Characteristics of Wood

Abstract

DURABILITY AND RESILIENCE Each wool fiber is a molecular coil-spring making the fiber remarkably elastic. Nature has folded the chemical polypeptide chains back upon themselves in such a way that they act like a coiled spring which elongates when it is extended and retracts when it is released. This molecular crimp, along with the 3-dimensional fiber, allows wool fibers to be stretched up to 50% when wet and 30% when dry, and still bounce back to their original shape when stress is released. But be careful: When wool is wet the fibers are weaker. Recovery from stress takes place faster when the fiber is in a humid environment; that's why steaming a wool garment will freshen the fabric and why a steam iron is recommended for pressing wool. The flexibility of the wool fiber also makes it more durable. A wool fiber can be bent back on itself more than 20,000 times without breaking, compared to about 3,000 times for cotton and 2,000 times for silk. The natural elasticity of wool also makes woolen fabrics resistant to tearing. In addition, the outer skin of the wool fiber acts as a protective film, giving wool cloth improved resistance to abrasion. FIBER ABSORBENCY Wool is a hygroscopic fiber; it takes up moisture in vapor form. Tiny pores in the epicuticle make the fiber semi-permeable, allowing vapor to pass through to the heart of the fiber. Wool can easily absorb up to 30% of its weight in moisture without feeling damp or clammy. The capacity to absorb makes wool a " temperature regulator " because it can protect the body in both cold and warm conditions. Wool always absorbs moisture from the atmosphere of greater humidity and releases it to the drier environment as it creates a balance in moisture conditions. This characteristic makes wool a versatile all-season fabric. Wool absorbs perspiration; thus it keeps a layer of dry air next to the skin which, in turn, helps to hold in body heat. As wool absorbs atmospheric moisture, the hydrogen bond of water is broken and chemically reacts with molecules of the wool to generate heat. Wool garments are therefore regarded as good protection against hypo-thermia… a condition that occurs when sudden drastic lowering of body temperature causes the body to lose heat faster than it can be produced. The same principle of moisture contact on the skin acts to protect against hot weather as well. The body cools itself naturally with the evaporation of per-spiration. Wool expedites this process by absorbing perspiration and keeping the same dry air next to the skin. This is why wool clothing is worn throughout the desert regions of the world where it's hot during the day and cool at night. BENEFITS