What is Plastic?
Polymers are long chains of molecules (mostly carbon) bonded to each other. The smallest molecule which has to be repeated again and again to form a long chain is called a monomer. In other words, a monomer is the repeating unit of a polymer.
Polymers can have a linear structure, branched or cross-linked structure. Most of the materials that are called Plastics are polymers.
Plastic is a specific type of polymer that can change its shape. Plastics are made from petroleum. Many things around us are made of Plastics. For example Polythene, toys, bags, chairs, tables, boxes etc.
There are some well-known Plastics around us. They are polypropylene (chair, tables etc), polystyrene(Plastic spoons & forks, cups etc), polyamide (usually known as nylon) used in toothbrushes, car parts etc. Polythene is a very commonly used Plastic, mostly in the form of carrying bags.
Types of Plastics
There are two major types of Plastics based on their heat management nature. They are:
1. Thermosetting Plastics
The Plastics which when cooled and hardened once lose their ability to change dimensions on heating are known as thermosetting Plastics. These Plastics retain their shapes and can not return to their original form i.e they are irreversible. This type of Plastic is used for making auto parts, aircraft parts etc.
Bakelite and melamine are some examples of thermosetting Plastics. Once they are given a shape and cooled, they cannot be melted again to form a new shape.
2. ThermoPlastics
Plastics that soften upon heating and return to their original form are called thermoPlastics. They can be moulded and remoulded again and again. ThermoPlastics are used for low-stress applications such as Plastic bags or high-stress mechanical parts. This type of Plastic is first heated and then cooled to get the final shape. The material can be reheated, reshaped and cooled repeatedly i.e thermoPlastics are recyclable. They do not lose their dimension changing ability.
For example, Polythene and poly-ethylene are the most commonly used thermoPlastics in our daily life.
Plastic Recycling
Recycling is a difficult process that involves many processing steps. Before recycling, we have to collect the Plastic material that is to be recycled i.e waste or scrap Plastic. Then, every Plastic item is separated according to its type because different types of Plastics must be processed in different ways and not all Plastics are recyclable. After this, washing has to be done to remove impurities that enhance the quality of the manufactured product. Cleaned and dried Plastic items are then melted at a regulated temperature and moulded into a new shape.
This reduces high rates of polluting land and water bodies. At the same time, recycling puts less pressure on virgin materials to produce new Plastic products.
Advantages of Plastics
Plastics of the following advantages over metals:
Plastics are highly flexible as compared to metals. For industries that need designing options, geometry and different kinds of textures, Plastics are going to be the most suited materials.
Plastics are cheaper as compared to metals. The manufacturing of Plastic parts is budget-friendly.
Plastics are highly durable and can last for an indefinitely long period. Metals, on the other hand, are much more prone to chemical and weather susceptibilities.
The specific gravity of Plastic is much lower making it an extremely lightweight material.
The manufacturing of Plastic is a faster process as compared to metals.
Uses of Plastics
Plastics are highly durable, lightweight and most importantly can be moulded into any form or shape. These properties account for the largest usage of Plastics. Plastics are extremely versatile materials and can be used for a wide variety of purposes. Some usage of Plastics are given below:
The ability to be moulded makes Plastic ideal packaging material. Plastics in packaging help to keep foods safe and fresh.
Being durable and lightweight, Plastics have helped in the electronic field. From computers and cell phones to television and microwave, almost all appliances around us make some use of Plastic.
Plastics are used to make safety gear like helmets, goggles etc. Plastics are used in the construction industry due to their low maintenance and high durability.
Plastic is strong and lightweight, that is why it is useful in making toys, electrical switches and other household products.
Being non-reactive with air and water, Plastic is used to store water in Plastic bottles and other chemicals in chemical laboratories.
Plastic is a poor conductor of electricity and heat. Its insulation property is used for coating the electric wire and to make handles of cooking utensils and various household products.
Fun Fact:
John Wesley Hyatt invented the first synthetic Plastic in 1869. In 1907, Leo Baekeland invented bakelite which was the world's first completely manufactured synthetic Plastic.
