MANUFACTURED SUBTANCES IN INDUSTRY BY : NURFARAHAIN BINTI AHMAD 4ST SMK SG ABONG
IntroductionMany industrial products are manufactured for our comfort.They are either made from sulphuric acid, ammonia, alloys, syntheticpolymers, glass, ceramics or composite materials.
MAIN MENU ALLOYSYNTHETIC POLYMERS GLASS & CERAMICSCOMPOSITE MATERIALS
ALLOYS∗ An alloy is a homogenous mixture of two or more elements (especially metals) mixed in a certain fixed percentage.∗ Alloys are made to improve the hardness, malleability and resistance to corrosion of pure metals.∗ General properties of pure metals : * ductile- can be drawn into wires
* malleable- can be hammered into sheets * high melting and boiling points * high density * high electrical and heat conductivity∗Most metals in their pure form are soft.∗Metals like iron and copper tend to undergo corrosion readilyto form oxides.
∗ A pure metal consists of layers of atoms arranged in an even, orderly, and close-packed manner at fixed position.
∗ Pure metals are rather soft because when a force is applied, one layer of atoms can slide over another.∗ Metals are ductile or can be stretched.
Some imperfections in the orderly arrangement of atoms in metals that allow some empty space in between the atoms. When a metal is knocked , atom slide. Metals are malleable or can be shaped.force the shape of the metal changes
∗ Alloys such as bronze, brass, steel, stainless, duralumin and pewter are commonly used in our daily lives.∗ The uses of each different type of alloys depend on the properties of the alloy.∗ For example, cutlery is made of stainless steel because stainless steel is shiny and does not rust.
∗ Table 1 The composition, properties and uses of some alloys Alloy Composition Properties UsesBronze • 90% copper • Hard and strong • In the building of • 10% tin • Does not corrode statues or monuments easily • In the making of • Has shiny surface medals, swords and artistic materialsBrass • 70% copper • Hard than copper In the making of musical • 30% zinc instruments and kitchenwareSteel • 99% iron • Hard and strong • In the construction of • 1% carbon buildings and bridges • In the building of the body of cars and railway tracks
Alloy Composition Properties UsesStainless • 74%iron • Shiny • In the making cutlerysteel • 8% carbon • Strong • In the making of • 18% chromium • Does not rust surgical instrumentsDuralumin • 93% aluminium • Light • In the building of the • 3% copper • Stong body of aeroplanes and • 3% magnesium bullet trains • 1% manganesePewter • 96% tin • Lustre • In the making of • 3% copper • Shiny souvenirs • 1% antimony • Strong
THE ARRANGEMENT OF ATOMS IN ALLOYS∗ The presence of atoms of other metals that are of different size disturb the orderly arrangement of atoms in the metal.∗ This reduces the layer of atoms from sliding.∗ Thus, an alloy is stronger and harder than its pure metal.
Pure metal A Pure metal B Alloy The formation of alloy
Synthetic Polymers∗ Polymers are large molecules made up of many identical repeating sub-units called monomers which are joined together by covalent bonds.∗ Monomers are joined into chains by a process of repeated linking known as polymerisation.
A polymer may consist of thousands of monomers. Some polymersoccur naturally.Starch, cellulose, wool, protein, silk and natural rubber are someexample of naturally occuring polymers.Synthetic polymerare man-made polymers.The monomers used are usually obtained from petroleum aftergoing through the refining and cracking processes.The monomers used are usually obtained from petroleum aftergoing through the refining and cracking processes.
Monomers in synthetic polymersSynthetic polymer Monomer UsesPolythene Ethene Plastic bags, shopping bags, plastic containers and insulation for electrical wiringPolypropene Propene Piping, bottle crates, carpets, car batteries and ropesPolyvinyl chloride, Chloroethene Artificial leather, water pipesPVC and records
Synthetic polymer Monomer UsesPerspex Methylmethacrylate Safety glass, reflectors, traffic signs and lensTerylene Hexane-1,6-diol Clothing, sails and ropes Benzene-1, 4-dicarboxylic acidNylon Hexane-1,6-diamine Ropes, clothing and Hexane-1, carpets 6-diodic acid
Synthetic polymer in daily lifeWith the increasing use of synthetic polymers, there are some drawbacks :Synthetic polymers are non-biodegradable. Disposal of synthetic polymerswill use up a large fraction of available landfill space.The raw materials for these polymers are obtained from petroleum, thusdepleting the supply of non-renewable source.Burning of synthetic polymers releases pollutant and toxic gases that areharmful to our health. For example, burning of PVC releases hydrogen chloridegas. Gases such as carbon monoxide, carbon dioxide, sulphur dioxide and oxideof nitrogen can cause the green house effect and acid rain.Improper disposal of synthetic polymers also destroy the beauty of thenature , causes flash flood and endanger the wildlife.
