RJTA Vol. 10 No. 1 2006
Cationization of Linen Fabric:
Studying the Process Parameters
1
A. Hebeish1, M. Hashem1, M. EL-Hosamy2 and S. Abass2
Textile Division, National Research Centre, Dokki, Cairo, Egypt
2
Faculty of Applied Arts, Helwan University, Cairo, Egypt
ABSTRACT
Mill scoured and bleached linen fabrics were cationized using Quat-188. Cationization was carried
out as per the exhaustion or the cold pad-batch technique under a variety of conditions. Factors
affecting the cationization reaction of linen fabric were studied. These factors include Quat-188
concentration, NaOH concentration (or pH of the reaction medium in case of exhaustion method),
reaction time and temperature as well as material to liquor ratio (in case of exhaustion method). The
cationized samples were monitored for nitrogen content, and the reaction efficiency calculated
thereof, as well as for K/S of the no-salt dyed samples. Results obtained indicate that the efficiency
of cationization of linen fabric with Quat-188 depends on the type of application technique and the
conditions used in each technique. Using the exhaustion technique, maximum reaction efficiency
between Quat-188 and linen fabric was achieved at Quat-188, 80 g/1 and pH, 13 and 70°C for 60
minutes using material to liquor ratio, 1:20. Lower material to liquor ratio was not practically
possible. The results also depict that any deviation from these conditions, for example, higher pH,
temperature or material to liquor ratio, leads to an increase in the hydrolysis of Quat-188 molecules
and hence, lower reaction efficiency. With the cold pad-batch technique, maximum reaction
efficiency was achieved when the linen fabric was padded in a solution containing NaOH, 50 g/1
and Quat-188, 125 g/1, then squeezed to a wet pickup of 100% and batched for 15 hours. Results
obtained also signify that both dry and wet wrinkle recovery angles increase as the degree of
cationization (expressed as N % of cationized linen fabric) increases. Moreover, the tensile strength
of cationized linen fabric is higher than that of uncationized linen and such an increase depends on
the degree of cationization.
Keywords: Cationization, Cellulose, Linen, No-salt dyeing
1.
Several studies (Chlagan et al. 2000; Evans et al.
1984; Blanchard et al. 1999; Hall et al. USP 1994;
Rollins et al. 1996; Wong and D. Lewis, 2002; Cai et
al. 1999, Yossef et al. 1998; Sekar, 1999) have been
done to explore the optimum reaction conditions for
the preparation of cationization cotton fabric using 3chloro-2-hydroxypropyl
trimethyl
ammonium
chloride (Quat-188). The reaction conditions were
examined either by the exhaustion method at high
temperature or by the cold pad-batch method.
The reaction mechanism as well as reaction
efficiency have been recently studied (Hashem et al.
(1) 2003). Desirable properties are imparted to
cellulosic textile fabrics when treated with Quat-188;
rendering them cationic in nature. The quaternary
ammonium group -⊕N(CH3) 4 has a very high positive
charge and can thereby lead to the formation of ionic
bonds (salt linkages) with negatively charged anionic
groups, such as those found in a wide array of anionic
Introduction
The favorable properties of linen fabric, including
comfort, hygiene and elegance, make it unique in the
manufacturing of high quality apparel, furnishings,
tableware and handkerchiefs. Although all cellulosic
fibers are of identical chemical composition, flax
fiber in linen fabric has different molecular and
morphological structure which will largely determine
the course of modification. For instance, flax fiber
has higher crystallinity and smaller pitch of the spiral
structure compared with that of cotton. This leads to
higher bending stiffness and processing difficulty.
Therefore, not all modifications carried out on cotton
fabric can be directly applied to linen fabric.
Accordingly, the development of fiber modification
and finishing treatments for linen fabric by
environmentally friendly processes has become the
highest priority.
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RJTA Vol. 10 No. 1 2006
sodium hydroxide, 10 g/1 sodium hydrosulphite, 5
g/1 Egyptol® (non-ionic wetting agent) were added
and the temperature was raised to 95 °C for 30mm.
The sample was then washed several times with
boiling water, then with cold water. The scoured
fabric was bleached in the same Jigger machine under
the following conditions: H2O2, 10 g/1; sodium
silicate, 4. g/1; NaOH, 3 g/1; Egyptol®, 2 g/1;
organic stabilizer, 2 g/1; MgSO4, 2 g/1; at 95°C for
45 minutes. The fabric was washed several times
with boiling water and then cold water, followed by
squeezing and drying.
dye classes or carboxyl containing compounds. The
former imparts no salt dyeing properties for cotton
fabric (Hauser and Tabba, 2002, 2001; Hauser, 2000;
Draper et-al. 2002; Harper and Stone, 1986; Lewis
and Lei, 1989; Wu and Chen, 1993; Evans et al.
