WHOSE FORESTS -TEXT

WHOSE FORESTS

ENVIRONMENTAL STUDIES

CBSE-V

Daughter of the jungle

Look at the picture. Where do you think these children are off to, with little bundles on their sticks? When you find out you too would want to go with them!

The children are going to the forest. There they jump, run, climb trees and sing songs in their language called Kuduk. They pick the fallen flowers and leaves, to weave them into necklaces.

They enjoy the wild fruits. They look for birds, whose calls they imitate. Joining them in all this fun is their favourite didi – Suryamani. Every Sunday Suryamani takes the children to the forest.

As they move around, she shows them how to recognize the trees, the plants, and animals. Children enjoy this special class in a forest! Suryamani always says, “To learn to read the forest is as important as reading books.”

She says,”We are forest people (adivasis). Our lives are linked to the forests. If the forests are not there, we too will not remain.”

Suryamani’s story is a true story. Suryamani is a ‘Girl Star’. ‘Girl Stars’ is a project which tells extraordinary tales of ordinary girls, who have changed their lives by going to school.

Growing Up

Suryamani loves the forest since she was a child. She would not take the direct road to school, but would choose the path through the forest. Suryamani’s father had a small field.

Her family used to collect leaves and herbs from the forest and sell these in the bazaar. Her mother would weave baskets from bamboo or make leaf plates out of the fallen leaves.

But now no one can pick up a single leaf from the forest. That is since Shambhu the contractor came there. The people of Suryamani’s village were afraid of the contractor.

Everyone except Budhiyamai. She would say, “We the people of this forest have a right over it. We look after our forests, we don't cut trees like these contractors do. The forest is like our ‘collective bank’ – not yours or mine alone. We take from it only as much as we need. We don’t use up all our wealth.”

Suryanani’s father could no longer support the family on the small land. He moved to the town in search of work. But things did not improve. Sometimes there would be no food in the house.

At times Maniya Chacha (uncle) would send some grain from his small shop to Suryamani’s house. Chacha tried hard and got admission for Suryamani in the school in Bishanpur.

Here they would not have to pay for the fees, uniforms and books. Suryamani would have to stay there and study. Suryamani didn't want to leave her village and forest. But Maniya Chacha was firm.

“If you do not study, what will you do? Go hungry?” Suryamani would argue, “Why should I go hungry? The jungle is there to help!” Chacha tried

to explain, “But we are being moved away from our forests.

Even the forests are disappearing – in their place mines are being dug, dams are being built. Believe me, it is important for you to study, to understand about the laws. Maybe then you can help to save our forests”. Young Suryamani listened, and tried to understand some of what he said

Suryamani’s journey:

Suryamani was filled with joy on seeing the school at Bishanpur. The school was near a thick forest. Suryamani studied hard and passed her B.A. after getting a scholarship.

She was the first girl in the village to do this. While she was in college she met Vasavi didi, a journalist. Suryamani soon joined her to work for the Jharkhand Jungle Bachao Andolan (Movement to Save the Forests of Jharkhand).

This work took Suryamani to far off towns and cities. Her father did not like this. But Suryamani continued her work. Not only that, she also started to fight for the rights of the village people. Her childhood friend Bijoy helped her in this work.

Suryamani had another friend ‘Mirchi’, who stayed with her day and night. Suryamani would share all her thoughts and dreams with Mirchi. Mirchi would listen and say “Keee Keee.” Suryamani had a dream. for her Kuduk community. She wanted all her people to feel proud of being adivasis.

Suryamani’s Torang:

Suryamani was 21 when she opened a centre, with the help of Vasavi didi and others. She called it ‘Torang’, which means jungle in the Kuduk language.

Suryamani wanted that on festivals people should sing their own songs. They should not forget their music and should enjoy wearing their traditional clothes.

Children should also learn about herbs, medicines, and the art of making things from bamboo. Children should learn the language of school but must link it with their own language.

All this happens in the ‘Torang’ centre. Many special books about the Kuduk community and other adivasis have been collected. Flutes and different types of drums are also kept there.

Whenever something is unfair, or if someone is afraid that his land and livelihood would be taken away, they turn to Suryamani. Suryamani fights for everyone’s rights.

Suryamani and Bijoy have got married and work together. Today their work is praised by many people. She is invited, even to other countries, to share her experiences. People of her area are also raising their voice for a new forest law.

Right to Forest Act 2007

People who have been living in the forests for at least 25 years, have a right over the forest land and what is grown on it. They should not be removed from the forest.

The work of protecting the forest should be done by their Gram Sabha. A forest is everything for us adivasis. We can’t live away from the forests even for a day. Government has started many projects in the name of development – dams and factories are being built.

Forests, which are ours are being taken away from us. Because of these projects, we need to think where the forest people will go and what will happen to their livelihood?

Where will the lakhs of animals living in the forests go? If there are no forests, and we dig out our lands for minerals like aluminium, what will be left? Only polluted air, water, and miles and miles of barren land...

Lottery for farming in Mizoram:

You read about the forests of Jharkhand in Suryamani’s story. Now read about forests on the hills of Mizoram. See how people live there, and

how farming is done.

Ding, Ding, Ding.... As soon as the school bell rang Lawmte-aa, Dingi, Dingima picked their bags and hurried home. On the way they stopped to drink water from a stream in a cup made of bamboo which was kept there.

Today not only the children, even ‘Saima Sir’ was in a hurry to get back. Today there would be a special meeting of the Village Council (Panchayat). At the meeting there would be a lottery to decide which family will get how much land for farming.

The land belongs to the whole village, not to separate people. So they take turns to do farming on different parts of the land. A beautiful pot made of bamboo was shaken well. One chit was taken out. Saima Sir’s family got the first chance.

He said, “I am happy that my family gets to choose first. But, this year we cannot take more land. Last year I had taken more and was not able to farm it well. After my sister Jhiri got married and went away it is difficult to manage farming alone.”

Saima Sir asked for ‘three tin’ of land. Little Mathini asked, “ What is three tin of land? Chamui explained, “The land on which we grow one tin of seeds is called one tin of land.” One by one, the village families got their piece of land for farming.

Jhoom farming:

Jhoom farming is very interesting. After cutting one crop, the land is left as it is for some years. Nothing is grown there. The bamboo or weeds which grow on that land are not pulled out. They are cut and burnt.

The ash makes the land fertile. While burning, care is taken so that the fire does not spread to the other parts of the forest. When the land is ready for farming it is lightly dug up, not ploughed.

Seeds are dropped on it. In one farm different types of crops like maize, vegetables, chillies, rice can be grown. Weeds and other unwanted plants are also not pulled out, they are just cut. So that they get mixed with the soil.

This also helps in making the soil fertile. If some family is not able to do farming on time, others help them and are given food.

The main crop here is rice. After it is cut, it is difficult to take it home. There are no roads, only hilly paths. People have to carry the crop on their

backs. This takes many weeks. When the work is over the entire village celebrates.

 People get together to cook and eat, sing and dance. They do their special ‘cheraw’ dance. In this dance people sit in pairs in front of each other, holding bamboo sticks on the ground.

As the drum beats, the bamboos are beaten to the ground. Dancers step in and out of the bamboo sticks, and dance to the beat.

Find out more about the ‘cheraw’ dance. Do it in your class. But be careful and don’t hurt yourself. About three-fourth people in Mizoram are linked to the forests.

Life is difficult but almost all children go to school. You can see some of them here, playfully blowing their leaf whistles! You too have made many such whistles, haven’t you!

THANKYOU,

NANDITHA AKUNURI

A SEED TELLS A FARMER’S STORY - TEXT

A SEED TELLS A FARMER’S STORY

ENVIRONMENTAL STUDIES

CBSE-V

I am a small seed!

