science

Polybutylene terephthalate

Polybutylene terephthalate is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Polybutylene terephthalate rather than just read about it. In short: Polybutylene terephthalate (PBT) is a thermoplastic engineering polymer that is used as an insulator in the electrical and electronics industries. It is a thermoplastic (semi-)crystalline polymer, and a type of polyester.

Key takeaways

Polybutylene terephthalate belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Polybutylene terephthalate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Polybutylene terephthalate from memory before moving on to harder problems.

Reference excerpt

Polybutylene terephthalate (PBT) is a thermoplastic engineering polymer that is used as an insulator in the electrical and electronics industries. It is a thermoplastic (semi-)crystalline polymer, and a type of polyester. PBT resists solvents, shrinks very little during forming, is mechanically strong, is heat-resistant up to 150 °C (or 200 °C with glass-fibre reinforcement), and can be treated with flame retardants to make it noncombustible. It was developed by Britain's Imperial Chemical Industries (ICI). PBT is closely related to other thermoplastic polyesters. Compared to PET (polyethylene terephthalate), PBT has slightly lower strength and rigidity, slightly better impact resistance, and a slightly lower glass transition temperature. PBT and PET are sensitive to hot water above 60 °C (140 °F). PBT and PET need UV protection if used outdoors, and most grades of these polyesters are flammable, although additives can be used to improve both UV and flammability properties. PBT is produced by the polymerization of 1,4-butanediol and terephthalic acid.

Applications Polybutylene terephthalate is used for housings in electrical engineering, but also in automotive construction as plug connectors and in households for example in showerheads or irons. It is also found processed into toothbrush fibers and false eyelashes and is used in the keycaps of some high-end computer keyboards because the texture is highly resistant to wear and the plastic is less vulnerable to ultraviolet degradation and discoloration than the conventional ABS alternative. PBT can also be made into yarn. This has a natural stretch similar to Lycra and can be incorporated into sportswear. Due to its chlorine resistance it is commonly found in swimwear. Further, recent studies have shown that PBT has superior UV properties to PET based fabrics such as T400. PBT, especially glass fibre grades, can be effectively fire-retarded with halogen-free products. Phosphorus-based flame retardant systems are used in these fire-safe polymers and are based on aluminium diethyl phosphinate and synergists. They are designed to meet UL 94 flammability tests as well as Glow Wire Ignition Tests (GWIT), Glow Wire Flammability Test (GWFI) and Comparative Tracking Index (CTI). Main applications are in the electrical and electronics (E&E) industry.

Producers Novaduran (Mitsubishi Chemical Group) Celanex (Celanese) Crastin (Celanese) Anjacom (almaak international GmbH) Arnite (ENVALIOR) Duranex PBT (Polyplastics) Dylox (Hoffmann + Voss GmbH) Kebater (BARLOG plastics GmbH) Later (LATI) Pocan (ENVALIOR) Precite (AKRO) Rialox (RIA-Polymers GmbH) Schuladur (A. Schulman) Ultradur (BASF) Valox (Sabic Innovative Plastics) Vestodur (Evonik Industries AG) Badadur PBT (Bada AG) Bergadur (PolyOne Th. Bergmann GmbH) Longlite (Chang Chun Plastics Co Ltd) Ensinger

References

Illustrations

Worked examples

Example 1 — a first encounter with Polybutylene terephthalate

Start with the simplest possible case. Write down what Polybutylene terephthalate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Polybutylene terephthalate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Polybutylene terephthalate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Polybutylene terephthalate

In research: Polybutylene terephthalate appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Polybutylene terephthalate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Polybutylene terephthalate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Plastics, Polyesters, Terephthalate esters, so understanding it makes those chapters shorter.
In everyday life: Look for Polybutylene terephthalate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Polybutylene terephthalate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Polybutylene terephthalate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Polybutylene terephthalate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Polybutylene terephthalate in simple terms?

Why does Polybutylene terephthalate matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Polybutylene terephthalate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Polybutylene terephthalate.