In this article, we will discuss plastic in a simple and easy way and look at some interesting facts related to it, so you must read this article till the end.
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What is plastic?
Plastic is a material made of synthetic polymers or semi-synthetic polymers, which is flexible and has the ability to be molded into any shape.
Apart from this, it has low density, low electrical conductivity and it is very light and strong.
- Cold drinks bottles made of polyethylene terephthalate (PET).
- Flexible pipes used in homes are made of Polyvinyl Chloride (PVC).
- Insulating Food Container, that is, the container that prevents the movement of energy, is made of Foamed Polystyrene. And,
- Shatterproof windows are made of Polymethyl Methacrylate (PMMC).
This is its introduction, let us now understand it in some detail;
What is Synthetic Polymer?
Synthetic polymers refer to man -made polymers, usually derived from petroleum oil.
Most plastics contain organic or organic polymers. Organic polymer means a polymer in which Carbon is present. Or rather, organic polymers are made up of a long chain of carbon atoms . In which atoms of other elements can also be included such as oxygen, sulphur, nitrogen etc.
Each polymer chain has thousands of repeating units. There is a main part of this chain which connects other units together, it is called backbone i.e. main chain. Other units that connect to this backbone are called side chains or sub-chains.
What is a polymer?
Polymer is derived from the Greek word meaning ‘ many parts ‘ . In fact, polymers are made up of many molecules or relatively large molecules (macro – molecules ), and which repeat one after the other. It can be understood in the same way, as in a garland of beads, the beads repeat one after the other to form a chain or garland.
> Remember here that these are macro -molecules and not micro . Macromolecules refers to a large number of molecules bound together or bound together. As protein is also a macro molecule .
~ Polymers can be synthetic , that is, man-made, or natural . Natural polymers are called biopolymers such as DNA and protein. Apart from this, many polymers are found naturally such as, wool, rubber, silk, hemp and cellulose etc.
Talking about synthetic polymers, it is called plastic in the broad term, but many varieties are popular, such as Polyethylene (this is what we call Polythene), Polystyrene, Polyvinyl Chloride (it is popular in the market as PVC), Synthetic Rubber, Bakelite, Nylon, Poly-acrylonitrile (known in the market as Acrylic) and Silicone etc.
Classification of Plastics
Based on the chemical composition of the backbone and side chain, it is classified into the following parts; That is, the backbone of all the plastics coming under it, that is, the main chain, is of the same type. For example;
Acrylics – It is made from a synthetic polymer called acrylonitrile . And it is made from acrylonitrile petroleum or coal based chemical. It is mostfamous in the market as acrylic paint . Which is also called plastic paint.
Polyesters – The most well-known name coming under this is Polyethylene Terephthalate (PET). What this is, it is well explained further. By the way, we use many products coming under polyester in common-life such as clothes, ropes etc.
[Remember from here that polyester can contain naturally occurring chemicals as well as man-made chemicals. The polyester which has more of natural chemical is biodegradable.
What we use as a fabric is usually made from a man-made chemical called Synthetic Polyester.]
Silicones – These are generally colorless oils or rubber-like substances. Silicones are used to make sealants (eg to prevent air and water flow), adhesives (eg Fevicol), lubricants (eg to reduce friction), medicine (eg to make capsules), Used in thermal insulation and electrical insulation etc.
Polyurethanes – It is also called PU. It refers to a class of polymers composed of organic units linked by carbamate (ie urethane) links. It is not a separate thing but a specific class of polymers which have become a part of normal life due to their structure and physical properties. It comes under the category of Thermosets.
It is characterized by its flexibility, relatively lightness, strength and sponginess. For example, you can take a sponge used for washing utensils. Along with this, the clothes (spandex) that can be adjusted according to the sole and body of the shoe are also made from it.
From the point of view of utility they are classified into the following categories;
Thermoplastics – Also called Thermosoft Plastics; It is a plastic polymer that becomes malleable or moldable at a certain elevated temperature and solidifies upon cooling. The polymer chains are linked by intermolecular forces, which rapidly weaken with increased temperature, leaving a viscous liquid. In this state, the thermoplastic can be reshaped.