1984), whereas the latter imparts ionic crosslinking
for cotton fabric and rendering it wrinkle recovery
(Hashem et al. (2) 2003). Moreover, the presence of
cationized groups in the cellulose imparts
antimicrobial properties to the fabric (Seong and Ko,
1998).
However to the author's knowledge, no work has yet
been published on cationization of linen fabric. This,
indeed, stimulates the present work which was
undertaken with a view to studying factors affecting
cationization of linen fabric using "Quat-188" along
with the examination of the physico-chemical
properties and dyeability of the cationized fabric
brought about thereof.
2.
Experimental
2.1
Materials
2.3
Two methods were used to cationize the bleached
linen fabric, namely, a pad-batch and an exhaustion
method. The experimental procedure adopted in the
exhaustion method was as follows: a bleached linen
sample was introduced into an aqueous solution
containing Quat-188. The pH of the solution was
adjusted by adding NaOH (5 % aqueous solution)
dropwise with continuous stirring. The reaction
temperature was raised gradually. At the end of the
reaction, the sample was washed several times with
cold water and acidified with 1% acetic acid. Finally,
the sample was washed with cold water and dried at
ambient conditions.
2.1.1 Linen Fabric
Grey 100% linen fabric (plain weave, 180 g/m2, 20
yarns /cm2 in warp and 23 yarns/cm2 in weft) was
used. The fabric was mill scoured and bleached as
detailed below.
In the cold pad-batch method, calculated amounts of
Quat-188 and NaOH were mixed at room
temperature. Bleached linen fabric was padded
through this mixture, and then squeezed to a wet
pickup of 100%. The sample was then batched at
room temperature in a plastic package for different
time intervals; afterwards, the cationized sample
was washed with cold water and acetic acid, then
washed several times with cold water and finally
dried at ambient conditions.
2.1.2 Chemicals
Sodium hydroxide, sodium sulphite, sodium
hydrosulphite, sodium sulphide, sodium sulphate,
sodium chloride, acetic acid, sodium carbonate, boric
acid, hydrochloric acid, copper sulphate, potassium
sulphate were of laboratory grade chemicals.
Hydrogen peroxide (35%) and Egyptol® (non-ionic
wetting agent based or ethylene oxide condensate)
were technical grade chemicals.
3-chloro-2hydroxypropyl trimethyl ammonium chloride, 65%
aqueous solution under the commercial name (Quat®188) was kindly supplied from DOW Chemical
Company, USA. The reactive dye used was Sunzol
Brilliant Red BB (C.I: Reactive Red 21).
2.2
Cationization of Linen Fabric Using 3Chloro-2-Hydroxypropyl
Trimethyl
Ammonium Chloride (Quat-188)
2.4
No-Salt Dyeing of Linen Fabric Before
and After Cationization
The degree of cationization of linen fabric was
tested by using no-salt dyeing. The reactive dye
used was Sunzol Brilliant Red BB (C.I: Reactive
Red 21).
After dyeing, the samples were
evaluated for K/S. Higher K/S of the dyed linen
fabric indicates higher extent of cationization and
vice versa. The no-salt dyeing method was used
as follows: the samples were introduced in an
aqueous solution containing the reactive dye with
Scouring and Bleaching of Linen Fabric
Grey linen fabric was mill scoured and bleached
using a Jigger machine as follows: the fabric was
introduced into Jigger along with water. The amount
of water was adjusted to give liquor ratio, 1:20. 40 g/1
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RJTA Vol. 10 No. 1 2006
continuous stirring, the temperature was raised to
60°C and dyeing continued at this temperature for
60 minutes. The samples were then washed in an
aqueous solution containing 5 g/1 soap at boiling
for 15 minutes. Finally, the samples were washed
with cold water and dried at ambient conditions.
2.5
- Nitrogen content, expressed as N % of the linen
fabric before and after cationization, was
determined by the Kjeldhal method (Vogel, 1975).
Based on the percent nitrogen, the fixation
percent F(%) was calculated as per the following
equations (Hashem et al (1) 2003):
The unfixed dyeing molecules were extracted by
treating the samples with an aqueous solution
containing DMF/water (50/50) at 100°C for 15
minutes, then washed with water and dried.
F (%) =
Amount of nitrogen fixed (det ected)
Total amount of nitrogen applied
- Tensile strength and elongation at break of linen
fabric before and after cationization was
measured according to ASTM (ASTM, Standard
Test Method 1994). The measurement was
undertaken using Shimadzu Autograph S-500 and
at a load scale of 10-50 kg.
x 100
2002, 2001; Hauser, 2000; Draper et-al. 2002, Harper
and Stone, 1986; Lewis and Lei, 1989; Wu and Chen,
1993; Evans et al. 1984, Hashem et al. (2) 2003).
