ABSTRACT
Synthesis and application of squarylium dyes has been undertaken in order to
characterise the synthesised dyes by different spectrometric techniques, (FT-IR, UVvisible
and GC–MS), and to study their fastness properties, such as wash, light,
perspiration, and hot pressing, on nylon 6 and polyester fabrics. Also, effects of time,
temperature, carrier concentration and pH was investigated on polyester and nylon 6
fabrics. The dyed fabrics were generally found to show good (4) to very good wash (5),
light fastness of (5) and (6), perspiration (4) and (5), hot pressing (4) and (5) on nylon 6
and good to very good on polyester fabric respectively. The dye-bath exhaustion was
found to be between 76 % and 92 % on nylon 6 and 57 % and 85 % on polyester
respectively. The percentage exhaustion on nylon 6 was found to be very good to
excellent and but on polyester it was found to be good to very good. It can be concluded
that squarylium dyes can be applied to nylon 6 and polyester fabrics, but better
performance was found on nylon 6 than polyester fabric due to the amorphous nature of
nylon 6 compared to polyester.
TABLE OF CONTENTS
Title Page- – – – – – – – – – i
Declaration- – – – – – – – – – ii
Certification- – – – – – – – – – iii
Dedication- – – – – – – – – – iv
Acknowledgements – – – – – – – v
Abstract- – – – – – – – – – vi
Table of Contents- – – – – – – – – vii
List of Figures – – – – – – – – – xii
List of Tables – – – – – – – – – xiv
List of Plates – – – – – – – – – xv
CHAPTER ONE
1.0 Introduction – – – – – – – – 1
1.1 classification of dyes according to use – – – – 2
1.1.2 Group 1 dyes – – – – – – – 2
1.1.3 Group 2 dyes – – – – – – – – 3
1.1.4 Dyeing machine – – – – – – 5
1.1.5 Factors that affect the choice of the dyestuff – – – – 6
1.2 Statement of the Research Problem – – – – – 6
1.3 Justification of the Study – – – – – – – 6
1.4 Aim and Objectives of the Research – – – – – 7
1.4.1 Aim – – – – – – – – – – 7
1.4.2 Objectives – – – – – – – – – 7
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CHAPTER TWO
2.0 Literature Review – – – – – – – – 8
2.1. 1 Squarylium Dyes – – – – – – – – 8
2.1. 2 Symmetrical Squarylium Dyes – – – – – – 10
2.1. 3 Unsymmetrical Squarylium Dyes – – – – – – 10
2.2 Application of Squarylium Dyes – – – – – – 11
2.2.1 Environmental application of squarylium dyes for detection of heavy metals – 11
2.2.2 Use of squarylium dyes in optical data recording – – – – 13
2.2.3 Molecular sensor and bioimaging application of squarylium dye- – 14
2.2.4 Xerographic application of squarylium dyes – – – – 15
2.2.5 Biological application of squarylium dyes – – – – – 16
2.3 Fibre Structure In Relation To Dyeing – – – – – 17
2.3.1 Polyester – – – – – – – – – 17
2.3.2 Properties of Polyester – – – – – – – 18
2.3.3 Uses of Polyester – – – – – – – – 19
2.3.4 Nylon 6 – – – – – – – – – 19
2.3.5 Properties of Nylon 6 – – – – – – – 20
2.3.6 Application of Nylon 6 – – – – – – – 20
CHAPTER THREE
3.0 Materials and Methods – – – – – – – 21
3.1 Materials – – – – – – – – – 21
3.2 Apparatus and Equipment – – – – – – 21
3.3 Synthesis of Squaric Acid – – – – – – 21
3.4 General Procedure for preparation of Squarylium Dyes – – 22
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3.5.1 Synthesis of Dye A – – – – – – – – 24
3.5.2 Synthesis of Dye B – – – – – – – – 24
3.5.3 Synthesis of Dye C – – – – – – – – 24
3.5.4 Synthesis of Dye D – – – – – – – – 24
3.5.5 Synthesis of Dye E – – – – – – – – 24
3.5.6 Synthesis of Dye F – – – – – – – – 25
3.5.7 Synthesis of Dye G – – – – – – – – 25
3.5.8 Synthesis of Dye H – – – – – – – – 25
3.5.9 Synthesis of Dye I – – – – – – – – 25