•To reduce the demand for landfill space, consumption of limited petroleum reserves and environmental pollution, we should :Reduce, reuse and recycle the non-biodegradable synthetic polymers.Use the biodegradable plastics (Bioplastic) such as polylactide acid (PLA)plastic and poly-3-hydroxybutyrate (PHB) plastic.Educate users to the right disposal methods.
GlassThe major component of glass is silica or silicon dioxide, SiO2.Silicon dioxide is the second most abundant elements in the Earth’scrust. It is commonly found in sand.The most way common of preparing glass is to heat the sand to thetemperature of 1700 degree celcius. The molten liquid obtained is thecooled quickly so that it solidifies to produce glass.
Silicon atom Oxygen atomStructure of silicon dioxide
During rapid cooling, the particles in the liquid do not have time to return toits original crystalline arrangement. They occupy randomly arranged latticesites and result s in an amorphus solid. This amorphus structure makes theglass brittle.The main characteristics of glass are : a. hard but brittle b. chemically inert c. transparent and impermeable (non-porous) d. withstand compression e. good heat and electrical insulators
Types, composition, properties and uses of glass1. There are four types of glasses : (a) Soda-lime glass (soft glass) * The most common and least expensive glass (b) Lead crystal glass (soft glass) (c) Borosilicate glass (hard glass) (d) Fused glass (hardest glass) * The simplest and most expensive glass
Type of Production Composition Properties Uses glass methodFused Silica is heated until • Silicon • Very high melting • Laboratoryglass it melts at 1 700 dioxide point glass rods degree celcius and • High transparency • Telescope cooled rapidly • Highest resistance mirrors to thermal shock • Optical (can be heated to fibres an extremely high • Lenses temperature and then plunged into icy, cold water without cracking)
Type of Production Composition Properties Uses glass methodSoda- Mixture of silica, • Silicon • Low melting point • Lightlime sodium carbonate dioxide • Easily shaped bulbsglass (soda lime) and • Sodium • High chemical • Window calcium carbonate oxide durability glass (limestone) is • Calcium • Does not withstand • Drinking heated to 1 500 oxide heat glass degree celcius and • High thermal • Mirrors cooled rapidly expansion coefficient (expand a lot when heated and contract a lot when cooled)
Type of Production Composition Properties Uses glass methodBorosilicate Boron (III) oxide • Silicon • High melting point • Oven glassglass is added to soda- dioxide • Resistant to thermal • Boiler gage lime glass • Sodium shock glassware oxide • Resistant to • Automobile • Calcium chemical attack headlights oxide • Low thermal • Boron (III) expansion oxide coefficient a little)
Type of Production Composition Properties Uses glass methodLead Lead (II) oxide is • Silicon dioxide • High density • Prismcrystal added to soda-lime • Sodium oxide • High refractive • Highglass glass • Lead (II) oxide index reflective • Soft and easy lenses to melt • Fine crystal tableware • Decorative glassware • Lead crystal glassware
Special glassesSome special glasses have been made for specific purposes such asphotochromic glass, conducting glass and bullet-resistant glass.Silver chloride in photochromic glass darkens the glass when exposed tosunlight and protects the eyes from ultraviolet radiation.Indium tin oxide (ITO) in conducting glass is able to conduct electricity. Itis mainly used to make transparent conductive coatings for liquid crystaldisplay (LCD), flat panel display and plasma display.
Bullet-resisitant glass is usually constructed using a strong but transparentmaterials such as polycarbonate thermoplastic sandwiched between layersof regular glass. The plastic provides impact resistance while the glassflattens the bullet, thereby preventing penetration.
CeramicsCeramics are made from clay. Kaolin, a hydrated aluminosilicate,Al2O.2SiO2.2H2O is an example of clay.The major component of ceramic is silicate. Silicate is a chemicalcompound containing silicon, oxygen, and one or more metals.The common way of preparing ceramic is to heat the mouldedclay at avery high temperature.