I am a small bajra seed. I have stayed in this beautiful wooden box since 1940. I want to tell you my story. This is a long story but not mine alone. It is also the story of my farmer Damjibhai and his family. If I do not tell my story now, it might be too late!

I was born in Vangaam in Gujarat. That year there was a good bajra (millet) crop. There was a festive mood in the village. Our area was famous for its grain and vegetables.

Each year Damjibhai kept aside some seeds from a good crop. This way

our bajra family went on from one generation to another. Good seeds were stored in dried gourd (lauki ) which was coated with mud.

But that year Damjibhai himself made a strong wooden box to store us. He put in neem leaves to protect us from insects. He put different seeds in different compartments of the box. That was our beautiful home!

In those days Damjibhai and his cousins lived together. It was a large family. Everyone in the village helped each other, even in farming. When

the crop was ready and harvested, everyone celebrated together.

Oh! Those wonderful days! With big feasts and lots to eat! In the winter, it would be time to enjoy the undhiya (a kind of stew). All the vegetables were put into a clay pot, along with fresh spices. The pot was sealed and kept between hot coals. The vegetables cooked slowly in this special cooker, on the fields.

Oh, I forgot, the pot was placed upside down! That is why the dish was called undhiya or “upside down” in Gujarati. Undhiya would be eaten with bajra rotis, freshly cooked on the chulha. Oh, what an earthy delicious flavour!

Along with that, home-made butter, curd and buttermilk was served.

Farmers would grow many different kinds of crops – grains and vegetables according to the season. The farmers kept enough for their needs and sold the rest to shopkeepers from the city.

Some farmers also grew cotton. At home, family members spun cotton on a charkha (spinning wheel) to make cloth.

When times changed:

Over the years, many changes took place in the village. Some places could get water from the canal. They said the canal brought water from far away – where a dam had been built on a big river.

Then electricity came. Switch on the button and there was light! People found that only one or two crops, like wheat and cotton, got better prices in the market.

So most farmers began to grow only these. Soon we – old friends bajra and jowar, and also vegetables – were forgotten and dismissed, even from

Damjibhai’s fields! Farmers even began to buy seeds from the market.

People said they were new kinds of seeds. So farmers did not need to store seeds from the old crop.

Now people in the village cooked and ate together only on very special days. As they ate, they would remember how tasty the food used to be in the past – fresh from the fields.

When the seeds have changed, how could food ever taste the same! Damjibhai was getting old. His son Hasmukh looked after the fields and the family. Hasmukh was making a lot of money from farming. He rebuilt the old house.

He brought new machines for farming. He used an electric motor to pump water. He bought a motorcycle to go to the city easily and also a tractor to plough the field. The tractor could do in a day, what the bullocks would take many days to do.

Hasmukh would say, “Now we are farming wisely. We grow only what we can sell in the market at a good price. With profits from our fields we can improve our life.

We can make progress.” Lying forgotten in the wooden box, I and

the other seeds had our doubts. Is all this really progress? There is no longer any need for seeds like us, and animals like the bullocks. After the tractor has come, even people who worked on the fields, are no longer needed. How will they earn money? What will they live on?

More and more expenses:

The next twenty years saw even more changes. Without cows and buffaloes, there was no cow dung, to be used in the fields as fertilizer. Hasmukh had to buy expensive fertilizer.

The new kinds of seeds were such that the crops were easily affected by harmful insects. Medicines had to be sprayed on the crops to keep away

the insects.

Oh, what a bad smell these had, and how expensive they were! The canal water was not enough for the new crops. All the farmers used pumps to lift

water from deep under the ground.

To meet all these expenses, loans had to be taken from the bank. Whatever little profit was made, was used to repay the loan. But there was little profit!

Everyone was growing cotton, so the cotton prices were not as high as before. The soil itself was no longer the same. Growing the same crop

over and over, and using so many chemicals, had affected the soil so much that now nothing could grow well there.

It was becoming difficult to earn a living by farming alone. Hasmukh too changed with the times. He is often tense and angry most of the time. His educated son Paresh did not want to do farming. He now started work as a truck driver.

After all, the bank loans still had to be repaid. Often Paresh doesn’t come home for days. At times he is away for a week. Two days back when he came home, Paresh started looking for something.

“Ba”, he asked his mother, “Where is Dadaji’s wooden seed box? It will be useful to keep the screws and tools for the truck.” Now do you understand why I told you my story?

Read the report from a newspaper and discuss it:

Tuesday, 18 December 2007, Andhra Pradesh Farmers in Andhra Pradesh have been sent to jail for not being able to pay back their loans.

They had suffered a big loss in farming. One of these farmers, Nallappa Reddy, had taken a bank loan of Rs. 24,000. To repay the loan, he had to take another loan from a private moneylender, at a very high rate of interest.

Even after repaying Rs. 34,000 Reddy could not repay the entire loan. Reddy says, “The bank sends farmers to jail for not paying back small loans. But what about the big businessmen? They take loans of crores of rupees.

Nothing happens to them when they do not return the money!” Nallappa Reddy’s story is shared by thousands of farmers in India who are suffering huge losses.

The situation is so bad that many farmers see no way out of this except to commit suicide. According to government figures 1,50,000 farmers have died like this between 1997 and 2005. This number may be much higher...

Bhaskarbhai’s Farm (Dehri village, Gujarat)

As we entered his farm, we were surprised. There were dead leaves, wild plants, and grass everywhere! Some of the tree branches seemed so dry, as if eaten by insects. At places we saw some plants with colourful leaves.

Why these? Bhaskarbhai said they were croton plants which gave him a signal when the soil became dry. We were surprised! How? He explained that the roots of the croton do not go deep in the ground.

So when the top layer of the soil becomes dry, the croton leaves bend and become limp. This signal tells Bhaskarbhai which part of his farm needs to be watered.

We found the soil soft and crumbly. We could see tall coconut trees, full of fresh coconuts. We thought he must be using some special fertilisers.

Bhaskarbhai said he does not buy fertilisers made in factories.

His soil is fertile because of all the dried leaves which slowly rot and mix with it. He dug the soil a little and told us to look. We saw thousands of earthworms! “These are my soil's best friends”, he said.

The earthworms soften the soil as they keep digging underneath to make tunnels. This way air and water can easily get into the soil. The earthworms also eat the dead leaves and plants, and their droppings fertilise the soil.

Pravin told us about his uncle in the city, who has dug a pit in his garden. He puts dried leaves in the pit, along with all the kitchen waste – peels of vegetables and fruits, and leftover food. He also has earthworms in the pit.

They turn the waste into compost (a natural fertiliser). So his uncle gets good fertiliser without spending extra money. We all had some fresh coconuts from the farm. They were really tasty! We also learnt so much about a new way of farming! Group members : Praful, Hansa, Krutika, Chakki, Praveen, Class–5C

Journey of a bajra seed–from a field to a plate

What can you see in each picture on the next page?

In picture 2 you can see the bajra cobs in the mortar (okhli, usedfor crushing). The cobs are crushed with a pestle (moosli ) andthe seeds are separated from the cob.

You can see the separatedseeds in picture 3. Now this work is also done by big machines,like threshers. We call both these as different ‘technologies’ –using our hands or big machines – to crush the seeds.

THAKYOU,

NANDITHA AKUNURI

HOME AND ABOARD_(TEXT)

HOME AND ABOARD

AENVIRONMENTAL STUDIES

CBSE-IV

Today, there was a lot of activity at Maalu’s house. Chittappan and his family were coming home after five years. Chittappan had got a job in a country called Abu Dhabi five years ago.

