Vegetable/Cellulosic Fiber Properties

cotton boll

Chemically, cotton is the purest vegetable fiber, containing >90% cellulose with little or no lignin. The other fibers contain 40–75% cellulose, depending on processing. Boiled and bleached fiax and degummed ramie may contain >95% cellulose. Kenaf and jute contain higher contents of lignin, which contributes to their stiff- ness. Although the cellulose contents are fairly uniform, the other components, eg, hemicelluloses, pectins, extractives, and lignin vary widely without obvious pattern. These differences may characterize specific fibers. Except for the seed-hair fibers, the vegetable fibers of bast or leaf origins are multicelled and are used as strands.

In contrast to the bast fibers, leaf fibers are not readily broken down into their ultimate cells. The ultimate cells are composites of micro- fibrils, which, in turn, are comprised of groups of parallel cellulose chains. Bast and leaf fibers are stronger (higher tensile strength and modulus of elasticity) but lower in elongation (extensibility) than cotton. Vegetable fibers are stiffer but less tough than synthetic fibers. Kapok and coir are relatively low in strength; kapok is known for its buoyancy.

Chemical Composition of Vegetable Fibers, wt %

Fiber Cellulose Hemicellulose Pectins Lignin Extractives
Bast Fibers
Flax 71.2 18.6 2.0 2.2 6.0
Hemp 74.9 17.9 0.9 3.7 3.1
Jute 71.5 13.4 0.2 13.1 1.8
Kenaf 63.0 18.0 - 17.0 2.0
Ramie 76.2 14.6 2.1 0.7 6.4
Leaf Fibers
Abaca 70.1 21.8 0.6 5.7 1.8
Phormium 71.3 - - - -
Sisal 73.1 13.3 0.9 11.0 1.6
Seed-hair Fibers
Coir 43.0 0.1 - 45.0 -
Cotton 92.9 2.6 2.6 - 1.9
Kapok 64.0 23.0 23.0 13.0 -

Dimensions of Ultimate Fibers and Strands


Ultimate fiber Cell cross-section
Fiber strand
Fiber Length,mm Diameter,µm Shape Diameter,µm Length,cm Width,mm
Bast Fibers
Chinese Jute 2-6.5 7.33



Flax 4-69 8-31 Polygonal 8.8-16.1 25-120 0.04-0.62
Hemp 5-55 16 Polygonal 13.1-23.6 100-400 0.5-5
Jute 0.7-6 15-25 Polygonal-Oval 12.3-18.6 150-360
Kenaf 2-11 13-33 Cylindrical
200-400
Ramie 60-250 16-120 Hexagonal-Oval 6.2-32.4 10-180
Sunn 2-11 13-64 Irregular 13.6-24.6 108-216
Nettle 4-70 20-70
50-50

Leaf Fibers
Abaca 2-12 6-40 Oval-Round 14-20 150-360 0.01-0.28
Cantala


13.8-16.4

Caroa 2-10 3-13
3.2-8.2

Henequen 1.5-4 8.3-33.2
11.6-22.2

Istle
9.6-16
1.2-13.4 30-75
Mauritius 1.3-6 15-32 Cylindrical
124-210
Phormium 2-11 5-25 Round 10-3-12.5 150-240
Sansevieria 1-7 13-40



Sisal 0.8-7.5 8-48 Cylindrical 11-16 60-120 0.1-0.5
Seed-hair Fibers
Coir 0.2-1 6.24


1
Cotton 10-50 12-25 Circular Elliptical
1.5-5.6 0.012-0.025
Kapok 15-30 10-30 Round
1.5-3 0.03-0.036
Other Fibers
Broom Root

Others
25-40

Mechanical Properties of Vegetable Fibers

Fiber Fineness km/kg Tensile Strength, km Elongation % Modulus of Elasticity, N/tex Modulus of repture, mN/tex
Bast (soft) fibers
Flax 2470 2-3 18-20 8-9
Hemp 139 38-62 1-6 18-22 6-9
Jute 489 25-53 1.5 17-18 2.7-3
Kenaf 180 24 2.7
Ramie 32-67 4.0 14-16 11
Urena 342 16 1.9
Leaf (hard) fibers
Abaca 32 32-69 2-4.5 6
Cantala 58 30
Henequen 32 20-42 3.5-5
Istle 34 22-27 4.8
Phormium 38 26
Sansevieria 118 43 4.0
Sisal 40 36-45 2-3 25-26 7-8
Seed-har fibers
Coir 18 16 4.3 16
Kapok 16-30 1.2 13 10

To convert N/tex to gf/den, multiply by 11.33. For conversion table, go here.

Textile-Associated Properties of Bast Fibers Compared to Polyester

Property Cotton Flax Hemp Jute Ramie Polyester
Density g/cm 1.54-1.50 1.50 1.48 1.50 1.51 1.22-1.35
Moisture regain, % 8-11 12 12 13.7 6 0.4-0.8
Fiber tenacity, mN/tex 260-440 230-240 510-600 260-510 450-653 180-790
Elongation, dry, % 3-10 2.7-3.3 1.6 1.2-1.9 3.0-7.0 18-67
Recovery from 2% Elongation, % 75 65 74 52 85-97
Length/width ration 1400 1200 3000

To convert N/tex to gf/den, multiply by 11.33. For conversion table, go here.