1 / 19

Introduction to Fibers II

Introduction to Fibers II. Measuring Properties – Moisture Terms. hydrophilic (Gr.: hydros = water + philos = love)-fibers with an affinity to water hydrophobic (Gr.: hydros = water + phobos = loathe)-fibers with no affinity to water

hoshi
Download Presentation

Introduction to Fibers II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to Fibers II

  2. Measuring Properties – Moisture Terms • hydrophilic (Gr.: hydros = water + philos = love)-fibers with an affinity to water • hydrophobic (Gr.: hydros = water +phobos = loathe)-fibers with no affinity to water • The moisture properties of a fiber is determined, in large measure, by its chemical composition; does it have an affinity for water. • Also hydrophilic fibers may either absorb or adsorb water. • Absorb – moisture penetrates into the fiber • Adsorb – moisture bound on the fiber’s surface

  3. Regain = (W – w)/w x 100% Regain & Moisture Content Moisture Content = (W – w)/W x 100%

  4. Mechanical Properties - Tenacity tenacity = strength/λ

  5. Mechanical Properties - Elongation elongation = “stretched length” – original length strain = elongation/original length Often these are multiplied by 100% to give percent elongation and percent strain

  6. Measurement of Mechanical Properties

  7. Measurement of Mechanical Properties • Initial modulus (stiffness) – resistance to deformation • Ultimate tenacity and strain • Specific work of rupture – energy (stored or released) at time of rupture 2 3 1

  8. Natural Fibers

  9. Cellulosic

  10. Cotton • Seed hair fiber • Hydrophilic – affinity between the hydroxyl groups (OH-) and water (H—OH) • Adsorbs

  11. Wool • 18 different amino acids all with the structure shown to the right General amino acid

  12. Polypeptide chain

  13. Crosslinking-cystine

  14. Wool • Depending upon the source, wool fibers range in length from 38-375 mm • round, and have a diameter of about 25 µm. • The fibers can be identified by the scales on the surface • Felting

  15. Wool • 2 types of cortical cells • Natural waviness • Because each amino acid has different properties • Hydrophilic • absorbs • Amphoteric – behaves like both acid and base

  16. Silk • Protein fiber • The secretion of the larva of the Bombyx mori moth, used to form its cocoon • The major fiber protein is fibroin, which is composed of 15 amino acids in a polypeptide chain • Very few cystine cross-links • Not amphoteric.

  17. Silk • The larva secretes two 'D' shaped filaments (called brins) simultaneously, held together by the protein gum sericin. • The fibers are highly regular and very lustrous. • The cocoon of the silkworm contains about 800-1200 meters of fiber (two strands); each fiber is about 10 µm thick sericin fibroin

  18. Asbestos • Asbestos is the only naturally occurring mineral fiber • There are 6 forms of asbestos: Six minerals are defined as "asbestos" including, chrysotile, amosite, crocidolite, tremolite, anthophyllite and actinolite • Vast majority of textile fibers are chrysotile asbestos, hydrated magnesium silicate, [Mg3Si2O5(OH)4] • Flame resistant chrysotile

  19. Next • Monday: Short reports • Tuesday: Manufactured Fibers

More Related