Question

Classification of plastics

Answer 1

PLASTIC  is nothing but POLYMERS mainly organic polymers.

POLYMERS are the compounds formed by repeating a single unit over and over again. The smallest repeating unit is known as MONOMER.

There are so many types of plastics known. As different type of plastics can be made by changing the composition slightly resulting in compound having different properties viz.density,melting point,strength etc.

Mainly there are  TWO types of plastics i.e. ​

1. THERMOPLASTICS
2. THERMOSETTING (THERMOSETS PLASTICS)

These above mentioned polymers are mainly classified as plastiscs.

THERMOSETS Thermosetting polymers are also known as thermosets and these are the polymers which possess a permanent shape and can not be reshaped by melting. They have high physical and mechanical strength as compared to thermoplastics. they do not melt.

some examples of thermosets are

• Phenolic Resins used in tool handles and insulators etc.
• Epoxy resins used as coating material,and used in manufacture of insulating materials.

THERMOPLASTICS These are plymers are somewhat flexible, can be reshaped by heating and are soluble in certain solvents unlike thermosetting polymers.

some examples of THERMOPLASTICS

• Polyamide used in making ropes belts etc.
• PVC ( POLYVINYLCHLORIDE) used in insulating materials and containers.

SOME SPECIFIC TYPE OF PLASTIC AND THEIR USES ARE

POLYETHYLENE is most common form of plastic we use in daily life. Two main types of polyethylene are

1. HIGH DENSITY POLYETHYLENE  

These have less branching that is have closely packed structure and hence have high tensile strength used in garbage cans,detergent jugs,toys etc.

LOW DENSITY POLYETHYLENE

These have more branching hence less tensile strength, loosely packed structure used in bottles,buckets,plastic bags ,wrapping material etc.

POLYPROPYLENE(PP) It is strong ,flexible ,tolerent to high temperature compared to other polymers used in tubesclothing,packing tapes,food packing as it is considered as food safe material.

POLYVINYLCHLORIDE(PVC) It is brittle plastic but stabalizers are added to it therefore make it soft and can be easily moulded into shapes easily. used in clothing ,furniture,waterpipes,cables waterbottles etc.

POLYETHYLENE TERETHALATE(PET)

It can be flexible and rigid depending on how it is made .One of the plastics which are most commonly used on daily basis. It is ideal for food storage and water bottles.It can also be drawn into fibers and sheets.

POLYSTYRENE Due ton environmental reasons it is not used commonly today. but it is light weight easy to mould and used in furniture,glasses,impact resistant surfaces etc.