Swelling Properties of Textile Fiber

1. GREEN UNIVERSITY OF BANGLADESH
Department Of Textile
ASSIGNMENT
Remarks:
Course Code : TE 306
Course Title : Textile Physics II
Submitted By:
Name : Md Rakibul Hassan
ID : 183014057
Section : E1
Department : Textile
Date Of Submission : 17 September
Assignment On : Swelling Properties of Textile Fiber
Submitted to:
Name : Mr. Md Ashraful Alam
Designation : Lecturer
Department : Textile

2. Swelling Properties of Textile Fiber
Introduction:
When fibres absorb water, they change in dimensions, swelling transversely and axially. This has
technical consequences in the dimensional stability of fabrics, the predominant transverse swelling
usually resulting in a shrinkage of twisted or interlaced structures. It also means that the pores of
closely woven fabrics will be completely blocked when the fibres are swollen, and they may then be
impermeable to water. This principle is utilised in hosepipe materials and the Ventile fabrics, which
were developed in the 1940s for showerproof garments. Swelling is also an important factor in
crêpeing, due to the increased twist angle in a swollen yarn, and in drying and dyeing. Swelling is
akin to solution in that there is an interchange of position between fibre molecules and water
molecules, but in swelling this occurs only to a limited extent, whereas in solution it continues until
there is a uniform mixture of the two substances.
Swelling =
Swellen Diemension−Dry DimenSion
Dry Dimension
× 100%
Significance of Swelling:
The predominant width-wise (transverse) swelling results in a shrinkage of twisted or interlaced
structure.
The closely woven fabrics will be completely blocked when the fabrics are swollen, and they may be
impermeable to water. Thus this property of fiber is used to make water proof fabric.
It is also an important factor in crepeing due to increased twist angle in swollen yarn, and in drying
and dyeing.
Swelling Phenomenon of Textile Fibres:
The molecular chains are laying roughly parallel to the fibre axis, as a result fibre has lower space
between the adjacent chains and swelling will be lower. When the fibres are immersed into water, the
water molecules enter into the fibre and occupy the molecular space of fibre and thus push the fibre
chains. As a result, there will be a considerable increase in diameter of the fibre but very little
increases in length.

3. Types of Swelling:
1. Transverse Diameter Swelling
2. Transverse Area Swelling
3. Axial Swelling
4. Volume Swelling
1. Transverse Diameter Swelling:
The fractional increase in diameter of a fibre after swelling is known as transverse diameter swelling.
Transverse diameter swelling of a fibre is denoted by SD.
So, SD= ΔD/D
Where, ΔD= increase diameter of fibre
D= original diameter of fibre.
2. Transverse Area Swelling:
The fractional increase in area of a fibre after swelling is known as transverse area swelling.
Transverse area swelling of a fibre is denoted by SA.
So, SA= ΔA/A
where ΔA= increase area of fibre
A= original area of fibre
3. Axial Swelling:
The fractional increase in length of a fibre after swelling is known as axial swelling. Axial swelling
of a fibre is denoted by SL.
So, SL= ΔL/L,
where ΔL= increase length of fibre
L= original length of fibre
4. Volume Swelling:
The fractional increase in volume of a fibre after swelling is known as volume swelling. Volume
swelling of a fibre is denoted by SV.
So, SV= ΔV/V,
where ΔV= increase volume of fibre
V= original volume of fibre
Relationship between SA & SD:
We know that,
Transverse area swelling, SA = ∆A / A

4. Transverse dia. swelling, SD = ∆D / D
For a circular fiber, area A = (π/4) D2
For a swollen fiber, we get, A+∆A = (π/4) (D+∆D)2
= (π/4) (D2 + 2D. ∆D + ∆D2)
Now, SA = ∆A / A
= (A+∆A-A) / A
= {(π/4) (D2 + 2D. ∆D + ∆D2) - (π/4) D2}/ (π/4) D2
= (π/4) (D2 + 2D. ∆D + ∆D2 - D2) / (π/4) D2
= (2D. ∆D + ∆D2) / D2
= (2D. ∆D / D2) + (∆D2/ D2)
= 2(∆D / D) + (∆D2/ D2)
= 2 SD + SD2
So, SA = 2 SD + SD2.
Relationship between SA, SV and SL:
We know that,
Transverse area swelling, SA = ∆A / A
Volume swelling, SV = ∆V / V
Axial swelling, SL = ∆L / L
For a circular fiber, volume, V=AL
For a swollen fiber, we get, V +∆V = (A +∆A) (L +∆L)
= AL + A∆L + ∆AL + ∆A ∆L
Now, SV = ∆V / V
= (V+ ∆V - V) / V
= (AL + A∆L + ∆AL + ∆A ∆L - AL)/AL
= ∆L / L+ ∆A/ A + ∆A/ A. ∆L / L
= SL + SA + SL. SA
So, SV = SL + SA + SL. SA.
Fiber Density And Its Measurement:
Fiber density is defined as the ratio of fiber mass (m) to fiber volume (V).
ρ=m/v

