molecules
Article
Physicochemical Properties of Jatropha Oil-Based
Polyol Produced by a Two Steps Method
Sariah Saalah 1 , Luqman Chuah Abdullah 2,3, *, Min Min Aung 3,4 , Mek Zah Salleh 5 ,
Dayang Radiah Awang Biak 2 , Mahiran Basri 4 , Emiliana Rose Jusoh 3 and Suhaini Mamat 2,6
1
2
3
4
5
6
*
Chemical Engineering Programme, Faculty of Engineering, Universiti Malaysia Sabah, Jalan UMS,
Kota Kinabalu 88400, Sabah, Malaysia; [email protected]
Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia,
Serdang 43400, Selangor, Malaysia; [email protected] (D.R.A.B.); [email protected] (S.M.)
Higher Institution Centre of Excellence Wood and Tropical Fibre (HICoE), Institute of Tropical Forestry and
Forest Products, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
[email protected] (M.M.A.); [email protected] (E.R.J.)
Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
[email protected]
Radiation Processing Technology Division, Malaysian Nuclear Agency, Kajang 43000, Selangor, Malaysia;
[email protected]
Universiti Kuala Lumpur, Malaysian Institute of Chemical and Bioengineering Technology (UniKL MICET),
Alor Gajah 78000, Melaka, Malaysia
Correspondence: [email protected] or [email protected]; Tel.: +60-3-8946-6288
Academic Editor: Derek J. McPhee
Received: 10 February 2017; Accepted: 25 March 2017; Published: 29 March 2017
Abstract: A low cost, abundant, and renewable vegetable oil source has been gaining increasing
attention due to its potential to be chemically modified to polyol and thence to become an alternative
replacement for the petroleum-based polyol in polyurethane production. In this study, jatropha
oil-based polyol (JOL) was synthesised from non-edible jatropha oil by a two steps process, namely
epoxidation and oxirane ring opening. In the first step, the effect of the reaction temperature, the
molar ratio of the oil double bond to formic acid, and the reaction time on the oxirane oxygen content
(OOC) of the epoxidised jatropha oil (EJO) were investigated. It was found that 4.3% OOC could be
achieved with a molar ratio of 1:0.6, a reaction temperature of 60 ◦ C, and 4 h of reaction. Consequently,
a series of polyols with hydroxyl numbers in the range of 138–217 mgKOH/g were produced by
oxirane ring opening of EJOs, and the physicochemical and rheological properties were studied. Both
the EJOs and the JOLs are liquid and have a number average molecular weight (Mn ) in the range of
834 to 1457 g/mol and 1349 to 2129 g/mol, respectively. The JOLs exhibited Newtonian behaviour,
with a low viscosity of 430–970 mPas. Finally, the JOL with a hydroxyl number of 161 mgKOH/g
was further used to synthesise aqueous polyurethane dispersion, and the urethane formation was
successfully monitored by Fourier Transform Infrared (FTIR).
Keywords: jatropha oil; polyol; epoxidation; oxirane ring opening; polyurethane
1. Introduction
The continuous depletion of fossil oil has led to the ever increasing price of such oil, which
subsequently has contributed to the increasing price of polymer raw materials. There is a significant
trend nowadays with regard to utilising products derived from natural molecules, such as vegetable
oil, which is due to the lower cost and the fact that the source is renewable. In addition, bio-based
products are more environmentally friendly due to possibility of being biodegradable [1]. Vegetable
oils such as soybean oil, castor oil, rapeseed oil, rubberseed oil, palm oil, canola oil, and linseed oil are
Molecules 2017, 22, 551; doi:10.3390/molecules22040551
www.mdpi.com/journal/molecules
Molecules 2017, 22, 551
2 of 17
among the most important classes of renewable resources that have been utilised for the preparation
of biopolymer products such as alkyd resins [2,3] and polyurethane [1,4,5].
Currently,
polyol
a 17
raw material
Molecules 2017,
22, 551 derived from jatropha oil appears a promising candidate as2 of
for polyurethane adhesives [6] and coatings [7,8]. Jatropha oil is a non-edible oil, and utilising such
oils such as soybean oil, castor oil, rapeseed oil, rubberseed oil, palm oil, canola oil, and linseed oil
an oil does
not exploit or harm the market for edible vegetable oil. As shown in Table 1, jatropha
are among the most important classes of renewable resources that have been utilised for the
oil consists
of 78.9%
unsaturation
percentage
in resins
its triglyceride
structure,
mainly corresponding to
preparation
of biopolymer
products
such as alkyd
[2,3] and polyurethane
[1,4,–5].
oleic and linoleic
acid
(Figure
1),from
which
provides
an interesting
platform
chemical
modification.
Currently,
polyol
derived
jatropha
oil appears
a promising candidate
as for
a raw
material for
polyurethane
adhesives
[6]
and
coatings
[7,8].
