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ERR - 8th - Chemistry [Synthetic Fibres and Plastics I]

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8th (Chemistry)
Synthetic Fibres and Plastics I
Types of Materials We may use many materials in our daily life. Some are made up of natural materials such as wood, cotton, stones and clay. A material can be used to make different kinds of things. For example: glass can be used to make bowls, tumblers, window panes etc. The material may be naturally occurring or man - made. For example, wool, cotton, jute and marble are naturally occurring materials. Glass, paints, steel, cement, thermocole, plastic, nylon are man - made materials. Clothes are one of our basic needs. We wear clothes mainly to protect our bodies from weather conditions, such as heat, cold and rain. We wear different types of clothes according to climate, occupation, culture, traditions and daily needs. People in different regions of the world wear different types of clothing. People living in hot countries wear light coloured clothes. People living in cold countries prefer woolen clothes to keep them warm like coats, sweaters, jackets etc. The clothes that we wear daily, the towels, the curtains, etc., are made from different types of fabrics. Fabric is commonly called cloth. Clothes are made of different materials. We get these materials from both plants and animals. Clothing material can be broadly classified into two types based on the material used : Natural material and Artificial material. Types of Materials : Natural fibres are of two types: plant fibres like cotton and jute and animal fibre like wool and silk. The fibres made from simple chemical molecules called monomers. Monomers join in large number to form a long chain of molecules called polymers. The polymers which occur in nature are called natural polymers. Cellulose, silk, wool, proteins are natural polymers. The polymers which are made in laboratories from small molecules are called man - made polymers for example nylon, polythene, rayon etc. Fiberglass Fiberglass is a composite material made of thin strands of glass fibers embedded in a matrix of resin. The glass fibers provide strength and reinforcement, while the resin matrix holds the fibers together and provides protection against environmental factors. Fiberglass is known for its lightweight, strength, and durability, making it a popular material in various applications. Majorly consists of silicon oxide: Fiberglass is composed of thin strands of glass, and glass is primarily made of silicon dioxide (silica). Prepared by reinforcing plastic matrix by fine fibers of glass: Fiberglass is commonly used as a reinforcement material in the form of fine glass fibers embedded in a plastic matrix, creating a composite material. Used to make space suits, boats, roofing pipes, etc.: Fiberglass is widely used in various applications, including space suits, boat construction, and the manufacturing of roofing pipes, due to its strength, durability, and lightweight characteristics. Optical fiber Optical fiber, also known as fiber optic, is a thin, flexible, and transparent fiber made of glass or plastic through which light signals can be transmitted over long distances. It is a technology that uses the principles of total internal reflection to transmit data in the form of light pulses. Asbestos fibers Asbestos fibers are composed of long, thin mineral fibers. Chrysotile, also known as white asbestos, is the most common type and accounts for the majority of asbestos used globally. Asbestos has excellent heat resistance and was widely used in various industries for its fire-retardant properties. Blended fibers Blended fibers refer to textile fibers that are made by combining two or more different types of fibers to create a material with improved or desirable characteristics. This blending is done to get the positive properties of each individual fiber, resulting in a fabric that combines the best features of each component. Commonly blended fibers include: Polyester-Cotton Blend: Combining the durability and wrinkle resistance of polyester with the breathability and comfort of cotton. Wool-Acrylic Blend: Blending the warmth and natural properties of wool with the lightweight and cost-effectiveness of acrylic.
Types of Materials We may use many materials in our daily life. Some are made up of natural materials such as wood, cotton, stones and clay. A material can be used to make different kinds of things. For example: glass can be used to make bowls, tumblers, window panes etc. The material may be naturally occurring or man - made. For example, wool, cotton, jute and marble are naturally occurring materials. Glass, paints, steel, cement, thermocole, plastic, nylon are man - made materials. Clothes are one of our basic needs. We wear clothes mainly to protect our bodies from weather conditions, such as heat, cold and rain. We wear different types of clothes according to climate, occupation, culture, traditions and daily needs. People in different regions of the world wear different types of clothing. People living in hot countries wear light coloured clothes. People living in cold countries prefer woolen clothes to keep them warm like coats, sweaters, jackets etc. The clothes that we wear daily, the towels, the curtains, etc., are made from different types of fabrics. Fabric is commonly called cloth. Clothes are made of different materials. We get these materials from both plants and animals. Clothing material can be broadly classified into two types based on the material used : Natural material and Artificial material. Types of Materials : Natural fibres are of two types: plant fibres like cotton and jute and animal fibre like wool and silk. The fibres made from simple chemical molecules called monomers. Monomers join in large number to form a long chain of molecules called polymers. The polymers which occur in nature are called natural polymers. Cellulose, silk, wool, proteins are natural polymers. The polymers which are made in laboratories from small molecules are called man - made polymers for example nylon, polythene, rayon etc.
