Samacheer Class 7 Science - Polymer Chemistry

1. Mix water, starch, vinegar and glycerin in a cooking pot.
4. Continuously mix on medium heat until the liquid turns clear.
5. When the liquid begins to bubble it is ready to be taken off the stove.
6. Spread the gel onto aluminium foil and cool.
3. Shape material to form a cup or bowl.
2. Let the article cool for 24 hours before we use it.

Burning of plastics and synthetic fabrics is not a good solution, as we end up wasting non-renewable resources and produce super toxic chemicals that are difficult to store or dispose safely.

The reason is due to their chemical composition.
The bucket is made of plastic which does not react with the oxygen and humidity present in air.
While the iron reacts with the oxygen, air corrodes to form rust.

Plastics do not decompose by natural processes and action of bacteria and are therefore not biodegradable.
A lot of the plastic produced globally is designed to be used only once and thrown away, creating a large amount of plastic waste.
Plastic waste ends up being recycled, incinerated, landfilled, dumped or ends up littering our environment.
So, it is better to avoid the use of plastic products.

In summer it is better to wear clothing that is made out of cotton materials rather than synthetic.
This is because most synthetic fibres absorb very little moisture and do not allow air circulation making them hot and uncomfortable to wear.

The increase in the use of plastics, particularly the one-time use and throw away plasticshas serious impacts on the environment, animals and our health.
We have seen garbage dumps with different plastics. One big problem with plastics is that they do not decompose or biodegrade.
This leads to large amounts of waste that will not disappear and end up accumulating and polluting the environment.
Many animals confuse plastic for food and eat it by accident. When leftover food is thrown away it is often packed in plastic. Animals smell the leftover food and eat the plastic by accident.

Advantages-and disadvantages of synthetic fibres.
Advantages of synthetic fibres
Disadvantages of synthetic fibres
1.
Do not wrinkle easily and they keep their colour and brightness for a much longer time than natural fibres such as cotton.
synthetic fibres such as polyester is that they are not heat resistant and catch fire easily.
2.
Using synthetic fibres such as nylon, is that they are stronger than many natural fibres such as silk or wool.
Most synthetic fibres absorb very little moisture and do not allow air circulation making them hot and uncomfortable to wear.
3.
These fibres are strong and elastic which gives it the properties to bounce.
Synthetic fibres are made out of petrochemicals and last in the environment for a very long time. It break down into very small pieces called microplastics which cause pollution to soil and water bodies such as rivers, lakes and oceans.

Refuse (Avoid):
The best thing to do is to avoid using plastic products.
One-time use throw away plastics can often be avoided.
Reduce : Reducing the amount of plastic we use is important.
Reuse : If possible products made of plastics can be used again and again.
Recycle:
It is better to recycle plastic waste.
Separating plastic waste (based on the resin code) and making sure it gets recycled is good as it turns waste materials into something new.
Then it will not be thrown away in landfills, open dumps or ending up as litter in the environment.
Solid waste can be converted into resources such as electricity and compost through thermal and biological means.

S.No
Name of the fibre
Type of the fibre- Natural /Synthetic
1.
Jute
Natural
2.
Cotton
Natural
3.
Rayon
Synthetic
4.
Wool
Natural
5.
Polyester
Synthetic

Product
Resin code number
Acronym
Category of safety
Use of product
Rain coat
03
PVC
Unsafe
During rain
Pens
06
PS
Unsafe
To write