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POLYMERS and their uses.

What are polymers ?

Polymers are large molecules made up of many identical repeating sub-unit called monomerswhich are joined together by covalent bonds.

Monomers are joined into chains by a process of repeated linking known as polymerisation.

Polymerisation

Polymer

Monomer

TYPES OF POLYMER.

TYPES OF POLYMER

Natural polymer Synthetic polymer

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SYNTHETIC POLYMER.

Synthetic polymers are man-made polymers that are produced from chemical compounds throughpolymerisation.

Example of synthetic polymers , their monomers and uses.

Synthetic polymer Monomer Uses

Polythene Ethene Make plastic bags , Shopping bags ,

plastic containers and insulation for

electrical wiring.

Polypropene Propene Make piping , bottle crates , carpets ,

car batteries and ropes.

Polyvinyl chloride ,

PVC

Chloroethene Make artificial leather , water pipes

and records.Perspex Methylmethacrylate Make lenses , safety glass reflectors

and traffic signs.

Terylene Hexane-1,6-diol

Benzene-1,4-dicarboxylic

acid

Make clothing , sails and ropes.

Nylon Hexane-1,6-diamine

Hexane-1,6-dioic acid

Make ropes , clothing and carpets.

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NATURAL POLYMER.

Natural polymer is a polymer that occurs naturally.

Natural polymers are normally made by living organisms.

Natural polymer Monomers

Rubber Isoprene

Cellulose Glucose

Starch Glucose

Protein Amino acid

Fat Fatty acids and glycerol

Nucleic acid Nucleotides

Examples of natural polymers and their monomers.

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Monomer Polymer

a) H HC C

H H

Ethene

H H

C C

H H n

Polythene (polyethene)

b) Cl HC C

H H

Chloroethene (Vinyl chloride)

Cl H

C C

H H n

Polyvinyl chloride (PVC)

(Polychloroethene)

c) H HC C

CH3 HPropene

H H

C C

CH3 H n

Polypropene

d) H CH3C C

H COOCH3Methyl-2-methylpropenoate

(Methyl methacrylate)

Cl CH3

C C

H COOCH n

Perspex

(Polymethyl methacrylate)

e) H HC C

H

Styrene

H H

C C

H n

Polystyrene

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Examples of synthetic polymers (product of additionpolymerisation) and their monomers.

Structural formula of amino acid and glucose.

Polymerisation of isoprene into polyisoprene (rubber).

H R O

H N C C O H

HAmino acid (monomer of protein)

CH2OH

C O

H H

HC C

OH OH

HO OH

C C

H H

Glucose (monomer of starch and cellulose)

Monomer Polymer

H CH3 H H

n H C C C C H

Isoprene (monomer of natural rubber)

H CH3 H H

C C C C

H H

n

Polyisoprene (polymer of natural rubber)

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Polymerisation

Polymerisation is a process ofcombining monomers to form a long chain of molecules.

TYPES OFPOLYMERISATION

Addition

polymerisation

Condensation

polymerisation

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ADDITION POLYMERISATION

Unsaturated monomers that contain double bonds between two carbon atoms undergo additionpolymerisation.

Monomers undergo addition polymerisation as shown :-

H H H H H H H H H H

n C C C C or ~ C C C C C C ~

H H H H n H H H H H HEthene (monomer) Polythene (polymer)

Example of addition polymerisation.

If the structure of a monomer is known , the structural formula of its synthetic polymer can bedetermined as shown below.

Step 1

Write the symbol for two carbon atoms with double bonds in themiddle. 'Push' the atom or molecule that is tied to the two carbon

atoms above or below the two carbon atoms.

Step 2 Change or 'open' the double bond into two single covalent bonds and

draw brackets.

Step 3 Write the letter 'n' at the bottom right-hand corner of the molecule.

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CONDENSATION POLYMERISATION

Small molecules such as water , H2O and ammonia , NH3 are released in condensation polymerization.Monomer Polymer

a) Adipic acid and hexanediamine Nylonb) 1,4-dicarboxylbenzene and

ethene-1,2-diol

Terylene

Examples of synthetic polymers (products of condensation polymerisation)and their monomers.

H H O O

n H N (CH2)6 N H + nHO C (CH2)4 C OH

hexanediamine adipic acid

H H O O

N (CH2)6 N C (CH2)4 C + nH2O

Nylon n

Example of condensation polymerisation.

H2O

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Synthetic polymers such as plastic Synthetic fibres and synthetic rubber have been used to replace

various natural items such as cotton, silk , glass , metal , timber and rock.