During cationization of cellulose, several
reactions occur simultaneously as suggested by
the reaction scheme represented by equations 1, 2
and 3.
- Wet and dry crease recovery angle of linen
fabric before and after cationization was
determined according to AATCC (AATCC
Standard Test Method 1990).
The above reaction scheme features the following
points:
- Color strength, expressed as the K/S value of the
dyed fabric samples before and after DMF extraction,
was measured using Spectrophotometer type I.C.S
Texicon (England). The K/S value was determined
using the Kubelka-Munk equation (Kubelka and
Munk, 1931).
a) The chlorohydrin form of the reagent is
converted to the epoxy intermediate (2,3epoxypropyl trimethyl ammonium chloride);
equation 1.
b) The epoxy reacts with the cellulose itself;
equation 2.
c) The epoxy is converted via hydrolysis to the nonreactive 2,3-dihydroxy derivatives; equation 3.
- Thermogravimeteric analysis was made on 5 mg
from linen sample before and after cationization
under nitrogen atmosphere with the heating rate of 10
degree/min, using Shimadzu-TGA 50, Japan.
3.
Testing and Analysis
It is also envisaged from the above reaction scheme
that the magnitude of cationization of linen fabric
would rely on NaOH concentration, reaction
temperature and reaction time as well as material to
liquor ratio (M:LR) and method of application. The
nitrogen content (N%) of the cationized fabric was
taken as a measure of the extent of cationization,
whereas K/S expresses the colour strength of the
dyed samples. The results obtained and the discussion
are given below.
Results and Discussion
It has been established that the reaction of cellulose
with
3- chloro-2-hydroxypropyl
trimethyl
ammonium chloride (Quat-188) requires the
addition of alkali in a multi-step process which is
governed by time, temperature and pH of the
reaction (Hashem et al. (1) 2003, Hauser and Tabba,
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RJTA Vol. 10 No. 1 2006
3.1
Cationization
Method
using
the
ii)
Exhaustion
3.1.1 pH of the Reaction Medium
Figure 1 shows the effect of pH on the extent of
cationization reaction of linen fabric using Quat-188.
The extent of the cationization reaction was
expressed as N%. The K/S values of the cationized
samples dyed with a reactive dye, Sunzol Brilliant
Red BB, were also taken to indicate the extent of
cationization. The K/S values were determined
before and after DMF extraction. Alkaline pH was
adjusted using 1 molar aqueous NaOH solution. In
addition, the following points were observed: a)
aqueous Quat-188 solution has pH 7 and; b) as the
cationization reaction proceeds, the pH of reaction
solution decreases. To overcome this, another
quantity of NaOH was added to keep the pH values
as the adjusted values to guarantee that the pH of the
reaction solution is kept constant during the entire
course of cationization.
The K/S values of the cationized and dyed
sample increase as the pH of the cationization
reaction increases. This is observed before and
after DMF extraction but the values of K/S is
marginally higher before than after DMF
extraction.
Enhancement in the extent of the cationization
reaction expressed as N% by increasing the pH of the
reaction medium up to pH 13 is a manifestation of
two requirements imposed by equations 1 and 2.
Formation of the epoxy group as well as their further
reaction with the hydroxyl groups of linen cellulose
necessitates a proper alkaline medium. Current data
advocate pH 13 as the most appropriate for the two
reactions to take place most favorably (suggested by
equations 1 and 2). The decrease in the extent of
cationization at pH higher than 13, i.e., in relatively
stronger alkaline medium, could be associated with
alkaline hydrolysis of Quat-188 as shown by the
reaction suggested by equation 3. Indeed this is also
evident from the K/S values as these values rely
largely on the extent of cationization and the amount
of cationic groups (cf., figure 1). The latter acts as a
built-in catalyst for the reactive dye besides the
possibility of affording an additional active site to
linen cellulose.
Results of Figure l reveal that:
i)
increasing the pH of the cationization reaction
from 7 to 13 is accompanied by a significant
increase in N% of cationization linen fabric
from 0.25% to 0.8%. Higher increase in pH is
accomplished by a decrease in N%.
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RJTA Vol. 10 No. 1 2006
30
0.9
k/s before DMF ext.
0.8
0.8
0.8
k/s after DMF ext.
