C A D

Give examples of natural and synthetic fibres. State most plastics and synthetic fibres are made from chemicals derived from oil. State synthetic materials are made by the chemical industry. Explain the terms ‘thermosetting’ and ‘thermoplastic’. Explain the problems with some plastics. Name examples of plastics including polythene, polystyrene etc. and give their uses.

* Plastics are widely used as they have many useful properties e.g. lightweight (low density) and waterproof. They are good heat insulators and also good electrical insulators. * Plastics and synthetic fibres are man-made materials, this is why they are called SYNTHETIC.. * In addition, plastics are easily moulded into a variety of shapes and are excellent insulators of both heat and electricity.

COTTON From fibres of the cotton plant. WOOL From spun hair of sheep.

* Most plastics and synthetic fibres are made from chemicals derived from ____________ and are made up of long chain molecules called polymers. * Plastics are examples of polymers - very large molecules formed by the joining of many small molecules called __________. crude oil monomers

NYLON Used to make jackets, sports bags, sportswear and ropes. POLYESTER Used to make trousers, shirts, sportswear. Some polyester clothes are labelled TERYLENE.

POLYTHENE Used to make bags, packaging, containers, food boxes. Nylon Nylon widely known as a fibre. Nylon as a plastic, is widely used in machine parts, as it is very strong.

PERSPEX Used as replacement for glass but not as brittle as glass. Can easily be shaped. Used to make jewellery. POLYPROPYLENE (POLYPROPENE) As a fibre used to make ropes and carpets. As a plastic it is used to make containers, packaging and combs.

POLYVINYL CHLORIDE (PVC) Used as floor covering, window frames, electrical insulation and water pipes.

POLYSTYRENE (Expanded) Used in packaging as it is light and absorbs knocks. It is a good heat insulator and is used in take-away food cartons. POLYSTYRENE (Non-expanded) This is a rigid plastic and is used to make casings for TV’s, computers, cameras.

* Thermoplastic: * ____________________________________ __________________________________ * Thermosetting: * ____________________________________ ________________________________ A plastic which softens on heating and can be reshaped e.g. P.V.C. and polythene. A plastic which does not soften on heating e.g. bakelite and formica.

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* Plastics are not biodegradable. This means they do not… _____________________________________ * Incomplete Combustion of Plastics * The poisonous gas produced on incomplete burning of plastics is called: ____________________ * Disposal of Plastics * Plastics can be disposed of by burying, incineration or recycling. rot away naturally by biological processes. Carbon monoxide

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* The name of the polymer comes from the name of the monomer used to make it e.g. the monomer ethene can be used to make the polymer poly(ethene). * Notice how the prefix poly- is put in front of the name of the monomer. Brackets are put around the name of the monomer. MonomerPolymerUse propenepoly(propene) phenylethenepoly(phenylethene) vinyl chloride poly(vinyl chloride) also known as PVC Electrical cable covering and frames for double- glazed windows ethene poly(ethene) also known as polythene Carrier bags styrenepoly(styrene) Packaging, drinking cups and CD/ DVD cases Packaging and labelling, textiles, stationary Domestic appliances, medical applications

B B

State what is meant by: monomer, polymer and polymerisation. To state that addition polymers are made from small unsaturated molecules, produced by cracking, by a process called addition polymerisation. Describe addition polymerisation as small unsaturated molecules joining together by the opening of the carbon to carbon double bond. Draw the structure of an addition polymer given the monomer structure, or the repeating unit / monomer given the polymer structure.

