Difference Between Thermoplastic and Thermosetting Plastic (Tabular Form)
Difference between Thermoplastic and Thermosetting Plastic is essential in chemistry and helps students understand various practical and theoretical applications related to this topic. Recognizing how different plastics respond to heat, pressure, and recycling is crucial for exams and real-life problem-solving.
What is Difference Between Thermoplastic and Thermosetting Plastic in Chemistry?
The difference between thermoplastic and thermosetting plastic in chemistry is based on how these plastics behave when heated. Thermoplastics are plastics that soften when heated and can be remolded multiple times, while thermosetting plastics permanently harden after being set and cannot be remolded. This concept appears in chapters related to Polymers, Types of Plastics, and Properties of Plastics, making it a foundational part of your chemistry syllabus.
Key Differences Table: Thermoplastic vs Thermosetting Plastic
| S.No. | Thermoplastic | Thermosetting Plastic |
|---|---|---|
| 1. | Softens and can be reshaped on heating | Becomes hard and cannot be reshaped after setting |
| 2. | Can be recycled | Generally non-recyclable |
| 3. | Linear or slightly branched polymer chains | Highly cross-linked polymer chains |
| 4. | Lower melting point | Higher thermal stability |
| 5. | Examples: Polyethylene, PVC, Polystyrene | Examples: Bakelite, Melamine |
Thermoplastics and thermosetting plastics are two main classes of synthetic polymers. Knowing their differences helps you understand why certain plastics are chosen for specific applications like bottles, switches, or handles. For more, read about Thermosetting Polymers.
Thermoplastic Plastics
Thermoplastics are plastics that soften when heated and can be molded into different shapes repeatedly. Their polymer chains are usually linear or slightly branched, allowing them to be flexible and recyclable.
- Can be heated, cooled, and reheated without chemical change
- Lightweight and flexible
- Common examples: Polyethylene (PE), Polyvinyl Chloride (PVC), Polystyrene (PS)
- Used to make bottles, toys, kitchenware, pipes, and packaging films
Thermosetting Plastics
Thermosetting plastics, or thermosets, become permanently hard after they are heated and shaped. On further heating, they do not melt but may char or degrade. Their structure has extensive cross-linking, making them rigid and durable.
- Cannot be remolded once set
- Excellent thermal and electrical resistance
- Common examples: Bakelite, Melamine, Urea-formaldehyde resin
- Used for electrical switches, handles of utensils, circuit boards, and fire-resistant fabrics
Summary: 10-Point Comparison
| Point | Thermoplastic | Thermosetting Plastic |
|---|---|---|
| 1 | Softens on heating | Hardens on heating |
| 2 | Can be remolded | Cannot be remolded |
| 3 | Linear chain structure | Highly cross-linked structure |
| 4 | Soluble in organic solvents | Insoluble |
| 5 | Mostly addition polymerization | Mostly condensation polymerization |
| 6 | Recyclable | Non-recyclable |
| 7 | Lower thermal resistance | Excellent thermal resistance |
| 8 | Used for bottles, bags, toys | Used for switches, adhesives |
| 9 | Examples: PVC, Teflon, Polythene | Examples: Bakelite, Melamine |
| 10 | Less durable | More durable and rigid |
Diagrammatic Representation
Below is a simple explanation of the molecular structure difference between thermoplastics and thermosetting plastics:
- Thermoplastic: Long linear or slightly branched chains (like cooked spaghetti, can slide past each other on heating)
- Thermosetting: Highly cross-linked chains, forming a rigid three-dimensional network (like a net, fixed once set)
This cross-linking explains why thermosetting plastics are rigid and cannot be remelted.
Uses of Difference Between Thermoplastic and Thermosetting Plastic in Real Life
The difference between thermoplastic and thermosetting plastic is highly relevant in everyday life. Thermoplastics are used for items needing flexibility and recycling, such as plastic bottles, bags, and containers. Thermosetting plastics are used when heat resistance and rigidity are required, such as electrical switches, plugs, handles of cooking pans, and components in electronics and automobiles. Understanding these differences helps us choose environmentally safer and more functional materials. For more uses, visit Uses of Plastics.
Relevance in Competitive Exams
Students preparing for JEE, NEET, and school-level Olympiads often encounter questions about difference between thermoplastic and thermosetting plastic, especially in conceptual, definition-based, or match-the-following sections. Mastery of these distinctions is crucial for scoring well in chemistry exams.
Relation with Other Chemistry Concepts
The difference between thermoplastic and thermosetting plastic connects with topics like Polymerization, Synthetic Polymers, and various polymerization methods. Understanding this relationship helps students grasp how plastics are made and used.
