225
In
to
the
constant,
order
the
of 9.2
dye
keep
pH
solution was buffered with 1.7
The
g/L
dyeing
Na2B407.
involved the
condi-
boiled-off cotton
experiments
tioned at 20°C and 65%
yam
relative
humidity.
DETERMINING TIME-DEPENDENT DYE SORPTION
of the
data of the
Interpretations
eluate after
spectrophotometric
the column are based on the calibra-
passing
tion
ofthe trichrome
to
This is
dyeing.
dyes
dye system prior
done
total
the concentrations of the
within
a
by varying
concentration
the
of 0.5
by
liquor
g/L
applying
’
inverse Lambert-Beer law in the form
where
c
the concentration
E is the extinction
is
matrix,
is the coefficient matrix.
and
P
P
can be calcu-
after the P-
matrix,
lated
linear
(MLR)
by multiple
regression
matrix method
[
12J:
ET
where
The
is the
matrix of E.
uptake
transposed
of the cotton
dye
yarn
time-dependent
to the
of the concentration/time
corresponds
integral
in
the
max-
curve obtained
the absorbance
by
dye
absorption
imum of each
[ 12]:
FIGURE 2.
cotton
curves of the trichrome direct
system
of
Dye-uptake
cakulateddata:
dyeing
m,(t) dye
on
total
m(t)
dye uptake.
ofthe inner
uptake
the outer
surface,
surface,
dye
O experimental
ma(t)
uptake
is
where
the standardized total
m(t)
to
dye uptake (mg/g)
the concentra-
total
data,
dye uptake.
1
of
cotton,
dye
referring
g
represents
co
tion
time
correlated with the concen-
after 60
at
(t
0)
(mg/mL)
dyeing equilibrium
normal
a
white standard
a
10°
reference
observer,
ofthe eluate in
tration
minutes,
D
65. The color differences were
and
daylight
(BaS04),
>
is the
concentration at time
is
c(t)
(t
0)
(mg/mL), v
dye
to DIN 6174
determined
[5].
according
of the
solution
is the
the How rate
(mUmin),
and g
dyeing experiment.
in Part
dye
yam (g)
in
amount ofcotton
the
Results and Discussion
I
to the mathematical modeldescribed
According
the
ofthe
ON BOTH
ofthis series
total
DETERMINING TIME DEPENDENT DYE UPTAKE
COTTON SURFACES
cotton,
[2],
and
m(t)
dye
dye uptake
at the outer and inner surfaces ofthe
uptakesmit)
met)
2),
can be
and the
fibers
(see
velocity
Figure
constants k,
k~ds
ofcot-
2 with
Wedetermined the
time-dependent dye uptake
this
is the
and
by
ki
kjdd
computed
model; ke
in
as shown
ton for the trichrome
system
60°C and 2.5
Figure
the
constants of
and
of the
velocity
sorption (~)
quotient
NaCl-concentra-
curves simulated
at
measurements
g/L
at the
and
is the
outer
surface,
desorption (ds) processes
ki
shows
tion.The
figure
also
dye uptake
of the
constants of the
and
velocity
quotient
sorption (kd)
model with
to the
of
the mathematical
regard
of
sorption
on
by
at the inner
surface
[2].
desorption (dd) processes
based
cotton
the
inner surfaces
the outer and
of the three
ofthe three
constants
and
dyes.
velocity
ks, kd, ds
dd
COLORIMETRIC MEASUREMENTS
Wedetermined differences in the
at
As
dyes
few
inner surface takes much
at the
sorption equilibrium
expected,
within
a
cotton is achieved
surface of
hueofthe
the outer
dyed
grey
while
cotton
colorimetric measurements
(Ahiba/Datacolor,
3880. The
param-
minutes,
sorption
by
differences in
are
There
with
a
Switzerland)
eters included
quantitative dye
ofcotton. to
great
ofthe different accessible
spectrophotometer
longer.
uptake
mm
~/0°
a
12
regions
Up
aperture, special
geometry,