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Course Title : Basic Science, , Course Code: 22102, , A, Session On, , 6. Paints, Varnishes, Insulators, Polymer, Adhesives & Lubricants, by, , Mrs. S. N. Gavandi, (Lecturer in Chemistry), , Humanity & Science Department, , Shanti Education Society’s, , A. G. PATIL POLYTECHNIC INSTITUTE, SOLAPUR, (All Programs NBA Accredited), , 411
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What we are going to learn today....., Basic Concepts:, 1. Polymer & Polymerization, , Key Takeaways:, 1. Classification, synthesis &, applications of polymers., , 2
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Concept Map, , 1.Polymer, , 2. Classification, Synthesis &, Applications of polymers., 3
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Polymers, Polymers: In Greek, poly = many, mers = parts or segments., “Polymers are very large molecule that are made up of thousands even millions of atoms that are, bonded together in a repeating pattern”. The molecular links in the polymer chain are called, repeated units. “The repeating units in the polymer chain called monomers”., , Polymerization: The process in which large number of small molecules (monomers) linking, together to form a large molecule (polymer) in presence of temperature, pressure and catalyst, is known as polymerization., Degree of Polymerization: “The number of repeating units present in polymer is called, as degree of polymerization.”, , 4
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Types of Polymerization:, , 8
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Types of Polymerization:, , 9
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Polyethylene, Properties, , Properties, 1) High Density Polyethylene (HDPE) has high tensile, 1) strength,, High Density, Polyethylene, high density,, it is relatively(HDPE) has high tensile strength, high density,igh, brittle and, has low impact, low, density, polyethylene, isstrength., used inIt has, products, and packaging such as water pipes, toys,, moisture absorption., 2) Low Density Polyethylene (LDPE) has low density,, low tensile strength, less brittle. It has, low moisture permeability., Applications, 1) High density polyethylene is used in products and, packaging such as water pipes, toys,, detergent bottles., 2) Low density polyethylene is used for both rigid, containers and plastic film applications, such, as plastic bags and film wrap., For example: in orthopaedic products, in consumer, packaging bags, bottles and liners., , 10
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Polyvinyl chloride(PVC), Properties, 1) It is chemically inert., 2) It is colourless, odourless, 3) It has excellent resistance to water., 4) It is non-inflammable., 5) It is resistant to light and atmospheric oxygen., 6) It has excellent resistance to aqueous solutions, but it is attacked by stronger solvents such, as aromatic hydrocarbons, ketones, esters, chlorinated solvents etc., 11
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Polyvinyl chloride(PVC), , 12
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Teflon (Polytetrafluoroethylene) (PTFE), , Properties, 1) It has high molecular weight., 2) It has low coefficient of friction., 3) It has low chemical reactivity., 4) It is resistance to water, alcohol., 5) It is harder and stronger than the other polymers., Applications, 1) It is used in containers and pipework for reactive, and corrosive chemicals., 2) It is used as an insulating material for motor,, transformers, cables, wires etc., 3) It is used for making gaskets, tank linings,, packings., 4) It is commonly used as a graft material in, surgical interventions., 13
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Polystyrene (PS), Properties, 1) It is transparent, hard and brittle., 2) It has low melting point., 3) It is a very good electrical insulator., 4) It has excellent optical clarity., 5) It has good chemical resistance to diluted acids, and bases., 6) It can be easily moulded., Applications, 1) It is used in food packing, optical, electronic,, medical and automotive parts., 2) It is used for making the products like dining, utensils, plastic cups, housewares, toys, CD, cases, cosmetic containers, covers and fixtures., 3) It is used for making battery cases, refrigerator, parts etc., 14
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Bakelite, Synthesis of phenol formaldehyde (Bakelite), It is prepared by polymerization of phenol and formaldehyde in, presence of acidic or alkaline, catalyst., , 15
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Bakelite, Properties, 1) It is hard, rigid, non-flexible and brittle., 2) It is resistant to heat, scratches and destructive solvents., 3) It is resistant to electricity., 4) It can withstand very high temperature., Applications, 1) It is used for making, radio, telephone casings, plugs, switch, boards etc., 2) It is used for making sheets, rods and tubes., 3) It is used as an adhesive., 4) For impregnating fabrics, wood and paper., 5) For making bearings, used in propeller shafts for paper, industry and rolling mills., , 16
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Epoxy resins:, Synthesis:, It is prepared by condensation of bis-phenol and epichlorohydrin in presence of alkaline catalyst., , 17
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Epoxy resins:, Properties, 1) It is highly resistant to water, acids, bases and, solvents., 2) It has excellent adhesion property., 3) Epoxy resin is thermosetting resin characterised, by toughness, adhesion, corrosion resistance., Applications, 1) It is used for metal coatings, use in electrical and, electronic components / LED, high tension, electrical insulators., 2) It is used in industrial floorings, adhesives and, solders., 3) Moulds made from epoxy resins used for the, production of components for aircrafts and, automobiles., 4) It is used for surface coatings and gas storage, vessels., 18
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