Friday, June 28, 2013

Differences Between Plant & Animal Fibers and Questions For You!

As I ponder which fiber to write about next and how not to repeat information that has been repeated a thousand times in a thousand other blogs and articles, I'm wondering: What do you want to know? What is useful to you?  What is interesting to you? Which fiber would you like me to discuss next?  I'm very interested in making my posts about what YOU want!

I started with the plant based fibers because, in my perception, knitters in general tend to have the least experience with and knowledge about them.  Crocheters tend to understand a bit more about how cotton works since most crochet threads are made of cotton.  Sewists are usually very familiar with plant fibers since most commonly available fabrics and the easiest to learn with are cotton or cotton blends.

Protein fibers seem to be what knitters are most familiar with, since most yarns that have been available over the centuries for knitting have been some type of sheep's wool. Where sheep were not native or traditionally raised, other fur bearing animal fibers have been used instead.  Many of these lesser known fibers have been making their way into the yarn shops over the past couple of decades.  Today we have quite the selection of protein fibers available to us: wools from many different breeds of sheep, alpaca, llama, yak, mohair, angora, cashmere, bison, qiviut, possum, mink, dog, cat, camel, guanaco, vacuna, and of course silk! And, I'm sure there are some I missed!  So you see my dilemma?  What do I start with and how in depth should I go? I would love to hear from you!  Tell me your interests, questions, "I've always wondered....?"

The various protein fibers have a few things in common.  First let me say that when I say 'protein fibers' in this context, I mean naturally occurring fibers from animal sources.  I mention this because there are also man-made protein fibers sourced from food production wastes like soy and milk.  These fibers are made in a similar fashion as rayon and have properties that are more rayon-like than natural animal fibers.

As I mentioned in last weeks post 'Blooming Plant Fibers' Friday June 21st, animal based fibers, except for silk, all have scales.  These microscopic, overlapping scales help the fibers hang together, give the fibers some elasticity, and they allow air space within each fiber strand which helps to hold in warmth.  Just the thing an animal that lives in a cold climate needs to stay toasty warm!  And why humans learned to use these fibers to also stay warm.  Each fiber has different sized scales-- smaller scales refract the light and gives the fiber softer sheen, larger scales allow a more brilliant sheen.  So the finest merino wool has a soft, almost matte like sheen and adult mohair has an awesome shiny luster and takes dye vibrantly.

The other thing that most animal fibers (except silk) have is 'crimp'.  Crimp refers to the natural wave the fibers have.  In general, and especially with sheep's wool, the finer the diameter of a strand of fiber, the more crimps per inch it also has.  So, the finest merino wools have many crimps per inch and the coarsest have the fewest, like adult mohair.  More crimps give more springy-ness and elasticity to a yarn (of course how the yarn is constructed also contributes, more about that in a future post), fewer crimps give more drape and less stretch.

Another area that protein fibers differ from plant fibers is the pH range that is damaging to the fibers.  Plant fibers are generally tolerant of alkaline conditions, this is why we can use common household bleach on cottons and linens without a severe amount of damage, but they do not tolerate acids as well. Protein fibers tolerate acids much better but are damaged by alkali.  Household bleach is alkaline.  For those of you wondering, this is why it's very difficult to find bright white wool for that wedding shawl you want to make.  Again silk is the exception to these generalities.  The pH tolerance of fibers is important to know when dying fibers, as there are different types of dyes used on the different types of fibers.  In general you use what is called a fiber reactive dye, alkali (soda ash) and a cold process on plant fibers.  On animal fibers you use an acid dye, vinegar, and a heating process. Silk can be dyed with either type of dye.  Then there is a third type of dye called a Union dye that also works on both types of fibers but does do slight damage to animal fibers.  The Union dye that you will most likely be familiar with is Rite Dye.

Next I'll be discussing whichever fiber you help me choose so let me hear from you!  Either leave a comment or email me at askTerry (at) jimmybeanswool (dot) com.

Terry


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