0.7
0.7
N (%)
22
0.6
20
0.7
21
20
19
0.6
k/s
0.5
15
0.4
11
0.29
10
0.25
0.25
10
N (%)
25
0.3
0.2
4
5
1
2
1
0.1
2
0
0
7
8
9
10
11
12
13
14
pH
Fig. 1. Effect of pH on the extent of reaction between quat-188 and linen fabric using the exhaustion
method
Reaction conditions used: [Quat-188], 80 g/l; reaction temperature, 70°C; reaction time, 60 min;
M:LR, 1:50.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR,
1:50.
samples is observed when the cationization reaction
was carried out at 70°C. Increasing the cationization
reaction of linen fabric using Quat-188 with
increasing temperature could be associated with the
favorable effect of the temperature on: (a) swelling of
linen fabric, (b) diffusion of Quat-188,
(c) compatibility of the reactants and (d) mobility of
the Quat-188 molecules and their probable collision
with linen molecules. Further increase in temperature
decreases N% of cationization linen fabric. Higher
temperature seems to enhance the hydrolysis reaction
of Quat-188 leading to lower N % (equation 3).
3.1.2 Temperature of Cationization Reaction
Figure 2 shows the effect of temperature on reaction
between Quat-188 and linen fabric using the
exhaustion method. It is seen that raising the reaction
temperature from 40°C to 70°C is accompanied by an
increase in N% from 0.39% to 0.81%. Higher
temperature is accompanied by a decrease in N%.
The same is true for K/S of the dyed cationized
samples before and after DMF extraction. The K/S
values of dyed samples increase as the reaction
temperature increases. Maximum K/S value of dyed
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RJTA Vol. 10 No. 1 2006
35
k/s before DMF ext.
0.81
k/s after DMF ext.
0.8
N (%)
30
0.77
0.69
0.63
25
24
0.6
22
18
k/s
17
0.39
0.4
15
N (%)
0.51
20
10
10
0.2
5
0
4
40
50
60
70
80
90
0
o
Temperature ( C)
Fig. 2. Effect of temperature on the extent of reaction between quat-188 and linen fabric using the
exhaustion method
Reaction conditions used: [Quat-188], 80 g/l; pH, 13; reaction time, 60 min; M:LR, 1:50.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
opportunity for better contact among
reactants and, therefore, higher extent of
reaction.
3.1.3 Duration of Cationization
Figure 3 shows the effect of reaction time on the
extent of cationization reaction of linen fabric
using Quat-188 when the reaction was carried out
by the exhaustion method. The results signify
that:
i)
ii)
A 60-minute duration presents the most
appropriate time for maximum cationization
of linen fabric with Quat-188 using the
exhaustion method. Further increase in
reaction time has no effect on the extent of
the reaction. Longer time provides better
78
Maximum K/S value was obtained after a
60-minute duration. Further increase in
reaction time has practically no effect on
the K/S values before and after DMF
extraction. This is rather expected since, as
already clarified, the K/S values are
determined by the amount of cationic
group, expressed as N % in the molecular
structure of linen.
RJTA Vol. 10 No. 1 2006
30
k/s before DMF ext.
0.8
0.8
k/s after DMF ext.
20
N (%)
22.5
22.5
18
0.7
0.6
20
16
k/s
22.5
17
0.5
15
0.4
N (%)
25
0.3
10
0.2
5
0.1
0
30
0
45
60
75
90
Time (min)
Fig 3. Effect of reaction time on the extent of reaction between quat-188 and linen fabric using the
exhaustion method
Reaction conditions used: [Quat-188], 80 g/l; pH, 13; reaction temperature, 70°C; M:LR, 1:50.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M: LR, 1:50.
fabric using the exhaustion method. The extent of the
reaction is expressed directly as N% and indirectly as
K/S before and after DMF extraction of the dyed
cationized linen samples. The reaction efficiency was
calculated from the nitrogen content of the cationized
samples as indicated in the experimental part. The
results signify that:
3.1.4 Material to Liquor Ratio
Figure 4 shows the effect of material to liquor ratio
(M:LR ratio) on the extent of reaction occurring
between linen fabric and Quat-188 using the
exhaustion method. It is clear that increasing the
liquor ratio decreases the N% of cationized linen
fabric. Also, K/S of the dyed fabric increases as the
liquor ratio used in cationization decreases. This is
observed before and after the dyed samples were
subject to DMF extraction. Yet as already indicated,
the K/S values are higher before than after DMF
extraction. Maximum N% and K/S could be
achieved when M: LR ratio 1: 20 was employed; a
point which suggests that at this particular M: LR
ratio, the probable molecular collision of the reactants
was maximal. Lower liquor ratios were practically
impossible under the experimental conditions used.
On the other hand, higher liquor ratio favors alkaline
hydrolysis of Quat-188 and as the results show, the N
% of cationized linen fabric decreases (equation 3).
3.1.5 Quat-188 Concentration
Figure 5 and Table 1 show the effect of Quat-188
concentration on the extent of its reaction with linen
79
i)
increasing Quat-188 concentration from 0 g/1
to 80 g/1 increases the N% of cationized linen
fabrics from 0.25% to 0.82%. Higher Quat188 concentration has no effect onN %. The
same holds true for K/S of the dyed
cationization samples before and after DMF
extraction. K/S of the dyed sample increases as
the concentration of Quat-188 increases;
maximum K/S value of the dyed samples is
observed at Quat-188 concentration of 80 g/1.
ii)
from Table 1, it is seen that the fixation percent
decreases from 8.5% when using 20 g/1 Quat188 to 6.3 at 40 g/1 Quat-188. Further increase
in Quat-188 concentration is accompanied by a
decrease in the fixation percent.