Natural Fibres Fibres that are obtained from plants and animals are called natural fibres. Cotton, jute, coir, hemp and flax are examples of fibres obtained from plants. Wool and silk fibres are obtained from animals. Wool is obtained from the fleece of sheep or goats. It is also obtained from the hair of rabbits, yaks and camels. Silk fibre is drawn from the cocoon of the silkworm. The fabric made from natural fibres is called natural fabric. Advantages of natural fibres:- These fabrics absorb more water and sweat. They allow air to pass through them. They are biodegradable and do not affect the environment. Disadvantages of natural fibres:- They do not retain their creases for long. They may shrink on ordinary washing. They can easily be attacked by moths and moulds. They do not dry rapidly. Natural silk is very expensive and not quite affordable.
Synthetic Fibres Human made or Synthetic Fibres Fibers that are made by man from chemical substances are called synthetic fibre. Example: Rayon, Nylon etc. The synthetic fibres are mostly obtained from petroleum. The fabric made up of synthetic fibres is called synthetic fabric. Types of Synthetic Fibres : Depending upon the type of chemicals used for manufacturing synthetic fibres, there are four major types of synthetic fibres (or man - made fibres). These are : (i) Rayon. (ii) Nylon (iii) Polyester, and (iv) Acrylic. NOTE : Rayan is a man-made fibre made from a natural material called cellulose (obtained from wood pulp) Nylon, polyester and acrylic are fully synthetic fibres which do not require a natural material (like cellulose) for their manufacture. These fully synthetic fibres are prepared by a number of processes by using raw materials (or chemical compounds) of petroleum origin, called petrochemicals. Advantages of synthetic fibres:- They are more durable and easy to maintain. They do not absorb much water, dry up fast and are wrinkle free. They are not affected by moths and moulds. These fibres have high lustre and they do not turn yellow with age. They do not shrink on washing. They need very little or no ironing. They last longer as compared to natural fibres. They are less expensive as compared to natural fibres. Most synthetic fibres can handle heavy loads without breaking. Disadvantages of synthetic fibre:- They do not allow air to pass through it, hence are not good for summers. They do not absorb sweat. Therefore, clothes made from synthetic fibres are very uncomfortable in summer or rainy season. They easily melt and burn to form small sticky beads at a very high temperature. Therefore, there is always a risk of getting burns, especially in kitchen. They are non – biodegradable and thus harmful for environment. They get electrically charged in dry weather. This electric charge causes skin problems in some persons..
Mixed Fibres Fibres made by blending natural fibres with synthetic fibres to obtain more superior and useful fibres are called mixed fibres. Examples : Terrycot (Terylene + cotton) :- By observing the term now terrycot is a blended fabric made of terylene and cotton. Terylene is a popular form of polyester, which can be drawn into very fine fibres. Terry wool (Polyester + wool) :- Terry wool is a blend of polyester and wool. Terry wool is actually a mixed fibre because clothes make completely from . polyester is uncomfortable to wear. uses: Terry wool has been used for blankets, horse rugs,saddle clothes, carpeting insulation and upholstery. Terrysilk (Polyester + Silk) :- It is made up of polyester and silk.