In other words, thermoplastics do not undergo chemical changes in their structure on heating and hence can be re-molded. For example, Polyethylene (PE) or what is called Polythene, in addition to Polystyrene (PS), and Polyvinyl chloride (PVC), etc.
Remember here that there are some polymers that can be shaped only once, that is, they disintegrate instead of taking any kind of shape when remelted. In this way the polymer is called a thermoset . The best example of this is the process of hardening rubber. Polyurethanes are another example of this.
Elastomers – Polymers that exhibit elasticity similar to rubber. That is, it tries to come back to its original position or it comes. It is also bound by weak intermolecular force. It is commonly known as Elastic in which rubber is used.
Biodegradable Plastics – These are plastics that can be used by living organisms; Usually by the action of microbes, water, carbon dioxide and biomass can be decomposed. In common life, they are found in the form of different types of products, such as cups, thali, plates etc.
Remember here that Bioplastic is different from Biodegradable Plastic . This is because most plastics are made from petrochemicals, while bioplastics are largely made from renewable plant materials such as cellulose and starch.
Conductive Polymers – As it is commonly known, plastic is an insulator. That is, electricity does not flow through it. But the same plastic is made Conductor or Semi-conductor by Dispersion technique.
Some examples of such polymers are – Polyacetylene, Polyphenylene vinylene and Polypyrrole etc.
Amorphous plastics – In many plastics the atomic, or molecular structure, does not follow a regular pattern. That is, the small unit from which it is made can be different from the units near it. This happens that its bond is not able to remain as strong.
Most medical tablets are amorphous solid, so as soon as they enter the stomach, their bond collapses and dissolves. Talking in terms of plastics, thermosets are amorphous plastics.
Remember here that the reverse of this, that is, when the molecular structure follows a regular pattern, it is called crystalline plastics. For example, take high-density polyethylene.
Synthetic fiber – Synthetic fibers are fibers made by humans through chemical synthesis.
Remember here that there are also natural fibers that are obtained directly from living organisms, such as from the cotton plant or the fur of animals.
There is a lot of confusion about fiber and plastic in general, so let’s understand it better.
Q. What is fiber?
Simply put, fiber, natural or man-made, is a substance whose length is many times more than its width. The clothes we wear are made from fabrics and fabrics are made from fiber.
Talking about natural fibers, cotton, wool, silk etc. can be taken. On the other hand, if we talk about man-made fiber, then you can take Nylon, Rayon, Polyester and Acrylic etc.
– Nylon fiber was the first man-made complete fiber. Today everything from clothing to parasuit ropes is made from Nylon fiber.
– RayonTalking about, it is also called Synthetic Silk. Since natural silk obtained from silkworms is very expensive, Rayon was created, which is similar to silk but man-made. Bed sheets are usually made by mixing cotton with Rayon. So that it becomes different from the clothes that he wears. Talking
about polyester , it is also a synthetic fiber which is a part of our common life. As we have discussed above also; The most well-known name coming under Polyester is Polyethylene Terephthalate (PET). From which bottles and utensils etc. are made. Here the thing to understand for us is that Polyester is made from the repeating units of a chemical called ester. Ester is found naturally in leguminous plants which gives the fruit its smell.
Different types of fibers and fabrics are made by mixing different types of natural fibers with polyesters. Just as polycot is made by mixing cotton with polyester, polywool is made by mixing wool.
Talking about acrylic , it is also a synthetic fiber which is used as an alternative to natural wool. Now here the question may come in your mind that we have read Acrylic above as plastic, whereas here we are reading it as fiber, then what is the difference between plastic and fiber?
Q. What is the difference between plastic and fiber?
When many small molecular units combine to form a single large unit, this unit is called a polymer. (Which we also understood above)
The thing to understand here is that fiber is also a polymer. For example cotton is a polymer called cellulose. Because it is made up of small units of glucose. That is to say that cotton is a natural polymer, or rather, cotton is a natural fiber.