RJTA Vol. 10 No. 1 2006
1
30
k/s before DMF ext.
29
k/s after DMF ext.
28
0.9
0.9
0.88
27
0.86
0.85
0.82
25
25
0.8
24
24
N (%)
26
k/s
0.95
N (%)
0.75
23
23
23
0.7
22
22
21
21
0.65
20
0.6
20
30
40
50
Liquor ratio
Fig. 4. Effect of material to liquor ratio on the extent of reaction between quat-188 and linen fabric using
the exhaustion method
Reaction conditions used: [Quat-188], 80 g/l; pH, 13; reaction temperature, 70°C; reaction time, 60 min.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
35
k/s before DMF ext.
0.82
k/s after DMF ext.
30
0.82
0.8
0.75
N (%)
0.7
0.6
22
21
23
22
0.6
19
20
k/s
17
0.4
0.5
16
15
N (%)
25
10
0.9
0.4
10
0.25
0.3
0.2
5
0.1
1
0
0
20
40
60
80
100
0
Quat-188 conc. (g/L)
Fig. 5. Effect of Quat188 concentration on the extent of its reaction with linen fabric using the
exhaustion method
Reaction conditions used: pH, 13; reaction temperature, 70°C; reaction time, 60 min; M:LR, 1:50.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M: LR, 1:50.
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RJTA Vol. 10 No. 1 2006
Table 1. Effect of Quat188 concentration on the extent of its reaction with linen fabric using the
exhaustion method
Quat-188 conc.
(g/l)
0
Nitrogen
content (%)
0.25
Nitrogen
added (%)
0.00
Fixation
(%)
0.00
K/S
Before DMF
After DMF
0.49
0.40
20
0.41
0.06
8.50
10.24
10.16
40
0.61
0.36
6.30
17.50
17.40
60
0.66
0.41
4.50
20.41
21.41
80
0.82
0.57
4.20
22.11
22.11
100
0.82
0.57
2.50
22.11
22.11
Reaction conditions used: pH, 13; reaction temperature, 70°C; reaction time, 60 min; M:LR, 1:50.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M: LR, 1:50.
3.2
3.2.2 Temperature of Cationization using the
Pad-batch Method
Cationization of Linen Fabric with Quat188 using the Pad-batch Method
Figure 7 shows the effect of temperature on reaction
between Quat-188 and linen fabric. The results
indicate that an increase in the reaction temperature
is accompanied by a decrease in N%; maximum N%
is observed when the batching temperature was at
room temperature (25°C). They also indicate that
K/S of the dyed cationized samples increases as the
batching temperature decreases. This is rather in
accordance with the results of the exhaustion method
and could be explained on a similar basis. The same
thing is also valid for the finding that the extent of
cationization reaction of linen fabric decreases at
higher batching temperatures.
3.2.1 Sodium Hydroxide Concentration
Figure 6 shows the effect of sodium hydroxide
concentration on the extent of cationization reaction
of linen fabric using Quat-188. The extent of the
cationization reaction is expressed as N% and
evidenced by the K/S values of the cationized
samples dyed with reactive dye, namely, Sunzol
Brilliant Red BB. The K/S values were determined
before and after DMF extraction.
It is seen (Figure 6) that increasing NaOH
concentration from zero to 50 g/1 is accompanied by
an increase in N% of cationized linen fabric ranging
from 0.25% to 0.80%. Further increase in NaOH
concentration is accompanied by a decrease in N%.
The same holds true for the K/S value of the dyed
sample before and after cationization using different
NaOH concentrations. The K/S value increases from
1 and 0.90 before and after DMF extraction,
respectively to 25 and 24. Further increase in NaOH
concentration is accompanied by a decrease in the
K/S values of the dyed cationized linen samples.
3.2.3 Duration of Cationization using the Padbatch Method
Figure 8 shows the effect of reaction time on the
extent of cationization reaction of linen fabric using
Quat-188 when the reaction was examined by the
pad-batch method. Obviously, a 15-hour duration is
long enough to achieve maximum cationization of
linen fabric with Quat-188 using the pad-batch
method. Further increase in reaction time has
practically no effect on the extent of the reaction,
expressed as N%. The same holds true for the K/S
values of the dyed cationized samples. K/S increases
because of the increasing batching time and reaching
maximal value after a 15-hour duration. Further
prolongation of the reaction time has no effect on K/S
value. Longer time, up to 15 hours, provides better
opportunity for better contact among reactants and
Results of Figure 6 also reveal that optimum sodium
hydroxide concentration for the reaction between
Quat-188 and linen fabric using pad-batch method is
50 g/l.. Higher NaOH concentration adversely affects
the extent of cationization reaction; a point which
could be ascribed to higher rate of alkaline hydrolysis
of Quat-188 at higher concentration of sodium
hydroxide (equation 3).
