Properties of plastics
Plastic is an essential part of our lives and is used in a wide variety of products and applications. From containers used to store food to the cables that provide infrastructure for electricity and telecommunications, plastic plays a vital role. But what are the properties of plastics that make them so useful?
What is plastic?
Plastics are synthetic materials made from polymers, which are large molecules composed of repeating units known as monomers. These polymers are created through a process called polymerization, where monomers are chemically linked to form long chains. Common monomers include ethylene, propylene, styrene, and vinyl chloride.
Polymerization: Monomers → Polymer
Basic properties of plastics
Durability and sturdiness
Plastics are known for being durable and strong. This is why they are often used in products that need to withstand pressure, force, or weight. Durability and strength come from the strong bonds between the monomers in plastic polymer chains.
Lightweight
Another key feature of plastics is their lightweight nature. Despite being strong, plastics are often much lighter than materials such as metal or wood. This makes them ideal for applications where weight is a concern, such as the automotive and aerospace industries.
Corrosion resistant
Unlike metals, plastics do not corrode when exposed to moisture or chemicals. This property makes plastics an excellent choice for products that come into contact with water or corrosive substances, such as pipes and containers.
Flexibility
Plastics can be very flexible, making them easy to mold and shape into a variety of forms and designs. This makes them valuable in products where intricate shapes and details are required.
Chemical properties
Thermoplastic vs thermosetting
Plastics can be divided into two main categories based on their response to heat:
- Thermoplastics: These plastics soften when heated and harden when cooled. This process is reversible, meaning objects made from thermoplastics can be reshaped. Examples include polyethylene and polystyrene.
- Thermosetting plastics: These plastics set permanently when heated. Once set, they cannot be reshaped or melted. Examples include epoxy and phenolic resins.
Insulation properties
Plastics are poor conductors of electricity and are often used as insulators to protect against electrical current. This is why they are a common choice for coating electrical wires to prevent electricity from leaking.
Chemical resistance
Plastics are often resistant to chemical attacks, making them suitable for use in laboratory settings and to safely store hazardous substances. They do not react easily with acids, bases, and other chemicals, preserving their structure and increasing their lifespan even in harsh environments.
Visual examples of plastic structures
How the properties of plastics work can be made even clearer with visual examples. Here are some simplified representations that show what polymer chains look like:
Environmental impact
Plastics are incredibly useful, but they also have a significant impact on the environment. Plastics can take hundreds of years to decompose in nature, leading to concerns about pollution and waste. Many plastics are not biodegradable, which means they do not break down easily and can accumulate in the environment.
Plastic recycling
Recycling plastic is important to reduce the impact on the environment. Recycling reduces the amount of plastic waste and conserves natural resources. Recycling processes can turn used plastic into new products, reducing the need to manufacture new materials from scratch.
Biodegradable and bio-based plastics
Researchers are also developing biodegradable and bio-based plastics that can easily decompose in the environment. These plastics are made from materials such as corn starch and sugar cane, and they offer the potential to reduce the environmental footprint of plastic products.
Applications of plastics
Everyday products
Plastics are used in countless everyday products, from packaging materials to household goods and personal care products. Plastics such as polyethylene and polypropylene are commonly found in bottles, bags, and containers.
Industry uses
In industry, plastics are used in the manufacture of vehicles, aviation parts, electronics, and medical devices. Their durability, resistance to chemicals, and flexibility make them an invaluable material in these areas.
Conclusion
Plastics are versatile and essential materials in the modern world. Their unique properties, such as durability, lightweight nature, flexibility, and resistance to corrosion, make them suitable for a wide range of applications. However, it is important to use and dispose of plastics responsibly to reduce their environmental impact. Through proper recycling, the development of biodegradable alternatives, and conscious consumer choices, we can ensure that plastics continue to benefit society without harming our planet.