Page 4 of pupil booklet * Polymerisation is the process in which the small monomer units __________ together to form a large polymer molecule. join

Plastics and synthetic fibres are made from giant molecules. Joining together many thousands of smaller molecules called MONOMERS makes these giant molecules. The giant molecule is called a POLYMER as joining many small molecules together makes it. POLY means many. Monomer molecules Small part of a polymer molecule. join together

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* Addition polymerisation is a process involving many small, __________ monomers combining to form one large polymer molecule. * The alkenes, ethene and propene are two important feedstocks in the petrochemical industry which can also be used to make addition polymers. * Addition polymers are made from monomers that contain a –C=C– double bond and result in a polymer ‘backbone’ made solely of ______atoms. unsaturated carbon One of the covalent bonds of the C=C breaks open, allowing the monomers to “ADD” to each, other building up the polymer chain. C H H CHH

The most common monomer is ethene, C 2 H 4. C H H CHH 3 ethene molecules MONOMERS The C=C breaks open allowing the molecules to join. CHH CHH CHH CHH CHH CHH The joining up reaction is called ADDITION POLYMERISATION as a polymer is made. A section of the POLYMER. The polymer is named by placing POLY in front of the monomer name. C H H CHH C H H CHH

* Formation of poly(propene) Propene monomers (x 3) Double bonds break poly(propene) is formed The repeating unit for polypropene is… All addition polymers have a chain of C–C single bonds forming the backbone of the polymer molecule. Animation Addition polymerisation

C CH 3 H CHH Propene C F F CFF Tetrafluoroethene C C6H5C6H5C6H5C6H5 H CHH Phenylethene (styrene) For each of these monomers, draw a section of the polymer produced when 3 molecules of each monomer above join. Name each polymer produced. This group of atoms is called the phenyl group.

* The repeating unit * Closing the double bond gives the monomer * Page 6 of pupil booklet If the structure of the polymer is given then the structure of the monomer can be worked out.

Starter answers (Nat )

To revise our previous knowledge of condensation reactions from Unit 2; forming esters. State that condensation polymers are made from monomers with two functional groups per molecule. Draw the structure of a polyester polymer given the monomer structures. Draw the repeating unit / monomers given the polymer structure.

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In unit 2 we learned that esters molecules are formed by condensation reactions. alcohol carboxylic acid + ester + water propan-1-ol ethanoic acid + propyl ethanoate + water water molecule eliminated ester link (carboxylate group) + + CH 3 CH 2 CH 2 OH + HOOCCH 3 CH 3 CH 2 CH 2 OOCCH 3 + H2OH2O

* Condensation polymerisation is a process whereby many small monomer molecules join together to form one large polymer, with _____, or some other small molecule (e.g. HCl) formed at the same time. The monomers have more than one functional group (-OH, -COOH, -NH 2 ). water

* Polyesters are examples of condensation polymers formed by the reaction between a diacid with a diol. Both monomers must have ____ functional groups (one at each end of the molecule). two Dialcohol (Diol) DICARBOXYLIC ACID (Diacid) MONOMERS of a POLYESTER

H2O molecule forms H2O molecule forms H2O molecule forms Ester link Ester linkEster link The structure of the polyester molecule repeats every TWO MONOMERS. This is called the REPEATING UNIT. REPEATING UNIT The polymer molecule contains many ester links, hence the name POLYESTER. Condensation polymerisation

DIALCOHOL DICARBOXYLIC ACID ethane-1,2-diol benzene-1,4-dicaboxylic acid (other name: terephthalic acid) n REPEATING UNIT H 2 O H 2 O H 2 O POLYESTER Condensation polymerisation

* If you are asked to identify the monomers from a condensation polymer, simply add a water molecule back across the ester link. This is called ________. * To break the ester link, firstly identify the ester link and then just add water. hydrolysis

* A polyester undergoes hydrolysis with the addition of water to create a ____ and a _____. diol diacid * In summary… * During hydrolysis, water attacks the ester link and adds across it. * Adding water across the ester link produces a carboxylic acid and an alcohol.