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RJTA Vol. 10 No. 1 2006
(i)
therefore, higher extent of reaction and, therefore,
higher color strength.
(ii)
3.2.4 Effect of Quat-188 Concentration on
Cationization Reaction using the Padbatch Method
(iii)
Figure 9 and Table 2 show the effect of Quat-188
concentration on the extent of its reaction with linen
fabric using the pad-batch method. The extent of the
reaction is expressed as N%. The K/S values before
and after DMF extraction of the cationized samples
dyed with reactive dye is also considered as an
indication for the extent of the reaction. The results
feature the following:
as the Quat-188 concentration increases, the
N% of cationized linen fabric increases.
the fixation percent increases from 83.3% at
Quat-188 concentration of 25 g/l to 95.8% at
Quat-188 concentration of 50 g/l. Higher
Quat-188 concentrations are accompanied by
marginal decrease in the fixation percent.
The K/S value of the dyed cationization
sample-before and after DMF extractionincreases as the concentration of Quat-188
increases. This tallies with the results obtained
when the exhaustion method was used as
pointed out earlier.
0.9
30
0.8
25
0.7
k/s
0.5
15
0.4
10
N (%)
0.6
20
0.3
k/s before DMF ext.
5
k/s after DMF ext.
0.2
0.1
N (%)
0
0
0
20
40
60
80
100
120
140
NaOH Conc. (g/L)
Fig. 6. Effect of sodium hydroxide concentration on the extent of the reaction between Quat-188 and
linen fabric using the pad-batch method
Reaction conditions used: [Quat-188], 120 g/l; padding at room temperature and squeezed to
wet pick up of 100 %; batching at 25°C for 15 hrs.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
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RJTA Vol. 10 No. 1 2006
40
k/s before DMF ext.
k/s after DMF ext.
N (%)
0.82
0.71
35
0.65
0.8
0.7
30
0.55
0.45
k/s
0.5
20
23
0.39
20
0.4
19
N (%)
25
0.6
24
25
14
15
0.3
13
10
10
11
0.2
5
0.1
0
0
0
10
20
30
40
50
60
Batching temperature (
70
80
90
100
o
C)
Fig. 7. Effect of batching temperature on the extent of the reaction between Quat-188 and
linen fabric using the pad-batch method
Reaction conditions used: [Quat-188], 120 g/l; [NaOH], 50 g/l; padding at room temperature
and squeezed to wet pickup of 100 %; batching for 15 hrs.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
26
1.2
25
25
25
24
24
1
22
0.76
0.8
19
20
k/s
0.76
17
18
0.6
0.57
16
N (%)
0.75
16
0.4
14
0.3
k/s before DMF ext.
k/s after DMF ext.
N (%)
12
0.2
10
0
0
5
10
15
20
25
30
Batching time (h)
Fig. 8. Effect of batching time on the extent of the reaction between Quat-188 and linen fabric using
the pad-batch method
Reaction conditions used: [Quat-188], 120 g/l; [NaOH], 50 g/l; padding at room temperature
and squeezed to wet pick up of 100 %; batching at 25°C.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
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RJTA Vol. 10 No. 1 2006
28
1.4
25
25
25
24
1.2
24
19
1
17
0.76
0.75
k/s
16
0.76
0.8
14
0.57
12
8
N (%)
20
0.6
0.4
0.3
k/s before DMF ext.
k/s after DMF ext.
4
0.2
N (%)
0
0
0
5
10
15
20
25
30
Quat-188 conc. (g/L)
Fig. 9. Effect of Quat-188 concentration on the extent of its reaction with linen fabric using the
pad-batch method
Reaction conditions used: [NaOH], 50 g/l; padding at room temperature and squeezed to
wet pick up of 100 %; batching at 25°C for 15 hrs.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
Table 2. Effect of Quat-188 concentration on the extent of its reaction with linen fabric using
the pad-batch method
Quat-188
conc. (g/l)
0
Nitrogen
content (%)
0.25
Nitrogen
added (%)
0.00
Fixation
(%)
0.00
K/S
Before DMF
After DMF
0.46
0.41
25
0.35
0.10
83.30
7.10
7.00
50
0.48
0.23
95.8
16.30
16.05
75
0.59
0.34
94.0
19.68
18.91
100
0.69
0.44
91.0
21.30
21.10
125
0.76
0.54
90.0
24.50
24.50
150
0.80
0.55
76.0
24.90
24.80
175
0.93
0.68
70.00
24.60
24.10
Reaction conditions used: [NaOH], 50 g/l; padding at room temperature and squeezed to wet pick up
of 100 %; batching at 25°C for 15 hrs.