3.6 Purification of Dyes – – – – – – – 25
3.7 Determination of Melting Point of the Dyes – – – – 25
3.8 Percentage Yield of Dye – – – – – – – 26
3.9 Infra – Red Spectra of the Dyes – – – – – – 26
3.10 Visible Absorption Measurement – – – – – – 26
3.11 Gas Chromatography-Mass Spectroscopy (GC- MS) of Synthesised Dyes – 27
3.12 Determination of Molar Extinction Coefficient – – – – 27
3.13 Application of Dyes to Substrates – – – – – – 27
3.13.1 Scouring – – – – – – – – – 28
3.13.2 Dyeing of polyester fabric – – – – – – – 28
3.14 Dyeing of nylon 6 fabric – – – – – – – 28
3.14.1 Effect of time on dyeing – – – – – – – 29
3.14.2 Effect of temperature on dyeing – – – – – – 29
3.14.3 Effect of pH on dyeing – – – – – – – 29
3.14.4 Effect of carrier concentration on dyeing – – – – – 29
3.14.5 Reduction clearing – – – – – – – – 30
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3.15 Determination of Dye Exhaustion – – – – – – 30
3.16 Wash Fastness Test – – – – – – – – 30
3.17 Assessment of Change in Colour – – – – – – 31
3.18 Assessment of Staining – – – – – – – 31
3.19 Perspiration Fastness Test – – – – – – – 31
3.19.1 Alkaline solution – – – – – – – – 31
3.19.2 Acidic solution- – – – – – – – 32
3.19.3 Procedure for perspiration test – – – – – – 32
3.20 Light Fastness Test – – – – – – – – 32
3.21 Determination of Fastness to Hot Pressing – – – – 33
3.21.1 Dry – – – – – – – – – – 33
3.21.2 Damp – – – – – – – – – 33
3.21.3 Wet – – – – – – – – – – 33
CHAPTER FOUR
4.0 Results – – – – – – – – – 34
4.1 Synthesised squaric acid and squarylium Dyes – – – 34
4.2 Physical Properties of Synthesised Dyes – – – – 35
4.3 Visible Absorption – – – – – – – – 37
4.4 Infra-Red Spectra of the Synthesised Dyes – – – – 38
4.5 Dye Application – – – – – – – – 40
4.6 Wash Fastness – – – – – – – – 43
CHAPTER FIVE
5.0 Discussion – – – – – – – – – 47
5.1 Physical Characteristics of the Synthesised Dyes – – – 47
xi
5.2 Infra-Red Analysis of the Synthesised Dyes – – – – 47
5.3 Mass Spectroscope of the Synthesised Dyes – – — – 48
5.4 Solvatochromism – – – – – – – – 49
5.5 Molar Extinction Coefficient (ε) – – – – 50
5.6 Dye Exhaustion on Nylon 6 and Polyester – – – – 50
5.7 Effect of pH – – – – – – – – – 52
5.8 Effect of Time – – – – – – – – 52
5.9 Effect of Carrier Concentration – – – – – – 53
5.10 Effect of Temperature – – – – – – – 53
5.11 Wash Fastness – – – – – – – – 55
5.12 Light Fastness – – – – – – – – 56
5.13 Perspiration Fastness Results – – – – – – 56
5.14 Fastness to Hot Pressing – – – – – – – 57
CHAPTER SIX
6.0 Summary, Conclusions and Recommendations – – – – 58
6.1 Summary – – – – – – – – – 58
6.2 Conclusions – – – – – – – – – 58
6.3 Recommendations – – – – – – – – 60
6.4 Contribution to Knowledge – – – – – – 60
REFERENCES – – – – – – – – 62
APPENDICES – – – – – – – – 66
CHAPTER ONE
1.0 INTRODUCTION
Dye is a chemical substance which is coloured and has the ability to impart its
colour onto a substrate from an aqueous dispersion or solution. The substrate may be a
textile fibre/fabric, leather, hair, food or cosmetics. In some cases, materials to be dyed
possess affinity for the dye and easily absorb the dye from their solution or aqueous
dispersion. Dyes and pigments owe their colour to their ability to selectively absorb
light within the visible region of the electromagnetic spectrum i.e., 400-700nm. This
ability of a dye/pigment to absorb light of these wavelength ranges derives from
electronic transitions between different molecular orbitals in the dye molecule and the
wavelengths absorbed depend on the energy difference between the orbitals (Wysecki
and Stiles, 1967).
