Fibrillar Structure and Microfibril Model
topic
High-resolution TEM and SAXS reveal polyester fibre structure as a fibrillar assembly: microfibrils (5–10 nm diameter) containing alternating crystalline and amorphous sequences with long period L = Lc + La (typically 10–15 nm). SAXS long period measured from peak position: L = 2π/q*. Fibrillar structure determines tensile modulus in fibre axis direction and fibrillation tendency under abrasion.
Role
The microfibrillar model provides quantitative structural parameters (crystallite size, long period, interfibrillar spacing) that correlate with macroscopic mechanical properties, enabling structure-based property prediction and process optimisation.