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TOPIC:PLASTICS

OUTLINES:DEFINITION OF PLASTICHISTORYTYPESPRODUCTIONUSESADVANTAGESDISADVANTAGESPROPERTIES

DEFINITION OF PLASTIC Plastics comes from the Greek word plastikos, which means to form or to mold.All synthetic polymers are considered plastics .

Plastic is a common name for Polymers: materials made of long strings of carbon and other elements.

HISTORY:

HISTORYThe development of plastic materials started with the use of natural materials with plastic properties (e.g., chewing gum) then evolved with the development of chemically modified natural materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally the wide range of completely synthetic material that we would recognise as modern plastics started to be developed around 100 years ago. Perhaps the earliest example was invented by Alexander Parkes in 1855. We know it today as celluloid, but he named it Parkesine. Polyvinyl chloride (PVC) was first polymerised between 1838-1872 and a key breakthrough came in 1907 when Leo Baekeland created Bakelite, the first real synthetic, mass-produced plastic.

TYPES OF PLASTIC:

TYPES:THERMOPLASTICSTHERMOSETS

THERMOPLASTICS:Soften with heat and harden with cooling.Thermoplastics can be reshaped anytime by reheating the part thus, making it easy to recycle.The concept of thermoplastics is much like wax from a candle. When heat is applied, it melts and turn into molten liquid. While in liquid state it can easily be shaped by a mold.

THERMOSETS:Are hardened by heat.Unlike thermoplastics, thermosets cannot be recycled.The concept of thermosetting is similar to baking cakes or bread. Firstly, the material is shaped like a dough and placed into a mold. Then heat is applied to the mold and the material expands (just like baking a bread in an oven) to take the shape of the mold. After curing, the final product is removed from the mold.

MANUFACTURING:

FROM RAW MATERIAL TO PLASTIC PRODUCT:

Energy Resources & Plastics:

USES:

ADVANTAGES:

ADVANTAGES:It lasts forever .It is very cheap to make.It does not decompose but it can instead be recycled.It can be converted back into oil.Easy to work with. Heat insulating.No electrical conductivity.Resistant.

Transportation:

Transportation:

DISADVANTAGES:

DISADVANTAGES:POLLUTION.

when it is melted the compound gas that is given off is very harmful for our health and environment; it weakens the ozone layer.The world is gradually running out of oil.

Properties:Plastics are used because they are: Easy to recycleHard and slippery Rubbery Tough and slippery Flexible Good insulators of heat or electricity Light weight Non-rusting Easy to shape and colour Cheap