Fiber Properties Quiz

Fiber Properties

• Luster: The way a fiber reflects light from its surface depends on the smoothness or irregularity of its surface. Smooth surfaces reflect more light. Chemical orientation (amorphous vs. crystalline regions) influences luster. Crystalline regions reflect more light while amorphous regions reflect less. Bright/shiny fibers (silk, nylon) have more crystalline regions, while dull/matte fibers (cotton, wool) have more amorphous regions.

• Color: Color varies by fiber type (wool, cotton, bast, man-made fibers). It affects the appearance of the final product.

• Moisture Absorption: Textiles are conditioned in a standard atmosphere before testing. A consistent 65 ± 2% relative humidity is used in tests for reliable comparisons between laboratories. Moisture absorption includes adsorption (attracting and retaining moisture in the fiber's pores), and wicking (the ability of the fiber to move moisture quickly along its surface).

• Elongation and Recovery: Elongation is the amount of stretch or extension a fiber, yarn, or fabric can accept. Percent elongation is the ratio of the extension to the original length ( ((extended length - original length)/original length) * 100).

• Resiliency (or Wrinkle Recovery): The ability of a fiber to return to its original shape after bending or folding. Good resiliency is important in apparel and fabrics like polyester. Compressive resiliency (or loft) is the ability of a fiber to return to its original thickness after being crushed.

• Thermal Properties: These properties are exhibited when a fiber is exposed to heat. The thermal properties of different fibers include melting points (T_m), the glass transition temperature (T_g) and the ability to withstand different ironing temperatures without damage. Different types of fibers react to heat/ fire in varied ways (protein, plant, synthetic).

• Electrical Conductivity: The ability of a fiber to conduct electricity. Natural fibers are generally conductors (hydrophilic) and synthetics are generally poor conductors (hydrophobic). Metal/carbon fibers are good conductors. Conductivity increases with higher moisture absorption; this characteristic is important for static control.

• Abrasion Resistance: The ability of a fiber/yarn/fabric to withstand surface wear, rubbing, or chafing during use. Yarn and fabric construction, fiber properties, and finishing techniques can influence abrasion resistance. Testing methods include flex abrasion and flat abrasion.