Polymers are both natural and synthetic, in the same way that fiber is both natural and synthetic. What we call plastics is usually synthetic or semi-synthetic polymers.
Fiber is also synthetic such as Nylon and Rayon; And it is also used as plastic. So is plastic a synthetic fiber , orIs fiber plastic?
Q. Is synthetic fiber only plastic ?
Actually, the difference between plastic and fiber depends on what kind of shape it is in or what is its orientation. For example, if a Nylon block is taken, it may be plastic but as it is oriented in the form of threads then it is called a fiber.
Overall, many fibers are plastics such as Nylon, Rayon, Polyester and Acrylic etc. Similarly, many plastics can be used as fibers. Remember here that not all fibers are plastics and not all plastics can also be used as fibers.
type of plastic
Plastics are generally divided into three types, (1) Commodity Plastics (2) Engineering plastics and (3) High-performance plastics.
(1) Commodity Plastics
It is called Commodity plastic because about 70 percent of the world’s plastic falls in this category. It mainly includes 6 types of plastics. Its special thing is that all this has a Resin Identification Code.
The advantage of this is that it can be found out just by looking at what kind of plastic it is. And you can see it printed on almost all types of plastic; So let us know about it in some detail –
Polyethylene terephthalate (PET) – This is a strong, rigid synthetic fiber, which is a member of the Polyester family and belongs to the category of thermoplastics. PET is produced by the polymerization of ethylene glycol and terephthalic acid. That is, when the two are heated together under the influence of chemical catalysts, ethylene glycol and terephthalic acid produce PET as a molten, viscous mass that can be spun directly into fibers or spun into plastics. can be deposited as
High-density polyethylene (PE-HD) – High-density polyethylene or ( HDPE ), also made from ethylene, is also a thermoplastic. HDPE is used in the production of plastic bottles, corrosion resistant piping, plastic lumber. Due to its high density, its tensile strength is much higher than Low Density Polyethylene. And it can withstand temperatures of about 120 degrees Celsius.
Polyvinyl chloride (PVC) – This is the world’s third most widely produced synthetic plastic polymer. About 40 million tonnes of PVC is produced every year. PVC comes in two basic forms: rigid and flexible. Rigid form, used in the manufacture of pipes and in applications such as doors and windows. The flexible form, is used in applications such as plumbing, electrical cable insulation, imitation leather, flooring, signage, phonograph records, etc. where it replaces rubber. Along with cotton or linen, it is used in the production of canvas.
Low-density polyethylene (PE-LD) – This is also made from ethylene and falls under the category of thermoplastic. Due to its low density, its tensile strength is less than HDPE and it can withstand temperatures from 60 to 80 degree Celsius. It is used for packaging material (such as the foam used to keep it safe in TV cartons, and face wash bottles etc.
Polypropylene (PP) – Also known as polypropene, it is also a thermoplastic polymer and is made from propylene. Its properties are similar to those of polyethylene, but it is slightly harder and more heat resistant. It can withstand temperatures up to 171 degrees Celsius. Its density is less than that of polyethylene and hence it is relatively lighter.
Polystyrene (PS) – This is a hard and transparent synthetic resin (resin), it also falls under the category of thermoplastic and is made from styrene. It is widely used in the food service industry as rigid trays and containers, disposable eating utensils, and foamed cups, plates, and bowls. It melts at a temperature around 100 °C.
(2) Engineering plastics
Engineering plastics are stronger and hence are used to make vehicle parts, building materials, electronic gadgets and some machine parts. Today, from mobile-laptop to car, it is not complete without these plastics. It has many forms, here we will discuss its most important parts;
Polycarbonate – This is a group of thermoplastic polymers that contain carbonate groups in their chemical structures. Its specialty is that they are very strong and tough. All budget phones are usually made of polycarbonate body. Apart from this compact discs, eyeglasses, riot shields, security windows, traffic lights, and lenses etc. are made of this.