Dyeing conditions: Dye shade, 2%; dyeing temperature, 60°C; dyeing time, 60 min; M:LR, 1:50.
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RJTA Vol. 10 No. 1 2006
preparation of the control sample causes only a
marginal increase in the dry and wet wrinkle recovery
angles. In other words, the improvement in wrinkle
recovery acquired by linen fabric as a result of the
treatment with 50 g/1 NaOH is not significant and
could be ascribed to the removal of stresses from the
linen structure under the action of alkali.
The enhancement in the extent of cationization by
increasing Quat-188 concentration (when the
exhaustion and the pad-batch method were used)
could be interpreted in terms of greater availability of
Quat-188 molecules in the proximity of linen
molecules when used at higher concentrations. It is
understandable that the essential functional groups in
linen molecules are the hydroxyl groups and these
groups are immobile.
Their reaction would,
therefore, depend upon the availability of the Quat188 molecules in their vicinity. This is most probably
fulfilled at higher concentrations of Quat-188.
3.
It is also seen from Table 3 that the dry and wet
wrinkle recovery angle increases as the extent of
cationization (expressed as N %) increases. However,
the values of wet wrinkle recovery angles are higher
than those of the dry wrinkle recovery angles at the
same nitrogen content of the cationized sample. The
value of dry wrinkle recovery angle increases from
66° to 130° and the wet wrinkle recovery from 70° to
173° when the nitrogen content increases from 0.25
N% for the blank sample to 0.93 N% for the
cationized sample. Nevertheless, the values of the
wrinkle recovery angle are still much behind those
required for washed and wear linen fabric. The
increase in wrinkle recovery angle is most likely due
to the increase in polar sites that can cross-link via
ionic bonding. Specifically speaking, the cationic
groups in cationized linen react with the anionic
groups i.e., carboxyl groups in the same substrate via
cross-linking. Table 3 also shows that the tensile
strength of linen fabric displays significant
improvement; the tensile strength increases as the
extent of cationization (expressed as N%) increases.
Improvement in the tensile strength is most likely due
to the ionic interaction between the cationic groups
and carboxyl groups of the linen fabric which is
formed during pretreatment and bleaching of the
fabric. On the other hand, elongation at break slightly
decreases as N% increases.
Wrinkle Recovery Angle, Tensile
Strength and Elongation at Break of
Cationized Linen Fabric
Table 3 shows the change in the mechanical
properties of cationized linen fabric (using the padbatch method) with the extent of cationization.
Different levels of cationized linen fabric could be
achieved by carrying out the cationization of linen
fabric using different concentrations of Quat-188.
The extent of cationization was determined through
measuring the nitrogen content of linen fabric before
and after cationization. The mechanical properties
examined include wrinkle recovery, tensile strength
and elongation at break. The mechanical properties
of bleached uncationized sample (blank sample) and
that treated with 50 g/l NaOH (control sample) are set
out in Table 3 for comparison.
It is seen (Table 3) that the dry and wet wrinkle
recovery angles increase from 66° and 70°
respectively for the blank sample to 76° and 78° for
the control sample. This indicates that the treatment
of the linen fabric with NaOH (50 g/l) for the
Table 3. Dependence of wrinkle Recovery angle, tensile strength and elongation at break
on the extent of cationization of linen fabric
N (%)
Wrinkle Recovery angle
Tensile Strength
Elongation at
(Kg.F)
break (%)
Dry
Wet
0.25 (blank sample)
66
70
52.33
4.5
0.18 (control sample)
76
78
52.5
6.1
0.35
89
105
53.6
6.3
0.42
98
117
57.0
5.5
0.48
102
122
63.0
4.5
0.53
116
150
67.0
4.0
0.60
119
160
68.0
4.1
0.82
125
169
68.0
4.2
0.93
130
173
69.0
4.1
a) Blank sample: beached uncationized linen fabric
b) Control sample: linen fabric treated with 50 g/l NaOH at room temperature, squeezed to a wet pickup 100%
and batched for 15 hrs.
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RJTA Vol. 10 No. 1 2006
3.4
Figure 10 shows thermogravimetric analysis (TGA)
of bleached, cationized, traditionally-dyed and no-salt
dyed linen fabrics. Table 4 summarizes the data
abstracted
from
that
thermogram.
