PolymersBy Mr. Dookoo

By PresenterMedia.com

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Distinguish between addition and condensationpolymers

Combine monomers to make meaningful polymers

• Objectives

Define polymers

Compare difference between polymers and monomers

Discuss the use of polymers in everydayLife and their negative effects

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• Look at this video and lets see what you come up with•What are polymers

MONOMERSPOLYMERS LINKAGE

http://www.xtranormal.com/watch/11168760

Polymers are macromolecules (macromolecules are giant molecular structures consisting of tens of thousands of atoms bonded together) formed by linking together thousands of small molecules called monomers, usually in chains. There may be up to 50,000 monomers in a polymer! Polymers are formed by polymerisation.

ADDITION CONDENSATION

•TYPES OF POLYMERS

Type of polymerisation

Type of polymer

ExamplesSynthetic Natural

Addition polymerisation

Polyalkenes PolyethenePolypropenePolystyrenePolyvinylchloride (P.V.C)

_____

Condensation polymerisation

Polyamides Nylon ProteinsPolyesters Terylene (Fats and oils are

esters but not polymers)

Polysaccharides

_______

StarchCelluloseGlycogen (animal starch)

ADDITION• Only alkenes would undergo

addition reaction• http://www.tvo.org/iqm/plast

ic/animations.html#• http://www.chemtube3d.co

m/polymer/index.html

• It is the addition of two molecules eliminating a small molecule usually water

CONDENSATION

•Understanding how it all works

Addition polymer is constructed of one type of monomer. This is an unsaturated molecule, usually an alkene. Because of this, addition polymers are often referred to as polyalkenes. The polymers is formed when the double bonds in the monomer units break and the units join together. Long chain- like molecules are formed. Suitable conditions of temperature, pressure and catalyst are required for this process to take place. Note: only one type of product results in addition polymerisation.

•Addition PolymersHere is the theory

An example of an addition polymer is polypropene formed from the monomer propene.

H H H H H H C=C C C C C H CH3 H CH3 H CH3 Propene Polypropene

The double bonds are broken.The prefix poly means many, therefore, polypropene literally

means ‘many propene’.Many polyalkenes posses properties of substances that are

commonly referred to as plastics, substances that can be easily molded. They have a wide range of uses in everyday life.

Name of polymer Structure of monomer Use to make

Polythene H H C=C H H

Packaging, plastic bags, plastic film and plastic wrap

Polystyrene H H C=C H C6H5

Disposable plates, cups and food containers, packaging material, heat insulator in buildings.

Polyvinylchloride(P.V.C)

H H C=C H Cl

Rain coats, upholstery, suitcase coverings, plumbing fittings, water pipes, insulation of electric wires.

Polypropene H H C=C H CH3

Plastic containers like buckets, food containers, bowls, coolers, hinges for lids.

Name of polymer Structure of monomer

Used to make

Teflon F F C=C F F

Non- stick coatings for irons and pots.

Poly(methyl methacrylate) (PMMA)

H CH3

C=C H COOCH3

Glass substitute in aircraft windows, reflectors on vehicles and sign boards.

•Condensation Polymers• A condensation polymer can have monomers of one or two types. The polymer is formed when monomer units join together with the elimination of a small molecule like water. Two products are formed as a result of this type of polymerisation, the polymer and the small, eliminated molecule.

• There are:Natural condensation polymers, e.g. protein and starch

Synthetic or man- made condensation polymers, e.g. nylon and terylene.

• polyamide

• The linkage is CONH

• polysaccharides

• The linkage is –o-

•CONDENSATION POLYMERS

• polyesters

• The linkage is COO

•PolyamidesA natural polyamide is protein. The monomers that make up proteins are amino acids. There are 20 different types different types of amino acids found in natural proteins. Two amino acids join together when the H from an amine, N-H in the one amino acid and the OH from the C-OH in another amino acid

O

are eliminated in the form of water. An amide linkage is formed. The resulting molecule is called a dipeptide.

The general formula for amino acids is:HO C R N H O H

A synthetic polyamide is nylon.

There are 2 types of monomers in this polymer:

A diacid HO C X C OH H O (For nylon X is C6H12)

A diamine H N Y N H H H (For nylon Y is C4H8)

•Polyesters• Polyesters are synthetic fibers, such as terylene, made as imitations of natural materials like wool and cotton. Polyester structure consists of many monomers joined together by ester bonds.

The monomers in a polyester are:A diacid- HO C X C OH

O O(In terylene X is C2H4)A dialcohol- HO Y OH(In terylene Y is C2H4)

PolysaccharidesPolysaccharides are natural polymers such as starch and cellulose. The monomers are monosaccharide or simple reducing sugars, e.g. glucose and fructose of molecular structure C6H12O6.Simple representation of glucose:HO X OHTwo glucose units join together by the elimination of water to produce a disaccharide, sucrose.HO X OH HO X OH HO X O X OH Two glucose molecules disaccharide- sucrose C12H22O11Many glucose units join together to give the polysaccharide starch.[ O X O X O ]n

•Hydrolysis of PolymersMany condensation polymers are produced by the removal of water from the monomers. Hydrolysis or addition of water to the polymer can reverse this process and produce the monomers. Carbohydrates and proteins can be hydrolyzed in:

In biological systems- hydrolysis is achieved by enzymes during digestion.

Polysaccharides and proteins can be hydrolyzed to monosaccharide and amino acids, respectively in the lab by boiling with dilute acid, H2SO4 or HCl.

The structure of a protein can be determined by hydrolyzing the protein and identifying the amino acids present by chromatography.

•Comparing the Properties of monomers and polymers

• Polymers tend to have totally different physical and chemical properties from their monomers. Consider two examples, starch and polythene.

Polymers Monomers Chemical Properties Physical Properties

Starch Glucose Starch turns iodine blue/ black. Glucose does not. Starch has no effect on Benedict’s solution. Glucose forms a red precipitate with this reagent.

Starch is insoluble in water but glucose is soluble. Starch is a white powdery substance while glucose is a white crystalline substance.

Polythene Ethene Polythene has no effect on bromine in the dark. Ethene decolorizes bromine.

Ethene is a gas while polythene is a solid.

Advantages Disadvantages

1. Easily shaped and molded 1. Non- biodegradable- contribute to land pollution

2. Inexpensive 2. Produce dense smoke and poisonous gases when burnt- contribute to air pollution.

3. Light in weight 3. Many are flammable-pose fire hazards.

4. Easily coloured 4. Difficult to recycle

5. Durable- do not rust, corrode or decay6. Good thermal and electrical insulators.7. Can be made flexible or rigid

8. Some are very strong

• Advantages and disadvantages of plastics

• That’s it! Hope you enjoyed

Fun with polymers•http://www.youtube.com/watch?v=gIoKxmlMpJw&feature=fvwrel -MAKING SLIME•http://www.youtube.com/watch?v=uziSZngpdc4&feature=related -USES OF PLASTICS IN EVERYDAY LIFE•http://www.youtube.com/watch?v=uCXBu8j6dlk - JUSTA REVIEW IF YOU DIDN’T UNDERSTOOD WHAT TOOK PLACE•HERE IS ANOTHER POWERPOINT YOU CAN USE VERY USEFUL..•PolymerPowerPointComp.ppt