Transcript 6_Wool
Chapter 10: Hatch Wool Fibers TMS 211 Wool Fall 2006 Sources of wool TMS 211 Wool Fall 2006 Wool Production in decline http://www.utexas.edu/centers/nfic/natstat/data/1w005.pdf Australia 30%, China, New Zealand (70/person), Iran Wool - clipped or pulled, graded, scoured • Specialty Wool Cashmere – from Kashmir (India/Pakistan) a goat Mohair - angora goat South Africa, Texas Cashgora - crossbreeding cashmere buck with angora doe TMS 211 Wool Fall 2006 Wool 2% of all apparel fiber processed in US today 73% used in apparel fabric 13% carpeting 15% various • 190 million lbs. scoured sheep wool converted to yarn and fabric in US 1989 TMS 211 Wool Fall 2006 Carpets and Rugs 12.6% Apparel 72.6% Industrial Textiles 4.8% Household and interior textiles 10% Wool - 26 million lbs. scoured fibers grown in the US in 2002 8 lbs./sheep/year gives 3-5 lbs clean wool Mohair - no crimp sweaters, coats and suits Cashmere - soft sweaters Camel hair - overcoats Vicuna - the softest, finest, rarest, most expensive Musk Ox (Qiviut) - warmer than sheep’s wool TMS 211 Wool Fall 2006 Photomicrograph of wool – Fig. 10.2 TMS 211 Wool Fall 2006 Photomicrographs of specialty wool fibers – Fig. 10.7 TMS 211 Wool Fall 2006 Wool Structure 3 dimensional crimp (up to 25 crimps/inch) length 1.5 - 15 inches (2 - 5 used in apparel) diameter 14m - 45m finer fiber considered best for apparel, coarser better for carpeting color is off-white to brown TMS 211 Wool Fall 2006 Wool Microstructure – scales 2000/inch point toward fiber tip, makes up “cuticle” – medulla - makes up hollow canal in center, larger for coarser fibers – cross-section is oval or elliptical – epicuticle - wax-like, few molecules thick cover scales - microscopic pores allow water vapor absorption TMS 211 Wool Fall 2006 Morphological components of wool – see also Fig 10.3 TMS 211 Wool Fall 2006 Submicroscopic structure of wool – Fig. 10.3 TMS 211 Wool Fall 2006 Wool Submicrostructure (cont.) Cortex (core) - 90% of fiber volume, countless spindle shaped cells, held together by intracellular cement 2 sections - orthocortex, paracortex wrap around each other, “bicomponent fiber,” causes crimp each cortical cell composed of hundreds of microfibrils microfibrils protofibrils 3 keratin (polypeptide) polymers which spiral around each other – Fig. 10.4 TMS 211 Wool Fall 2006 Structure of amino acid and alpha (α)-helix keratin polymer TMS 211 Wool Fall 2006 The Keratin Polymer Keratin polymer - helix of amino acids 18 different amino acids polar groups on amino acids account for hydrophilicity size of substituents interferes with close packing of chains, hence low crystallinity 25 - 35% crystalline, low orientation due to spiraling high resilience TMS 211 Wool Fall 2006 Structures of five amino acids TMS 211 Wool Fall 2006 Wool Properties Interpolymer Bonding x-linking, ionic bonding, H-bonding 2 cystine amino acids form cystine cross-link ionic bonding, hydrogen bonding • Properties Relatively weak High degree of elongation and elastic recovery Absorption of H2O increases flexibility TMS 211 Wool Fall 2006 Ionic bonds and crosslinks TMS 211 Wool Fall 2006 Wool Comfort high heat of wetting water repellent crimp results in high amount of air volume in fabrics, lowering thermal conductivity high resilience, as water content low luster high pilling odor absorbent TMS 211 Wool Fall 2006 Wool Maintenance Fabric Maintenance wool fibers weaken when wet shrink when agitated in water - felting degrade in mild alkaline solutions (detergents) alkalinity weakens keratin polymers at cystine linkages, felting bleach degrades TMS 211 Wool Fall 2006 Wool Properties dry heat causes fibers to become brittle medium resistance to concentrated acids decomposition by bacteria and enzymes low flammability chemical filtration TMS 211 Wool Fall 2006 Wool Fiber Properties TMS 211 Wool Fall 2006 Related web sites About wool in general www.childrenswoolens.com/aboutwoolbod y.htm Altering surfaces www.fibtex.lodz.pl/46_16_58.pdf Blending soy fiber with wool / http://textileinfo.com/en/tech/soybean TMS 211 Wool Fall 2006