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Difference Between Thermoplastic and Thermosetting Plastic for JEE Main 2025

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Last updated date: 13th Jul 2024
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What is Thermoplastic and Thermosetting Plastic: Introduction

To explain thermoplastic and thermosetting plastic: Thermoplastics are a type of polymer material that can be melted and reshaped multiple times without undergoing significant chemical change. They have a linear or branched molecular structure and are held together by weak intermolecular forces. On the other hand, thermosetting plastics have a cross-linked molecular structure, which provides them with excellent heat resistance and dimensional stability. Unlike thermoplastics, thermosetting plastics cannot be remelted or reformed after they have been cured. In this article, we’ll look at some of the most important ways that the characteristics of thermoplastic and thermosetting plastic are the same and different.


Category:

JEE Main Difference Between

Content-Type:

Text, Images, Videos and PDF

Exam:

JEE Main

Topic Name:

Differences between Thermoplastic and Thermosetting Plastic

Academic Session:

2025

Medium:

English Medium

Subject:

Chemistry

Available Material:

Chapter-wise Difference Between Topics


Defining Thermoplastic 

The term "thermoplastic" describes a class of polymer material that may be repeatedly melted and reformed without significantly changing chemically. Its molecular structure is straight or branched, and cooling and solidification do not change its physical characteristics. The polymer chains in thermoplastics are held together by weaker intermolecular forces, allowing them to move more freely. This property gives thermoplastics their ability to be melted, molded, and recycled.


Thermoplastics find applications in numerous industries, including automotive, packaging, construction, electronics, healthcare, and consumer goods. Examples of thermoplastics include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET). Thermoplastics are different from thermosetting plastic in the following ways:


  • Melting and reshaping: Thermoplastics can be melted and reshaped multiple times without significant degradation or chemical change.

  • Linear or branched structure: Thermoplastics have a molecular structure consisting of long polymer chains that can be linear or branched.

  • Weak intermolecular forces: The polymer chains in thermoplastics are held together by relatively weak intermolecular forces, allowing them to be easily separated when heated.

  • Reversible process: Thermoplastics exhibit a reversible process of melting, solidification, and re-melting, allowing them to be recycled and reprocessed.

  • Wide range of applications: Thermoplastics are used in various industries for applications such as packaging, automotive parts, consumer goods, pipes, and more.

  • Recycling capability: The ability to be melted and reshaped makes thermoplastics recyclable, contributing to their sustainability and environmental benefits.


Defining Thermosetting Plastic

A form of polymer material known as thermosetting plastic cures by a chemical reaction that creates a persistent cross-linked molecular structure. Due to their cross-linked structure, thermosetting plastics are generally more durable and resistant to chemical and environmental degradation compared to thermoplastics. Thermosetting polymers, which offer excellent heat resistance and dimensional stability, cannot be melted or altered once they have been cured. They can withstand high temperatures without softening or losing their shape, making them suitable for applications requiring heat resistance, such as electrical insulation, automotive parts, and aerospace components. Epoxy, phenolic, and polyester resins are a few examples. Some characteristics of thermosetting plastics:


  • Dimensional stability: Once cured, thermosetting plastics maintain their shape and dimensions even under high temperatures and mechanical stress.

  • Irreversible curing: Thermosetting plastics undergo a chemical reaction during curing, resulting in the formation of a three-dimensional cross-linked molecular structure. This process is irreversible; the material cannot be melted or reshaped after curing.

  • Strong and rigid: Thermosetting plastics tend to be rigid and have high strength properties, providing structural integrity to the finished products.

  • Chemical resistance: They often display good resistance to chemicals, making them suitable for applications where exposure to harsh substances is expected.

  • Electrical insulation: Thermosetting plastics are commonly used as electrical insulators due to their high dielectric strength and resistance to electrical conductivity.

  • Applications: Thermosetting plastics find applications in various industries, including aerospace, automotive, electrical, and construction, where their heat resistance and dimensional stability are valued. 


Thermoplastic and Thermosetting Plastic Difference

S.No

Category 

Thermoplastics

Thermosetting Plastics

1

Mechanical properties

Thermoplastics are more ductile and can deform without breaking. 

Thermosetting plastics are rigid and strong. 

2

Molecular structure 

Thermoplastics have linear or branched chains-like structures. 

