Air Jet Spun Yarn Mechanics in Elastic Woven Fabrics
Air jet core-spun yarns deliver torque-free, pill-resistant elastic wovens by locking polyurethane filaments inside parallel staple cores bound by vortex wrappers.
Polyurethane Degradation
Chemical Cleavage
Elastomeric polymer coatings and stretch fibers undergo structural breakdown when exposed to environmental stressors such as heat, moisture, and chemical agents. The progression of polyurethane degradation involves the cleavage of urethane bonds, which results in a loss of elasticity and strength. This process splits the long-chain polymers into shorter fragments that can no longer support high mechanical loads.
Ultraviolet radiation accelerates this reaction by breaking the carbon-nitrogen bonds in the polymer backbone. Over time, the material becomes brittle and prone to cracking under low stress.
Hydrolytic Attack
Exposure to high humidity and warm temperatures initiates the water-driven breakdown of polyester-type polyurethanes. Water molecules react with ester groups in the soft segments of the polymer to form carboxylic acids. These acids act as catalysts that speed up the breakdown of remaining chains.
Using polyether-type polyurethanes improves resistance to this specific water-based degradation.
Physical Loss
Coated fabrics exhibit peeling, stickiness, or flaking as the polymer structure fails. The coating loses its adhesion to the base fabric and separates during mechanical bending. This changes the hand and reduces the waterproof performance of the material.
Performance Testing
Laboratory assessment of durability involves accelerated aging chambers that simulate years of exposure in a few days. Testing measures the loss of tensile strength after exposure to heat and moisture. This helps predict fabric lifespan.