Spandex (elastane/Lycra); it specifically provides stretch and recovery (the ability to return to original shape after stretching), which is exactly the property needed for a fitted legging that must stretch during movement and then recover its shape.

Because spandex’s primary value is the specific property of stretch and recovery, which is best used to enhance another fiber’s other properties (like cotton’s breathability or wool’s warmth); blending a small percentage of spandex adds this stretch benefit while the majority fiber still provides its own primary characteristics, rather than replacing those characteristics entirely with spandex’s own more limited property profile.

Stretch and recovery; the added spandex allows the cotton-spandex blend to stretch with movement and return to its original shape, a property that 100% cotton alone doesn’t provide, even though the cotton-spandex blend likely still retains much of cotton’s breathability.

Nylon; it is specifically described as strong, lightweight, and quick-drying, and commonly used in activewear and outerwear for its durability and moisture resistance – properties that directly suit a rain jacket’s functional requirements.

Rayon; it offers a soft hand and good drape at a typically lower cost than silk, making it a reasonable alternative for a designer seeking silk-like qualities on a more limited budget, though the designer should also weigh rayon’s noted limitation of being less durable when wet.

Rayon is a semi-synthetic fiber made from processed natural cellulose (a plant-based source material that undergoes chemical processing), while polyester and nylon are fully synthetic, petroleum-based fibers; this distinction in source material is why rayon is categorized differently (semi-synthetic) rather than simply grouped with fully synthetic fibers.

The blend can retain some of wool’s warmth and structure while adding polyester’s wrinkle resistance and typically lower cost compared to 100% wool – combining desirable qualities from both fibers rather than relying on wool alone for all of the garment’s performance and cost characteristics.

Polyester is described as less breathable than natural fibers, potentially feeling less comfortable against skin in hot conditions; choosing 100% polyester (rather than blending it with a more breathable natural fiber, or choosing a more breathable fiber like cotton or linen) could create discomfort in a hot, humid climate specifically because of this reduced breathability.

Because blending allows a designer to combine the specific strengths of different fibers – gaining benefits like natural fiber comfort and breathability alongside synthetic fiber durability, wrinkle resistance, or stretch – rather than being limited to only the strengths (and accepting all the limitations) of a single fiber type used alone.

The decision should be guided by which specific properties the design actually needs and in what balance; a higher spandex percentage would provide more stretch and recovery but reduce the proportion of cotton’s breathability and natural feel, so the right ratio depends on how much stretch performance is genuinely needed relative to how much of cotton’s specific properties need to be preserved for that particular garment’s purpose.

Yes, this aligns with the lesson’s description; rayon is specifically noted as being less durable when wet, so fiber weakening after extended exposure to a very wet, humid environment is consistent with this known limitation of the fiber, rather than being an unexpected or contradictory outcome.

The core purpose of fiber blending is to combine the specific strengths of two or more fibers so a fabric can offer benefits that no single fiber alone would provide as effectively; for example, a cotton-spandex blend combines cotton’s natural breathability with spandex’s stretch and recovery, giving a garment both comfort in warm conditions and the ability to move and return to shape with the body – a combination that neither fiber alone would achieve as well by itself.