Since then he had lived there. Maalu and her Appa went to the airport to receive them. 

After the plane landed, the passengers had to wait for some time to collect their luggage.

At last Chittappan, Kunjamma and their two children could be seen coming out. “How big Shanta and Sashi have grown,” Appa said. 

Many  suitcases and bags were fitted into the taxi and everyone was on the way to Maalu’s house. “Shanta, you must be very tired after your long journey, Appa told me that Abu Dhabi is another country, far from India,” said Maalu.

Chittappan – Father’s younger brother in Malayalam. Kunjamma – Father’s younger brother’s wife in Malayalam. “We are not tired. Even though it is far, our flight took only two hours,” said Shanta. “The plane flies very fast.” Maalu was surprised.

She remembered that when she had gone on a school trip to Chennai, they had spent almost 12 hours in the train. And on the map, Kochi and Chennai seemed quite near.

Maalu, Shanta and Sashi chatted all the way home from the airport. Maalu remembered how much fun she had on her school trips. She wanted Shanta to tell them all about her trip from Abu Dhabi.

Dust All Around!

“Did you see many interesting things from the plane?” asked Maalu.

“Most of the time we saw only clouds because the plane was flying so high, even higher than the clouds,” said Shanta.

“But before it went so high, we could see that we were flying over sandy areas. It was sand but the colour of the sand kept changing – white, brown, yellow, red, black.

We saw mountains made only of sand.”  “They are called sand dunes,” added Sashi. “I have seen sand only at the seashore,” said Maalu. “Then you should come to visit us,” said Chittappan.

“The countries around Abu Dhabi are located in a desert area. Even if one drives a little away from the city, one can see miles and miles of sand – no trees, no greenery – just sand.”

“I used to dream of the thick greenery and cool water around our home in Kerala,” said Kunjamma. “I am so happy to see all this after such a long time.”

“The children have almost forgotten how it feels when it rains. You know it almost never rains in desert areas,” said Chittappan. “Water is really very precious over there. No rain, no rivers, no lakes, no ponds.

Even below the ground there is no water.” “But,” added Sashi, “there is a lot of oil under the sandy soil. So petrol is easily available in these countries.” “In fact petrol is cheaper than water,” said Chittappan.

By this time the taxi had reached Maalu’s house. Shanta and Sashi were surprised to see so many fruit trees– coconuts, bananas, jackfruit, papaya, betelnut … so many kind of trees!

Sashi said, “We used to see only one kind of tree there – the date palms – because it is the only one that can grow in the desert. The date is the

most common fruit.”

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After they had met everyone, Kunjamma unpacked their bags. They had brought gifts for everyone.

They gave dates for everyone to eat. The dates were very sweet and tasty.

Sashi showed Maalu some notes and coins. Shanta explained that the money they used in Abu Dhabi was different and was called Dirham.

It had some writings in their local language – Arabic. They also showed many photographs of the place where they lived. Chitappan gave Maalu a globe. He said, “Maalu, why don’t you locate Abu Dhabi on this? Locate Kerala also.”

The children enjoyed playing with the globe and looking for different places on the globe. Maalu found Chennai and Kochi also. 

In the evening everyone sat in the verandah, enjoying the breeze and looking at the photographs.

They saw that in Abu Dhabi the buildings were tall with many storeys and big glass windows. Maalu said, “You must be getting nice cool breeze

through the big windows.” Chittappan said, “We cannot open the windows because of the heat. It is air-conditioned inside where everyone stays.

As the weather is very hot, people wear loose cotton clothes and keep themselves fully covered – even the head is covered. This protects them from the strong

sun.”

Maalu enjoyed looking at the pictures and finding out about the other country from her cousins. She constantly kept comparing her city with the things that they described about Abu Dhabi. She decided that she would make a project report about Abu Dhabi for her class.

THANKYOU,

NANDITHA

FAMILIES CAN BE DIFFERENT-TEXT

FAMILIES CAN BE DIFFERENT

ENVIRONMENTAL STUDIES

CBSE CLASS III

Come, let us play a game together. You must be familiar with this game. All the children stand in a circle.

Let one child stand in the centre and play a tune. Everyone must run in a circle as long as the music plays. The child who is playing the music, will suddenly stop it and call out a small number like ‘five’, ‘four’ or ‘two’ loudly. Children have to form groups according to the number called out.

The children who cannot join any group will have to leavethe game. Continue to play this game till only two children are left in the circle.

All of us prefer to live with people than to live alone. We always live in groups. Let’s see one such group – Gurleen, Nagarajan and their children Tanya and Samar.

The people in the picture you saw belong to one family. We often see pictures or photographs of such families. Where do we see such a family? Are all families similar to this one ? Let us read about a few families.

Sitamma

Sitamma lives in her ancestral house in a small city Guntoor. Her dada, dadi, younger chacha and bua live on the ground floor. In one portion of the first floor, Sitamma lives with her father, mother and younger sister Gitamma. In the other portion live her tauji and his three children.

Her taiji died just a few months ago. Her elder chacha and the new chachi live in one of the rooms on the terrace. They are newly married.

Before dinner, Sitamma’s mother teaches all the children. Food for the whole family is cooked in the same kitchen on the ground floor. They all make special effort to be together at dinner time.

Nowadays, tauji ’s younger daughter sleeps with Sitamma’s mother at night. In the morning Sitamma helps her get ready for school.

Tara lives with her amma and nana in Chennai. Her amma Meenakshi is not married. She has adopted Tara. Meenakshi goes to the office in the morning and returns in the evening.

When Tara returns from school, her nana takes care of her. He is the one who feeds her, helps her to do homework and also plays with her.

During vacations, the three of them go to far off places and enjoy themselves. At times, Tara’s mausi, mausa and their children also come to their house. At such times they play together for long hours and also chit chat.

Sara and Habib live in a city. Both are employed. Habib is a clerk in a government office and Sara teaches in a school. Habib’s abbu is retired and lives with them.

In the evening, the three of them sit together and watch television or play cards. Abbu enjoys watching television with the others. He enjoys the discussion as well. On holidays, the neighbour’s children come to their house and create a lot of fun. Everybody enjoys together. They play games, go out and at times go for plays and movies.

Totaram

Totaram lives with his father, uncle and cousin brothers in a colony in Mumbai. Totaram and his brothers have come to Mumbai to study. His father and uncle work here.

Everybody does the household work together. Food cooked by Totaram’s chacha is liked by everyone.Totaram’s father does the shopping.

A part of the money earned is sent to Totaram’s dada in the village. Totaram’s mother, dada, dadi, chachi and younger brothers and sisters live in their parental house in the village. Once a year, Totaram goes to his village. He misses his mother very much. He writes long letters to her.

Krishna and kavari

Krishna and Kaveri live with their father. In the morning, all the three leave home together. krishna lives kavari at school and goes to college. Their father go to the shop for the day.

Kaveri returns from school in the afternoon. She unlocks the house

and waits for Krishna. On returning from college,Krishna and kavari eat food together.Kaveri goes out to play after doing her school work.

 On returning she either plays carom with her brother or watches television. When father returns home, they cook food and then eat together.

During vacations, Kaveri goes to stay with her mother. Krishna

also stays there for a few days, but he likes to stay in his own

house – all his things and his father are here.

There may be other differences: some couples may marry at a young age and some people find a partner when they are older; some families with children are led by one parent because of death, separation, or divorce; some couples have no children, yet they consider themselves to be a family; some people have one child, while others have many children born to them.

Many families adopt a child or several children.  When we talk about our family, we usually refer to the people who live with us.

All of our relatives, such as cousins, aunts, uncles, and grandparents, are part of our family. Whether they live in a separate place down the block or across town, or even far away from us in another part of Canada or in a foreign land, they are still part of our family.

