Mechanical Properties of Polyester
category
Polyester fibres exhibit a distinctive stress–strain behaviour characterised by an initial high-modulus region, yield point, post-yield plateau, and strain hardening to break. Key properties: tenacity 3–8 cN/dtex, elongation at break 15–50%, initial modulus 50–120 cN/dtex, elastic recovery >90% at 5% extension. Properties are structure-dependent and tunable through processing.
Role
Mechanical properties of polyester fibre are the foundation of its selection for engineering and apparel applications. Their measurement, structure dependence, and failure mechanisms are core topics in textile materials science and fibre physics.
Subtopics
- Stress–Strain Behaviour and Yield Point PET fibre stress–strain curve (at 20°C, 65% RH, 20 mm gauge length, 20%/min strain rate): linear ela…
- Elastic Recovery and Viscoelastic Behaviour Elastic recovery of polyester: >90% at 5% extension (recoverable elastic strain stored in crystallin…
- Initial Modulus and Stiffness Control Initial modulus of PET fibre (tangent modulus at origin of stress–strain curve): 50–80 cN/dtex (comm…
- Abrasion Resistance and Pilling Behaviour Polyester's high tenacity and elastic recovery make it resistant to abrasion (Martindale abrasion: >…
- Fatigue Behaviour under Cyclic Loading Polyester fibre fatigue under cyclic tensile loading: S–N curve shows endurance limit at ~50% of bre…
- Tensile Strength and Structure–Property Models Tenacity models for polyester: Termonia model (molecular network model, crystallites as crosslinks i…
- Compressive Behaviour, Bending and Buckling Polyester fibres are weak in compression (compressive strength ~20% of tensile: ~0.7 cN/dtex for FDY…
- Friction and Tribology of Polyester Fibres Polyester fibre friction characterised by: fibre–fibre friction coefficient (µff, 0.15–0.30 dry), fi…
- Moisture Regain and Sorption Behaviour Polyester has very low moisture regain: 0.4% at 65% RH, 20°C (cf. cotton 8.5%, wool 14%). Moisture a…
- Thermal Properties and Flame Behaviour PET limiting oxygen index (LOI): 20–22 (flammable, below 21% atmospheric O₂). Burns with melting and…