Natural compounds that have been replaced by

synthetic polymers

The advantages of synthetic polymers

compared to natural compounds

Cotton and silk Stronger , more durable , withstands dirt and

does not wrinkle easily

Paper Waterproof , does not wrinkle or tear easily

Timber Does not rot easily

Metal Lighter , does not corrode easily , more easily

forged and coloured

Glass and ceramics Does not break easily

Marble (rock) Cheaper

Advantages of synthetic polymers used to replace natural compounds

Effects of the disposal of items made from synthetic polymers on the environment

Synthetic polymers are not biodegradable (not decomposed by microorganisms). The careless disposal of items made from synthetic polymers such as plastic causes environmental

pollution.

The effects of burning and careless disposal of items made from synthetic polymers on theenvironment as follows :

The best way to manage used items made from synthetic polymers is to recycle them. Plastics that are biodegradable can be used instead to reduced environmental pollution.

Burning of synthetic polymers

Releases pollutants that endanger

health such as smoke , gases that are

smelly , poisonous and corrosive such

as sulphur dioxide , pollutants that

cause acid rain and the greenhouse

effect.

Careless disposal of syntheticpolymers

spoils the beauty of the environment.

causes flash floods during heavy

rainfall.

endangers marine life like turtles that

accidentally eat polymers such asplastic as its food.

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GLASS AND CERAMICS.

GLASS The main component of glass is silica or silicon dioxide , SiO2 ,which is obtained from sand. The most simple glass is the fused silica gas.This glass mainly contains silica , SiO2. Most of the glasses are produced by mixing molten silica , SiO2 , with other compounds. Glass can be recycled . Glass can also be melted and solidified repeatedly.

The main characteristics of glass.

GLASS

BrittleNot permeable

to gas and liquid

(fluid)

Heat

insulator

Does not

conduct

electricity

Trasnparent

Chemically

inert

Hard

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Different types of glass have different properties and uses.

Types of glass Properties Uses

1) Fused silicaglass

Very high melting point Not easy to change its shape Does not easily expand or

shrink with changes of

temperature Transparent to ultraviolet rays

Make lenses Make spectacles Make laboratory

glassware

Make ultravioletcolumn

2) Soda-limeglass

Transparent Low melting point Easily shaped Easily broken Cannot withstand heat and

chemical reactions

Make bottles Make glass containers Make mirrors Make electrical bulbs Make glass windows

3) Borosilicateglass

Withstand heat and chemicalreactions

High melting point Transparent to light and

infrared ray but not ultraviolet

rays

Expands and shrinks verylittle and only when

temperature changes

Make bowls Make plates Make saucers Make pots Make cookware Make laboratory

glassware such as testtubes, beakers and

flasks.

4) Lead crystalglass

Very transparent Shiny High refractive index High density

Make lenses Make prisms Make glasses Make ornamental items

(crystals)

TYPES OFGLASS

Fused silica

glass

Soda-lime

glass

Borosilicate

glass

Lead crystal

glass

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CERAMICS

Ceramics are made from clay that has been heated at a very high temperature. The main component of ceramics is silicate. Most ceramics contain silicon , Si , oxygen , O and aluminium , Al. Unlike glass , ceramics cannot be recycled. Ceramics that have been solidifiedcannot bemelted

again as they are extremely heat resistant.

The common properties of ceramics.

CERAMICS

BrittleCracks when

temperature

change

drastically

Inert to

chemicals

(withstandcorrosion)

Good

insulators of

heat and

electricity

Withstand

compression

Highmelting

point

Extremely

hard

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Several uses of ceramics.

Uses of ceramics :

Manufacture of computer microchips

Make dentures (enamel)

Make porcelain , vase and ornamental items

Make plates , bowls and pots

Used in manufacturing of car engines , spacecraft superconductors and nuclear

reactors

Make construction materials such as bricks , cement , tiles , underground piping

or roof tiles

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COMPOSITE MATERIALS.

Composite materials are produced from the combination of two or more different compounds such asalloys , metals , glass , polymers and ceramics.

The characterists of the produced material are much more superior than those original components.

The Uses of Composite Materials :

In this modern world , the demand for this items with

spesific properties is high.

Compounds with spesific properties are combined to produce a

composite material that meets the requirements of industry ,

construction and transportation.

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Examples of composite materials are :-

Made from a mixture of cement , gravel , sand , water , iron or

steel to produce nets , rods or bars.

Strong , high tensile strength and cheap.

Construction material for buildings bridges highways and dams.

ReinforcedConcrete

Made from various components such as the mixture of

niobium and germanium.

