[Chemistry Class Notes] on Plastics Pdf for Exam

Introduction:

In 1846, the renowned German chemist Christian Schonbein discovered plastic. Plastics have actually been mistakenly identified. In his kitchen, Christian was experimenting, and he accidentally spilled a mixture of nitric acid and sulphuric acid. He took a cloth to mop up the solution (a mixture of nitric and sulphuric acid) and placed it over the stove after moping. After some time, the fabric vanished and got name plastic. In this article, you will study what is plastic, different types of plastic,  properties of plastic, and recycling of plastic.

What is Plastic?

Plastic is defined as a material that contains an organic substance of greater molecular weight as an important ingredient. It is also characterized as polymers with long chains of carbon. All plastics are said to be polymers. 

The word  plastic was derived in Greek from the word ‘Plastikos’ which means ‘to mold.’ Fossil fuels have hydrogen and carbon (hydrocarbon) containing compounds that act as building blocks for long polymer molecules. Such building blocks are referred to as monomers, which bind together to form long chains of carbon called polymers.

Types of Plastic and Their Uses

There are two different types of plastic

1. Thermoplastic: 

plastics that are easy to bend when heated.  Thermoplastics include linear polymers and a mixture of linear and cross-linked polymers. For instance, PVC, nylon, polythene, etc.

2. Thermosetting: 

Plastics that, once molded, can not be softened again by heating. Heavily cross-linked polymers fall into the thermosetting plastics group. Bakelite, melamine, etc. Example: Bakelite is used to make electrical switches, while floor tiles use melamine.

Speaking about the variations between thermoplastic and thermosetting plastic, the key differentiating factor between the two is that thermoplastic products usually have low melting points, meaning they can be quickly remolded or recycled further. 

The thermosetting plastic, on the other hand, is quite the contrary. They can withstand high temperatures and, even with the application of heat, can not be reformed or recycled once hardened. In any event, let’s take a look at some of the major differences below between these two compounds.

Types of Plastic Materials

 Examples of thermoplastics are listed below.

1. Polystyrene

2. Teflon

3. Acrylic

4. Nylon

Examples of thermosetting polymers include:

1. Vulcanized rubber

2. Bakelite

3. Polyurethane

4. Epoxy resin

5. Vinyl ester resin

Plastic Material Properties

Here are some plastic material properties-

• They are light weighted.

• They are highly resistant to chemicals.

• They are high electrical strength.

• They can easily be molded to desired shape and size.

• They can be made transparent or colored.

• Operations like drilling, sawing, and punching can be done on plastics.

• They are cheap as compared to metals.

• They are strong and ductile

• They are poor conductors of electricity.

• Plastic resists corrosion.

Recycling of Plastic

Plastic recycling is very significant. If they are not recycled at the right time, they are mixed with other chemicals or products, making them harder to recycle and a source of pollution. 

They are non-biodegradable, and the microbial effect does not decompose them. 

It is important to use biopolymers or biodegradable polymers to prevent this.

Did You Know?

In a landfill, plastic takes up to 1,000 years to decay. It takes 88 percent less energy to recycle plastic than to produce plastic from raw materials. Every year, enough plastic is thrown away to orbit the Earth four times. Each year, Americans throw 35 billion plastic bottles away.