* The 'backbone' of a polymer can tell us whether it is an addition polymer or a condensation polymer. * A horizontal chain can be seen in the polymer below [poly(ethenol)]: * This polymer only has carbon atoms in it's backbone. * This indicates that the molecule was formed by _______ polymerisation. addition

* The polymer below (Kevlar) has a more complicated backbone. * This backbone includes atoms of carbon and nitrogen. * If the polymer backbone has any atom other than carbon in it (such as nitrogen or oxygen), then it was formed by ___________ polymerisation. condensation

B A

Revise that carbohydrates are compounds containing the elements carbon, hydrogen and oxygen only. State that starch is a natural condensation polymer made of many glucose molecules linked together. Understand the classifications mono-, di- and polysaccharides in relation to the terms monomer and polymer. Describe the tests for starch.

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* Polymers are not simply an invention of chemists. Many are synthesised in nature and even in our bodies. The most common natural polymers are carbohydrates like starch and cellulose, and proteins. Carbohydrate Cellulose

Starch and cellulose (carbohydrates) are natural condensation polymers. All carbohydrates are based on the monomers glucose or fructose (C 6 H 12 O 6 ). These carbohydrates are classified as MONOSACCHARIDES. A monosaccharide can be represented as: C 6 H 12 O 6 When 2 monosaccharides join a disaccharide is produced and a water molecule is lost. + C 12 H 22 O 11 H2OH2O + 2 monosaccharides disaccharide

When many monosaccharides join a polysaccharide is produced and many water molecules are lost. n C 6 H 12 O 6 + many monosaccharides + n = a large number n = a large number H 2 O molecule is lost from each C 6 H 12 O 6 making the polymer chain made of many C 6 H 10 O 5 units. (C 6 H 10 O 5 ) n n H 2 O + many water molecules polysaccharide Starch and cellulose are polysaccharides.

* Physical test * The Tyndall Beam experiment can be used to distinguish starch from glucose by shining a beam of light through 'solutions' of each. * Dispersal only happens in starch as the large starch molecules are big enough to affect the light and disperse it. * The light will pass straight through the solution of glucose. * Chemical test * In the presence of starch, iodine changes from yellow/brown to a blue/black colour. It is possible to distinguish starch from other carbohydrates using this iodine solution test. * For example, if iodine is added to a peeled potato then it will turn black.

* During digestion starch is broken down into glucose. Glucose is small enough to pass through the gut wall but starch cannot. This is done in the lab using dilute acid; or in the body using enzymes (biological catalysts). The main enzyme for digestion is amylase. Enzymes work best at body temperature (37 o C). * Water must be added which is the reverse of condensation polymerisation. This is known as hydrolysis. * Hydrolysis is when one large molecule is broken down into smaller molecules by reaction with water. + G -OH HO- + +H 2 O G -OH HO- G -OH HO- G -O O- G -O O- G -O O-

* Nitrogen is an essential nutrient for all plants and animals, as it is needed to make proteins. * Proteins are natural __________ polymers formed by joining together thousands of amino acid molecules. condensation * Amino acids have two functional groups; a carboxyl group and an amine group.

The monomers of proteins are amino acids. There are 20 amino acids used to make proteins. The different amino acids have the same basic structure, with the R group being different. Here are three amino acids. glycine alanine serine

Two amino acids combine in a condensation reaction to form a protein and a water molecule. H 2 O molecule forms H 2 O molecule forms In a protein the is called a PEPTIDE LINK. peptide link peptide link Part of a PROTEIN molecule. Each protein has its own sequence of amino acids making up the polymer chain. Condensation polymerisation

* Proteins have many important jobs within the body. They form the major structural materials of animal tissue including hair, nails and muscle etc. Other proteins are involved in regulating life processes. These include haemoglobin, enzymes and certain hormones like insulin.

* During digestion the proteins we eat are broken down into _____ acids (by hydrolysis). * These amino acids are transported around the body by blood. In the bloodstream, condensation reactions build the amino acids up to produce proteins required by the body. amino

B D

Give examples of new polymers with special properties and their uses.