Rayon Silk Properties and Uses In Class 7th, we studied that silk is a natural fibre oblained from silkworms. The fabric (or cloth) made from natural silk fibres is very costly. But the beautiful texture (feel, appearance, shine) of natural silk fabrics fascinated everyone. So, attempts were made to make silk artificially which would be cheaper than natural silk. Towards the end of 19th century, scientists were successful in obtaining fibres having properties similar to that of silk. This fibre was called rayon. Rayon is often regarded as artificial silk. Rayon is a man-made fibre prepared from, a natural raw material (called cellulose) by chemical treatment. The cellulose required for making rayon is obtained from 'wood pulp'. So, we can also say that rayon is obtained by the chemical treatment of wood pulp (which contains cellulose). Rayon is produced as follows : (i) Wood pulp is dissolved in an alkaline solution (sodium hydroxide solution) to form a sticky liquid called 'viscose'. (ii) Viscose is forced to pass through the tiny holes of a metal cylinder (called spinneret) into a solution of sulphuric acid when a silk like thread of rayon is formed. Rayon is different from truly synthetic fibres because it is obtained from a natural material (wood pulp). Although rayon is obtained from a natural resource called wood pulp, yet it is said to be a man-made fibre. This is because it is obtained by the chemical treatment of wood pulp in factories. Rayon fibre is chemically identical to cotton but it has shine like silk Since rayon resembles silk in appearance, therefore, rayon is also called artificial silk. NOTE : Rayon is also called artificial silk, has a silky texture and is prepared from cellulose. The original raw material cellulose is broken down and then reformed in the lustrous fibre called 'rayon'. Rayon was the first synthetic fibre formed from natural raw material. As it is prepared from cellulose so it is not a true synthetic fibre. It is known as semi - synthetic fibre. Properties :- It is first synthetic fibre. It absorbs sweat because blended with cotton. Rayon clothes are therefore preferred over other synthetic fibres in summer. It is shiny and lustrous and resembles silk in appearance. Uses :- It is used in the textile industry making fabrics, which are mixed with cotton or silk to make smooth and silky clothes. It is blended with wool to for making carpets. Used to making reinforced tyre. Rayon is used for making shirts, ties, home furnishings and bandages.
Nylon Properties and Uses Nylon is the first true synthetic fibre. It was the first synthetic fibre produced chemically. It was discovered by Wallace Carothers in 1931. Nylon is a synthetic fibre. In fact, nylon is the first fully synthetic fibre made by man without using any natural raw materials (from plants or animals). It was made in the year 1931. The chemical compounds (or monomers) used in making, nylon is made are now obtained from petroleum products called petrochemicals. Actually, nylon is made up of the repeating units of a chemical called an 'amide'. So nylon is a polyamide (which is a polymer). The name NYLON comes from the fact that it was developed in New York (NY) and London (LON). Properties:- Nylon fibres are very strong, fairly clastic, lightweight and lustrous. Nylon fibres absorb very little waler so clothes made of nylon are easy to wash and dry. Nylon is wrinkle resistant. Nylon fibres have high abrasion resistance (high wear and tear resistance), so they are very durable (long lasting). Nylon is not attacked by moths and ordinary chemicals. Due to al these properties, nylon fibres have become very popular for making clothes. It is elastic and does not lose strength even after repeated use. Uses :- Nylon is used for making textiles (fabrics) like sarees, shirts, neck-ties, tights socks and other garments. Nylon is used in making curtains, sleeping bags and tents.Nylon is used in making ropes, car seat-belts, fishing nets, tyre cord, strings for sports rackets and musical instruments, bristles for toothbrushes and paint brushes. Nylon is used for making parachutes and ropes for rock climbing. All these uses of nylon are due to the high strength of nylon fibres. A nylon thread is actually stronger than a steel wire of similar thickness. Nylon is used as a plastic for making machine parts. It is used for making elastic hosiery
