PLASTICPLASTIC

What is plasticsWhat is plastics

Are materials which can be shaped Are materials which can be shaped or moulded under appropriate or moulded under appropriate conditions of temperature and conditions of temperature and pressure, and then hold their pressure, and then hold their shape.shape.

IntroductionIntroduction

Plastic has become increasingly important in our Plastic has become increasingly important in our every day lives. every day lives.

For the most part, plastics are organic high polymers, For the most part, plastics are organic high polymers, which means they are made of large chain that which means they are made of large chain that contain carbon. contain carbon.

These polymers are changed into a plastic state These polymers are changed into a plastic state either as they transition from a small-molecule either as they transition from a small-molecule chemical to a solid.chemical to a solid.

Types of PlasticsTypes of Plastics

Thermoplastic Thermosetting

i. Thermoplastici. Thermoplastic Become soft when heated and harden when cool and the Become soft when heated and harden when cool and the

process can be repeated is called process can be repeated is called thermo-softening thermo-softening plasticplastic or simply or simply thermoplasticsthermoplastics..

Is like waxIs like wax

Thermoplastics are linear with no crosslinks between the Thermoplastics are linear with no crosslinks between the polymeric chains. polymeric chains.

Can be recycling because can be melted and re-molded.Can be recycling because can be melted and re-molded.

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Structure of thermoplastic Structure of thermoplastic

Thermoplastic

Have linear structures and soften when heated hence it can be reshaped and recycled.

Monomer- linear

Conc… thermoplasticConc… thermoplastic The bonds holding the polymer chains together The bonds holding the polymer chains together

are usually the weak Van der Waals force.are usually the weak Van der Waals force.

When heated, the distance between the chain When heated, the distance between the chain increases and the polymer becomes soft. increases and the polymer becomes soft.

Allow the polymer chains to slide past one Allow the polymer chains to slide past one another.another.

On cooling, the chains come closer and the On cooling, the chains come closer and the polymer becomes hard.polymer becomes hard.

Picture of thermoplasticsPicture of thermoplasticsPE PlasticsPE Plastics

Picture of thermoplasticsPicture of thermoplasticsPP PlasticsPP Plastics

Picture of thermoplasticsPicture of thermoplasticsPVC PlasticsPVC Plastics

Picture of thermoplasticsPicture of thermoplasticsPET PlasticsPET Plastics

Picture of thermoplasticsPicture of thermoplasticsPolyamides PlasticsPolyamides Plastics

Picture of thermoplasticPicture of thermoplasticNylonNylon

Examples of ThermoplasticExamples of ThermoplasticTypesTypes UsesUses

Polyethene (PE)Polyethene (PE) Wide range of inexpensive uses including Wide range of inexpensive uses including supermarket bags, plastic bottles.supermarket bags, plastic bottles.

Polypropene (PP)Polypropene (PP) Food containers, appliances, car fenders Food containers, appliances, car fenders (bumpers). (bumpers).

Nylon (Polyamide)Nylon (Polyamide) Synthetic fiber, substituted for silk ( in silk Synthetic fiber, substituted for silk ( in silk stockings), tufted carpet, machine gear stockings), tufted carpet, machine gear wheelswheels

PolyvinylchloridePolyvinylchloride

(PVC)(PVC)

Plumbing pipes and guttering, shower Plumbing pipes and guttering, shower curtains, window frames, flooring, erotic curtains, window frames, flooring, erotic clothing.clothing.

PETPET Carbonated drinks bottles, jars, plastic Carbonated drinks bottles, jars, plastic film, microwavable packaging. film, microwavable packaging.

Properties and Uses of ThermoplasticsProperties and Uses of Thermoplastics

ii. Thermosetting Plasticsii. Thermosetting Plastics

Is like concrete.Is like concrete.

Highly cross-linked chains and hence usually Highly cross-linked chains and hence usually are rigid and brittle. are rigid and brittle.

They must be given their shape before their They must be given their shape before their final chemical structure is produced. final chemical structure is produced.

2nd

Structure ofStructure ofthermosetting plasticsthermosetting plastics

Cross-linked

Cross-linked:

1. More tougher 2. More elastic

3. More heat resistant 4. High Melting point

5. Less soluble in organic solvent

6. 6. More chemical innert

Conc…thermosetting plasticsConc…thermosetting plastics

They cannot be molten, but will decompose at They cannot be molten, but will decompose at high temperatures.high temperatures.

They are entirely insoluble and will not swell They are entirely insoluble and will not swell when treated with solvents.when treated with solvents.

They do not lend themselves to recycling. They do not lend themselves to recycling.

( like with eggs, once hard boiled, they cannot ( like with eggs, once hard boiled, they cannot be softened ).be softened ).

