Which polymer type is commonly stretched into fibres for textiles and industrial yarns?

Introduction / Context:
Many thermoplastics can be melt-spun or solution-spun into fibres. Understanding which polymer families are fibre-forming is fundamental in polymer engineering and textile technology.

Given Data / Assumptions:

• Saturated polyesters (e.g., polyethylene terephthalate, PET) are major fibre-formers (Dacron/Terylene).
• Unsaturated polyesters are thermosetting resins used for composites, not typical fibres.
• Isoprene forms elastomers (polyisoprene) rather than structural fibres.
• Bakelite (phenol-formaldehyde) is a thermoset, not spinnable into fibres.

Concept / Approach:
Fibre-forming polymers require adequate molecular weight, chain rigidity, and ability to orient and crystallise upon drawing. PET meets these conditions, giving high-strength, high-modulus filaments. Thermosetting resins cannot be melt-spun due to irreversible crosslinking. Elastomers do not typically yield strong drawn fibres because of their low glass transition and high elasticity without crystallisable structure under draw.

Step-by-Step Solution:
Identify fibre-forming candidates: saturated polyester (PET).Eliminate thermosets and elastomers (unsaturated polyester, Bakelite, isoprene).Choose saturated polyester for textile fibres.

Verification / Alternative check:
Global fibre production statistics consistently list polyester (PET) as the dominant synthetic textile fibre.

Why Other Options Are Wrong:
Unsaturated polyester: crosslinking for composites; not spinnable.Isoprene: elastomeric; not a structural fibre.Bakelite: thermoset; cannot be drawn into fibres.

Common Pitfalls:
Confusing “polyester” as a single type; only saturated aromatic polyesters like PET are fibre-forming mainstream materials.

Final Answer:
Saturated polyester