Definition of terms, Addition and condensation polymerization, classification and preparation, properties and uses of polymers.

SECOND TERM E-LEARNING NOTES

SUBJECT: CHEMISTRY

CLASS: SS3

WEEK 3

TOPIC:

Definition of Terms , Addition and condensation polymerization, classification and preparation, properties and makes use of of polymers.

WEEK 3

TOPIC: SYNTHETIC POLYMERS

CONTENT:

1. DEFINITION OF TERMS

2. ADDITION AND CONDENSATION POLYMERIZATION

3. CLASSIFICATION AND PREPARATION

4. PROPERTIES AND USES OF POLYMERS

PERIOD 1: DEFINITION OF TERMS

1. Artificial polymers: are polymers made within the trade from chemical substances. Via scientific analysis, scientists are in a position to copy the constructions of pure polymers to supply artificial polymers. Lots of the uncooked supplies for artificial polymers are obtained from petroleum, after the refining and cracking processes. The forms of artificial polymers embrace: (a). Plastics (b). Fibre (c).elastomers

2. Elastomer: is a polymer that may regain its unique form after being stretched or pressed. Each pure rubber and artificial rubber are examples of elastomers. Examples of artificial rubber are neoprene and styrene-butadiene rubber (SBR).SBR is used to make automobile tyres.

3. Polymers: are giant molecules made up of many smaller and similar repeating items joined collectively by covalent bonds. These molecules are referred to as monomers.

1. Monomers: are the straightforward molecules from which the massive molecules are constructed or the small molecule or repeating unit or the constructing block within the
   construction of polymer known as monomer. To be a monomer, the substance unit ought to have a performance of at the least two; some compounds have two performance different have double or triple bonds within the molecule.

5. Polymerization: is the chemical course of by which the monomers are joined collectively to type a giant molecule generally known as a polymer. A polymer is macromolecules (a really large molecule). Therefore, the relative molecular mass of a polymer is giant. The properties of a polymer are totally different from its monomers. The situations crucial for polymerization are: excessive temperature, excessive strain and the presence of chain-initiating substance (initiator) comparable to traces of oxygen or natural peroxide catalyst. Polymerization known as homo-polymerization if the monomeric items are all the identical molecule. It’s, nonetheless, referred to as co-polymerization if two or extra totally different molecules function monomeric items.

EVALUATION

1. Outline the time period polymerization.
2. What’s artificial polymer?

PERIOD 2: TYPES OF POLYMERIZATION

On a broad foundation, polymerization is of two varieties:

1. Addition Polymerization: That is an addition response between monomers. Fairly often one forms of monomer is concerned. For instance, ethene polyermerize to type polythene

n (CH₂= CH₂) (-CH₂ –CH₂-) _n

2. Condensation Polymerization: It is a condensation response between monomers. Within the response, a small molecule, often a water molecule is eradicated from two bigger molecules. It often entails two totally different monomers joined by condensation. Many pure polymers are condensation polymers. For instance:

EVALUATION

1. Title two forms of polymerization.
2. How are the next polymers shaped?

(i) Polyvinyl chloride (PVC);

(ii)Polypropene

PERIOD 3: CLASSIFICATION AND PREPARATION OF POLYMERS

There are a number of methods of classification of polymers based mostly on some particular
concerns

(A) Classification Based mostly on Supply underneath: The sort of classification, there are three sub classes:
1. Pure polymers: These polymers are present in nature, instance crops and animals. Examples are proteins, cellulose, starch, resins and rubber.
2. Semi-synthetic polymers: The polymers obtained by easy chemical remedy of pure polymers to vary their bodily properties like Starch, silicones. [mediator_tech]
3. Artificial polymers: The fibers obtained by polymerization of easy chemical molecules in laboratory are artificial polymers, instance: Nylon, polyethene, polystyrene, artificial rubber, PVC, Teflon…. and so forth.

EVALUATION

1. Title two lessons of polymer?
2. Differentiate between pure and artificial polymers

PERIOD 4: PROPERTIES AND USES OF POLYMERS

1. PROPERTIES OF POLYMERS

Virtually all the pieces round us is manufactured from some kind of plastic. The next components have made our current plastic age potential.

1. Plastics have properties which make them appropriate for a lot of functions. Plastic are robust however mild; inert to air, water, and different chemical substances; immune to fungal and bacterial assaults; and good insulators of warmth and electrical energy.

2. Plastics: may be tailored tour precise necessities. They are often made into arduous, inflexible blocks; skinny, versatile sheets; fibres that may be made into ropes and materials; and really mild foams. They’ve extensive functions.

3. Polystyrene: is a transparent clear plastic which is tough however brittle. When air, coupled with a foaming agent, is blown into heated polystyrene, it expanded polystyrene or Styrofoam.

4. Perspex: is a robust, arduous, clear thermoplastic with a shiny floor.

5. Nylon: have very excessive tensile power which makes it appropriate for artificial fibre.

6. Terylene: it’s gentle and is able to retaining an nearly everlasting crease.

USES OF POLYMERS

1. Polystyrene: is used for making see-through containers, because of its excessive compressibility, it’s broadly used as packing supplies or as shock absorbers for fragile objects throughout transportation. It’s also used for making disposable cups and meals containers, particularly in fast-food outlets.

2. Poly (propenonitrile) is used mainly for making textile. It’s spun into threads and used for making woolly clothes. One such materials is popularly generally known as Orlon.

3. Perspex: Due to its glasslike look, it’s usually used as a alternative for glass. It’s used to make automobile back lights, wind-shields, window-panes, fish tank, contact lenses, street-lamp housing and others.

4. Nylon: Its fibers are used for making ropes, fishing traces, nets and strings. It’s also used for making all types of clothes. Such clothes drip-dry simply, and are crease-free and immune to fungal and moth assaults.

5. Terylene: woven terylene is used for making the sails of boats the place a robust rot-proof materials is required.

EVALUATION

1. State the property which is widespread to compounds that may be simply polymerized.
2. Enumerate 5 makes use of of polymer