Like synthetic fibres, plastics are also polymers. Plastics form an important class of synthetic materials. In plastics, the arrangement of the individual units may be linear or cross linked.
These can be of two types: thermoplastics and thermosetting plastics
THERMOPLASTICS
- Linear and lightly cross-linked polymers form a class of plastics called thermoplastics.
- Thermoplastics can be melted by heating and thereafter mounded into desired shapes. This is a reversible process.
- PVC (polyvinyl chloride) and LDPE (low-density polyethene) are examples of thermoplastics.
THERMOSETTING PLASTICS
- Heavy cross-linking after shaping the plastic forms a class of plastics called thermosetting plastics.
- Unlike thermoplastics, thermosetting plastics can not be remoulded after reheating.
- Melamine and bakelite are examples of thermosetting plastics.
WHAT ARE THE USES OF PLASTICS CLASS 8TH
PET(POLYETHYLENE TEREPHTHALATE)
Making containers for microwave cooking, bottles of carbonated beverages, water bottles, and other food containers.
HDPE (HIGH-DENSITY POLYETHYLENE)
Making containers for strong and corrosive household and industrial chemicals such as bleaches and acids.
LDPE (LOW -DENSITY POLYETHYLENE)
Making polybags ,grocery bags,and packaging of foods and bread.
PVC (POLYVINYL CHLORIDE)
Making pipes for sanitary fittings (like water pipes)
PP (POLYPROPYLENE)
Making ketchup bottles, yogurt containers, medicine bottles, and automobile battery casings.
PS (POLYSTYRENE)
Thermocol, a form of PS, is used for making disposable cups and packaging material for fragile items like computers and televisions.