Long answer type questions
What are blended fibers? Are they better than synthetic fiber? Explain with an example.
Blended fibers are the fibers created by combining two different fibers so that they have the advantages of both. Generally, a synthetic fiber is added to a natural fiber.
e.g. Cotton blended with polyester (polycot) will give you the comfort of cotton along with the wrinkle- resistant of polyester so they are better than synthetic fiber and these are highly durable and last longer.
Why are plastics preferred these days? Explain giving example?
Plastic are strong, lightweight, electrical insulators and resistant to chemicals and they are generally cheaper than metal so these properties make them highly versatile materials for making numerous household and industrial goods.
For e.g. Polythene, a thermoplastic is use widely as packaging material for liquid. Polystyrene is used for making electronic items.
Write three uses of plastics?
1. Polyethylene terephthalate (PET) is used making containers that can be used in microwave ovens and bottles for packing mineral water and medicines.
2. Polyvinyl chloride (PVC) is used for making plumbing pipes, concealing electrical lining and furniture.
3. Bakelite is used for making electrical fitting.
What are biodegradable and non- biodegradable materials? Give one example of each of them?
Biodegradable- A substance is biodegradable if it can be decomposed by the action of microorganisms through a natural process. E.g. Paper, wood
Non- biodegradable- Substances that cannot decay by natural process when acted upon by decomposers are called non- degradable substances. E.g. Plastic
How is rayon made? Why it is called artificial silk?
Rayon is made from wood pulp. Wood pulp is first dissolved in an alkaline solution. The thick liquid produced is then passed through tiny holes to make fibers. The fibres are then hardened and spun into yarn and woven into clothes. It is called artificial silk because of its close resemblance to silk it has the shine of silk but costs much less than silk.