Picture of Thermosetting plasticsPicture of Thermosetting plasticsBakelitBakelit

Picture of Thermosetting plasticsPicture of Thermosetting plasticsBakelitBakelit

Properties and Uses of Properties and Uses of Thermosetting PlasticsThermosetting Plastics

Examples of Thermosetting plasticsExamples of Thermosetting plastics

TypesTypes UsesUsesVulcanized rubber Vulcanized rubber Tyres, gloves and tubingTyres, gloves and tubing

BakelitBakelit Electrical insulators and plastic wearElectrical insulators and plastic wear

Polyester Polyester Glass-reinforced plastics / fibreglass (Glass-reinforced plastics / fibreglass (GRPGRP))

Epoxy Epoxy Adhesive and in fibre reinforced plastic Adhesive and in fibre reinforced plastic such as glass reinforced plastic and such as glass reinforced plastic and graphite-reinforced plastic.graphite-reinforced plastic.

Acrylonitrile Acrylonitrile butadiene styrene butadiene styrene (ABS) (ABS) 

Electronic equipment cases (e.g., computer Electronic equipment cases (e.g., computer monitors, printers, keyboards).monitors, printers, keyboards).

Processing of plasticProcessing of plastic

Processing of thermosetting plasticProcessing of thermosetting plastic

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Processing of thermosetting Processing of thermosetting plasticsplastics

Compression molding forms thermosetting plastic Compression molding forms thermosetting plastic objects in a steel mold. objects in a steel mold.

When heat and pressure are applied, the softened When heat and pressure are applied, the softened plastic squeezes into all parts of the mold to form the plastic squeezes into all parts of the mold to form the desired shape. desired shape.

Laminating binds layers of materials together in a plastic Laminating binds layers of materials together in a plastic matrix. matrix.

The layers are fused when heated plates melt the plastic The layers are fused when heated plates melt the plastic and squeeze the material together. and squeeze the material together.

Processing of thermoplasticProcessing of thermoplastic

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Processing of ThermoplasticsProcessing of Thermoplastics Calendering process, continuous plastic sheets are formed by forcing Calendering process, continuous plastic sheets are formed by forcing

hot plastic between successive sets of heated rollers. hot plastic between successive sets of heated rollers.

Injection molding uses a screw to push plastic through a heated tube Injection molding uses a screw to push plastic through a heated tube into a mold. into a mold.

Extrusion is a continuous process that heats plastic pellets in a long Extrusion is a continuous process that heats plastic pellets in a long barrel. A screw pushes the heated plastic through a die opening to barrel. A screw pushes the heated plastic through a die opening to form objects such as garden hose and piping. form objects such as garden hose and piping.

In thermoforming a hot plastic sheet is draped over a mold and a In thermoforming a hot plastic sheet is draped over a mold and a vacuum draws the plastic down into the mold. vacuum draws the plastic down into the mold.

Blow molding forms containers from soft, hollow plastic tubes that Blow molding forms containers from soft, hollow plastic tubes that have a mold fitted around the outside. The tube is heated, and air have a mold fitted around the outside. The tube is heated, and air injected into the heated tube expands the plastic against the walls of injected into the heated tube expands the plastic against the walls of the mold. the mold.

Additives Additives are used in both forms of are used in both forms of plasticplastic

These can include: These can include: StabilisersStabilisers to prevent degradation due to moisture or UV light. to prevent degradation due to moisture or UV light.

LubricantsLubricants such as sulphides and waxes to make the polymer easier to such as sulphides and waxes to make the polymer easier to form and self lubricating in use. form and self lubricating in use.

PigmentsPigments - often referred to as 'master batch' adding colours to the plastic. - often referred to as 'master batch' adding colours to the plastic.

PlasticisersPlasticisers - added to make the plastic les hard or brittle.- added to make the plastic les hard or brittle.

FillersFillers - these can be added to enhance properties such as - these can be added to enhance properties such as wear/strength/toughness/durability and talc and clay may be used to bulk wear/strength/toughness/durability and talc and clay may be used to bulk out the plastic reducing costs. out the plastic reducing costs.

Flame retardantsFlame retardants - to prevent combustion in materials such as domestic - to prevent combustion in materials such as domestic foams. foams.

Blowing agentsBlowing agents - to permit foams to be blown. - to permit foams to be blown.

Anti-static agentsAnti-static agents - used to prevent the build up of electrical charge. - used to prevent the build up of electrical charge.

Common properties of plasticsCommon properties of plastics RigidRigid SolidSolid HardHard Transparent Transparent (most of them)(most of them)

Resistant to stainResistant to stain Non- biodegradableNon- biodegradable Resistant to chemicalsResistant to chemicals Resistant to oxidation agentResistant to oxidation agent

EndEndThank YouThank You