Important Questions Test: Synthetic Fibres And Plastics - UPSC MCQ

As for making cotton cloth we turn it into yarn to make cloth so for that we need cotton so for fabric we need fibre.

A polymer is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life.

Its answer is nylon because it is the first fully synthetic fibre made by using cool air and water it is strong as nylon rope is used for parachutes and rock climbing also a nylon thread is much stronger than a steel wire.

 

Nylon is the first man-made fiber. It was invented by Wallace Carothers and first introduced to the public in 1938. 

The plastics which cannot be remoulded again on heating are called thermosetting plastics. The most common examples of thermosets are Bakelite and Melamine.

Polyester is a synthetic polymer made of purified terephthalic acid (PTA) or its dimethyl ester dimethyl terephthalate (DMT) and monoethylene glycol (MEG). With 18% market share of all plastic materials produced, it ranges third after polyethylene (33.5%) and polypropylene (19.5%).

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. We use many articles made from nylon, such as socks, ropes, tents, toothbrushes, car seat belts, sleeping bags, curtains etc.

Answer:
The fibre made up by the chemical treatment of wood pulp is Rayon. Here is a detailed explanation of why Rayon is the correct answer:
What is Rayon?
Rayon is a synthetic fiber that is made from the chemical treatment of wood pulp. It is a versatile and widely used fiber in the textile industry.
Explanation:
- Rayon is derived from cellulose, which is extracted from wood pulp. The wood pulp goes through a chemical process to break down the cellulose and convert it into a soluble compound.
- The resulting solution is then extruded through fine holes and solidified into fibers. These fibers can be spun into yarns and used for making various textiles and fabrics.
- Rayon is known for its soft and smooth texture, and it can mimic the feel and drape of natural fibers like cotton and silk.
- It is widely used in the production of clothing, upholstery, and other textile products.
- Rayon is also known for its moisture-absorbing properties, making it a popular choice for summer clothing.
- However, it is important to note that while Rayon is made from wood pulp, it is considered a synthetic fiber rather than a natural fiber due to the extensive chemical processing involved in its production.
In conclusion, the correct answer is A: Rayon.

The correct answer is C as A synthetic fibre which works like wool is ACRYLIC

The raw materials used in making nylon:

1. Coal: Coal is one of the primary raw materials used in the production of nylon. It is a carbon-rich substance derived from fossilized plant remains.


2. Water: Water is another essential raw material used in the manufacturing process of nylon. It is used for various purposes, including steam generation and chemical reactions.


3. Air: Air, specifically oxygen, is required for the oxidation reactions that take place during nylon production. It plays a crucial role in the polymerization process.

Explanation:
Nylon is a synthetic polymer that is widely used in various industries, including textiles, automotive, and packaging. It is made through a process called polymerization, where monomers are linked together to form long chains.
The raw materials used in making nylon include coal, water, and air. Coal is a carbon-rich substance that provides the carbon element required for the polymer chain formation. Water is used for various purposes, such as steam generation, cooling, and chemical reactions. Air, particularly oxygen, is essential for the oxidation reactions that occur during nylon production.
These raw materials are combined and undergo a series of chemical reactions, including polymerization and condensation, to produce nylon. The resulting material is then processed and shaped into various forms, such as fibers or plastics, depending on its intended use.
In conclusion, the raw materials used in making nylon are coal, water, and air. These substances undergo chemical reactions to produce the synthetic polymer, which is then processed into various end products.

Is Polyester a Natural Fiber?

No, polyester is not a natural fiber. It is a synthetic fiber that is made from a chemical reaction between coal, petroleum, air, and water.

Explanation:

Polyester is a man-made or synthetic fiber that is created through a process called polymerization. It is derived from petroleum, which is a non-renewable resource. Here is how polyester is made:

• Purified terephthalic acid (PTA) or dimethyl terephthalate (DMT) is combined with ethylene glycol.


• This combination is then heated and cooled to form a liquid polymer.


• The liquid polymer is then extruded through spinnerets to form long filaments.


• These filaments are then spun into yarns, which can be further processed into fabrics.

Despite its synthetic nature, polyester is widely used in the textile industry due to its desirable properties such as durability, wrinkle resistance, and ease of care. It is commonly used in clothing, upholstery, bedding, and various other applications.

In contrast, natural fibers are derived from plants, animals, or minerals. Examples of natural fibers include cotton, silk, wool, linen, and hemp. These fibers are biodegradable and have different characteristics compared to synthetic fibers like polyester.

Therefore, the statement that "polyester is a natural fiber" is false. Polyester is a synthetic fiber that is derived from petroleum.

Cotton, like rayon and wood pulp fibers, is made of cellulose. Cellulose is a macromolecule made up of anhydroglucose unit connected by 1, 4 oxygen bridges with the polymer repeating unit being anhydro-beta-cellulose.

It takes 1000 years for polythene bags to degrade. Polythene bags don't Biodegrade, they photo - degrade, breaking down into smaller and smaller toxic bits contaminating soil and waterways. It pollutes our environment.
So, we should not use polythene bags.

Is silk the most expensive natural fiber?
Explanation:
Silk is indeed considered the most expensive natural fiber due to several factors. Here's a detailed explanation:
1. Rarity:
- Silk is produced by silkworms, which are not as abundant as other sources of natural fibers like cotton or wool.
- The limited availability of silkworms and their specific requirements for silk production contribute to the rarity of silk fibers.
2. Labor-Intensive Production Process:
- Silk production involves a complex and labor-intensive process.
- The silk cocoons are carefully harvested, and the fibers are extracted by hand.
- This process requires significant skill and time, adding to the cost of production.
3. Luxurious Properties:
- Silk is known for its luxurious properties, including its softness, smoothness, and lustrous appearance.
- These desirable characteristics make silk a popular choice for high-end fashion and home decor products.
- The demand for silk drives up its price in the market.
4. Other Factors:
- The cost of silk can also be influenced by factors such as the quality of the silk fibers, the region of production, and the brand reputation.
- Certain types of silk, such as mulberry silk, are considered to be of higher quality and command a higher price.
Conclusion:
Considering the rarity, labor-intensive production process, luxurious properties, and market demand, silk is indeed the most expensive natural fiber available.