Thermosetting plastics have cross-linked three-dimensional structures. 

3

Melting behavior 

Thermoplastics can be melted and reshaped so many  times. 

Thermosetting plastics have irreversible curing and cannot be remelted. 

4

Thermal behavior

Thermoplastics gets often when heated and gets harden when cooled. 

Thermosetting plastics retain their shape and strength at high temperatures. 

5

Applications 

Thermoplastics can be used in Packaging, consumer goods, pipes, etc. 

Thermosetting plastics can be used in aerospace, automotive, electrical components, etc. 

6

Examples 

Polyethylene, polypropylene, PVC, etc.

Epoxy, phenolic, polyester resins, etc. 


While some similarities exist between the two, it's important to note that the properties, behavior, and applications of thermoplastic and thermosetting plastic difference due to their distinct molecular structures and responses to heat. Now, we can easily differentiate what is thermoplastic and thermosetting plastic. 


Summary

Thermoplastics are polymers that can be melted and reshaped multiple times when heated, and solidify when cooled without undergoing any significant chemical change. This characteristic is due to the weak intermolecular forces between the polymer chains, allowing them to move freely. Examples of thermoplastics include polyethylene, polypropylene, PVC, and PET. They are widely used in various applications and industries due to their ease of processing, recyclability, toughness, and flexibility. 


On the other hand, thermosetting plastics, also known as thermosets, are polymers that undergo a chemical reaction when heated and hardened. Once cured, they cannot be re-melted or reshaped as the polymer chains become cross-linked, forming a rigid and three-dimensional network. Epoxy, phenolic, melamine, and urea-formaldehyde are examples of thermosetting plastics. They offer excellent heat resistance, chemical resistance, and mechanical properties, making them suitable for demanding applications such as electrical insulators, circuit boards, automotive parts, and composites. 

FAQs on Difference Between Thermoplastic and Thermosetting Plastic for JEE Main 2025

1. What is the main difference between thermoplastic and thermosetting plastic? 

The main difference between thermoplastic and thermosetting plastic is that thermoplastics can be melted and reshaped multiple times without significant chemical change, while thermosetting plastics undergo irreversible curing and cannot be remelted or reshaped after curing. Thermoplastics are less resistant to chemicals, on the other hand, thermosetting plastics are highly resistant to chemicals. Thermoplastics are recyclable and can be remolded whereas thermosetting plastics are non-recyclable and cannot be remolded. 

2. Explain thermoplastic and thermosetting plastic.

Thermoplastics can be melted and re-melted without degradation, while thermosetting plastics undergo a chemical reaction upon curing and cannot be remelted. Thermoplastics are recyclable and have reversible properties, while thermosetting plastics are non-recyclable and have irreversible properties. Thermoplastics have linear or branched chains-like structures whereas thermosetting plastics have cross-linked three-dimensional structures. Theemoplastics offer advantages such as easy processing, recyclability, toughness, and flexibility, oh the other hand, thermosetting plastics offer excellent heat resistance, chemical resistance, and mechanical properties, making them suitable for demanding environments.

3. How thermoplastics are formed?

Thermoplastics are formed through a process called polymerization, where monomers are chemically reacted to create long polymer chains. The resulting molten polymer material is then shaped using methods like injection molding or extrusion, and it solidifies upon cooling to retain its new shape. Thermoplastics can be melted and reshaped so many times without any significant chemical change.

4. What are the characteristics of thermoplastic and thermosetting plastic? 

Characteristics of thermoplastics: They can be melted and reshaped multiple times without significant chemical change and have a molecular structure consisting of long polymer chains that can be linear or branched. The polymer chains in thermoplastics are held together by relatively weak intermolecular forces. They exhibit a reversible process of melting, solidification, and re-melting and tend to be more ductile, meaning they have a higher tendency to deform under stress without breaking.


Characteristics of thermosetting plastics: Thermosetting plastics undergo a chemical reaction during curing, resulting in a permanent cross-linked molecular structure and a three-dimensional cross-linked molecular structure. The polymer chains in thermosetting plastics are held together by strong covalent bonds. Once cured, thermosetting plastics cannot be remelted or reshaped and tend to be rigid and have high-strength properties. They exhibit excellent heat resistance and dimensional stability.