PROJECT 2:PLASTICS

Martín Mora

Sarai de la Rosa

Adrián Utrera

Paula Monzón

Student 1

1st Sourcing of raw materials Raw materials can come from: minerals, plants, or animals. They are extracted from nature. Then they are modified so they obtain plastic properties.

Examples:

-Plant origin

Rubbers and gums are made from latex, a liquid extracted from tropical trees.

Rayon and cellophane are made from cotton and wood cellulose. Varnishes are made from the oil of oily seeds.

Rubbers from Cellophane from Varnishes from latex wood cellulose oily seeds

-Animal origin

For making shellac it is used the resin secretion from an insect called lac. Galalith and lanital are made from one protein called casein found in milk.

lac bug galalith

-Mineral origin The basic substances, called monomers are extracted from fossil

fuels.

2nd Synthesis of monomers

In this process, the basic substances are extracted from raw materials throw chemical reactions.

Then they are transformed into plastic substances. Is carried out in petrochemical industries.

Shaping and finishing This process is when the plastic substance are manufactured and

transformed into products.

Thermocompression For making thermosetting plastic products. The process:

The plastic is pass trough a hot mold then is compresd and when it has the mold shape and has cold down it is pulled out.

Extrusion molding

The plastic is introduced in a heat pipe then the hot screw moves the plastic foreward.

Then the melted plastic is shaped. Finally is cooled down and cut in measured pieces.

Blow molding

The plastic is form with a different method. Then is introduced in a closed mold with pressurized air which makes the plastic to the

walls. Finally when its called down is removed.

Thermocompression Extrusion molding Blow molding

Student 23rd Synthesis of basic polymers

Plastics are made up of different components.

The quantities vary according to the kind of plastic we want to obtain.

Then, chemical ractions (polymerization,polycondensation and polyaddition occur).

This chemical processes change the properties and the shape of the components.

4th Incorporation of additives

Chemical products that give several properties to the polymers

Dyes: change the color of the polymers

Plastizers: make the surface of the material brighter

Antistatic agents: take dust away by reducing the static electricity charge

Additives

Fireproof agents: make the polymers resist fire

UV stabilizers: make the polymers resist UV radiation and atmospheric phenomena

Fillers, reinforcements, and lubricants: made better mechanical processes and make easier the manufacturing process

Mold release agents: made easier the extraction of the polymer from a mold

Antioxidants: prevent the oxygen to cause chemical reactions

-UV stabilizers action

Elastomers Thermoplastics Thermosetting

Shaping and finishing

Injection molding: Is the process in which a polymer is injected ,in a liquid state, inside a mold

Foam molding: process that concerns some gases and its usually used to create softpolymers

Shaping and finishing

Vacuum forming: you place a plastic sheet in a mold with some channels, it is heated so that a vacuum which will compress the sheet so that it take the shape

Calandering: in this process we have to pass the polymer between the hot rollers and it will be compressed by them

Student 3

Physical Properties of Plastics electrical conductivity:

- is an electrical phenomenon.

- where a material contains particles with electric charge.

-Has a high capacity of insulation

Thermal conductivity: - is the property of a material to conduct heat. -In SI units, thermal conductivity is measured in watts per meter kelvin.

Density: -It was discovered by Arquimedes. -High thermal and chemical resistance. -Low density polymer.

Thermal Expansion -When an object is heated or cooled, its length change by an amount

proportional to the original length and the change in temperature.

Melting point It depends of what the plastic its made of : -If it is made of LDPE its melting point will be at the temperature of 150 Cº. -And it is made of HLPE its melting point will be 135 Cº.

Mechanical Properties of Plastics

Types of stress

-Traction: two opposites forces that pull the plastic to the sides.

-Compression: Two opposites forces that pull the plastic to the centre.

-Shearing: its the deformation of a plastic in two different directions

.

-Torsion: Bend a plastic without breaking it.

-Plasticity: it’s a capacity of plastics to undergo a deformation in a compressed form.

-Elasticity: Its how much flexibility have an object.

-Malleability: When you can deform a plastic althought its cold.

-Ductility: Is an ability of a hard material.

-Resistance: It’s the ability os supporting an stress without breaking.

-Hardness: resistance without scratching.

-Weldability: Ability of joining with other materials when the material heats.

Chemical properties -Permeability(NO) Ability of passing throught a solid without changing its

structure.

-Solubility: (NO) : ability of mixing with homogeneous mixtures.

-Combustibility (YES) : ability of burning.

Biological Properties

-Recyclability (YES) : ability of changing into an useful material

-Toxicity (YES) : When materials are affected by toxic products.

-Biodegradability (NO) : it’s the effect that causes the descomposition of the environment

Student 4Plastic materials classification

Thermosetting: -properties: fragile, difficulty of processing.

-characteristics: Light weight, high flexibility.

-applications: handle of frying pan, car body.

Thermoplastics: -properties: deform with heat, recycleable.

-characteristics: very fragile, very rigid.

-applications: bottles, polyethylene.

Elastomers: -properties: can’t melt, insoluble.

-characteristics: low density, resistance.

-applications: silicones, rubbers……

Bibliography

http://wemaketechnology3eso.wikispaces.com/file/view/Materials+-+plastics.pdf

http://en.wikipedia.org/wiki/Plastic

http://www.ensinger-online.com/en/materials/basics-of-plastics/plastics-classification/

http://plc.cwru.edu/tutorial/enhanced/files/polymers/synth/synth.htm