuous aligned and discontinuous randomly oriented fibre composites.e.g. – glass fibre reinforced composite, carbon fibre reinforced and aramid fibre reinforced composites.Technique: -Resin is coated on fibre cloth or fibre mat on both the sides. Rollers are used to spread the resin uniformly. Alternative layers of the resin – fibre material arranged with same or different orientation for getting proper thickness then passing through mould for proper temperature.
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1) It is used as an adhesive for decorative laminate applications (7%).
2) It is used in wet laid fiber glass mats, air filtration, coated and bonded abrasives.
3) Urea Formaldehyde is used as wood adhesives they are mainly used for the manufacture of wood products intended for interior use only. Q9) What is Epoxy Resins?A9) Epoxy resins are a wonderful chemical known for its versatile nature. Epoxy is highly useful chemical compounds; epoxy resins have carved their niche in a number of industrial applications.
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1) Epoxies are used in paint industry as it dries quickly and provides protective layers that are highly tough.
2) Epoxies are used as structural or engineering adhesives used in the construction of aircrafts, automobiles, boats.
3) These are an integral part of the electronic industry and used in over molding transistors, integrated circuits, PCB’s and hybrid circuits.
4) As an imperative part of aerospace industry, epoxies are used as structural matrix material.
5) In a highly technical application, epoxy resin is used for embedding samples for their use under electron microscope.
6) Not limited just to technical applications, artists have also used epoxies as a painting medium by mixing it with pigment to obtain colors. Q11) What is conducting polymer? Explain with its applications.A11) Conductive polymers or more precisely, intrinsically conducting polymers (ICPs) are organic polymers that conduct electricity. Such compounds may have metallic conductivity or can be semiconductors. The biggest advantage of conductive polymers is their processability, mainly by dispersion. Conductive polymers are generally not thermoplastics, i.e., they are not thermo formable. But, like insulating polymers, they are organic materials. They can offer high electrical conductivity but do not show similar mechanical properties to other commercially available polymers. The electrical properties can be fine-tuned using the methods of organic synthesis and by advanced dispersion techniques.Applications:1) They are anti-static substance for photographic film.2) They are corrosion inhibitors.3) They are compact capacitors.4) They are anti static coated.5) Electromagnetic shielding for computers.6) They are used in transistors.7) They are used in Light Emitting Diodes.8) They are used in solar cells. Q12) Discuss about the composition of composite materials.A12)
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UNIT IIIADVANCED MATERIALS Q1) Give a brief idea about the polymer and its properties.A1) Polymer chemists study large, complex molecules that are built up from many smaller units. They study about the smaller building blocks combine, and create useful materials with specific characteristics by manipulating the molecular structure of the monomers/polymers used, the composition of the monomer/polymer combinations, and applying chemical and processing techniques that can to a large extent, affect the properties of the final product. Polymer chemists are unique within the chemistry community because their understanding of the relationship between structure and property spans from the molecular scale to the macroscopic scale. It is a long molecule formed by joining together of thousands of small molecular units by chemical bonds. Polymers are giant molecules also called macromolecules that are essential to our existence. They are important chemicals in our bodies in plants (starch, cellulose) and in our everyday lives (fibers, plastics, elastomers). Polymers are made by transforming small molecules into molecules with very large molecular weights. Although the chemical properties of polymers are similar to those of analogous small molecules, their physical properties are quite different. Every polymer has its own characteristics, but most polymers have the following general properties: Polymers can be very resistant to chemicals.Polymers can be both thermal and electrical insulators.Generally, polymers are light in weight with varying degrees of strength.Polymers can be processed in various ways to produce thin fibers or intricate parts. Q2) What are thermoplastic polymer?A2) A thermoplastic is a resin that is solid at room temperature but becomes plastic and soft upon heating, flowing due to crystal melting or by virtue of crossing the glass transition temperature (Tg). Upon processing, usually via injection-moulding or blow-moulding-like processes, thermoplastics take the shape of the mould within which they are poured as melt, and cool to solidify into the desired shape. The significant aspect of thermoplastics is their reversibility, the ability to undergo reheating, melt again, and change shape. This allows for additional processing of the same material, even after being prepared as a solid. Processes such as extrusion, thermoforming, and injection moulding rely on such resin behaviour. Some common thermoplastic materials include polyethylene (PE), polycarbonate (PC), and polyvinyl chloride (PVC). Q3) What is thermosetting polymer?A3) A thermosetting resin, or thermosetting polymer, is generally a liquid material at room temperature which hardens irreversibly upon heating or chemical addition. When it is placed in a mould and heated, the most solidifies into the specified shape, but this solidification process includes the formation of certain bonds, called cross links, that hold the molecules in place and change the basic nature of the material, preventing it from melting. As a result, a there most, as opposed to a thermoplastic, cannot return to its initial phase, rendering the process irreversible. There most, upon heating, become set, fixed in a specific form. During overheating, there most tend to degrade without entering a fluid phase. Processes such as compression molding, resin transfer molding, pultrusion, hand lay-up, and filament winding depend on thermosetting polymer behavior. Some common there most include epoxy, polyimide, and phenolic, many of which are significant in composites. Q4) Explain phenol formaldehyde with its structure.A4) Phenol formaldehyde is the synthetic high polymers. They are formed by the reaction of phenol and substitute of phenol with formaldehyde. Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignin’s in thermo setting materials. They are formed by the step growth polymerization reaction.
