PLASTICSBy: Jesús Castillo, Bruno Koster and Sergio

Vicente.

Student OneRaw materials: COAL, NATURAL GAS,

MINERALS, PLANTS and CRUDE OIL.With the synthesis of monomers you obtain

a polymer.

METHODS.Thermocompression: Ex:

doorknob

METHODS.Extrusion molding: Ex: tubes

METHODS.Blow molding: Ex: bottle

Student TwoSYNTHESIS OF BASIC POLYMERS: Plastics change shape and for.

ADDITIVES:Chemical products to give plastic new

qualities.

INJECTION MOLDING: Process consisted in injecting materials into a mould.

FOAM MOLDING:Is a process in which you make soft

plastics.

VACUUM FORMING:Is a process in which you apply heat and

absorb the air inside.

CALENDERING:A sheet of plastic passes between two

rolls.

Student ThreePHYSICAL PROPERTIES OF PLASTIC

 

Electical conductivity:Capacity of a material for allowing the electric current to pass.

It has a high capacity of insulation.Used for protecting the wires.

Thermal conductivity:It describes the behaviour of the polymers against the action of heat

PHYSICAL PROPERTIES OF PLASTICS Density: Discovered by Arquimedes. (not for plastics)

Low Density Polyethylene also known as LDPE Low density polymerHigh thermal , chemical resistance.

Expansion:Plastics expand if you increase their temperature.

Melting point:If the plastic is made of LDPE the melting point would be 150·cIf the plastic is made of HDPE the meltin point would be 135·c

MECHANICAL PROPERTIES OF PLASTICSThere are different types of stress:

Traction: The resistance to traction is the highest effort a material can resist Compression: Mold because of compression is the oldest.You put a plastic on a mold with a cavity

Bending:You can bend a plastic by using an electric resistanceShearing:

Torsion: A plastic would be resistance to torsion if you can bend the plastic without breaking it.

MECHANICAL PROPERTIES OF PLASTICS Elasticity: Plastics have a high capacity of

elasticity.Used for wheels Malleability:When you can deform a plastic althought it is cold.Ductility:When plastic can be elongated with out breaking.Hardness:Is the capacity for penetrating in plastic.Weldability:The ability of welding plastics depends on time, temperature and pressure and the design of the plastic

CHEMICAL PROPERTIES OF PLASTIC Permeability: Is the ability of passing

through a solid without changing its structure. A plastic bag is NOT permeable.

Solubility: Plastics do not have the ability of solubility , except polyethenol and polyalcohol.

Combustibility: Plastic , when it reaches certain temperatures , can be defored or melted.

BIOLOGICAL PROPERTIES OF PLASTIC Recyclability :Is the process of recycling

plastic , and making other new products.Toxicity:

BIOLOGICAL PROPERTIES OF PLASTICBiodegradability : Biodegradation of plastics

by microorganisms and enzymes seems to be the most effective process.