Thermogravimetric analysis (TGA) was done using
Shimadzu TGA-50 in nitrogen atmosphere and using
temperature range from room temperature up to
1000°C. Results of Figure 10 and Table 4 signify the
following:
Thermo-Gravimetric
Analysis
of
Bleached, Cationized, Traditionally Dyed
and No-salt Dyed Linen Fabric
Thermal methods of analysis may be broadly defined
as methods in which the effect of heat on a sample is
studied to provide qualitative or quantitative
analytical information. Thermal events are usually
studied in order to derive a thermal analysis curve or
thermogram through recording the change in thermal
properties as the temperature varies. Such curves are
characteristic of sample (fingerprint) both
qualitatively and quantitatively. Thermogravimetry is
the study of the change in the mass of a sample as the
temperature varies.
There is an initial decrease in the sample weight as
the temperature increases from room temperature to
180°C. This decrease in the sample weight is equal
for all samples and amounts to 6% and could be
attributed to the release of humidity from the samples.
Fig. 10. TGA curve of bleached, cationized, traditionally-dyed and no-salt dyed linen fabric
Table 4. Data abstracted from TGA curves of bleached, cationized, traditionally dyed and
no-salt dyed linen fabric
Treatment
Humidity (%)
Releasing Temp.
°C
Temperature (°C) at which
Starts
decompose
50 %
decompose
75 %
decompose
Charring
bleached
350
490
590
800
(6 %) 170 °C
Cationized (a)
300
490
500
> 1000
(6 %) 180 °C
Traditionally dyed (b)
330
500
590
1000
(6 %) 150 °C
No-salt dyed (b)
280
450
610
> 1000
(6 %) 150 °C
(a) Linen fabric was cationized using aqueous solution containing Quat-188, 125 g/l; NaOH, 50 g/l;
squeezed to a wet pickup 100%, batched at room temperature for 15 hrs. After cationization the
nitrogen content of the fabric was 0.79%
(b) Traditionally-dyeing and no-salt dyeing using Sunzol Brilliant Red BB (C.I: Reactive red 21)
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RJTA Vol. 10 No. 1 2006
much lower (you need to insert an object here) via
salt linkage.
All samples show one-step degradation process but at
different temperatures and with different manner.
The dissimilarity in the behavior among the modified
linen samples (bleached, cationized, traditionally
dyed and no-salt dyed) during TGA reflects chemical
differences in the structure of these samples.
Bleached linen sample displays charring at 800°C,
whereas the traditionally-dyed sample exhibits
charring at 1000°C and both cationized and the nosalt dyed sample shows charring at above 1000°C.
Bleached unmodified linen fabric shows almost no
decomposition up to 350°C, whereas cationized linen
fabric starts to decompose at 300°C. The difference
in the temperature at which the bleached and
cationized linen fabric starts to decompose could be
attributed to the decomposition of cationic groups in
cationized linen fabric. It is known that in case of
thermally stable polymer like cellulose (which does
not melt or evaporate, at elevated temperature),
single-ended modified groups in the macromolecular
structure start to decompose first. On the other hand,
dye molecules decompose at lower temperatures
compared to that of cellulose. Therefore, the
traditionally-dyed linen sample starts to decompose at
330°C, whereas the cationized samples which were
dyed in absence of salt (no-salt dyeing) with the same
dye start to decompose at 280°C. Differences in
temperatures at which the dyed and undyed samples
start to decompose could be attributed to the
decomposition of dye molecules. Meanwhile the
difference between the dyed unmodified linen
samples and the dyed cationized linen sample is a
manifestation of the presence of cationic groups in
the modified linen molecules which open up the linen
structure beside different modes of attachment of the
dye to the linen substrate as detailed below.
4.
Conclusion
The efficiency of cationization of linen fabric with
Quat-188 depends on the application technique and
the conditions used in each technique. Using the
exhaustion technique, maximum reaction efficiency
between Quat-188 and linen fabric was achieved at
Quat-188, 80 g/l and pH, 13 and 70°C for 60 minutes
using material to liquor ratio, 1:20. Any deviation
from these conditions, for example, higher pH,
temperature or material to liquor ratio, leads to an
increase in the hydrolysis of Quat-188 molecules and
hence, lower reaction efficiency. With the cold padbatch technique, maximum reaction efficiency was
achieved when the linen fabric was padded in
solution containing NaOH, 50 g/l and Quat-188, 125
g/l, then squeezed to a wet- pickup of 100 % and
batched for 15 hours at room temperature. Cationized
linen fabrics show higher tensile strength, dry and wet
wrinkle recovery angle compared with that of
uncationized linen and such an increase relies on the
degree of cationization. Cationization alters, to some
extent, the behavior of linen fabric to thermal
treatments as evidenced by TGA.
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Although cellulose shows no decomposition above
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molecules. That is why 50% of bleached unmodified
linen fabric decomposes at 490°C. Cationized linen
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indicating that cellulose molecules in cationized linen
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stage. 50% of the traditionally-dyed linen sample
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