Step-by-Step Reaction Example
1. Take polystyrene beads (a thermoplastic) and heat them gently.2. The beads soften and can be molded into a different shape.
3. Cool the molded shape; it solidifies but can be reheated and reshaped again.
4. Now take bakelite resin (a thermoset) and cure it by heating.
5. It becomes hard and, after cooling, retains its shape. On reheating, it will not soften but may burn if overheated.
6. Final Answer: Thermoplastics can be reshaped, thermosets cannot.
Lab or Experimental Tips
Remember the difference between thermoplastic and thermosetting plastic by the "Heat, shape, and reshape" rule for thermoplastics, and "Set once—forever set" rule for thermosets. Vedantu educators often demonstrate melting polythene vs. charring bakelite to help visualize these properties.
Try This Yourself
- List three thermoplastic and two thermosetting plastic examples from your home.
- Describe what happens when you heat a plastic bottle vs. a switchboard handle.
- Explain how cross-linking affects remolding ability of a plastic.
Final Wrap-Up
We explored the difference between thermoplastic and thermosetting plastic—including definitions, structures, properties, exam tips, and real-life examples. For deeper explanations and exam-focused study, check out live classes, revision notes, and practice material on Vedantu.
Explore related topics: Types of Plastics, Thermosetting Polymers, Polymer Chemistry, and Properties of Plastics.
FAQs on Difference Between Thermoplastic and Thermosetting Plastic
1. What is the main difference between thermoplastic and thermosetting plastic?
The primary difference lies in their response to heat. Thermoplastics soften when heated and can be repeatedly remolded, while thermosetting plastics harden permanently upon initial heating (curing) and cannot be reshaped. This difference stems from their molecular structures.
2. Can you give examples of thermoplastics and thermosetting plastics?
Thermoplastics include polyethylene (used in plastic bags), polypropylene (used in containers), polyvinyl chloride (PVC) (used in pipes), and polystyrene (used in disposable cups). Thermosetting plastics include bakelite (used in electrical insulators), melamine (used in tableware), and epoxy resins (used in adhesives).
3. Why can't thermosetting plastics be remolded?
Thermosetting plastics undergo irreversible chemical changes during curing, forming strong cross-links between polymer chains. These strong, rigid bonds prevent the material from softening upon reheating, making remolding impossible. They degrade rather than melt.
4. Is PVC a thermoplastic or thermosetting plastic?
PVC (polyvinyl chloride) is a thermoplastic. It softens upon heating, allowing it to be remolded.
5. Which plastics are suitable for recycling?
Generally, thermoplastics are more easily recyclable because they can be melted down and reshaped. Thermosetting plastics, due to their cross-linked structure, are much harder to recycle effectively.
6. What happens at the molecular level when a thermoplastic is heated and cooled repeatedly?
Repeated heating and cooling of a thermoplastic causes its polymer chains to temporarily break and reform their intermolecular bonds. This process doesn't change the chemical structure of the polymer itself; the bonds are weakened and strengthened but remain the same type of bond.
7. How does the cross-linking density in thermosetting plastics affect their mechanical properties?
Higher cross-linking density in thermosetting plastics leads to increased strength, rigidity, and heat resistance. Conversely, lower density results in a more flexible and less heat-resistant material.
8. Why are some thermosetting plastics used in electrical insulation?
Thermosetting plastics often exhibit excellent dielectric properties (resistance to electrical current flow) and high heat resistance. These properties make them ideal for use as electrical insulators in various applications.
9. Are there hybrid plastics with properties of both thermoplastics and thermosets?
Yes, some hybrid plastics incorporate aspects of both thermoplastics and thermosets. These materials might achieve a balance between moldability and enhanced strength/heat resistance.
10. What environmental challenges are associated with thermosetting plastics compared to thermoplastics?
Thermosetting plastics pose greater environmental challenges due to their difficulty in recycling. The strong cross-linking makes them resistant to degradation, leading to longer persistence in the environment and contributing to plastic pollution. Thermoplastics, while still posing challenges, are generally easier to recycle.
11. What are the differences in the synthesis methods of thermoplastics and thermosetting plastics?
Thermoplastics are often synthesized through addition polymerization, while thermosetting plastics are typically made via condensation polymerization. These different methods result in the distinct molecular structures responsible for their different behaviors.
12. Explain the difference in the molecular structures of thermoplastics and thermosets.
Thermoplastics have a linear or branched molecular structure with weak intermolecular forces. Thermosets have a cross-linked, three-dimensional network structure with strong covalent bonds between polymer chains.