Ceramic that has been hardened after heating cannot be melted again dueto its extremely high heat resistance.The main characteristics of ceramic are (a) extremely hard but brittle (b) chemically inert (c) opaque and porous (d) withstand compression (e) good heat and electrical insulators
Properties and uses of ceramics Properties Uses ExampleHard and strong Construction materials Tiles, cement, bricksWithstand high Construction materials Furnaces, nuclearpressure and heat reactorsResistant to chemicals, Ornamental articles Plates, bowls, vases,do not corrode and porcelain, toilet walllong-lasting tiles, floorGood electric and heat Electrical appliances Ovens, toasters, fuses,insulators spark plugsHave semiconducting Semiconductors Microchipsproperties and canstore charges
Special ceramicsBoron nitride is a lubricious ceramic that has high temperature and excellentelectrical resistance. It is used to make microwave tubes and low frictionseals.Silicon nitride ceramic that has relatively good shock resistance is used tomake skateboard bearings and ignition source of domestic gas appliances.Silicon nitride ceramic that has relatively good shock resistance is used tomake skateboard bearings and ignition source of domestic gas appliances.Perovskites, YBa2Cu3O7 is another new ceramic superconductor thatcontains yttrium, barium, copper and oxygen. It can conduct electricity withvirtually no loss of heat energy at 98K.
Composite materialsA composite materials is a structural material that is form by combining twoor more different substances such as metal, alloys, glass, ceramics andpolymers.A composite materials is a structural material that is form by combining twoor more different substances such as metal, alloys, glass, ceramics andpolymers.
1) Reinforced concreteConcrete is a composite material which consists of mixture of stones, chipsand sand bound together by cement.Concrete is strong but brittle and weak in tension. Steel has good tensilestrength.When concrete is reinforced with steel bars, steel wires of rods, it produces avery tough materials with more tensile strength called reinforced concrete.
Reinforced concrete is relatively cheap and can be moulded into any shape.It is also stronger and better able to withstand tensile forces than concretealone.It is used in high-rise buildings, bridges, oil platforms and highway.
2) SuperconductorA superconductor is capable to conduct electricity without any electricalresistance when it is cooled to an extremely low temperature.Metal such as mercury can be a superconductor in 4.2K but it is veryexpensive to maintain such extremely low temperature.Using a combination of metals and metal oxide, a ceramic composite isfound to be superconducting at temperatures higher than 30K.Perovskites is the latest ceramic superconductor that has zero resistanceat 95K.Superconductors have low power dissipation, high-speed operation andhigh sensitivity.Superconductors are used in bullet trains (maglev train), magneticresonance imaging (MRI), computer chips, generators and transformers.
3) Fibre opticA fibre optic capable consists of a bundle of glass or plastic threads thatare surrounded by a glass cladding.It has high transmission capacity and chemical stability, but lowsusceptibility to interference and material costs.It is used in video cameras and local area networks for computers.Besides that, it is used in instruments for examining internal parts of thebody or manufactured structural products and to transmit data, voiceand image in a digital format.
4) Fibre glassGlass is hard, strong, has high density but it is relatively brittle. Plastic iselastic, flexible, has low density but it is not strong.When glass fibres are reinforced in plastic, a strong composite materialcalled fibre glass is produced.It has high tensile strength, low density, can be easily coloured,moulded and shaped. It can even be made into thin layers, yet verystrong.It is used in water storage tanks, badminton rackets, small boats andhelmets.
5) Photochromic glass∗ Silver chloride and copper (I) chloride crystal are embedded in glass to produce photochromic glass.∗ When photochromic glass is exposed to light , the chloride ions are oxidised to produce chlorine atoms by releasing electrons. Cl-(aq) Cl(s) + e-∗ The electron are transferred to silver ions. Silver ions are reduced by gaining electrons to produce silver atoms. Ag+(aq) + e- Ag(s)
Silver atoms cluster together and block the transmittance of light. The glass turns dark.∗ When the glass is removed from light, chlorine atoms are reduced by copper (I) ions to form chloride ions and copper (II) ions. Cl(s) + Cu+(aq) Cl-(aq) + Cu2+(aq)∗ The copper (II) ions are further reduced by silver atoms to form silver ions and copper (I) ions. Cu2+(aq) + Ag(s) Cu+(aq) + Ag+(aq) The glass becomes transparent again when silver atoms are converted back to silver ions.∗ Photochromic glass is used in optical lenses, car windshields, lenses in cameras, optical switches and light intensity meters.
The uses of composite materials The needs for new materials for specific purposesWith the high demand of items with specificproperties, scientists have invented many newsubstances to replace many traditional ones.For example, plastics replace wood, optical fibresreplace copper wires and synthetic fibres replace cottonand wool.However, alloys, ceramics, glass, polymers producedstill have their disadvantages and do not meet certainrequirements in industry, communication, constructionand transportation.Therefore, composite materials are created forspecific application.