5. The measurement of fiber mass can be readily obtained by a suitable weighing balance. The task of
measuring fiber volume for a given mass by a classical method of displacement of liquid in a
measuring cylinder is complicated because of entrapped air and the absorption characteristics of
textile fibers.
Level after fiber
added
Initial
level
Fibers
Fig: Fiber Measurement by Displacement of Liquid
Swelling of Fiber in Water:
Transverse swelling (% ) .
Diameter Area
Axial
Swelling
(%)
Volume
Swelling
(%)
Cotton 20, 23, 7
15
40, 47, 21
1.2
Cotton (mercerized) 17 46, 24 0.1
Sisa 39.5
Abaca 42.2
Jute 20, 21 40 0.37 44.3
Sunn 45.4
Flax 47 0.1, 0.2 29.5
Flax (raw) 65
Ramie 32.0
Importance of Swelling:
 Improve the absorption capability of dyes and chemicals.
 It has technical consequences in the dimensional stability of the fabric, the predominant
transverse swelling measurement.
 Due to swelling the pores of interlaced structure will be blocked, this idea is used to produced
shower proof fabric.
 Improve fastness of dyed materials.
 Elastic properties changed.
 Static Electricity is reduced.
Liquid

6. Rates of Swelling Depends on:
 Size and form of the sample, such as - fiber, yarn, fabric etc.
 Composition of the material, such as - cotton, polyester, acrylic, nylon etc.
 External condition, i.e. Temperature.
 Chemical content, i.e. oil, wax and other impurities.
Reason Behind Swelling of Textile:
We know, a fibre is consisted of polymer chains. This chains are arranged differently in different
regions. The region having parallel arrangement of chains are called Crystalline region and
disoriented region is called amorphous region.
This polymer chains have empty spaces among them, known as the ‘molecular space’. When a fibre
is immersed into water, water molecules enter into these spaces and pushes the fiber chains. As a
result, Swelling occures.
Water Penetration During Swelling
More Orientation Means Less Swelling and Vice-Versa
In a highly oriented fiber, the moleculear chains are lying parallel to the fiber axis. Which results in
low molecular space, so swelling will be lower
For the same reason, less oriented fibre has high swelling, because they have high molecular space
for water molecules to enter!
That’s why Viscose swelling is greater than Nylon swelling, cause Nylon is much more oriented than
Viscose.
Factors Influencing Swelling Properties Of Textile Fibres:
1. Composition of the material (such as cotton, polyester, acrylic, nylon etc.)
2. Size and form of the sample (such as fiber, yarn, fabric etc.)
3. External condition (temperature, humidity)
4. Chemical content (such as oil, wax and other impurities)
Effects Of Swelling On Textile Fibres:
1. Swelling improves the absorption of dyes and chemicals in fibre.
2. Due to swelling the pores of closely interlaced woven fabric will be completely blocked and
thus it may act as water proof fabric.
3. Swelling changes the dimensional stability of fabric.
4. Swelling changes the electric and tensile properties of fibre.
5. Swelling minimizes static charge formation.

7. Swelling (%) of Different Fibers:
Fiber
Transverse Dia.
Swelling(%)
(SD)
Transverse area
Swelling(%)
(SA)
Axial
Swelling(%)
(SL)
Volume
Swelling(%)
(SV)
Cotton 20 40 - -
Flax 20 47 0.1 -
Jute 20 40 - -
Viscose
Rayon
35 67 3.7 119
Wool 14.8 25 - 37
Silk 16.5 19 1.6 30
Nylon 1.9 1.6 2.7 8.1
Conclusion:
Swelling is the dimensional changes that take place due to the absorption of water or moisture by
any fibre.it has huge significance on numerous properties. Swelling occurs in transverse direction
(width wise) and axial direction (length wise). It can be expressed in terms of increase in diameter,
length. The swelling of textile materials, One of the most important properties of textiles is their
ability to absorb various chemical reagents.
---The End---
Submitted by
Md Rakibul Hassan
Id: 183014057
Reference-
1.Sheet (Swelling properties) which was given to us
2.https://diutestudents.blogspot.com/2017/01/swelling-properties-of-textile-fibres.html
3. https://textilestudycenter.com/swelling-of-fibre-and-types-of-swelling/
4. https://textilelearner.blogspot.com/2016/06/swelling-of-textile-fibers.html