Q5) Explain the applications of phenol formaldehyde.A5)1) Phenolic resins are mainly used in the circuit board production that is for making circuit board like PCB.2) It is also used in Laminated Material like Laminated sheets, rods and tubes.3) Phenolic resin is used as a binder in loudspeaker driver suspension components which are made of cloth.4) Phenolic resins are used in making of Duroplast, used in the Trabant automobiles. Q6) What is Urea formaldehyde?A6) Urea-formaldehyde is also known as urea-methanal. It is a non-transparent thermosetting resin which is made from urea and formaldehyde when they are heated in the presence of a mild base such as ammonia or pyridine. These resins are commonly used in adhesives, finishes and molded objects.A class of synthetic resins called Urea-formaldehyde resin is obtained by chemical combination of urea (a solid crystal obtained from ammonia) and formaldehyde (a highly reactive gas obtained from methane). Urea-formaldehyde resins are used mostly as adhesives for the bonding of plywood, particle board and other structured wood products.
Q7) Explain the synthesis of Urea Formaldehyde.A7)
Q8) Mention the applications of Urea formaldehyde.A8)
Q10) Mention the applications of epoxy resins.A10)
Q13) Explain Glass reinforced plastics.A13) GRP is an acronym for Glass Reinforced Plastic is also often referred to as fibreglass (fibre glass in the US) or glass fibre composite and belongs to a family of products known as FRP or Fibre Reinforced Plastics. These are composed on fibres embedded in the matrix material. These can be further divided into 3 categories – continuous aligned, discontinuous aligned and discontinuous randomly oriented fibre composites.e.g. – glass fibre reinforced composite, carbon fibre reinforced and aramid fibre reinforced composites.Technique: -Resin is coated on fibre cloth or fibre mat on both the sides. Rollers are used to spread the resin uniformly. Alternative layers of the resin – fibre material arranged with same or different orientation for getting proper thickness then passing through mould for proper temperature.
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1) It is used as an adhesive for decorative laminate applications (7%).
2) It is used in wet laid fiber glass mats, air filtration, coated and bonded abrasives.
3) Urea Formaldehyde is used as wood adhesives they are mainly used for the manufacture of wood products intended for interior use only. Q9) What is Epoxy Resins?A9) Epoxy resins are a wonderful chemical known for its versatile nature. Epoxy is highly useful chemical compounds; epoxy resins have carved their niche in a number of industrial applications.
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1) Epoxies are used in paint industry as it dries quickly and provides protective layers that are highly tough.
2) Epoxies are used as structural or engineering adhesives used in the construction of aircrafts, automobiles, boats.
3) These are an integral part of the electronic industry and used in over molding transistors, integrated circuits, PCB’s and hybrid circuits.
4) As an imperative part of aerospace industry, epoxies are used as structural matrix material.
5) In a highly technical application, epoxy resin is used for embedding samples for their use under electron microscope.
6) Not limited just to technical applications, artists have also used epoxies as a painting medium by mixing it with pigment to obtain colors. Q11) What is conducting polymer? Explain with its applications.A11) Conductive polymers or more precisely, intrinsically conducting polymers (ICPs) are organic polymers that conduct electricity. Such compounds may have metallic conductivity or can be semiconductors. The biggest advantage of conductive polymers is their processability, mainly by dispersion. Conductive polymers are generally not thermoplastics, i.e., they are not thermo formable. But, like insulating polymers, they are organic materials. They can offer high electrical conductivity but do not show similar mechanical properties to other commercially available polymers. The electrical properties can be fine-tuned using the methods of organic synthesis and by advanced dispersion techniques.Applications:1) They are anti-static substance for photographic film.2) They are corrosion inhibitors.3) They are compact capacitors.4) They are anti static coated.5) Electromagnetic shielding for computers.6) They are used in transistors.7) They are used in Light Emitting Diodes.8) They are used in solar cells. Q12) Discuss about the composition of composite materials.A12)
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