Not everyone knows all their grandparents  because they are no longer alive. These family members are remembered in stories told about the good times when you were a baby or before you were born.

 Nowadays, it is wonderful for families that even those who live far away can both hear and see each other through the use of computer web-cams and other modern communication systems.And all through it shines by God’s love.

THANK YOU,

N.NANDITHA

Synthetic Fibers And Plastics - Text

Synthetic Fibres And Plastics

Class VIII Biology

CBSE

Clothes that we wear on a daily basis are made of fabrics. Fabrics are made of fibres which are obtained from natural and artificial sources. fibres like cotton, wool, silk, etc., are obtained from plants or animals. Wool, silk, and cotton are a few examples of natural fibres. The synthetic fibres, on the other hand, are made by human beings. That is why these are called synthetic or man-made fibres . Fibres like polyesters and terylene are a few examples of synthetic fibres.

A synthetic fibre is also a chain of small units joined together. Each small unit is actually a chemical substance. Many such small units combine to form a large single unit called a polymer. The word ‘polymer’ comes from two Greek words; poly meaning many and mer meaning part/unit. So, a polymer is made of many repeating units.

Synthetic fibres and plastics, similar to natural fibres are made up of very large units. The larger units are called polymers. These are made up by combining many similar or dissimilar small units. The small units are called monomers.

Natural fibres are obtained from plant and animal sources, synthetic fibres are obtained by chemical processing of petrochemicals. The synthetic fibres can be woven into a fabric, just like natural fibres.Synthetic fibres have a wide range of uses ranging from many household articles like ropes, buckets, furniture, containers, etc. to highly specialized use in aircrafts, ships, spacecrafts, health care, etc. Depending upon the types of chemicals used for the manufacture, some synthetic fibres are rayon, nylon, polyester and acrylic. A synthetic fibre, as well as plastic, is made up of a chain of small units (called Monomers) which combine to form polymers.

Monomers: A monomer is a single molecule that can bond with other identical molecules to form polymers through a process called Polymerization. Monomer is defined as a simple molecule with two or more binding sites through which it forms covalent linkages with other monomer molecules to form the macromolecule.

Phoebus Levene discovered the monomers of nucleic acids around 1900. Many of the monomers synthesized enzymatically by cells are thought to have originally accumulated spontaneously on Earth as a result of nonenzymatic reactions. These include amino acids, components of proteins and nucleotides, components of nucleic acids (DNA, RNA).

Monomers are thus building blocks of polymers. All simple molecules cannot behave as monomers but only those with two or more bonding sites can act as monomers. Thus molecules like ammonia, water, ethanol etc are not monomers. Alkenes, vinyl chloride, adipic acid, glycol with two bonding sites act as monomers. Monomers and their dimer counterparts are archetypal plasmonic structures and a versatile theory could rightfully be expected to offer new insights for both individual monomers as well as for assemblies of such building blocks.

Polymers: Polymer is a Greek word in which 'poly' means 'many' and 'mer' means units. Hence, polymers are large molecule made up of several molecules (or monomers) linked together. Hermann Staudinger (1881-1965) is known as the founder of polymer chemistry and the father of modern polymer science

polymer, any of a class of natural or synthetic substances composed of very large molecules, called macromolecules, that are multiples of simpler chemical units called monomers. Polymers make up many of the materials in living organisms, including, for example, proteins, cellulose, and nucleic acids. Moreover, they constitute the basis of such minerals as diamond, quartz, and feldspar and such man-made materials as concrete, glass, paper, plastics, and rubbers.

The word polymer designates an unspecified number of monomer units. When the number of monomers is very large, the compound is sometimes called a high polymer. Polymers are not restricted to monomers of the same chemical composition or molecular weight and structure. Some natural polymers are composed of one kind of monomer. Most natural and synthetic polymers, however, are made up of two or more different types of monomers; such polymers are known as copolymers.

Example of Polymers: All synthetic fibers, such as Rayon and Nylon, are polymers. Polymers are also found in Nature. ‘Cotton’ is a polymer called ‘Cellulose’. ‘Cellulose’ is made up of a number of single units (or monomers) called ‘Glucose’. Polymerization Reaction: The process of linking small monomers together to form polymers is called Polymerization.

Natural polymers: organic and inorganic

Organic polymers play a crucial role in living things, providing basic structural materials and participating in vital life processes. For example, the solid parts of all plants are made up of polymers. These include cellulose, lignin, and various resins.

Cellulose is a polysaccharide, a polymer that is composed of sugar molecules. Lignin consists of a complicated three-dimensional network of polymers. Wood resins are polymers of a simple hydrocarbon, isoprene. Another familiar isoprene polymer is rubber.

Other important natural polymers include the proteins, which are polymers of amino acids, and the nucleic acids, which are polymers of nucleotides—complex molecules composed of nitrogen-containing bases, sugars, and phosphoric acid. The nucleic acids carry genetic information in the cell. Starches, important sources of food energy derived from plants, are natural polymers composed of glucose.

Many inorganic polymers also are found in nature, including diamond and graphite. Both are composed of carbon. In diamond, carbon atoms are linked in a three-dimensional network that gives the material its hardness. In graphite, used as a lubricant and in pencil “leads,” the carbon atoms link in planes that can slide across one another.

Types of Synthetic Fibers

Rayon You have read in Class VII that silk fibre obtained from silkworm was discovered in China and was kept as a closely guarded secret for a long time. Fabric obtained from silk fibre was very costly. But its beautiful texture fascinated everybody. Attempts were made to make silk artificially. Towards the end of the nineteenth century, scientists were successful in obtaining a fibre having properties similar to that of silk. Such a fibre was obtained by chemical treatment of wood pulp. This fibre was called rayon or artificial silk.

Although rayon is obtained from a natural source, wood pulp, yet it is a man-made fibre. It is cheaper than silk and can be woven like silk fibres. It can also be dyed in a wide variety of colours. Rayon is mixed with cotton to make bed sheets or mixed with wool to make carpets.

Rayon or Artificial Silk

Rayon is a versatile fibre and can imitate the feel and texture of silk, wool, cotton and linen with drape and slipperiness akin to nylon. Rayon, invented in 1846, began to be manufactured in the United States in 1911. Called artificial silk until 1924 when the name rayon was coined, rayon was a less expensive alternative to silk clothing and accessories. This paper focused on the time period of 1910-1924.

History of Rayon Fiber

In the 1860s, the silk fiber industry in France was in trouble, leading to a demand for regenerated fiber. Count Hilaire de Chardonnet addressed this issue by inventing artificial silk from cellulosic material and obtaining a patent in 1885. The term “rayon” was actually coined by the Federal Trade Commission (FTC), and by 1925, rayon production was in full swing. Rayon fiber is now a very popular fiber because it closely resembles natural materials like cotton and silk. People value rayon for its breathability and its capacity to absorb moisture.

Properties of Rayon Fiber

Rayon fiber comes from natural cellulose sources. It has the ability to mimic the tactile sensations and fabric textures of silk, wool, cotton, and linen. Traditional viscose rayons are less durable and tend to lose their appearance, especially when wet. The flexibility of lyocell rayon fabric affects its ability to resist excessive shrinking or looseness in clothing.

These fibers easily take on a wide range of dye colors. Rayon fibers vary in denier, with measurements spanning from 1.5 to 15. Rayon has the least elastic recovery of any fiber. Rayon fiber naturally has a shiny appearance. Rayon fiber is valued for its softness, comfort, and versatility. When wet, rayon temporarily weakens. Rayon fiber are extremely soft, smooth, cool, and very absorbent, though they may not always provide warmth.

