Project 2- Plastics By Ana Díaz Sánchez Ángela Oliva Jiménez María Osuna Galisteo Paula Parra García-Bravo

Explain the first and the second steps of the process of obtaining plastics:

•1st sourcing of raw materials;

• Coil, oil and natural gas.

• Before the manufacturing process, raw materials often are altered.

• They can be from

• Crude oil is processed to increase the concentration of metal, then, additional processes are used to produce the plastic.

STUDENT 1

Animal originPlant originMineral origin

• 2nd Synthesis of monomers:

• Monomers: structural repeated unit.

• Small subunits that ultimately link together to form larger molecules are called monomers.

• Monomers are taken from plastics by chemical reactions.

·Explain the following methods of shaping and finishing plastics. Mention at least one object that could be made with each technique:

Thermocompression

·Two metals, e.g gold, are brought into contact applying force and heat simultaneously.

Ashtrays are made by thermocompression

Extrusion moulding

• Extrusion moulding is a manufacturing process.

• Granules melt into a liquid.

• Forming a long 'tube like' shape

Hoses are made by extrusion moulding

Blow Molding• Manufacturing process by which hollow plastic parts are

formed.

• Begins with melting down the plastic.

• The parison (tube like piece) is then clamped into a mold and air is blown into it.

Bottles are made by blow molding

3rd Synthesis of the basic polymer

Polymerization: Process in which many monomers are combined.

• Chain-growth polymerization: monomers are added to the chain one at a time only

• Step-growth polymerization: chains of monomers may combine with one another directly

STUDENT 2

Explain the third and the fourth steps of the process of obtaining plastics

4th Incorporation of additives

Additives: • Materials mixed with polymer to make plastics.

• Additives turn basic polymers in to useful plastics

• Additives make plastics clean and healthy, safe, work longer, look good…

Some types of additives:

• Antioxidants: to protect the polymer from degradation by ozone or oxygen

• Ultraviolet stabilizers: to protect against weathering

• Plasticizers: to increase the polymer’s flexibility

• Lubricants: to reduce friction problems

• Pigments: to give the plastic colour

Explain the following methods of shaping and finishing plastics. Mention at least one object that could be made with each technique

• Injection molding: It is the process by which a material is injected into a mould so it takes the mould’s form.

• Foam molding: It is the process which combines plastics and gas.

• Vacuum forming: Sheets of plastic are heated, streched into a single-surface mold and pressed against a mold by a vacuum.

• Calandering: This process consist of multiple hard pressure rollers used to give form and smooth a material (plastic)

Provide information about the following properties in plastic material Physical properties:

• Electrical conductivity: Ability to transport an electric charge.

• Thermal conductivity: Capacity of a body to store thermal energy.

• Expansion: The size and the temperature increase.

• Density: Mass per unit of volume.

• Melting point: State in which the temperature changes from solid to liquid. This process depends on pressure.

• Fussibility: State in which a material melts. Refractory materials are those that melt at high temperatures.

STUDENT 3

Mechanical properties• Types of stress: • Traction: Two opposite forces that pull it to the sides• Compression: Two opposite forces that pull it to the centre.• Bending: Forces that bend the object.• Shearing: Deformation of a material in two opposite directions. • Torsion: Spin around it axis.

• Plasticity: Capacity os a material to undergo a deformation when it is compressed.

• Elasticity: Flexibility of an object.• Malleability: Ability to deform a under pressure object.• Ductility: Ability of a solid material.• Resistance: Ability to undergo a stress without breaking.• Hardness: Ability and resistance without scratching.• Weldability: Ability to join with another materials using heat.

Chemical properties

• Permeability,NO: Property of being permeable.• Solubility,NO: Ability to mix in a homogeneous mixture.• Combustibility,YES: Ability to burn.

Biological properties • Reciclability,YES: Ability to transform materials into useful

objects.• Toxicity, YES: When a material is affected by toxic substances.• Biodegradability, NO: Effect of environmental decomposition. •

Plastic materials are classified in three groups:

Thermosetting polymer (thermoset): • Petrochemical material

• Liquid or malleable prior

• Others are solid (molding compound used in semiconductors and integrated circuits)

STUDENT 4

Thermoplastic (thermosoftening plastic):• It is a plastic material (polymer)

• High molecular weight

Elastomers (elastic polymer):• It has viscoelasticity

• Very weak intermolecular forces

Bibliography• http://www.investopedia.com/terms/r/rawmaterials.asp• http://

global.britannica.com/EBchecked/topic/369072/materials-processing• http://

www.finetechusa.com/bonders/technologies/thermocompression.html• http://en.wikipedia.org/wiki/Thermocompression_bonding• http://en.wikipedia.org/wiki/Polymer#Polymer_synthesis• http://www.bpf.co.uk/plastipedia/additives/default.aspx• www.thomasnet.com/about/thermoset-plastics-61020277.htmls• www.ehow.com/about_5545184_properties-thermoplastic.html• www.adhesiveandglue.com/elastomer.html• www.dupont.com/products-and-services/plastics-polymers-resins/elastome

rs/articles/guide-to-elastomer-properties.html