Difference Between Polymer and Plastic

The key difference between polymer and plastic is that the polymer can be either natural or synthetic whereas the plastic is a synthetic polymer.

Polymers are macromolecules containing a large number of repeating units linked to each other via covalent chemical bonds. There is mainly two type of polymers as natural and synthetic polymers. Plastic is a type of synthetic polymer.

CONTENTS

1. Overview and Key Difference
2. What is Polymer
3. What is Plastic
4. Side by Side Comparison – Polymer vs Plastic in Tabular Form
5. Summary

What is Polymer?

Polymers are large molecules that have the same structural unit repeating over and over. The repeating units are the monomers of that polymer. These monomers bind with each other via covalent bonds to form a polymer. They have high molecular weight and consist over 10,000 atoms. Moreover, in the synthesis process (polymerization), longer polymer chains form.

There are two main types of polymers depending on their synthesis methods. If the monomers have double bonds between carbons from addition reactions, we can synthesize polymers. We name them as addition polymers. Sometimes, when two monomers join with each other, a small molecule like water removes. Such polymers are condensation polymers.

Figure 01: Different Structures of Polymers

Polymers have very different physical and chemical properties than their monomers. Moreover, according to the number of repeating units in the polymer, properties differ. There are a large number of polymers present in the natural environment, and they play very important roles. Synthetic polymers are also useful widely for different purposes. Polyethylene, polypropylene, PVC, nylon, and Bakelite are some of the synthetic polymers. Furthermore, when producing synthetic polymers, we should control the process properly to get the desired product. Polymers are useful as adhesives, lubricants, paints, films, fibres, plastic goods, etc.

What is Plastic?

Plastic is also polymer that has a large molecular mass. The monomers of plastic can be either natural or synthetic. We produce plastic from petrochemicals. Hence, plastic is a synthetic polymer. Thermoplastics and thermosetting polymers are two types of plastics. Thermoplastics becomes soft when we heat it and if we cool it, solidifies again. Therefore, with continuous heating and cooling, we can change the shape without a problem (e.g. Polyethylene, polypropylene, PVC, polystyrene).

However, if we heat and cool thermosetting polymers, it becomes hardened permanently. When heated, it can be moulded, but if heated again, it will decompose (E.g., Bakelite, which we use to make handles of pots and pans).

Figure 02: Plastic Bottles

Plastics are widely in use in different forms, such as bottles, bags, boxes, fibres, films, etc. Plastics can be very resistant to chemicals, and they are thermal and electric insulators. Different plastics have different strengths but have a lightweight. We can produce this material by condensation and addition reactions. Furthermore, cross-linking is possible between polymer chains in the synthesizing process. For instance, we can produce polyethene by an addition reaction of the monomer ethylene. Its repeating unit is –CH_2-.

Depending on the way it undergoes polymerization, the properties of the synthesized polyethene changes. PVC or polyvinyl chloride is similar to polyethylene, with a monomer of CH₂=CH₂Cl, but the difference is, PVC has chlorine atoms. PVC is rigid and useful in manufacturing pipes. However, plastic has become a very controversial issue at the present day due to its incapability of degradation. Also, this material makes up a considerable percentage in our garbage; therefore, it keeps on increasing on the earth surface. Hence, this problem has caught the attention of researchers, and thus, they have synthesized recyclable plastics.

What is the Difference Between Polymer and Plastic?

Polymers are large molecules that have the same structural unit repeating over and over while plastic is a polymer that has a large molecular mass. However, the two materials have few differences. The key difference between polymer and plastic is that polymers can be either natural or synthetic whereas plastic is a synthetic polymer. Most of the polymers have long polymer chains, but there can be short chains as well, but plastics essentially have very long polymer chains. As another important difference between polymer and plastic, we can give the versatility of each material; most of the polymers are versatile while plastics are extremely versatile materials.

Summary – Polymer vs Plastic

Polymers are giant molecules. Plastics are a type of polymers. However, there are few differences between the two materials. The key difference between polymer and plastic is that the polymers can be either natural or synthetic whereas the plastic is a synthetic polymer.

Reference:

1. 16, 2018 Posted May. “Polymer vs Plastic: What’s the Difference?” Osborne Industries, 16 May 2018. Available here  

Image Courtesy:

1.”AFT Architecture”By Chem538w10grp4 – Own work, (Public Domain) via Commons Wikimedia  
2.”5761129451″ by Twentyfour Students (CC BY-SA 2.0) via Flickr