Thermoplastics: Versatile All-Rounders for Industry and Everyday Life

What Are Thermoplastics? – A Definition

Thermoplastics are plastics that can be shaped by heating and reshaped into a new form as often as required without their chemical structure undergoing any fundamental change.

Unlike other types of plastic, they consist of linear or slightly branched polymer chains that are not permanently cross-linked. When heated, the intermolecular forces break down – the material softens or melts. When cooled, it solidifies again.

In short: thermoplastics can be melted, shaped and reprocessed.

Thermoplastics: Distinction From Duroplastics and Elastomers

Thermoplastics are one of the three basic types of plastic. These are the key differences:

Property

Thermoplastics

Thermosets

Elastomers

Structure

Linear or slightly branched polymer chains

Tightly cross-linked polymer structure

Loosely cross-linked polymer structure

Behaviour under heat

Soften and melt; can be reshaped

Do not melt; degrade at high temperatures

Do not melt; remain elastic

Formability

Can be reshaped multiple times

Cannot be reshaped after curing

Elastically deformable; return to original shape

Recycling

Mechanical recycling widely established

Recycling possible with specialised processes

Recycling technically possible, but more complex

Typical properties

Versatile, easy to process

Rigid, dimensionally stable, heat-resistant

Flexible, rubber-like

Examples

PE, PP, PVC, PA

Epoxy resins, phenolic resins

Natural rubber, silicone

Thermoplastics are the only group of plastics that can be reprocessed repeatedly by melting – a key advantage for industrial manufacturing and recycling processes.

The differences in recycling stem primarily from their molecular structure: whilst thermoplastics can be reshaped by heating, cross-linked plastics such as thermosets and elastomers require different, often more complex recycling processes.

Thermoplastics combine properties that make them particularly versatile and cost-effective in many applications. What matters is not just what they can do – but the advantages that result from this:

Meltability and mouldability: Thermoplastics soften when heated and can be shaped into almost any form. This process is reversible and can be repeated multiple times.
This enables flexible processing and efficient mass production, for example in injection moulding or extrusion.

Recyclability: As they can be remelted, thermoplastics can be mechanically recycled and reused.
A key advantage for the circular economy and the increasing use of recycled materials.

Good processability: Thermoplastics are suitable for numerous industrial processes and can be processed precisely and automatically.
This makes them particularly attractive for applications involving high volumes and consistent quality requirements.

Customisable mechanical properties: Depending on the polymer and additives, thermoplastics can be designed to be flexible, tough or rigid.
This enables the targeted selection of materials for a wide range of requirements – from lightweight construction to heavy-duty components.

Chemical resistance: Many thermoplastics are resistant to moisture, chemicals and corrosion.
This broadens their range of applications, for example in packaging, construction or medical technology.

Depending on their performance characteristics, thermoplastics can be divided into three groups:

Standard thermoplastics

Widely used and cost-effective – particularly for everyday applications. They are typically used in high-volume applications where cost-effectiveness is a priority.

Examples:

• Polyethylene (PE): packaging, films
• Polypropylene (PP): packaging, automotive parts
• Polyvinyl chloride (PVC): construction products, pipes

Engineering thermoplastics

With improved mechanical and thermal properties for more demanding applications. They are used where higher load-bearing capacity and functionality are required.

Examples:

• Polyamide (PA): mechanical engineering, automotive
• Polycarbonate (PC): transparent components, housings
• Polyoxymethylene (POM): precision parts

High-performance thermoplastics

For extreme conditions such as high temperatures or aggressive chemicals. They enable applications where other plastics reach their limits.

Examples:

• Polyetheretherketone (PEEK): aerospace, medical technology
• Polysulfone (PSU): medical applications
• Polyphenylene sulfide (PPS): electronics

In summary: Thermoplastics cover a broad spectrum – from cost-effective packaging to high-tech applications.

Where Are Thermoplastics Used?

Thermoplastics are found in virtually every industry and link different value chains.

• Automotive and mobility: Lightweight parts and functional components – a key driver for reducing weight and CO₂ emissions, particularly in e-mobility.
• Packaging: films, bottles and containers – central to issues such as recycling, reusable packaging and design for recycling.
• Medical technology: Disposable products, device components and high-performance plastics – crucial for hygiene and safety.
• Electronics: Enclosures, connectors and insulation materials – growing in importance due to digitalisation.
• Construction: Pipes, profiles and insulation materials – valued for their durability and weather resistance.

Thermoplastics are therefore a key material in modern industry – from the mass market to high-tech applications.

Are Thermoplastics Sustainable?

Thermoplastics are considered to be relatively easy to recycle, as they can be reshaped and reprocessed by heating. This makes them an important material for circular economy initiatives and the use of recycled materials.

However, factors such as material diversity, additives or inadequate sorting can make recycling more difficult. The quality of the material can also deteriorate with repeated reprocessing.

Thermoplastics offer good conditions for circularity. Their potential is fully realised when products are designed accordingly and materials are consistently kept in the loop.

Conclusion: Why Thermoplastics Are So Important

Thermoplastics are far more than just a basic type of plastic – they form the foundation of countless applications in industry and everyday life. Their combination of mouldability, processability and recyclability makes them a key material across many value chains.

Understanding thermoplastics means understanding a vital part of modern plastic applications.

Mini Quiz: Thermoplastic – Yes or No?

Which of these materials are thermoplastics?

Polycarbonate

yes

That's right!

no

That's wrong!

Polyethylene

yes

That's right!

no

That's wrong!

Epoxy resin

yes

That's wrong! Epoxy resin is a thermosetting plastic.

no

That's right! Epoxy resin is a thermosetting plastic.

Silicone

yes

That's wrong! Silicone is an elastomer.

no

That's right! Silicone is an elastomer.

Polyurethane

yes

Trick question! It depends: depending on its structure, PU can act as a thermoplastic, a thermoset or an elastomer.

no

Trick question! It depends: depending on its structure, PU can act as a thermoplastic, a thermoset or an elastomer.

Author: Elena Blume | K-Mag

Elena Blume has been writing for various industry magazines for eight years and joined the K-Mag editorial team in 2021. She is particularly interested in topics related to innovative plastics solutions that contribute to sustainability and address current challenges relevant to industry and society.

At a glance

• Thermoplastics are plastics that can be reshaped by heating and reprocessed multiple times.
• They cover a wide range of applications – from packaging to high-tech components.
• Their importance is growing, particularly in the context of recycling and the circular economy.

Key Takeaway:

Thermoplastics are versatile, re-mouldable plastics whose properties and wide range of applications make them key materials in virtually all industries.