Jatropha
oil
is
a
non-edible
oil,
and
utilising
such
an
The double bond group in the jatropha oil triglyceride molecules can be functionalised to a hydroxyl
not exploit or harm the market for edible vegetable oil. As shown in Table 1, jatropha oil
group byoiladoes
two-step
method; namely, epoxidation and oxirane ring opening.
consists of 78.9% unsaturation percentage in its triglyceride structure, mainly corresponding to oleic
and linoleic acid (Figure 1), which provides an interesting platform for chemical modification. The
List ofoil
fatty
acid compositions
in jatropha
oil [9]. to a hydroxyl
double bond group Table
in the 1.
jatropha
triglyceride
molecules can
be functionalised
group by a two-step method; namely, epoxidation and oxirane ring opening.
Fatty Acid
Unsaturates
Saturates
Table 1. List of fatty acid compositions in jatropha oil [9].
Palmitoleic (C16/1 )
Oleic (C18/ ) Linoleic (C18/2 ) Palmitic (C16/0 )
Stearic (C18/0 )
Unsaturates
Saturates
% Fatty Acid Palmitoleic
1.4
43.1
6.9
(C16/1)
Oleic
(C18/)
Linoleic 34.4
(C18/2)
Palmitic (C16/014.2
)
Stearic (C18/0)
%
1.4
43.1
34.4
14.2
6.9
Total (%)
78.9
21.1
Total (%)
78.9
21.1
O
a) Linoleic acid
b) Oleic acid
OH
O
OH
Figure 1. Chemical structure of main fatty acids in jatropha oil.
Figure 1. Chemical structure of main fatty acids in jatropha oil.
Studies of the epoxidation of vegetable oils have become interesting as the products have become
important oleochemicals for commercialisation. Despite being used as a starting material to produce
Studies of the epoxidation of vegetable oils have become interesting as the products have become
polyol, vegetable oils with epoxy groups are now accepted as an alternative to petrochemical based
important
oleochemicals
for
commercialisation.
Despitestabilizers,
being used
as a starting
feedstock
to be used as
plasticizers
for polyvinyl chloride,
and lubricants
[10]. material to produce
polyol, vegetable
with epoxy
are time,
nowthe
accepted
as an
alternative
to petrochemical
based
Certainoils
parameters
such asgroups
the reaction
molar ratio
of hydrogen
peroxide
to the oil
double
molar ratiofor
of either
formic chloride,
or acetic acid
as the peroxygen
carrier to the
oil
feedstock
to bebond,
usedand
as the
plasticizers
polyvinyl
stabilizers,
and lubricants
[10].
double bond can be manipulated to obtain epoxidised oil with a different oxirane oxygen content
Certain parameters such as the reaction time, the molar ratio of hydrogen peroxide to the oil
(OOC). Higher amounts of peroxygen carrier and hydrogen peroxide as well as higher temperatures
double bond,
and the
ratio
ofbut
either
the peroxygen
carrier
to the
will increase
themolar
reaction
rate,
it isformic
difficultor
toacetic
controlacid
the as
temperature
since the
reaction
is oil double
bond can
be manipulated
obtain
with ahas
different
oxirane
oxygen
(OOC).
exothermic.
The use of atolow
percentepoxidised
strong acid asoil
a catalyst
been reported
[11], but,
due tocontent
the
environmental
issue
of
the
waste
sulphuric
acid,
the
use
of
an
ion
exchanger
catalyst
has
become
the
Higher amounts of peroxygen carrier and hydrogen peroxide as well as higher temperatures will
preferred approach [12]. In addition, an ion exchanger is preferred because sulphuric acid is reported to
increase the reaction rate, but it is difficult to control the temperature since the reaction is exothermic.
be unsuitable for certain oils due to the low yield of epoxide [13]. In some studies, the use of a
The use of
a low
percent
strongbutacid
as a catalyst
hashydrogen
been reported
[11],
due to together
the environmental
catalyst
is even
eliminated,
the more
concentrated
peroxide has
to but,
be employed
higher sulphuric
loading of formic
andexchanger
co-workers [15]
reported
thatbecome
epoxidised
issue of with
the awaste
acid,acid
the[13,14].
use ofMeyer
an ion
catalyst
has
the preferred
jatropha
could achieve
OOC of up tois
4.75%
at a reaction
temperature
of 50 °Cacid
and 10
of
approach
[12]. oil
In(EJO)
addition,
an ionanexchanger
preferred
because
sulphuric
is hreported
to be
reaction time. By increasing the reaction temperature to 65 °C, the reaction time can be reduced to
unsuitable for certain oils due to the low yield of epoxide [13]. In some studies, the use of a catalyst is
5 h with OOC reduced to 4.3% [15].
even eliminated,
but polyol
the more
hydrogen
peroxide
has to
together
with a
Producing
from concentrated
epoxidised vegetable
oil involves
the opening
of be
the employed
oxirane group
to
produce of
a hydroxyl
group.[13,14].
A higherMeyer
OOC value
favourable if[15]
a high
hydroxylthat
value
of polyol is jatropha oil
higher loading
formic acid
and isco-workers
reported
epoxidised
expected.