Compound that has no electrical resistance ( zero resistance ).

can function only under extremely low temperatures.

Used in the transportation , telecomunications andastronomy industries and in the medical field.

Superconductor

Made from silica , SiO2 , sodium carbonate , Na2CO3 calcium

carbonate , CaCO3.

Good insulator of heat and electricity.

Used to make protective apparel for astronauts and firefighter.

Fibre Glass

Made from glass , copper and aluminium.

Enables information to be transmitted in light form at high

speeds ( speed of light ).

Used in the fieldof communications to make electrical cablesand in the field of medicine to observe internal organs withoutperforming surgery.

Fibre Optics

Produced from molten silica that is mixed with a little silver

chloride , AgCl.

Dark in colour when exposed to bright light ( ultraviolet ray )

and bright when in the dark.

Used to make optical lenses and glass windows ( windshields )

of certai vehicles.

PhotochromicGlass

Produced by exposing glass that contains certain amount of

metals to ultraviolet rays and heating it at high temperatures.

Withstand heat.

Used to make cooking materials and rocket heads.

Ceramic Glass

Made of plastic and glass fibres.

Composite plastics that are very strong , light , easily formed

and can withstand corrosion.

Used to make helmets , the body of cars and aeroplanes , rods

and other parts of aeroplanes.

PlasticStrengthened

with GlassFibres

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MANUFACTURE OF SULPHURIC ACID.

Uses of sulphuric acid , H2SO4 , in our daily life are as follows :

Uses of Sulphuric Acid :

Manufacture of fertilisers such as ammonia sulphate , (NH4)2SO4.

Manufacture of electrolyte in lead-acid accumulators (car battery).

Manufacture of soaps and detergents.

Manufacture of pestisides (insecticide).

Manufacture of plastic items such as rayon and nylon.

Manufacture of paints and dyes.

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Manufacture of Sulphuric Acid in Industry.

Sulphuric acid , H2SO4 , is manufactured in industry through the Contact Process. The manufacturing of sulphuric acid , H2SO4 , in industry involves three stage :-

The three stages involved in the Contact Process.

Stage Aim

Stage 1Sulphur dioxide , SO2 , gas can be produced by

burning sulphur in air.

S(s) + O2(g) SO2(g)Sulphur dioxide

To produce sulphur dioxide ,

SO2 , gas.

Stage 2

The gas mixture of sulphur dioxide , SO2 , and

oxygen , O2 , is passed over vanadium(V) oxide ,

V2O5 , (catalyst) at a temperature of 450-500oC and

under the pressure of 1 atmosphere.

2SO2(g) + O2(g) 2SO3(g)Sulphure trioxide

To produce sulphur trioxide ,

SO3 , gas.

Stage 3

Sulphur trioxide , SO3 , gas is dissolved in

concentrated sulphuric acid , H2SO4 , to form oleum ,

H2S2O7.

SO3(g) + H2SO4(l) H2S2O7(l)

Oleum

Water is then added to the oleum , H2S2O7 , to dilute

it to produce sulphuric acid , H2SO4.

H2S2O7(l) + H2O(l) 2H2SO4(l)Sulphuric acid

To produce sulphuric acid ,

H2SO4.

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Environmental pollution by sulphur dioxide.

1) Fossil fuels such as petrol and manufactured products of sulphuric acid , H2SO4 , contain sulphur , S.2) Burning of these products will oxidise sulphur , S , to form sulphur dioxide , SO2.

S(s) + O2(g) SO2(g)Sulphur dioxide

3) Sulphur dioxide , SO2 , is an acidic gas . When it dissolves in rainwater , it forms sulphurousacid , H2SO3 , and causes acid rain.

SO2(g) + H2O(l) H2SO3(aq)Sulphurous acid

4) Sulphur trioxide , SO3 , will also form when sulphur dioxide , SO2 , reacts with oxygen , O2 ,gas in air.

2SO2(g) + O2(g) 2SO3(g)Sulphure trioxide

5) When sulphur trioxide , SO3 , dissolves in rainwater , sulphuric acid , H2SO4 , is also formedcausing acid rain.

SO3(g) + H2O H2SO4(aq)Sulphuric acid

The effects of acid rain on the environment

Corrodes and destroys property such as bridges , buildings and statues.Reduces pH of soil and causes it to be unsuitable for plant life.Reduces Ph of water and causes the death of aquatic life.Destroys the beauty of the environment such as the collapse of limestone caves.

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MANUFACTURE OF AMMONIA AND ITS SALT.

