Monday, February 10, 2014

Fabric 101: Cellulose Fibers [Part 2]

Today we get to explore my favorite type of fiber - natural fiber! Looking back at our handy fiber tree  (from my first post), we will be discussing both cellulose and protein fibers. Today we will focus on cellulose.

Cellulose fibers - All cellulose fibers come from three parts of the plant: seed, bast (stem or root), and leaf. Cotton is a seed fiber, and linen is a bast fiber. Both cotton and linen are lightweight and breathable - which is great for summer months!

Note: You may be questioning where bamboo fits in,  and why I don't have it listed as a fiber. We will be discussing that when we talk about regenerated fibers, as it needs to be modified significantly from its natural state to be used in clothing.

Let us begin our discussion with King Cotton.

Photo from Cotton Australia
Cotton is a seed fiber between 1/2 to 2 inches that is off-white in color, and accounts for over 50% of all garments made. It is classified by its length, color, and character.

There are three lengths of cotton:

Short Staple - Under 3/4 inch in length, usually produced in India
Upland - Between 7/8 and 1 1/4 inches, primarily produced in the United States.
Long Staple (Egyptian, Pima, Sea Island) - 1 3/8 to 2 inches long, long staple cotton is primarily grown in Egypt and South America. However, a very small percentage is grown in the United States

Cotton's color varies based on nature, weather, and even how the fiber has been picked and ginned. The whiter the cotton, the higher the classification.

Character is essentially uniformity, strength, and maturity. These are important because you want to have your fibers remain consistent when blending so it has the same appearance. Stronger is always better, and maturity means that the fiber is finer and not coarse, which allows for a lightweight weave and better luster.

It is also super absorbent (because it is a hydrophilic fiber). Cotton is actually 30% stronger when wet!

Now on to our friend, linen. Linen is a bast fiber, which has the same overall properties of seed fibers, but it is generally a longer fiber.

Photo from Henfaes Research Centre

What many of you may not know is that linen is made from the flax plant. It is the oldest natural fiber (it shares that title with wool). Flax is grown in Western Europe, New Zealand, and some former Soviet states. There are three steps to harvesting flax, but they are boring (so I won't share).

However! Two interesting facts are:
1. To harvest flax you need to remove the entire plant from the soil. You can't keep using the same plant to make linen.
2. You can either harvest flax for linen or for flax seed/oil. In order to use the fiber for linen, the plant must be harvested before the seed is ready. It isn't a two-for-one operation.

Linen has a great natural luster (slight sheen) and is relatively stiff. Its natural luster becomes more apparent when it is ironed. In order to get the wrinkles out you have to use steam (linen is also hydrophilic).

It is important to note that, while linen holds up remarkably well over time, if it is continually folded in the same spot it will eventually break along the fold.

And, of course, the downside to linen is its excessive wrinkling.  

Next week we will explore protein fibers!