FASH 15 textiles
fiber identification
fiber identification
the procedure for identifying fibers in a fabric
depends on:
• the nature of the sample
• the experience of the analyst
• the facilities available
microscopic appearance is most useful for natural
fibers
solubility tests & sophisticated spectroscopic
analyses are most effective for manufactured fibers
fiber identification: visual inspection
visual inspection of a textile for appearance and hand
is always the first step in fiber identification
length of fiber—
Untwist the yarn to determine fiber length. Any fiber can be made in staple
length, but not all fibers can be filament. For example, cotton and wool are
always staple, never filament.
luster or lack of luster—
Manufactured fiber luster may range from harsh and shiny to dull and
matte.
body, texture, hand—
These factors indicate whether the fiber is soft to hard, rough to smooth,
warm to cool, or stiff to flexible and relate to fiber size, surface contour,
stiffness and cross-sectional shape.
fiber identification: burn test
the burn test can be used to identify a fiber’s general
chemical composition—cellulose, protein, mineral, or
synthetic (blends cannot be identified)
EXAMPLE: if sample is cellulose & filament, probably rayon
safety precautions:
• work in well-ventilated area or under a hood
• remove paper and other flammable materials
from area
• check apparel and hair are safely out of the way
fiber identification: burn test
follow these general directions:
• ravel out and test several yarns from each
direction of the fabric to determine if they are the
same fiber type—differences in luster, twist, and color suggest
that there might be more than one generic fiber in the fabric
• hold the yarn horizontally—it is helpful to roll long
pieces of yarn into a flat ball or clump
• use tweezers to protect your fingers
• move yarns slowly into the edge of the flame and
observe what happens
• repeat this step several times to check your
results
fiber identification: microscopy
knowing the physical structure of fibers will be of use
when using a microscope in fiber identification—
photomicrographs of fibers included in Ch. 4-9
for best accuracy, examination of both the lengthwise
appearance (longitudinal) and crosswise appearance
(cross-section) of an unknown fiber is best
positive identification of manufactured fibers by
microscopy is not possible
fiber identification: microscopy
directions for using the microscope:
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clean the microscope lens, glass slide, and cover glass
place a drop of distilled water or glycerin on the slide
untwist a yarn and place several fibers from the yarn
on the slide; cover with the cover glass and tap to
remove air bubbles
place the slide on the stage of the microscope
focus with low power first—center fiber(s) in the viewing
field then move to a lens with greater magnification (as
magnification increases, viewing field decreases)
if fabric contains 2 or more fiber types, examine both
warp and filling yarns
fiber identification: solubility tests
solubility tests are used to identify manufactured
fibers by generic class and to confirm identification of
natural fibers
fiber identification: solubility tests
directions for solubility tests:
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place the specimen in the liquid in the order listed—
following this order will help in identifying specific fiber
stir the specimen for 5 minutes and note the effect
fiber, yarns, or small pieces of fabric may be used
remember that the liquids are hazardous—handle them
with care!
use chemical laboratory exhaust hoods, gloves, aprons &
goggles
fiber identification
LAB #1—burn tests
…please read and follow all the directions on your
lab sheets VERY CAREFULLY
…please listen to the instructor before you begin
anything
…if you have questions, please ask