Rayon

This is a type of synthetic fibre obtained from wood pulp. Rayon is soft, absorbent and comfortable. It is easy to dye in wide range of colors. Rayon is mixed with cotton to make bedsheets. Rayon is mixed with wool to make carpets. t is a man-made fibre obtained from a natural source called wood pulp. It can be dyed in a wide variety of colours. Rayon is mixed with cotton to make bedsheets or mixed with wool to make carpets. Rayon resembles silk in appearance, texture and shine. Hence, it is also known as Artificial Silk. Silk fibre was discovered in China and made from silkworms. It had a beautiful texture and was very costly. By the end of the 19th century, scientists managed to make an artificial silk-like fibre made by treating wood pulp chemically.

Use of Rayon

This man-made fibre uses natural material (wood pulp) and can be woven like silk fibre. It is cheaper than silk and can be dyed in a variety of colours. It can be: Make apparels like suits, slacks, jackets etc. Make automobile tyre cords (because of its strength) Mixed with cotton to make bedsheets and bedspreads Mixed with wool to make carpets and blankets Used to make other home furnishings, such as curtains and tablecloths.

Breezy Clothing: Rayon’s natural drape is perfect for creating light and breathable garments like loose tops and bottoms.

Sporty Styles: Rayon’s moisture-wicking and breathability properties make it a popular option for athletic wear, ensuring you remain cool and dry during exercise.

Chic Outfits: Rayon’s smooth, shiny texture, cost-effectiveness, and low maintenance have made it a top choice to replace natural silk in various clothing items, from blouses to lingerie.

Advantages of Rayon Fiber

It’s budget-friendly. It breathes easily, similar to cotton fiber. It mixes well with different fibers, especially woven fabrics. Many appreciate its silk-like texture. It’s a great option for people who want a luxurious appearance without spending too much. It can be dyed with ease, resulting in vivid, stunning colors. It gracefully hangs and drapes well.

Disadvantages of Rayon Fiber

It readily absorbs moisture, body oils, and water, potentially causing stains. It tends to stretch and sag without recovering well. Its production harms the environment, making it unsustainable despite coming from wood. Treating stains may lead to permanent marks. The fabric is fragile, especially when wet. Dry cleaning is the recommended cleaning method. It’s not suitable for home furnishings due to its tendency to stretch.

Nylon Fiber

Nylon fiber is a family of synthetic polymers, made up of repeating units linked by amide bonds. This material is versatile, as it’s a thermoplastic with a smooth, silky texture, allowing it to be melted and shaped into fibers, films, or different forms. Nylon polymers often include various additives to give them a wide range of properties. Nylon polymers are crucial in making fabrics. They are also important in various types of textile fibers, like those used in clothing, flooring, and strengthening rubber. Additionally, nylon fiber is molded into various shapes for applications such as making automotive parts and electrical equipment.

Nylon is another man-made fibre. In 1931, it was made without using any natural raw material (from plant or animal). It was prepared from coal, water and air. It was the first fully synthetic fibre. Nylon fibre was strong, elastic and light. It was lustrous and easy to wash. So, it became very popular for making clothes. Nylon is very lustrous, easy to wash and elastic. It dries quickly and retains its shape.

Uses of Nylon

We use many articles made from nylon, such as socks, ropes, tents, toothbrushes, car seat belts, sleeping bags, curtains, etc. Nylon is also used for making parachutes and ropes for rock climbing. A nylon thread is actually stronger than a steel wire.

Apparel: High-tenacity nylons have a range of applications in the clothing industry. They are used to make parachute fabrics, cords, and ropes. These nylons are valued for their excellent dimensional stability, making them a great choice for producing items like women’s gloves, hosiery, underwear, swimwear, stockings, and hosiery fabrics.

Household: Nylon is a popular material for various household items, such as carpets and upholstery. It is also employed in the construction of ropes and cords for various domestic purposes.

Industrial Applications: Nylon plays a vital role in industrial settings, with uses in finishing nets, tire cords, filtering cloths, sewing threads, and tow ropes. It is also used in the production of belts for various types of machinery, including flat belts and V-belts.

Types of Nylon

There are eight types of nylon fiber, such as Nylon 6, Nylon 6,6, Nylon 4,6, Nylon 6,9, Nylon 6,10, Nylon 6,12, Nylon 11, and Nylon 12. Here are a few examples: Nylon 6, developed by Paul Schlack, is made using a ring-opening polymerization method. 

Physical Properties of Nylon Fiber

Tenacity: Dry strength ranges from 4 to 9 gm/den, with wet strength reaching 90% of the dry strength.

Elasticity: Typically stretches by 20-40% before reaching the breaking point. Stiffness: Falls within the range of 20 to 40 gm/den. Moisture regains: Approximately 3.5-5%, although it’s not highly absorbent due to its crystalline structure. Specific gravity: Around 1.14. Abrasion resistance: Demonstrates excellent durability against wear and tear. Dimensional stability: Shows good resistance to changes in shape or size. Resiliency: Exhibits an excellent ability to bounce back. Softening point: Nylon 6,6 softens at 229°C, while Nylon 6 softens at 149°C. Melting point: Nylon 6,6 has a melting point of 252°C, whereas Nylon 6 melts at 215°C.Hand feel: Known for its soft and smooth texture.

Chemical Properties of Nylon Fiber

Acid: Nylon 6,6 is highly vulnerable to mineral acids and can dissolve when exposed to them. However, it remains unreactive to dilute acetic and formic acids, even when heated. Concentrated formic acid can dissolve Nylon 6,6. Nylon 6 is also sensitive to mineral acids but can withstand mild boiling organic acids.

Bleaches: Nylon fiber is generally resistant to damage from both oxidizing and reducing bleaches, but it may be negatively impacted by chlorine and strong oxidizing bleaches. Alkali: Nylon is notably resistant to alkalis. Organic Solvent: Most solvents have little to no effect on nylon. However, phenol, metacresol, and formic acid can dissolve the fiber. Fortunately, the solvents commonly used for stain removal and dry cleaning do not harm it. Light: Nylon does not change color when exposed to light. Nonetheless, Nylon 6 gradually loses strength when exposed to prolonged light. Biological: Nylon is not susceptible to damage from microorganisms or moth larvae. Electrical: Nylon has high insulating properties, which can result in the accumulation of static charges on the fiber. Flammability: Nylon burns slowly.

Advantages of Nylon Fiber

Strength: Nylon possesses exceptional tensile strength, making it a prime choice for applications like ropes, gears, and machinery components. Its robust resistance to abrasion also renders it well-suited for situations where wear and tear are a concern.

Versatility: Nylon fiber can take on various forms, including fibers, films, and moldings. Its ease of color customization proves advantageous for products that necessitate consistent coloration, like clothing and textiles.

Durability: Nylon’s remarkable resistance to wear and tear makes it an outstanding option for products subjected to frequent and prolonged use. This durability is especially valuable for applications that require enduring performance, such as gears, ropes, and backpacks.

Moisture Resistance: Nylon exhibits impressive resistance to moisture, making it a perfect choice for products exposed to water or other liquids. It is frequently utilized in outdoor gear, clothing, and applications that prioritize hygiene, such as medical devices and packaging.

Chemical Resistance: Nylon can withstand a broad array of chemicals, including acids and bases. This property finds utility in laboratory equipment and industrial products.

Lightweight: Nylon’s lightweight nature is pivotal for reducing weight in applications such as aircraft and automotive parts, as well as gear, ropes, and backpacks.

Ease of Processing: Nylon is easily processed and can be molded into intricate shapes and designs. This characteristic diminishes the need for additional machining or assembly processes, resulting in a cost-effective solution.