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* A novel material is a new material; one that does not resemble anything that was previously known or used. * A smart material is one that changes shape in response to changes in its environment * Hydrogels are smart materials that have found a lot of uses in daily life because they are polymers that absorb _____. water

* The first hydrogels were used in the 1950s to develop early contact lenses and many different types have now been developed. * In simple terms they are all insoluble substances that form a tangled, three-dimensional network of fibres. * When a gel is in contact with water, functional groups along the fibres (carboxyl, -COOH groups) ionise (become charged) and the negative charges repel each other, forcing the fibres to become less tangled and to expand.

* Water is a polar molecule (slightly charged) and is attracted to the negative charges that exist within the structure. This is why water is absorbed. Hydrogel experiment

A hydrogel polymer is used in disposable nappies. Plant storage crystals are hydrogels. They absorb water and swell up. If put in plant tubs and hanging baskets they slowly release water extending the time between watering's, for example when you go on holiday. Soft contact lenses are hydrogels. Their ability to absorb water means they don’t dry out in use, and are compatible with tears which lubricate the eye making them more comfortable to wear.

Polyvinyl alcohol (PVA) is a water- soluble polymer. It is used as an adhesive. As a film it is used to make the packaging of “liqui-tabs”, which hold detergent for dishwashers and washing machines.

* Kevlar is a condensation polymer. It is very strong but also very light and can therefore be used aircraft wings, bulletproof vests and other products where strength and weight are important.

* This plastic is soluble in water and can therefore be used to make laundry bags and surgical stitches.

* Most plastics are insulators. * However, specific polymer materials like polyaniline, polythiophene and polypyrrole have been developed and can conduct electricity for the development of flexible touch screens etc. * One of the earliest conducting polymers to be developed was polypyrrole.

* Packaging that incorporates nanomaterials can be “smart,” which means that it can respond to environmental conditions or repair itself or alert a consumer to contamination and/or the presence of pathogens. * These can be used in food packaging to let consumers know the condition of the food. Colour changing disposable beverage lids showing increasing redness from left to right.

Bioplastics are polymers made from plant sources. Starch-based plastics currently represent the mostly widely used bioplastic. Protective packaging is an example of this type of polymer. Polylactic acid (PLA) is made from corn or sugar cane. It is used to make disposable cutlery, waste sacks and sutures used for internal stitches in the body during surgery. Bioplastics are biodegradable.

1. Poly(ethenol) is a water soluble plastic that has many uses from laundry bags to dishwasher tablets. a) Plastics are synthetic. What is meant by the term ‘synthetic’? b) When heated, poly(ethenol) softens and can be reshaped. What name is given to such plastics? 2. Styrene, which is also known as phenylethene, can be extracted from the sap of the styrax tree. Styrene is the monomer used to produce polystyrene. a) Name the type of polymerisation that takes place to form polystyrene. b) Draw a section of the polystyrene polymer showing three monomer units combined.

3. Poly(butene) is an addition polymer made up of butene, C 4 H 8, monomers. a) Draw a section of poly(butene) showing three monomer units joined together. b) Draw the repeating unit for poly(butene).

4. The structure for part of the poly(chloroethene) polymer chain is: a) Draw the structure of its repeating unit. b) Draw the structure of the monomer unit. c) Name the monomer unit. d) Find out the common name for poly(chloroethene).

5. Poly(lactic acid) is made from the monomer lactic acid which has the structural formula shown: a) Rearrange the molecule above so that there is a hydroxyl group at either end of this molecule. b) Use your rearranged molecule to draw a section of poly(lactic acid) showing three monomer units linked together. [HINT: the monomers will be joined by ESTER links] c) State the type of polymerisation that poly(lactic acid) is formed by.

6. Part of the structure of Kevlar is shown: Draw the structures of the two monomers used to make Kevlar.

1. a) What is a smart material? b) A hydrogel is a smart material; give one common use for hydrogels. c) c) Name two natural polymers. 2. PVC is a very useful plastic. It can be used to make window frames and to make the insulating cover for electrical cables. PVC is not biodegradable. a) What is meant by the term biodegradable? b) Why have biodegradable polymers been developed?