Synthetic Fibres And Plastics

Some fibres are called synthetic fibres because they are man-made and not natural. These fibres are produced by the combination of different types of chemicals in industries. They can be of different varities and their nature is also very different as compared to natural fibre.

The correct answer is option (b).

Rayon is different from synthetic fibres because it is obtained from wood pulp.

(a) Synthetic fibres are also called man-made or artificial fibres.

(b) Synthetic fibres are synthesised from raw materials called petrochemicals

(c) Like synthetic fibres, plastic is also a polymer.

Nylon fibres are very strong as indicated by these examples:

1) for making ropes used for climbing rocks and for making parachutes.

2) They are used to make tents.

3) They are also use in car seat belts and sleeping bags, etc.

The characteristics that make plastics favorable for storing food items are:

(i) Light in weight.

(ii) Cheap in price.

(iii) Good strength.

(iv) Can be easily handled.

(a) Saucepan handles are made of thermosetting plastics because these plastics do not get softened on heating. Also, these plastics, example, Bakelite are poor conductors of heat. So, when you heat the pan, it cannot be transferred to the handle and thus the person holding the pan will be safe.

(b) Thermosetting plastics such as Bakelite are poor conductors of both heat and electricity. Therefore, they are used for making electric plugs, switches, plug boards, etc.

Rana should buy shirts made from cotton. This is because cotton is a natural fibre and not a synthetic fibres. Cotton is a good absorber of water. It can soak the sweat coming out of our body and expose it to the environment. Thus, it helps in evaporating the sweat, thereby cooling our body.

Plastics are non-corrosive in nature because they do not react with air, water or other substances. They do not get corroded even if they come in contact with strong chemicals. This is because of their non-reactive nature with most materials. For example, the cleansing chemicals that we use at home are stored in plastic bottles, instead of metal containers.

No, the handle and bristles of a tooth brush be made from different material. The handle and bristles of a tooth brush should be made of different materials. The handle of a toothbrush should be hard and strong, so should be made from hard plastic while the bristles should be soft and flexible, so should be made from soft plastic.

We must avoid plastics because they are non-biodegradable and take thousand years to decompose. Plastics are the cause of environmental pollution. When plastic material is burnt, they release poisonous gases, polluting the air. Plastic bags thrown in the garbage dump are swallowed by animals like cows. These plastic bags choke their respiratory system and can even prove fatal. Therefore, we should avoid plastics as far as possible.

The synthetic fibres are made from petrochemicals, which are not derived from trees. Raw materials for natural fibres are mainly derived from plants and this means cutting a lot of trees. This leads to deforestation. Hence, manufacturing synthetic fibres helps in the conservation of forests.

We will show by designing an electric circuit that thermoplastics are poor conductors of electricity.

The things we require are:

* a bulb

* Some wires

* A battery

* A piece of metal, and

* A plastic pipe.

Set up the circuit first with the metal and then with the plastic pipe (as shown in the figure).’

After you switch on the current, you will observe that the bulb glows in the former case, in which we have connected metal. In the latter case, the bulb does not glow, in which we have connected plastic pipe. Hence, a plastic pipe (which is a thermoplastic) is shown to be a poor conductor of electricity.