Disadvantages of Nylon Fiber

Cost: Nylon can be more expensive than other synthetic materials like acetate, acrylic, lyocell, microfiber, and similar options.

Hydrolysis: Nylon is vulnerable to hydrolysis, a chemical reaction that causes it to deteriorate in the presence of moisture. This degradation can lead to a decrease in nylon’s strength and durability over time, making it less suitable for long-term applications or use in moist environments.

UV Sensitivity: Nylon is sensitive to ultraviolet (UV) light and may degrade when exposed to sunlight. This makes it a less ideal choice for outdoor applications.

Limited Temperature Resistance: Nylon has restricted resistance to high temperatures, and it may deform or lose strength when exposed to heat. Therefore, it’s not the best option for high-heat applications, such as electrical insulation.

Flammability: Nylon is a flammable material and can catch fire easily. For safety reasons, consider alternative materials that are less prone to ignition.

Environmental Impact: Nylon fiber production consumes a significant amount of energy and can have detrimental effects on the environment. It also contributes to the accumulation of plastic waste in natural surroundings.

Polyester: Polyester is another synthetic fibre. Fabric made from this fibre does not get wrinkled easily. It remains crisp and is easy to wash. So, it is quite suitable for making dress material. You must have seen people wearing polyester shirts and other dresses.

Terylene is a popular polyester. It can be drawn into very fine PET is a very familiar form of polyester. It is used for making bottles, utensils, films, wires and many other useful products.

Polyester (Poly+ester) is actually made up of the repeating units of a chemical called an ester. Esters are the chemicals which give fruits their smell. Fabrics are sold by names like polycot, polywool, terrycot, etc. As the name suggests, these are made by mixing two types of fibres. Polycot is a mixture of polyester and cotton. Polywool is a mixture of polyester and wool. PET (polyethene terephthalate) is used for making bottles, utensils, films, wires and many other useful products.

History of Polyester

To understand the history of polyester fabric, you must take a step back to the creation of polyester plastic. The first research into polyester plastic began in 1926. Polyester was invented in the mid-1930s by W.H. Carothers along with his team while working at DuPont. However, this work was not further developed until 1941 when it was expanded upon and patented by a group of British scientists who created the first polyester fiber.

Polyester Innovations

Some of the other inventions and developments that impacted modern polyester include:

The resin that binds polyester has dramatically improved in the last 50 years. The higher quality resin creates smaller seams which irritate sensitive skin less. Resin is one of the most valuable developments, and this technology is a closely guarded trade secret. Companies began adding different polyester additives that changed the fabric’s color and appearance. The additives made polyester retain its color, hang more naturally, and make it less shiny.

The development of microfiber was a game changer. Microfibers are much smaller than traditional polyester fabric fibers (about 1/100 the size of a human hair). Microfibers make modern clothing of this fabric more comfortable. The ability to crimp, stretch, and change the shape of polyester fibers also significantly impacted the popularity, feel, and quality of the clothing. Polyester is now one of the most popular fabrics in the world. Companies use polyester to make clothing, furniture, carpets, tires, and insulation.

Characteristics of Polyester Fabric

Polyester fabric has many characteristics and properties that make it useful in the modern world. Polyester is wrinkle-resistant, easy to care for, and often blended with other fibers to create a more durable material.

Fabric Breathability: Polyester is a breathable fabric and often gets blended with cotton or other materials to improve its breathability. Polyester and cotton blends are some of the most popular in the world and combinates the comfort of cotton with the quick drying nature of polyester.

Moisture-Wicking Abilities: Polyester is one of the best fabrics you can find if you require a moisture-wicking material. This synthetic material moves moisture away from the body, keeping you dry. It’s also breathable, lightweight, and shows durability. You’ll find that outdoor clothing typically contains polyester for this reason.

Heat Retentin Abilities: Unfortunately, since you make polyester with petroleum, it means that polyester is flammable, and the fabric will melt if it comes into contact with a flame. As a result, drying polyester fabrics at high temperatures can permanently damage the fabric.

Stretchiness: Since polyester fibers are artificial, they contain no elasticity. So, 100% polyester yarns will usually not have any stretchiness. However, textile experts have discovered that new weaving methods can incorporate a bit of stretch into the fabric, and you’ll find that polyester blends usually have some stretch characteristics.

Pilling/Bubbling: Polyester is susceptible to pilling, which is when small balls of fabric form on the fabric’s surface. Pilling happens when materials rub against each other and when you wash a garment. Once pilling begins on a polyester fabric, the damage is permanent.

Types of Polyester

There are two types of polyester: Polyethylene Terephthalate (PET or PETE), Polybutylene Terephthalate (PBT) PBT is a type of polyester that you make from Polybutylene Terephthalate. PBT is a less common polyester type, but it is sometimes used instead of PET because it has a higher melting point.

In addition to PET and PBT, polyester comes in several different forms. The four most common forms of polyester are filament, tow, staple, and fiberfill. A polyester filament is a single long strand most frequently used to produce clothing. Polyester staples are shorter pieces of filament cut at predetermined lengths. Industry leaders commonly use polyester staples when blending polyester with other fabrics.

Multiple filaments comprise a tow of polyester. The filaments are close together but still leave space for additional fabric. Finally, fiberfill is a type of polyester that has the most volume. It helps produce insulation, pillows, and cold-weather clothing. It can take the place of materials like goose down. The fluffiness of fiberfill makes it an excellent insulator. Of the four types of polyester, filament and staple are the two most common types.

Advantages of Polyester

The advantages of polyester have many benefits, making it a popular choice for fabric. It is wrinkle-resistant and has a high resistance to tearing. Polyester is also easy to care for, as it can be washed in the machine and does not require ironing. Polyester is also a budget-friendly fabric option. Polyester is often used in sportswear and active wear because it is lightweight and breathable. The fabric is also a popular choice for making blankets and bedding sheets, as it is warm and cozy. Another advantage of polyester is that it is static-resistant. Companies use polyester to make clothing for people who work in environments prone to static electricity, such as laboratories and cleanrooms.

Disadvantages of Polyester

There are several disadvantages of polyester as well. Polyester is not as absorbent as natural fibers, so it can feel sweaty and uncomfortable to wear in hot weather. Polyester is also not a good choice for people with allergies, as it can cause skin irritation. One of the most significant disadvantages of polyester is that it is not biodegradable, so it can cause environmental pollution. It is not biodegradable because you make it out of petroleum.

Acrylic: Acrylic is artificial wool. We wear sweaters and use shawls or blankets in the winter. Many of these are actually not made from natural wool, though they appear to resemble wool. These are prepared from another type of synthetic fibre called acrylic. The wool obtained from natural sources is quite expensive, whereas clothes made from acrylic are relatively cheap. They are available in a variety of colours.

Synthetic fibres are more durable and affordable which makes them more popular than natural fibres. You have already performed an activity of burning natural and synthetic fibres (Activity 3.6 of Class VII). What did you observe? When you burn synthetic fibres you find that their behaviour is different from that of the natural fibres. You must have noticed that synthetic fibres melt on heating.

This is actually a disadvantage of synthetic fibres. If the clothes catch fire, it can be disastrous. The fabric melts and sticks to the body of the person wearing it. We should, therefore, not wear synthetic clothes while working in in the kitchen or in a laboratory. Acrylic fiber is made from synthetic plastic. It comes from man-made polymer textile fibers created using chemicals from fossil fuels. Making acrylic fiber is similar to making polyamide, nylon fibers, and polyester fibers.

