Chapter 3: Intro to fibers in science

Fiber

• the fundamental unit used in the fabrication of textile yarns and fabrics

• any substance, natural or manufactured, with a high length-to-width ratio and with suitable characteristics for being processes into fabric

Suitable characteristics of a fiber

• strength

• pliability

• length

• cohesiveness

fiber physcial structures

• length

• diameter

• cross-sectional shape

• surface contour, outer surface along the length

• crimp

• fiber parts

Staple fibers

• short fibers

• only a few inches

• cotton, flax, wool

filament fibers

• long fibers

• infinite length, miles long

• silk is the only natural example

Large diameter characteristics

• large diameter: soft and pliable

denier

the weight in grams of 9,000 meters of fiber or yarn

Tex

the weight in grams of 1,000 meters of fiber or yarn

cross sectional shape and surface contour

• cohesiveness

• luster

• hand

• texture

• soiling

What characteristics does crimp effect

• cohesiveness

• resiliency

• stretch

• bulk

• warmth

• absorbency

serviceability

• textile product’s ability to meet consumer’s needs

  • aesthetics

  • durability

  • comfort and safety

  • appearance retention

  • care

  • environmental impact

  • cost

aesthetic properties

• luster

• drape

• texture

• hand

durability properties

• tenacity

• elongation

• abrasion

• flexibility

• sunlight resistance

tenacity

• the ability to resist the stress

• number of grams of force to break a fiber

• affected by

  • molecular structure

  • degree of polymerization

  • % of crystalline region

  • orientation

elongation

• the ability to be stretched or extended

• affected by

  • % of amorphous region

  • crimp

abrasion resistance

• the ability of a fiber to resist damage from rubbing

• affected by

  • physical structure

  • chemical structure

flexibility

• the ability to bend repeatedly without breaking

• affected by

  • % of amorphous region

sunlight resistance

• ability to withstand the degradation from sunlight

• affected by: chemical composition

  • interaction between molecular structure of the fiber and ultraviolet light (UV light)

comfort properties

• water absorbency

• wicking

• heat retention

• heat conductivity

• electrical conductivity

• density

heat retention

• ability to retain heat

• affected by

  • chemical composition

  • physical structure (crimp, cross section shape)

heat conductivity

• The ability to transfer heat

• affected by

  • chemical composition

  • physical structure (crimp, cross section shape)

Electrical conductivity

• ability to transfer electrical charge

• affected by

  • chemical composition (hydrophilic group)

Appearance properties

• resiliency

• loft

• dimensional stability

• elasticity: elastic recovery

• piling

resiliency

• the ability to return to original shape after bending, twisting, compressing, or a combination deformation

• loft

• affected by

  • chemical composition

  • crimp

Loft

• the measure of a material’s thickness, fluffiness, and ability to trap air when it is not compressed

dimensional stability

• ability to retain size and shape through use and care

Elasticity

• the ability of a textile to return to its original dimension shape after elongation

• related to: appearance and fit

• affected by: chemical structure

Pilling

• the formation of balls on the fabric surface

• affected by

  • fiber strength

Properties related to care instruction

• wash, bleach, dry, iron, dry clean

• wet strength

• absorbency

  • water: hydrophilic/hydrophobic

  • oil: oleophilic/oleophobic

• chemical reactivity

  • alkali

  • acid

  • bleach

• heat sensitivity

Hydrophilic v. hydrophobic

hydrophilic: attracts water and wets easily

• usually natural fibers like cotton, wool

hydrophobic: water-fearing, repels water

• usually synthetic materials

Acid

• harms cotton, flax, rayon, nylon

Alkali

• harm wool, silk

bleach (5% sodium hypochlorite)

dissolve wool, silk

Heat sensitivity

• ability to shrink, soften, or melt when exposed to heat

Color Properties

• colorfastness

color fastness

ability of a textile structure to retain coloration when exposed to certain conditions

• wash

• perspiration

• sun light

• crocking

fiber identifications

• why idenify fibers:

  • laws require fiber content on the label of product

  • consumers only need to look for the label

  • professionals confirm or verify fiber content label

main methods for fiber identification

• visual inspection

• burn test

• solubility test

• microscopy

visual inspection

• first step in fiber identification

• not possible to use alone for fiber identification

• what to inspect

  • length of fiber: untwist yarn to determine length

  • luster or lack of luster

  • body, texture and hand

microscopy

• more useful in identifying natural fibers

• manufactured fibers are more difficult to identify

Why are natural fibers difficult to identify

• they all look alike

• easy to modify their cross section shape and lengthwise appearance in the manufacturing process

• positive identification of manufactured fibers is not possible