Uses of ammonia , NH3 , in daily life are as follow :-

Properties of ammonia , NH3.

Uses of Ammonia :

Manufacture of nitrogenous fertiliser such as ammonia phosphate , (NH4)3PO4.

Manufacture of nitric acid , HNO3 , through the Ostwald process.

Manufacture of electrolytes in dry cells.

Manufacture of cleaning agents such as washing powder and detergents.

Manufacture of explosives such as trinitrotoluene (TNT).

Manufacture of dyes.

AMMONIA ,

NH3

Very

soluble in

water.Produces thick

white fumeswith hydrogen

chloride , HCl ,

gas.

Less

densethan air.

Pungent

smell

Hascharacteristics of

weak alkaliwhen dissolved

in water , H2O.

Colourles

s gas.

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Manufacture of ammonia

Ammonia , NH3 , is manufactured on a large scale in factories through the Haber process. In the haber process , nitrogen , N2 , and hydrogen , H2 , gas are mixed in the ratio of 1:3

volumes (moles).

N2(g) + 3H2(g) 2NH3(g)

The hydrogen , H2 , gas is obtained from methane CH4 , type of natural gas , while nitrogen ,N2 , gas is obtained from air by fractional distillation of liquefied air.

The gas mixture is passed over ion (catalyst)at a temperature of 450-550 oC and compressedunder a pressure of 200-500 atmosphere.

The ammonia , NH3 , gas obtained is cooled ( temperature of 50 oC ) to become liquidammonia , NH3(l).

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Synthesis of ammonia , NH3 , in industry.

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Flow chart of the Contact Process.

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Flow chart of production of ammonia , NH3 , through the Haber process.

Preparation of Ammonia fertilisers in the laboratory

Ammonia fertilisers are nitrogenous fertilisers that can provide nitrogen elements to plants. Examples of ammonia salts used as fertilisers are ammonia nitrate , NH4NO3 , ammonia

sulphate , (NH4)2SO4 and ammonia phosphate , (NH4)3PO4.

Ammonia , NH3 , dissolves in water to form ammonia solution , NH3(aq) , (aqueous ammoniaor ammonia hydroxide , NH4OH).

Neutralisation reaction between ammonia solution NH3(aq) , and acid solution producesammonia , NH4

+, salt which is used as fertiliser.

Production of ammonia fertilisers.

Neutralisation reaction Ammonia salt (fertiliser)

Ammonia solution + phosphoric acid Ammonia phosphate

Ammonia solution + nitric acid Ammonia nitrate

Ammonia solution + sulphuric acid Ammonia sulphate

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ALLOYS

An alloy is a compound formed from a mixture of metal and other elements. A foreign atom (impurity atom) may be atoms of other metals or non-metals such as carbon. The process of mixing atoms of impurities with atoms of pure metal by melting is called

alloying.

The aims of alloying are to :i. Increase the strength and hardness of the metal.

ii. Prevent corrosion of the metal.iii. Improve the appearance of the metal so that it is more attractive.

Arrangement of atoms in pure metal

1) Pure metal is soft and not very strong.2) Atoms of pure metals have similar size and shape and are arranged closely but there is still

space between the atoms.

3) When force is applied to pure metals , the atoms slide along one another easily.4) This property causes pure metal to be ductile , that is , it can be stretched into a wire.5) When knocked or hammered , metal atoms slide along one another to fill spaces between the

metal atoms.

6) This property causes pure metal pure metal to be malleable , that is , it can be knocked orpressed into various desired shapes.

Alloy Pure metal atom Main foreign atomSteel 99% Ion 1% Carbon

Stainless steel 74% Ion 18% Chromium,8% Carbon

Bronze 90% Copper 10% Tin

Brass 70% Copper 30% Zinc

Pewter 97% Tin 2% Copper,1% Antimony

Duralumin 93% Aluminium 3% Copper,3% Magnesium ,1% Manganese

Copper nickel 75% Copper 25% Nickel

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Arrangement of alloys1)impurity atoms which are mixed may be larger or smaller than atoms of pure metal.

2)Impurity atoms fill the empty spaces between the atoms in pure metal.

3)Impurity atoms can prevent the layers of metal atoms from sliding along one onother easily.

4)Due to this ,an alloy is harder and strong than pure metal.5)For example,stell is harder than iron.

Properties of alloys and their uses

The properties of alloy such as its strength,ability to withstand corrosion and its shiny appearance

cause it to be suitable to be made into various items for daily use.

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FINISH ,

THANK YOU

MANUFACTURE

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SUBTANCES IN

INDUSTRY