History And Origin of Acrylic

Acrylic was developed in Germany in 1893 to mimic wool. In 1950, the E.I. Dupont Company introduced it in the U.S. By 1991, it was popular for wash-and-wear items like sweaters and blankets. Acrylic fibers are made using wet and dry spinning methods, with the latter being more common. Care labels are important when handling acrylic, as it has unique characteristics. Acrylic is similar to wool fibers but has some differences. It gets crimped during dry spinning, providing warmth without extra weight. It’s a cost-effective alternative to wool, favored by consumers for its affordability and availability.

Types of Acrylic Fiber

In the market, you can find four main types of acrylic fabrics: Acrylic: Regular acrylic fiber, made of at least 85% pure acrylonitrile. Produced through wet or dry spinning methods. Texturized to give it a light, bulky, wool-like texture. Resistant to both acid and sunlight.

Modacrylic: A variant of acrylic fiber, featuring a composition that includes acrylonitrile and a significant amount of vinylidene chloride. Offers a warm, pleasant feel with enhanced drivability, resiliency, and wrinkle resistance. Provides better resistance to pilling, flames, and abrasion compared to acrylic fabric. Excels in maintaining its shape, resisting wrinkles, and retaining creases. Often used in specialty applications.

Nytril: Unlike other acrylic variants relying on acrylonitrile, Nytril is primarily composed of vinylidene dinitrile. Produced from polymers containing at least 85% vinylidene dinitrile units and a vinyl acetate co-monomer. More popular in the Asian market than in the United States. It can be challenging to dye, and global production quantities are relatively small.

Lastrile: Lastrile fibers are formed by blending copolymers of acrylonitrile and diene, such as butadiene. These fibers contain 10%-50% acrylonitrile units and are known for their elasticity. They are used in applications requiring greater elasticity in acrylic fibers. However, Lastrile fibers have not been widely produced for commercial use.

Properties of Acrylic Fiber

Acrylic fibers resist many chemicals, including acids, alkaline solutions, bleaches, and oxidizing agents. They can take sudden impacts without breaking because they have strong impact resistance. Acrylic fibers don’t easily absorb moisture due to their hydrophobic nature, but they can hold on to atmospheric moisture. They are durable, with excellent fatigue resistance that allows them to withstand repeated loads.

Acrylic fibers can handle high temperatures from 160-250°C without melting.They don’t easily degrade or fade when exposed to sunlight, making them UV resistant. While they may slowly deform under constant load or stress due to low creep resistance. Acrylic fibers don’t dissolve in water or most organic solvents. They are flammable and can melt and drip when exposed to heat, but they self-extinguish when the heat source is removed.

They also resist mildew and other microorganisms. Acrylic fibers are strong and can endure bending and twisting without breaking. They also have moderate to good abrasion resistance against wear and tear. By making chemical modifications, acrylic fibers can be customized to enhance specific properties or create different types of acrylic fibers.

Advantages of Acrylic Fiber

It’s lightweight. It’s impressively durable. The fabric has exceptional elasticity, quickly returning to its original shape after stretching. It feels gentle to the touch. It keeps the wearer warm. It exhibits remarkable resistance to sunlight and weathering. It can be washed, depending on the fabric type and finish.

Disadvantages of Acrylic Fiber

It can stretch and shrink easily. It has moderate strength. Because it repels moisture, it may cause static electricity and pilling. It degrades and changes color when exposed to extreme heat.

Use of Acrylic Fiber

Apparel includes sweaters, socks, fleece clothing, circular-knit garments, sportswear, and children’s wear. Household textiles consist of carpets, blankets, area rugs, upholstery, and pile fabrics. Outdoor uses involve car tops, boat covers, awnings, and outdoor furniture. Industrial applications include filtration materials, construction reinforcement, and components for automotive batteries.

Plastics

Plastics is the term commonly used to describe a wide range of synthetic or semi-synthetic materials that are used in a huge and growing range of applications. Plastic is defined as a material that contains an essential ingredient an organic substance of large molecular weight. It is also defined as polymers of long carbon chains. Carbon atoms are linked in chains and are produced in long-chain molecules.

Plastic was discovered by famous German chemist Christian Schonbein in 1846. Plastics were actually discovered accidentally. Christian was experimenting in his kitchen and by accident, he spilt a mixture of nitric acid and sulphuric acid. To mop that solution (a mixture of nitric and sulphuric acid) he took a cloth and after moping he kept it over the stove. After some time, the cloth disappeared and from their plastic got its name.

The word, plastic, was derived from the word ‘Plastikos’ meaning ‘to mould’ in Greek. Fossil fuels have compounds containing hydrogen and carbon (hydrocarbon) which act as building blocks for long polymer molecules. These building blocks are known as monomers, they link together to form long carbon chains called polymers.

The 20th century saw a revolution in plastic production: the advent of entirely synthetic plastics. Plastics originated from natural polymers like cellulose but were transformed through human innovation using synthetic polymers made from fossil fuels. The first synthetic plastic, celluloid, was invented in 1869 as an ivory substitute.

Later plastics like Bakelite provided more possibilities. After World War II, plastic production and usage increased dramatically. While initially seen as positive, plastics are now a major source of environmental waste and potential health concerns due to chemicals used in production. Scientists are working on more sustainable bioplastics and improved recycling to address these issues and ensure plastics have a place in the future.

Types of Plastics

You must be familiar with many plastic articles used everyday. Make a list of such items and their uses. Plastic is also a polymer like the synthetic fibre. All plastics do not have the same type of arrangement of units. In some it is linear, whereas in others it is cross-linked.. Plastic articles are available in all possible shapes and sizes as you can see in market.

Have you ever wondered how this is possible? The fact is that plastic is easily mouldable i.e. can be shaped in any form. Plastic can be recycled, reused, coloured, melted, rolled into sheets or made into wires. That is why it finds such a variety of uses. Polythene (Poly+ethene) is an example of a plastic. It is used for making commonly used polythene bags. Now, try to bend a piece of plastic yourself. Depending on physical properties, plastics are divided into two types: Thermoplastic and thermosetting.

Thermoplastic: Can all the plastic articles be bent easily? You will observe that some plastic articles can bend easily while some break when forced to bend. When we add hot water to a plastic bottle, it gets deformed. Such plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics. Polythene and PVC are some of the examples of thermoplastics. These are used for manufacturing toys, combs and various types of containers.

Thermosetting: On the other hand, there are some plastics which when moulded once, can not be softened by heating. These are called thermosetting plastics. Two examples are bakelite and melamine. Bakelite is a poor conductor of heat and electricity. It is used for making electrical switches, handles of various utensils, etc. Melamine is a versatile material. It resists fire and can tolerate heat better than other plastics. It is used for making floor tiles, kitchenware and fabrics which resist fire.

Plastics as Materials of Choice Today if we think of storing a food item, water, milk, pickles, dry food etc., plastic containers seem most convenient. This is because of their light weight, lower price, good strength and easy handling. Being lighter as compared to metals, plastics are used in cars, aircrafts and spacecrafts, too. The list is endless if we start counting articles like slippers, furniture, decoration pieces, etc. Now, let us discuss the characteristic properties of plastics

The Primary Characteristics of Plastics

Plastics have a few unique properties that make them practical for a wide range of applications. Plastic materials are regarded as: Usually lightweight with a high strength-to-weight ratio. Very versatile. Moldable into different shapes and sizes. Thermally and electrically insulating. Inexpensive. Resistant to chemicals. Very durable.

Non-biodegradable. Usually clear and can be colored in different hues. Different textures are possible. Plastic can come in many different colors and textures, depending on the type of plastic and how it has been treated or processed. Plastic is a synthetic polymer made from various organic materials that can be molded into almost any shape.

