Pus​hing Textiles  Forward through technology-

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 At the Museum of the Great Plains, in Cache, Oklahoma there is a replica of an old west trading post that was just recently refurbished.  In its day, the most in demand items at the trading post included wool blankets and kettles.  The wool blankets were preferable over bearskin because wool stays warm when wet, unlike bearskin.


Science does not have all the answers as to why wool is so phenomenal, but we can delve into the many ways science can explain the amazing properties of wool, a working fiber.


Warmth


Moist conditions from sea spray, sweating, or light rain and fog activate wool's heating properties, just when you need it most.  The moisture triggers a chemical reaction, known as the heat of adsorption, that releases energy in the form of heat.  


Heat of Adsorption


Wool fibers (see above diagram) consist mostly of the protien keratin. Keratin simultaneously attracts and repels moisture, resulting in a fiber that can retain 30% of its weight in water, without feeling wet, all the while, generating and retaining heat.   In fact, one pound of damp wool can generate as much heat as an electric blanket over the course of about 9 hours.  Heat of adsorption works like this, the inner cortex of the keratin fiber is hydrophilic, it attracts moisture.  As the moisture attaches to the inner cortex, energy is released in the form of heat.  This is called an exothermic reaction.  The outer cuticle is hydrophobic and repels moisture.  The heated moisture is now contained between the inner and outer layers of the fiber, in the airy crimped fibers that slow down heat loss, acting as insulation, retaining heat.   

 

Strength 

 

Wool gets its strength from its central cortex consisting of spindle shaped cells that results in crimped fibers. Crimped fiber consisting of helical coiled cells have a large surface area where stress and tension can expand across the fiber making it less likely to break.  Fiber strength and resiliency are important characteristics in converting fibers into yarn, fabric and clothing or blankets.  


Wire Insulation/Flame resistance


In the early days of electricity, prior to plastics being invented, wool was used as wire insulation.  The airy nature of the crimped fibers trap air resulting in low thermal conductivity.  The air itself is a poor conductor of heat.  Also, the crimped nature of the fiber reduces contact between fibers and reduces thermal conductivity.  Wool is also naturally flame resistant due to its high nitrogen and moisture content.  Wool tends to char rather than combust or melt.  Condensation, which can result in ignition, is also limited in wool fibers.  Wool's ability to store condensation without being wet to the touch made it a safer material for insulating wires than other organic materials available at the time.

Wool also has good stretch and recovery, making it easier to wrap around the copper wire.


Antimicrobial 


Wool cannot kill bacteria, but its surface structure can make it inhospitable to bacteria.


Lanolin is secreted from the sheep's sebaceous glands onto the wool creating a waxy layer that makes bacteria hard to spread.   Lanolin is a hydrophobic, yellow fat compound of long-chain waxy esters or sterol esters without glycerides.  


The layered structure of keratin's scaly exterior (see diagram) also slows down bacteria's growth.  Bacteria thrives in moist conditions, but wool's unique ability to contain moisture slows bacterial growth.


Other properties like pH and surface chemistry contribute to slow bacterial growth.


Closing


The properties of wool result in a cozy temperature, even in damp climates, that lends itself to knitwear.     






Wool and Lanolin