Colour absorbs light in a characteristic way and the unabsorbed light, called the
complementary colour, is always reflected. Therefore, as dye/pigment which absorbs
light within the blue range (435-480 nm) is seen in day light as yellow, which is the
complementary colour of that absorbed (Wysecki and Stiles, 1967).
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Table 1: Relation of complementary colour observed to wavelength of light absorbed
(Griffiths, 1976)
Colour Absorbed Wavelength Absorbed (nm) Colour Seen
Violet
Blue
Greenish-blue
Bluish-green
Green
Yellow-green
Yellow
Orange
Red
Red + violet
400-435
435-480
480-490
490-500
500-560
560-580
580-595
595-605
605-750
400-435
Yellow-green
Yellow
Orange
Red
Purple
Violet
Blue
Green-blue
Blue-green
Green
Since no single wavelength of light correspond to purple colour, a mixture of red and
violet must be removed from white to obtain the visual effect of green. So all green
dyes will have two absorption peaks, in the region 650 nm and 420 nm.
1.1 Classification of dyes according to use
Textiles dyes are classified by the dyer according to their method of application to
textiles fibres, but the chemist uses a different method of classification based on their
chemical constitution. To emphasise certain common features of a particular importance
in relation to general dyeing behaviour and the wet-fastness of the dyeing, the different
application classes of dyes can be treated under groups 1 and 2 (Nkeonye ,1987).
1.1.1 Group 1 dyes
This comprises the following
i. Acid and metal – complex acids dyes (anionic) for wool, nylon.
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ii. Basic ( or cationic) dyes for acrylics
Disperse dyes (non –ionic) for cellulose acetate and synthetic – polymer fibres. All the
classes of dye in this group are soluble in water, although disperse dyes are only
sparingly soluble.The are absorbed by the fibre from aqueous solution by a reversible
process, with two important consequences.
a) An unlevel dyeing can be made more uniform by extending the dyeing time, and
b) Dye can be desorbed from the dyed material during wet processing subsequent
to dyeing and during washing – off, etc. This means that dyeings of maximum
fasteness to wet treatment cannot be achieved with the classes of dye in group 1.
1.1.2 Group 2 dyes
The group 2 dyes can be further divided into four classes A- D
A) These are dyes which are present in the fibre in the form of large water- insoluble
particles.dyeing of high fasteness to wet treatment is obtained with these dyes. In
this class are the following dyes type
1) Vat dyes .This sub- group include the water- insoluble vat dyes and the
solubilised vat dyes
2) Sulphur dyes. Include in this group are conventional sulpur dyes, leuco
sulphur dyes, solubilised sulphur dyes and condense sulhur dyes.
3) Azoic dyes. The application of these dyes is based upon the synthesis of a
water- insoluble azo compound inside the fibre.
4) Ingrain dyes. This is a small group of dyes, almost all of them based on
phthalocyanines, which form insoluble colorants inside the fibre under the
prescribed application conditions
4
5) Oxidation dyes. This is the name given to small group of dyes which yield
insoluble colorants inside the fibre on chemical oxidation. All the dyes under
class A are applied mainly to cellulosic fibres, especially cotton
B) Reactive dyes.