Some types of plastic are clear and transparent, like those used in disposable water bottles, while others are opaque and available in a range of colors. Plastic can also have different surface textures, ranging from smooth and shiny to rough and matte. Some types of plastic have soft and flexible textures, while others are rigid.

Properties of Plastic

Plastics can have a wide range of physical and chemical properties, depending on their chemical structures and how they are processed. However, some general physical and chemical properties are common to most plastics. These properties are given below:

Physical Properties of Plastic

Density: Plastics come in many different densities, from as low as 0.9 g/cm³ for foamed plastics to as high as 1.5 g/cm³ for some engineering plastics. Melting Point: The melting points of plastics vary widely depending on the type of polymer. Some plastics have low melting points and can be easily molded while others have high melting points and require specialized processing techniques. Hardness: Plastics can range from soft and flexible to hard and rigid, depending on the specific polymer and its processing.

Transparency: Some plastics are optically transparent while others are opaque and block light. Many transparent plastics can accept dye if you need them to be opaque. Permeability: Plastics can be permeable to gasses and liquids, which can be an advantage in some applications (such as food packaging) and a disadvantage in others (such as chemical storage).

Chemical Properties of Plastic

Resistance to Chemicals: Many types of plastic are resistant to industrial chemicals, acids, and other corrosive substances. This makes them useful in a variety of industrial applications.

Stability: Some plastics are sensitive to heat, light, and radiation, which can cause them to degrade over time. UV stabilizers and antioxidants are often added to plastics to improve their stability.

Flammability: Plastics can be highly flammable, and many of them release toxic gasses when burned. Flame retardants are often added to plastics to improve their fire resistance.

Degradation: The rate at which plastics degrade depends on a variety of factors, including the type of plastic, the conditions to which they are exposed, and the specific environmental factors they encounter. Some plastics, such as polyethylene (PE) and polypropylene (PP), degrade very slowly so they will persist in the environment for hundreds of years. Other plastics, such as polylactic acid (PLA), are designed to be biodegradable and can break down much more quickly when exposed to moisture, heat, or microorganisms. Some plastics can undergo physical degradation, such as cracking or fragmentation, even if they do not break down chemically. This can be caused by sunlight, temperature changes, or mechanical stress, and can lead to the release of hazardous plastic particles called microplastics into the environment.

Solubility: Each plastic has unique solubility characteristics. Plastics that are amorphous (not crystalline), like polystyrene and polycarbonate, are more soluble in typical organic solvents than crystalline ones. Certain highly crystalline polymers, including nylon and polyolefin, resist dissolution while others like polyvinyl acetate (PVA) are highly soluble in water.

Reactivity: Plastics can be reactive in different ways, depending on their chemical composition. For example, polyethylene reacts with oxygen to form carbon dioxide and water while polypropylene is relatively unreactive and stable in most chemical environments.

Biodegradability: Some plastics, such as polyethylene, are not biodegradable and can persist in the environment for hundreds of years. Others, such as polycaprolactone (PCL), are biodegradable and can be broken down by bacteria and fungi over time.

Recyclability: Plastics can be difficult to recycle since they each have different chemical compositions and properties. Some types of plastics are easier to recycle than others, and recycling methods vary depending on the type of plastic. Recycling of plastic is very important. If they are not recycled at the proper time, then they get mixed with other chemicals or materials and hence become more difficult to recycle and become a source of pollution.

Plastic is Non-reactive

You know that metals like iron get rusted when left exposed to moisture and air. But plastics do not react with water and air. They are not corroded easily. That is why they are used to store various kinds of material, including many chemicals.

Uses of Plastic: Key Industries That Use It: Plastic has many different applications and we see engineers from many industries quoting plastic parts with Xometry. Some of the most common uses of plastic we have seen are listed below:

Automotive

Plastics are used in various parts of automobiles, including dashboards, bumpers, engine parts, and interior panels. Since they’re both lightweight and durable, they reduce the vehicle’s weight and improve fuel efficiency.

Medical Devices Plastic is an ideal material to use for product packaging. Plastics are adaptable, hygienic, light, flexible, and durable. Packaging is thus responsible for the majority of the plastics used globally, coming in the form of vending packaging, baby products, protective packaging, containers, bottles, drums, trays, boxes, cups, and much more. Plastics are used extensively in the medical industry, including, but not limited to, disposable syringes, IV and blood bags, prosthetic limbs, implantable devices, dialysis machines, heart valves, tubing, and wound dressing. Medical-grade plastics are sterile and biocompatible and can be easily molded into complex shapes. Plus, they’re often less expensive than traditional medical materials.

Toys

Plastics are often used in the production of toys because they can be molded into various shapes and colors. Plastic toys are durable and lightweight, so they withstand wear and tear.

Electronics

Plastics are non-conductive, meaning they can protect electronic components and allow for easy assembly. This is why you find plastic in computer and phone cases and as the insulation on wires.

Plastics are highly durable, lightweight and, most significantly, can be moulded into any form or shape. These properties are a few reasons for the use of plastics. Plastics are extremely versatile materials that can be useful for a wide range of applications. The potential to be moulded makes plastic ideal packaging material. Plastics in packaging help keep food healthy and fresh. As durable and lightweight, plastics have helped in the field of electronics. From computers and cell phones to TV and refrigerator, nearly all of the appliances around us use plastic. Plastics help in making safety gears such as helmets, goggles, etc.

Plastics are also useful in the construction sector because of their low maintenance and high durability. Because of plastic’s strength and it’s lightweight properties, it is useful in making toys, electrical switches and other household goods. As it is non-reactive to air and water, they help store water in plastic bottles and chemicals in chemical laboratories. Plastic is a weak conductor of electricity and heat, so its insulation properties help in the coating of electrical wire and various household products like utensils handles, etc.

Plastics are Poor Conductors

You have learnt above that plastics are poor conductors of heat and electricity. That is why electrical wires have plastic covering, and handles of screw drivers are made of plastic. As mentioned above, handles of frying pans are also made of plastic.

Plastics and the Environment

When we go to the market, we usually get things wrapped in plastic or packed in polythene bags. That is one reason why plastic waste keeps getting accumulated in our homes. Ultimately, plastic finds its way to the garbage. Disposal of plastic is a major problem. Why? A material which gets decomposed through natural processes, such as action by bacteria, is called biodegradable. A material which is not easily decomposed by natural processes is termed non-biodegradable. Since plastic takes several years to decompose, it is not environment friendly. It causes environmental pollution. Besides, the burning process in the synthetic material is quite slow and it does not get completely burnt easily. In the process it releases lots of poisonous fumes into the atmosphere causing air pollution.

How can this problem be solved?

Have you ever seen a garbage dump where animals, especially cows, are eating garbage? In the process of eating the food waste they swallow materials like polythene bags and wrappers of food. Can you imagine the consequences? The plastic material chokes the respiratory system of these animals, or forms a lining in their stomachs and can be the cause of their death. The polybags carelessly thrown here and there are responsible for clogging the drains, too. Sometimes we are very careless and throw the wrappers of chips, biscuits and other eatables on the road or in parks or picnic places. Should we not think twice before doing so ? As a responsible citizen what measures do you suggest to keep public places clean and free of plastic?

Avoid the use of plastics as far as possible. Make use of bags made of cotton or jute when you go for shopping. The biodegradable and nonbiodegradable wastes should be collected separately and disposed off separately. Practise this in your homes. It is better to recycle plastic waste. Most of the thermoplastics can be recycled. Make a list of items that can be recycled. 

However, during recycling certain colouring agents are added. This limits its usage especially for storage of food. As a responsible citizen remember the 4 R principle. Reduce, Reuse, Recycle and Recover. Develop habits which are environment friendly.

Thank You

N Nanditha Akunuri