The utility of fibers are broadly categorized into 2 different uses- one is Apparel or Domestic use and the other is Industrial use. In order to be used in each of these each of these categories, the fiber has to meet some specific requirements. They are:
Apparel/Domestic Requirements
Tenacity: 3 – 5-gram denier
Elongation at break: 10 – 35%
Recovery from elongation: 100% at strains up to 5%
Modulus of elasticity: 30 – 60-gram denier
Moisture absorbency: 2 – 5%
Zero strength temperature (excessive creep and softening point):
above 215°C
High abrasion resistance (varies with type fabric structure)
Dye-able
Low flammability
Insoluble with low swelling in water, in moderately strong acids
and bases and conventional organic solvents at room temperature
to 100°c
Ease of care
Industrial Requirements
Tenacity: 7 – 8 grad denier
Elongation at break: 8 – 15%
Modulus of elasticity: 80 grad denier or more conditioned, 50 grad denier wet
Zero strength temperature: 250° C or above
Basic Textile Fiber Properties
There are several primary properties necessary for a polymeric material to make an adequate fiber. Certain other fiber properties increase its value and desirability in its intended end-use but are not necessary properties essential to make a fiber. Such secondary properties include moisture absorption characteristics, fiber resiliency, abrasion resistance, density, luster, chemical resistance, thermal characteristics, and flammability.
Some Primary Properties of Textile Fibers are:
Fiber length to width ratio,
Fiber uniformity,
Fiber strength and flexibility,
Fiber extensibility and elasticity, and
Fiber cohesiveness.
How heat affects Textile Fiber’s properties
Examples of Fiber Shapes
Heat helps the fiber /fabric to gain certain special qualities at certain times and are also harmful at other times. But under special guidance, heat helps fiber acquire the following characteristics
Softening, melting, or decomposition temperatures
The tendency of the fiber and fabric to shrink when heat-relaxed, or stretch when heated and under tension
The ability of the fabric to heat set
The ability of the fabric to function properly at elevated temperatures at one time or repeated use
The ability of the fabric to function properly at room temperature (or some other lower temperature) after exposure at high temperature for a given period of time
Thermal Properties of Common Fibers
Fiber
Melting Point
Softening Sticking Point
Safe Ironing Temperature
°F
°C
°F
°C
°F
°C
Natural Fibers
Cotton
Nonmelting
425
218
Flax
Nonmelting
450
232
Silk
Nonmelting
300
149
Wool
Nonmelting
300
149
Manmade Fibers
Acetate
446
230
364
184
350
177
Arnel Triacetate
575
302
482
250
464
240
Acrylic
400-490
204-254
300-350
149-176
Aramid
Does not melt, carbonizes above 800F
Glass
1400-3033
Modacrylic
410
210
300
149
200-250
93-121
Novoloid
Nonmelting
Nylon6
414
212
340
171
300
149
Nylon66
482
250
445
229
350
177
Olefin
275
135
260
127
150
66
Polyester PET
480
249
460
238
325
163
Polyester PCDT
550
311
490
254
350
177
Rayon
Nonmelting
375
191
Saran
350
177
300
149
Do not iron
Spandex
446
230
347
175
300
149
Vinyon
285
140
200
93
Do not iron
Density and Moisture Regain of Fibers
Fiber
Density (g/cc)
Moisture Regain
Density: Ratio of weight of a given volume of fiber to an equal volume of water.
