Tensile Strength and Structure–Property Models
topic
Tenacity models for polyester: Termonia model (molecular network model, crystallites as crosslinks in amorphous network); series–parallel aggregate model; Hierarchical fibrillar model. Theoretical maximum tenacity of PET (fully extended, oriented chain): ~200 cN/dtex. Commercial HT PET achieves 7–9 cN/dtex (~5% of theoretical) — limited by chain folding in crystals, fibrillar misalignment, flaws. Gel-spun UHMWPE achieves 30–40% of theoretical; liquid crystal polymers (LCP) achieve 15–25%.
Role
Structure–tenacity models for polyester illustrate the gap between theoretical and actual fibre strength, motivating high-performance fibre research. Comparing PET to gel-spun fibres and LCPs contextualises the role of molecular architecture in tensile performance.