This PSEB 8th Class Science Notes Chapter 3 Synthetic Fibres and Plastics will help you in revision during exams.
PSEB 8th Class Science Notes Chapter 3 Synthetic Fibres and Plastics
→ Clothes are made of fabrics.
→ Fabrics are made by using fibres.
→ Fibers can be obtained from natural or artificial sources.
→ Synthetic fibres are also known as man-made or artificial fibres.
→ Synthetic or natural fibres are chains of small units joined together. Long chains are called polymers.
→ Cellulose is a natural polymer.
→ Rayon, Nylon, Polyester, or Acrylic are man-made fibres.
→ The Source of natural fabric (cotton, silk, etc.) is plants or animals.
→ The Source of artificial fabric is either plants (wood) or fossil fuels (coal etc).
→ Nylon was the first fully synthetic fibre.
→ Different fabrics have different strengths, water holding capacities, cost, durability, availability, and maintenance requirements.
→ Plastics are also polymers having different types of arrangement of units.
→ Plastics are of two types:
- Thermoplastics
- Thermosetting plastics
→ Polythene is a type of plastic.
→ Plastic is a light, strong, durable, non-corrosive, poor conductor of electricity and heat.
→ Plastic waste is not environmentally friendly. It is non-biodegradable.
→ On burning, it produces harmful gases and a bad odour.
→ Dumping in the soil makes the soil barren because it does not decompose quickly.
→ 4R principle (Reduce, Reuse. Recycle and Recover) must be used for the disposal of synthetic waste.
→ Man-made Fibres: The fibres made by human beings are called man-made fibres.
→ Polymer: A large unit made up of a chain of smaller units of chemical substances or a large unit made up of many repeating units.
→ Rayon: A synthetic fibre having properties of silk and is also known as artificial silk.
→ PET: A familiar form of polyester used for making bottles, films, ropes, and utensils, etc.
→ Thermoplastic: A type of plastic that gets deformed on heating and can be bent easily is known as thermoplastic.
→ Thermosetting Plastic: A plastic that does not get deformed on heating is called thermosetting plastic. It can be moulded only once.