Silicones – We have also read about this above; It is usually a colorless oil or rubber-like substance. Its other features are as follows; It repels water. It can operate in temperaturesfrom -100 to 250 o C. Inhibits the growth of microorganisms. The conductivity of heat is low etc.
Polymethyl methacrylate (PMMA) – Also known as acrylic, acrylic glass, perspex, or plexiglass. It is a synthetic resin made from methyl methacrylate. It is a transparent and hard plastic that is often used as a substitute for glass in products such as shatterproof windows, skylights, and aircraft canopies.
(3) High-performance plastics
These plastics are usually expensive, their use being limited to specialized applications that make use of their superior properties. Some of the plastics that come under it are as follows;
Aramids – This is a class of heat resistant and strong synthetic fibres. These are used in aerospace and military applications. For example ballistic-rated body armor fabric commonly called bullet proof jacket; This is how it is made.
Its specialty is that it is one of the strongest synthetic polymers. One is lightweight and can withstand temperatures up to 500 degrees C. It is popular in the market under the brand names Kevlar, Nomex, and Twaron.
Polysulfone – This is a family of high performance thermoplastics. These polymers are known for their hardness and stability at high temperatures. Due to the high cost of raw materials and processing, polysulfone is used in specialized applications and is often a better replacement for polycarbonate.
Carbon fiber – Carbon fibers are fibers about 5 to 10 micrometers in diameter and are mostly made up of carbon atoms. Carbon fiber has many advantages including high rigidity, such as high tensile strength, greater strength than weight, high chemical resistance, high temperature tolerance, etc.
These qualities have made carbon fiber very popular in aerospace, civil engineering, military and motorsports. However, they are relatively expensive compared to similar fibers such as glass fiber, plastic fiber.
Some Facts about Plastics
- Teflon (Teflon) is a special type of plastic on which oil and water do not stick. To make non-sticky utensils, this coating is done on the utensils.
- Usually synthetic fiber catches fire immediately. But you will be surprised to know that the melamine plastic coating is done on the fireman’s uniform, which is fire resistant, that is, it does not catch fire.
- Nylon came into the market around 1939, and women’s stockings made from it became so popular at that time that women used to stand in line for hours to get it. And once a riot also broke out which is known as Nylon Riots.
The word plastic is derived from the Greek words plastikos and plastoses and means – that which is flexible or can be molded, bent or shaped as desired.
The first synthetic polymer was invented in 1869 by John Wesley Hyatt. It is said that $10,000 was offered by a New York firm to find an alternative to ivory, and to win, Wesley created a new substance by mixing cellulose obtained from cotton fiber with camphor, called plastic.
It could be produced in a variety of shapes and could provide a substitute for ivory.
Indeed the increasing popularity of billiards at the time put a strain on the supply of natural ivory obtained through the slaughter of wild elephants. That is why a substance was needed that could take its place.
This discovery was revolutionary. For the first time human creation was not constrained by the limits of nature. Nature supplied only wood, metal, stone, bone, tusks and horns but now humans could make whatever they wanted.
This was further improved in 1907 when Leo Baekeland invented Bakelite, the first fully synthetic plastic, meaning it did not contain naturally occurring molecules.
Bakelite was not only a good insulator but it was also durable, heat resistant. Bakelite could be molded into almost anything or shape, providing endless possibilities. That’s why it was called “the material of a thousand uses”.
The plastics industry expanded greatly during and after World War II, as the need to conserve scarce natural resources made the production of synthetic alternatives a priority. And plastics provided those options.
Plastic has become an important part of life today. Knowing how harmful it is to nature and the living world; We are using it a lot. Along with using plastic, it is also necessary today to know about the ways to deal with them, understand and implement them.
Plastic – Wikipedia
Rodriguez, Ferdinand. “plastic”. Encyclopedia Britannica, 20 Dec. 2021, https://www.britannica.com/science/plastic. Accessed 15 January 2022.