These dyes derive their names from their ability to undergo a chemical reaction
with the fibre, being subsequently attached to it by a covalent linkage. In
consequence, they give dyeing of high fasteness to wet treatments. Reactive dyes
are applied to cellulose and to polyamide fibres
C) Mordant (chrome) dyes.
Dyes in this class are applied to fibre in conjunction with a metal salt, which
serves as the―mordant‖ .the dye – metal complex, which forms inside the fibre,
exhibits greater fasteness than the original unmetallised dye. They are of
importance in wool dyeing
D) Pigments
These are water – insoluble colorants which can be introduce into the fibre during
manufacture by mixing them with the fibre- forming substance prior to extrusion
to form the filaments. This coloration method is called ―mass- pigmentation‖ or
―mass- coloration‖ and is only possible with the man – made fibres. Textile can
also coloured with pigments with the aid of a resin (binder), which polymerises
during baking to form a transparent film around the fibres in which the coloured
pigment particles are embedded.both natural and man-made fibres can be coloured
by this technique, to give dyeing of very high fasteness to wet treatments.
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1.1.3 Dyeing machines
Textiles materials may be dyed in various forms, the most common being loose
stock, yarn and fabric. The form in which a textile is dyed is determined by a
number of factors. Thus fibres likely to show dyeing variations from batch to
batch, e g wool, may be dyed as loose stock and sub- sequentely spun into
yarns. Yarns may also be required to be dyed for special purposes eg weaving
on jacquard or carpet looms. Fabric dyeing is the most widely practiced, due to
their versatility to customer demands and to changes in fashion. Different forms
of textile require different machines in order to achieve the best results. In a
dyeing machine, dye liquor must pass continuously over the surface of the
fibres being dyed, and the necessary movement is achieved in either of three
ways
I. By circulating the liquor through the stationary material
II. By moving the material through the liquor
III. By moving both the material and the liquor
In machine were the liquor is circulated, the rate of flow should be high as
possible without demage to the material being dyed, as the rate of dyeing is
higher at high speeds of liquor circulation.other important features of a dyeing
machine, in addition to pump or propeller, include a heating device ( steam
heating is most common) a temperature control device ( manual or automatic)
,water-inlet and outlet valves and a dye storage tanks.
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1.1.4 Factors that affect the choices of the dyestuffs
1. Cheap
2. Non- toxic
3. Compatible to other dyes and chemicals
4. High color strength
5. Better bridgtness
6. Better fastness
7. Good levelness on the materials
1.2 Statement of the Research Problem
The application of squarylium dyes onto substrates is very difficult because of reduced
solubility and crystalline nature of the dyes. An attempt to apply the synthesised dyes
on textile substrates was undertaken in the present study.
1.3 Justification
Although several works have been done on squarylium dyes, as infra-red dyes, little
work has been done on the application of squarylium dyes on textile substrates. This
study is an attempt to study the application conditions for the squarylium dyes on
polyester and nylon 6 fabrics.
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1.4 Aim and Objectives of the Research
1.4.1 Aim
The aim of this work is to synthesize squarylium dyes derived from squaric acid (3-4-
dihydroxycyclo but-3-en-1- 2-dione), and study their application on polyester and nylon
6 fabrics.
1.4.2 Objectives
The specific objectives of this research include:
i. To synthesise squarylium dyes from squaric acid (3-4-dihydroxycyclobut-3-en-
1- 2-dione)
ii. To characterize the dyes using FTIR, UV-spectrophotometer and GC-MS
iii. To investigate the application of the synthesised dyes on polyester and nylon 6
by varying time, pH, temperature and carrier concentrations.
iv. To determine the % exhaustion of the dyes
v. To determine the fastness properties of the dyed fabrics.
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