Polyester Properties and Uses Polyethylene Terephthalate (PETE or PET) It is a well known polyester polymer. This is also known as terylene or dacron. They are made from petroleum products. Terylene, dacrons and terene are polyester fibre. Polyester clothes are long lasting, water and wrinkle resistant and are of different types. The most commonly used polyester is Terylene. It is blended with natural fibres to improve its properties. Among synthetic fibres the polysters, are most widely used. They account for about one- half of all synthetic fibres. Terycot is a blend of cotton and terylene. Terylene is blended with wool to make terrywool. Properties It is strong, lightweight, and has good elasticity. It is wrinkle resistant as it resists wrinking and springs back into shape when creased. Polyester fabrics can be washed and dried easily and quickly. Uses Used for making sarees, dress materials, curtains and clothes. It is used for making sails for sail boats. It is used for making conveyor belts. It is used for making lightweight sails. Polyester films known as Mylar are used for making magnetic recording tapes, in audio cassettes, video cassettes etc. Polyester is another synthetic fibre. Actually polyester is the general name of synthetic fibres which contain many ester groups. Polyester (poly+ester) is made up of the repeating units of a chemical called an 'ester' (Esters are the organic chemical substances which give fruits their sweet smell). We can now say that polyester is a synthetic fibre in which the polymer units are linked by ester groups. Terylene is a popular polyester fibre. The chemical compunds (or monomers) used in making polyester fibres are made from petroleum products called petrochemicals. Like nylon, polyester is also a thermoplastic polymer. When molten polyester is forced through the tiny holes of a spinneret, then thin polyester fibres (or polyester threads) are formed. The polyester yarn can be woven to make fabrics. PET can be made into a fibre or a plastic. In discussing synthetic fibres, PET is generafly referred to as 'polyester' while the term PET is usually used for the plastic form. PET as a plastic is very lightweight. It is naturally colourless with high transparency. PET is strong and impact-resistant. As a plastic, PET is replacing materials like glass.(Unlike glass, PET is shatterproof. PET is used for making bottles, jars and utensils. For example, PET bottles are used for fizzy drinks and PET jars are used for storing sugar, salt, spices and rice, etc.., in our homes (see Figure 4). PET is also used for making thin films and many other useful products. It is clear that polyester fibres and PET bottles and jars are made of the same material.
Acrylic Properties and Uses Acrylic Acrylic fibre also called Orion and Acrylon, closely resemble wool. Acrylic is a synthetic fibre. Acrylic fibre is made from a chemical called 'acrylonitrile' by the process of polymerisation. Due to its wool-like feel, acrylic fibre is often used as a substitute for wool. The wool obtained from natural sources (like sheep) is quite expensive. Acrylic offers a less expensive alternative to natural wool. So, the clothes made from acrylic are relatively cheaper but more durable than those made from natural wool. Many of the sweaters which the people wear in winter, and the shawls and blankets which people use, are actually not made from natural wool, though they appear to be made from wool. They are made from synthetic fibre called acrylic. Acrylic fibre is used for making sweater shawls, blankets, jackets, sportswear, socks, furnishing fabrics, carpets and as lining for boots and gloves. Acrylic fibers are synthetic fibers made from a polymer (polyacrylonitrile) . These fibres are mainly consist of 85 % acrylonitrile monomer. Typical other monomers are vinyl acetate or methyl acrylate. Properties :- Acrylic is lightweight, soft and warm with a wool-like feel. Acrylic retains its shape, resists shrinkage and wrinkles. It can be dyed very well. Acrylic fibres are strong and durable. Acrylic absorbs very little water so it has 'quick-dry' quality. Acrylic fibres are resistant to moths and most chemicals. It is resistant to moths and chemicals. They are resistant to weathering. Uses :- It is used for making thread for knitting sweaters. They are also used to make wool like in blankets and shawls, which are very light and warm Acrylic is extremely strong. If it breaks or gets damaged, it will not shelter. Acrylic fibre is used for making sweater shawls, blankets, jackets, sportswear, socks, furnishing fabrics, carpets and as lining for boots and gloves.
Spandex Properties and Uses Spandex is a lightweight, soft smooth synthetic fiber which has a unique elasticity. Spandex is made of synthetic polymer called polyurethane which has extraordinary stretch ability. Spandex, also known as Lycra, was invented by the DuPont chemist Joseph Shivers in 1959. Properties :- It has excellent elasticity, which makes it suitable for use in clothes that require snug fitting. It can be stretched over 500 % without breaking. Even after repetitively stretching , cloth can recover its original length. It is lightweight. It is abrasion resistant. Have poor strength, but stronger and more durable than rubber, soft, smooth, and resistant to body oils, perspiration, lotions and detergents. Uses :- · Spandex is used for making swimming costumes. It is often mixed with other Fibres, like cotton, to get stretch fabrics. It is also used for making caps and T-shirts.

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