True

• Natural fibres are obtained from plants and animals.


• Plants such as cotton, jute, flax, and hemp are sources of natural fibres.


• Cotton fibres are obtained from the cotton plant's seed pod.


• Jute fibres come from the stem and outer skin of the jute plant.


• Flax fibres are obtained from the stem of the flax plant.


• Hemp fibres are derived from the stem of the hemp plant.


• Animals like sheep, goats, rabbits, and silkworms also provide natural fibres.


• Wool is obtained from sheep and goats.


• Angora wool is obtained from rabbits.


• Silk is produced by silkworms.

Overall, natural fibres can be sourced from both plants and animals, making the statement true.

Acrylic as a Synthetic Fiber
Acrylic is a synthetic fiber that is commonly used as a substitute for wool in various applications. Here is a detailed explanation of why the statement is true:
1. Definition of Acrylic:
- Acrylic is a type of synthetic fiber that is made from a polymer called polyacrylonitrile.
- It is produced through a chemical process known as polymerization.
2. Similarities with Wool:
- Acrylic fibers are known for their wool-like characteristics, including softness and warmth.
- They have a similar texture and appearance to wool, making them a popular alternative in the textile industry.
- Acrylic fibers can be easily dyed and have good color retention properties, just like wool.
3. Advantages of Acrylic:
- Acrylic fibers are lightweight and have a high strength-to-weight ratio, making them suitable for various applications.
- They are resistant to sunlight, moisture, and most chemicals, making them durable and long-lasting.
- Acrylic fibers are easy to care for and can be machine-washed without losing their shape or color.
4. Differences with Wool:
- While acrylic fibers mimic the properties of wool, they are not as breathable or moisture-wicking.
- Acrylic fibers can be prone to pilling and may not have the same level of natural insulation as wool.
5. Applications:
- Acrylic fibers are commonly used in the production of clothing, such as sweaters, hats, and scarves.
- They are also used in the manufacturing of carpets, upholstery, blankets, and other household textiles.
- Acrylic fibers are often blended with other fibers, such as cotton or wool, to enhance their properties.
In conclusion, the statement is true. Acrylic is a synthetic fiber that closely resembles wool in terms of appearance and texture. However, it is important to note that there are some differences in terms of breathability and insulation. Acrylic fibers offer several advantages, including durability, color retention, and ease of care, making them a popular choice in various textile applications.

Heading: Nylon was made first in 1931 - True or False?
Key Points:
- Nylon was indeed invented in 1931.
- It was created by a team of chemists at DuPont, led by Wallace Carothers.
- The development of nylon was a result of extensive research and experimentation.
- Nylon was the first synthetic fiber to be commercially produced.
- Initially, nylon was used in a variety of applications, including toothbrush bristles and women's stockings.
- Nylon quickly gained popularity due to its strength, durability, and versatility.
- Over the years, nylon has been used in various industries, such as textiles, automotive, and aerospace.
Explanation:
Nylon was invented in 1931 by a team of chemists at DuPont, led by Wallace Carothers. It was the first synthetic fiber to be commercially produced. Initially, nylon found its application in toothbrush bristles and women's stockings. However, its popularity quickly grew due to its strength, durability, and versatility. Nylon has been widely used in the textile industry for manufacturing clothing, carpets, and upholstery. It has also found applications in industries such as automotive and aerospace, where its properties are highly beneficial. Therefore, the statement that nylon was made first in 1931 is true.

Rayon was prepared by coal, water and air.
Answer: False
Explanation:
Rayon is a synthetic fiber that is made from cellulose, which is derived from plants. It is not prepared using coal, water, and air. Here is a detailed explanation:
1. Rayon Production Process:
- The production of rayon involves several steps, including:
- Extraction of cellulose: Cellulose is obtained from wood pulp or other plant sources, such as bamboo or cotton.
- Chemical treatment: The extracted cellulose is then chemically treated to remove impurities and create a viscous solution.
- Spinning: The viscous solution is forced through spinnerets into a coagulating bath where it solidifies into fibers.
- Drawing and drying: The solidified fibers are stretched and dried to improve their strength and durability.
2. Role of Coal, Water, and Air in Rayon Production:
- Coal: Coal is not used in the production of rayon. It is primarily used as a fossil fuel for energy generation.
- Water: Water is used in the rayon production process for various purposes, such as dissolving chemicals and washing the fibers. However, it is not a primary raw material.
- Air: Air is not directly involved in the production of rayon. It may be used in the manufacturing facility for ventilation purposes.
In conclusion, rayon is not prepared using coal, water, and air. It is made from cellulose derived from plants through a multi-step chemical process.

"Cotton and jute” are the two common natural fibres not synthetic fibres.

PVC is a thermoplastic. Thermosetting plastics are crosslinking plastics that require a chemical reaction to cause them to harden. Epoxies and urethanes are two common examples of thermosetting plastics.

Thermoplastics harden by cooling. The plastic beads are melted by heat using mechanical means in an extrusion screw. Unless the thermoplastic is ruined by over heating, it can be reused many times. Unlike a thermosetting plastic that once the two chemicals have been mixed causing the reaction cannot be reused in the same way. They may become fillers but not have the same properties.