Natural Fibers
Cotton
1.52
7-11
Flax
1.52
12
Silk
1.25
11
Wool
1.32
13-18
Man-made Fibers
Acetate
1.32
6.0
Arnel Triacrylic
–
3.2
Acrylic
1.17-1.18
1.3-2.5
Aramid
1.38-1.44
4.5
Fluorocarbon
2.20
0
Glass
2.49-2.73
0-0.3
Modacrylic
1.30-1.37
0.4-4.0
Nylon
1.14
4.0-4.5
Nylon Qiana
1.03
2.5
Olefin
0.91
0.01-0.1
Polyester
1.22/1.38
0.4-0.8
Rayon
1.50-1.52
15
Rayon HWM
–
11.5-13
Spandex
1.20-1.22
0.75-1.3
The chemical composition of some common fibers
Type of fiber
Cellulose
Lignin
Pentosan
Ash
Seed flax
43-47
21-23
24-26
5
Kenaf (Bast)
44-57
15-19
22-23
2-5
Jute (Bast)
45-63
21-26
18-21
0.5-2
Hemp
57-77
9-13
14-17
0.8
Ramie
87-91
–
5-8
–
Kenaf (Core)
37-49
15-21
18-24
0.8
Jute (Core)
41-48
21-24
18-22
–
Abaca
56-63
7-9
15-17
1-3
Sisal
43-62
7-9
21-24
0.6-1
Cotton
85-96
0.7-1.6
1-3
0.8-2
The diameter of Natural and Meltblown Fibers
Material
Diameter Mean Value (microns)
Coeff Variation(%)
Spider silk
3.57
14.8
B. mori Silk
12.90
24.8
Merino Wool
25.50
25.6
Polyester
13.30
2.4
Nylon 6 Filament
16.20
3.1
Kevlar 29
13.80
6.1
Effects of Acids on Common Fibers – Comparison
Fiber
Effects of Acids
Acrylic
Resistant to most acids
Modacrylic
Resistant to most acids
Polyester
Resistant to most mineral acids disintegrated by 96% sulphuric
Rayon
Disintegrates in hot dilute and cold concentrated acids
Acetate
Soluble in acetic acid, decomposed by strong acids
Triacetate
Similar to acetate
Nylon 66
Decomposed by strong mineral acids, resistant to weak acids
Olefin
Very resistant
Glass
Resists most acids. Etched by hydrofluoric acid and hot phosphoric acid
Cotton
Similar to rayon
Wool
Destroyed by hot sulfuric, otherwise unaffected by acids
Effects of Alkalies on Common Fibers – Comparison
Fiber
Effects of Alkalies
Acrylic
Destroyed by strong alkalies at a boil, resists weak alkalies
Modacrylic
Resistant to alkalies
Polyester
Resistant to cold alkalies, slowly decomposed at a boil by strong alkalies
Rayon
No effect by cold, weak alkalies, swells and loses strength in concentrated alkalies
Acetate
Saponified, little effect from cold weak alkalies
Triacetate
Not effected up to pH 9.8,205′ F; better than acetate
Nylon 66
Little or no effect
Olefin
Very resistant
Glass
Attacked by hot weak alkalies and concentrated alkalies
Cotton
Swells when treated with caustic soda but is not damaged
Wool
Attacked by weak alkalies, destroyed by strong alkalies
Effects of Organic Solvents on Common Fibers – Comparison
Fiber
Effects of Organic Solvents
Acrylic
Unaffected
Modacrylic
Soluble in warm acetone, otherwise unaffected
Polyester
Soluble in some phenolic compounds, otherwise unaffected
Rayon
Unaffected
Acetate
Soluble in acetone, dissolved or swollen by many others
Triacetate
Soluble in acetone, chloroform and swollen by others
Nylon 66
Generally unaffected, soluble in some phenolic compounds
Olefin
Soluble in chlorinated hydrocarbons above 160′
Glass
Unaffected
Cotton
Resistant
Wool
Generally resistant
Effects of Sunlight on Common Fibers – Comparison
Fiber
Effects of Sunlight
Acrylic
Little or no effect
Modacrylic
Highly resistant, some loss of strength and discoloration after constant exposure
Polyester
Some loss of strength, no discoloration, very resistant
behind glass
Rayon
Generally resistant loses strength after long exposure
Acetate
Approximately same as rayon
Triacetate
Resistant loses strength after long exposure
Nylon 66
No discoloration, strength loss after long exposure
Olefin
Very resistant retains 95% strength after 6 months exposure
Thanks for share such a great article about
fibersrworld.blogspot.com
fiber