FAQs on Uses of Plastics
1. What exactly is plastic and how is it made?
Plastic is a type of polymer, which is a long chain of repeating smaller molecules called monomers. Most plastics are synthetic and derived from non-renewable resources like petroleum. The manufacturing process involves heating and processing these raw materials to form a malleable compound that can be moulded into various solid shapes.
2. What are the two main types of plastics based on their reaction to heat?
Plastics are broadly classified into two main types based on how they behave when heated:
- Thermoplastics: These plastics soften when heated and harden when cooled. This process is reversible, meaning they can be melted and remoulded multiple times, making them recyclable. A common example is Polythene.
- Thermosetting Plastics: These plastics, once moulded and hardened, cannot be softened or remoulded by heating. The change is permanent and irreversible. They are known for their durability and heat resistance. Examples include Bakelite and melamine.
3. What is the fundamental difference between a thermoplastic like Polythene and a thermosetting plastic like Bakelite?
The key difference lies in their molecular structure and behaviour upon heating. Polythene, a thermoplastic, has a linear or branched structure that allows its chains to move freely when heated, enabling it to be reshaped. In contrast, Bakelite, a thermosetting plastic, forms strong, cross-linked chemical bonds during its initial setting. These bonds are permanent and prevent the material from melting or changing shape when reheated, making it rigid and non-recyclable.
4. What are some of the most common uses of plastic in daily life?
Due to its versatility, plastic is used in a vast range of everyday items. Some common uses include:
- Packaging: Bottles, containers, and wrappers that keep food fresh and safe.
- Electronics: Casings for computers, mobile phones, and televisions.
- Household Goods: Chairs, tables, toys, and storage boxes.
- Construction: Pipes, insulation, and window frames due to durability and low maintenance.
- Safety Gear: Helmets and protective goggles because it is strong and lightweight.
- Automotive: Car parts like bumpers and dashboards to reduce vehicle weight.
5. Why is plastic considered such a useful and versatile material for so many applications?
Plastic's widespread use stems from its unique combination of properties. It is highly valued because it is:
- Lightweight: Plastics have a low density, making products easier to handle and transport.
- Durable: They are resistant to corrosion and many chemicals, giving them a long lifespan.
- Easily Mouldable: Plastic can be shaped into complex forms, allowing for design flexibility.
- An Insulator: It is a poor conductor of heat and electricity, making it ideal for electrical wire coatings and utensil handles.
- Cost-Effective: The manufacturing process for plastic parts is often cheaper and faster than for materials like metal.
6. If plastics are so useful, why is their increasing usage a major environmental concern?
Despite its benefits, plastic poses significant environmental threats. The main concerns are:
- Non-Biodegradable Nature: Most plastics do not decompose naturally. Instead, they break down into tiny particles called microplastics, which pollute soil, water, and ecosystems for centuries.
- Resource Depletion: Plastics are primarily made from crude oil, a finite, non-renewable resource.
- Pollution: Improper disposal leads to plastic waste choking drains, harming wildlife that ingests it, and contaminating oceans.
- Air Pollution: Burning plastic waste releases toxic gases and fumes, which can be harmful to human health and contribute to air pollution.
7. How does recycling plastic help mitigate its negative impact on the environment?
Plastic recycling is the process of converting plastic waste into new, usable products. This process helps the environment significantly by:
- Conserving Resources: It reduces the need to extract virgin raw materials like petroleum to create new plastic.
- Reducing Landfill Waste: Recycling diverts large volumes of plastic from landfills, where it would otherwise take up space and persist for hundreds of years.
- Saving Energy: Manufacturing products from recycled plastic often requires less energy than producing them from raw materials.
- Minimizing Pollution: It helps reduce plastic pollution in oceans and on land, protecting ecosystems and wildlife.
8. What are some specific examples of plastics and their typical applications?
Different types of plastics have properties suited for specific uses. For instance:
- Polythene (PE): Widely used for plastic bags, packaging films, and bottles.
- Polypropylene (PP): Used for making durable items like chairs, automotive parts, and food containers.
- Polystyrene (PS): Commonly found in disposable cups, insulation materials, and protective packaging.
- Polyamide (Nylon): Known for its strength, it is used in textiles, toothbrush bristles, and machine parts.
- Bakelite: As a thermosetting plastic, its heat resistance makes it ideal for electrical switches and handles for cooking utensils.
