Blended fibres are the fibres created by combining two different fibres so that they have the advantages of both. Generally, a synthetic fibre is added to a natural fibre.
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 fibre and these are highly durable and last longer.
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.
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.
Biodegradable- A substance is biodegradable if it can be decomposed by the action of micro-organisms 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
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 fibres. 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.
Terylene and PET are two widely used polyester fabrics. Terylene is used to make very fine yarn by which various dress materials are made. PET is one of the familiar form of polyester that is used to make bottles, utensils, wires and many other things.
Polyester could be blended with natural fibres to enhance its properties. The common varieties of polyester are:
PET (Polyethylene terephthalate)
Terrycot: It is made by blending polyester and cotton.
Terrysilk: It is made by blending polyester and silk.
Terrywool: It is made by blending polyester and wool.
a. Synthetic fibres cannot absorb moisture. This makes them unsuitable to be warm during summer because in summer when our body sweats. These fibres make body sticky and sometimes cause skin irritation.
b.They cannot be easily ironed as they melt very easily.
c.They are dangerous to be worn near fire or heat, as they easily catch fire and is unfit to be worm.
the process of combining monomers to make a long chain or polymer is called polymerization.
A.Linear polymerization
B.Cross-linked polymerization
Linear polymerization- when monomers are linked linearly it is linear polymerization.
Cross -linking polymerization- when monomers are cross-linked, it is cross – linking polymerization.
Yes, plastics are hazardous to environment. Plastics are non-biodegradable in nature.. If use of plastics were not reduced, our earth would turn into a big garbage bin.
The major problems due to plastics are:
If plastics are burnt, they release poisonous gases. which destroys the ozone layer of the earth and pollute the environment.
If the plastics are disposed in drains, they clog the drains causing waterlogging.
If animals swallow these plastics, they harm their digestive system, which leads to their death.
It is less expensive than silk.
It absorbs moisture and is comfortable to wear.
It blends well with other fibres particularly the woven ones.
It can be easily dyed to produce beautiful and vivid colors.
Feminine hygiene products and disposable diapers contain rayon.
PET is a thermoplastic polymer, contains elements like carbon, hydrogen, and oxygen. It is used in making bottles for carbonated drinks, for acidic drinks, fruit juice. PET films are used as a base for recording tape.
all electric wires re insulated with plastics and those plastic covers do not cause any electric shock when touched.
plastics do not react with water or air and hence are not rusted.
Synthetic fibres melt on heating so, if they catch fire, they melt and stick to the body of the person wearing them and it becomes risky for the person’s life.
Plastics are non-reactive.
these uniforms have a coating of melamine, which is a thermosetting plastic to make them flame resistant.
It is less expensive alternative to silk fibre. Hence it is called artificial silk.
Acrylic fabrics are durable, warm, less expensive, wrinkle resistant, strong, resistant to moths, retain shape.
yes, as it has high strength and good frictional resistance.
As it clogs the drains and also harms the animals present inside it.
This synthetic fibres and Plastics Class 8 CBSE Important questions is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
