Objective 4.01
FIBER IDENTIFICATION BURNING TESTS
Did You Know...
...you can differentiate fabrics based on how they burn?
Introduction:
The burning test provides valuable information regarding care of fabrics and aids in identifying classes of fibers such as manufactured versus natural fibers and cellulose versus protein fibers. It is important to remember that a number of factors may alter the results of burning tests. The type of dyes, finishes, and combination of fibers used in the fabrics can change the flammability, odor, and the residue. In blends, the fiber of greater percentage will become more evident.
Procedures:
Using the internet, research to find answers the following reactions for a burn test to the fabrics listed on the chart:
a. The flame--Did it burn readily? Did it leave a glowing ember when the flame was extinguished? Did it self-extinguish with no ember? Did it melt, drip, and leave no ember when the flame was extinguished? Did it melt and not burn?
b. The odor--Odor can sometimes be unreliable since chemicals and inks added can alter the odor of the fiber itself. Odor identification is primarily useful with natural cellulose and protein-based fibers. Cellulosic fibers will smell like paper burning and protein fibers normally smell like hair burning.
c. The residue--The residue is usually very distinctive. Cellulosic fibers leave almost no residue except for a very soft white ash which leaves a smudge when rubbed with the fingers. Protein fibers curl away from the flame and bead up. The residue is light and forms a very brittle cinder which is easily crushed. Manufactured fibers draw away from the flame and melt into beads that drip into molten globs. These beads solidify into a hard mass when cooled and are difficult to crush. Edges of the fabric usually fuse together into a hard beaded edge.
*Suggested web search: “fiber id burn tests”
2. Record the reactions of each fiber tested for flammability, odor, and type of residue remaining AND answer each of the questions based on your observations and conclusions. You have 6 Unknown fibers. You need to determine the fiber specimen based on the 3 categories below. Be sure to label A – F on the chart. You will not have all of the fibers listed.
NAME______DATE______PERIOD______
FIBER / FLAME / ODOR / RESIDUECOTTON
LINENWOOL
SILK
RAYON
ACETATE
ACRYLIC
NYLON
POLYESTER
SPANDEX
1. Which fiber(s) reacted to the flame by burning readily and leaving a glowing ember when the flame was extinguished? ______
2. Which fiber(s) reacted to the flame by self-extinguishing with no ember?
______
3. Which fiber(s) reacted by melting, dripping, and forming a hard mass?
______
______
4. Which fiber(s) produced a smell similar to burning paper or wood?
______
5. Which fiber(s) produced a smell resembling burning hair?
______
______
6. Which fiber(s) reacted by leaving a soft white ash resulting in a smudge when rubbed?
______
______
7. Evaluate the answers to each of the previous questions. You will find that the fibers you listed for each question have a common factor. (Ex. the most likely answers to the first question will be cotton and flax, and rayon and acetate--they are all cellulosic natural or cellulosic manufactured fibers.) What is the common factor for answers to each of the other questions?
8. List some reasons why a fiber id burn test would be used:
______
______
KEY
FIBER IDENTIFICATION TEST LAB
FIBER / FLAME / ODOR / RESIDUECOTTON
natural cellulosic / does not shrink away, burns quickly and has glowing ember after burning. / similar to burning paper. / light, feathery, light to charcoal gray in color.LINEN
natural cellulosic / does not shrink away, burns quickly, glowing ember after fire extinguished. / similar to burning paper. / light, feathery, light charcoal gray in color.
WOOL
natural protein / curls away from flame, burns slowly, self-extinguishing. / similar to burning hair. / brittle, small black bead.
SILK
natural protein / curls away from flame, burns slowly and sputters, self-extinguishing. / similar to burning hair. / bead-like, crushable black.
RAYON
manufactured cellulosic / does not shrink away, burns quickly, continues to burn with glowing ember. / similar to burning paper. / light, fluffy residue, very small amount.
ACETATE
manufactured cellulosic / fuses and melts away from flame, burns quickly and continues to burn. / similar to hot vinegar. / irregular shaped, hard, black bead.
ACRYLIC
manufactured / melts, ignites readily, burns rapidly and sputters while burning, will drip while burning. / similar to hot vinegar. / hard, black, irregular bead.
NYLON
manufactured / melts away from flame and burns slowly, fuses and melts, self-extinguishing. / similar to celery. / hard, tough, gray or tan bead.
POLYESTER
manufactured / melts away from flame and burns slowly, fuses and melts, self-extinguishing. / chemical odor. / hard, tough, black or brown bead.
SPANDEX
manufactured / fuses but does not melt away from flame. / chemical odor. / soft, sticky, and gummy.
KEY
FIBER IDENTIFICATION TEST LAB
1. Which fiber(s) reacted to the flame by burning readily and leaving a glowing ember when the flame was extinguished?
cotton and flax (natural cellulosic)
rayon and acetate (manufactured cellulosic)
2. Which fiber(s) reacted to the flame by self-extinguishing with no ember?
wool, silk (natural protein)
3. Which fiber(s) reacted by melting, dripping and forming a hard mass?
acetate, acrylic, nylon, polyester (all manufactured)
4. Which fiber(s) produced a smell similar to burning paper or wood?
cotton, flax, rayon (natural and manufactured cellulosic)
5. Which fiber(s) produced a smell resembling burning hair?
silk and wool (natural protein)
6. Which fiber(s) reacted by leaving a soft white ash resulting in a smudge when rubbed?
cotton and flax (natural cellulosic)
7. Evaluate the answers to each of the previous questions. You will find that the fibers you listed for each question have a common factor. (Ex. the most likely answers to the first question will be cotton and flax, and rayon and acetate--they are all cellulosic natural or cellulosic manufactured fibers.) What is the common factor for answers to each of the other questions?
Fabrics that burn quickly and have a glowing ember are cellulosic or plant-based. Fabrics that
reacted by self-extinguishing with no ember are fibers which are good flame-retardants. Fabrics
that melted and dripped are generally manufactured plastics and are not good flame-retardants.
Fashion Merchandising
D-22