The hydroxyl
value
refers to
average distribution
of OH of
groups
(EJO) could
achieve
an OOC
of of
uppolyol
to 4.75%
atthe
a reaction
temperature
50 ◦present
C andin10theh of reaction
triglycerides [16], which will determine the properties◦ of the polyurethane. However, a systematic
time. By increasing the reaction temperature to 65 C, the reaction time can be reduced to 5 h with
study of the effect of the epoxidation condition on the properties of polyol derived from jatropha oil
OOC reduced
to 4.3% [15].
is not available.
The aim
of this
studyepoxidised
is to investigate
the effectoil
of the
molar ratio,
temperature,
and
Producing
polyol
from
vegetable
involves
the reaction
opening
of the oxirane
group to
on the OOC
of EJO.A
During
the OOC
epoxidation
less concentrated
peroxide value
will be of polyol is
producetime
a hydroxyl
group.
higher
valuestep,
is favourable
if ahydrogen
high hydroxyl
utilised and the reaction will be performed without using a strong acid catalyst. It is intended to
expected. The hydroxyl value of polyol refers to the average distribution of OH groups present in the
establish the relationship between the hydroxyl value of the polyol and the oxirane oxygen content
triglycerides [16], which will determine the properties of the polyurethane. However, a systematic
study of the effect of the epoxidation condition on the properties of polyol derived from jatropha oil is
not available.
The aim of this study is to investigate the effect of the molar ratio, reaction temperature, and time
on the OOC of EJO. During the epoxidation step, less concentrated hydrogen peroxide will be utilised
Molecules 2017, 22, 551
3 of 17
and the reaction will be performed without using a strong acid catalyst. It is intended to establish
the relationship between the hydroxyl value of the polyol and the oxirane oxygen content of the
epoxidised
oil.
Other
Molecules
2017,
22, 551physico-chemical properties of the EJOs and JOLs, such as the molecular
3 of 17weight
Molecules 2017, 22, 551
3 of 17
and rheology, will be investigated as part of the required information for handling and processing
of the epoxidised oil. Other physico-chemical properties of the EJOs and JOLs, such as the molecular
purposes.
the potential
of producing polyurethane
dispersion
from
synthesised
of theFurthermore,
epoxidised
oil. Other
of the
EJOs and
JOLs, suchfor
as handling
thethe
molecular
weight
and rheology,
will physico-chemical
be investigated asproperties
part of the
required
information
and
jatropha
oil-based
polyol will
weight
and rheology,
willbe
beinvestigated.
investigated as part of the required information for handling and
processing purposes. Furthermore, the potential of producing polyurethane dispersion from the
processing purposes.
Furthermore,
of producing polyurethane dispersion from the
synthesised
jatropha oil-based
polyolthe
willpotential
be investigated.
2. Results
and Discussion
synthesised
jatropha oil-based polyol will be investigated.
2. Resultsoil-based
and Discussion
Jatropha
polyols were produced by the epoxidation and oxirane ring opening route,
2. Results and Discussion
as shown Jatropha
in Figure
2. In the
jatropha
triglyceride,
the oil double
bond in
theopening
linoleic
and oleic
oil-based
polyols
were oil
produced
by the epoxidation
and oxirane
ring
route,
Jatropha
oil-based
wereoil
produced
by the
epoxidation
and in
oxirane
opening
route,
as shown
in Figure
2. In polyols
the
jatropha
triglyceride,
the
oil double
bond
the linoleic
and oleic
fatty
fatty acid
was
transformed
to epoxy,
which
was then
opened
to incorporate
a ring
hydroxyl
and
methoxy
as shown
in Figure 2. to
In epoxy,
the jatropha
oil
triglyceride,
thetooil
double bond
in the linoleic
and oleic
fatty
acid
was
transformed
which
was
then
opened
incorporate
a
hydroxyl
and
methoxy
group.
group. The resulting jatropha oil-based polyol contained a secondary hydroxyl group. The formation
acid was
transformed
to oil-based
epoxy, which
was then opened
to incorporate
a hydroxyl
and
methoxy
group.
The
resulting
jatropha
a secondary
hydroxyl
group.
The
formation
ofepoxy
of epoxidised
jatropha
oil and
polyolpolyol
werecontained
confirmed
by
FTIR analysis.
On
the other
hand, the
The
resulting
jatropha
oil-based
polyol
contained
a
secondary
hydroxyl
group.
The
formation
of
epoxidised jatropha oil and polyol were confirmed by FTIR analysis. On the other hand, the epoxy
groupsepoxidised
in the epoxidised
oil
were
reported
as oxirane
oxygen
content
(OOC),
while
theepoxy
amount of
jatropha
oil
and
polyol
were
confirmed
by
FTIR
analysis.
On
the
other
hand,
the
groups in the epoxidised oil were reported as oxirane oxygen content (OOC), while the amount of
hydroxyl
groups
in the
polyol
was
reported
as oxygen
theOH
OHnumber.
number.
Photographs
ofjatropha
the jatropha
groups
ingroups
theformed
epoxidised
oilthe
were
reported
as oxirane
content
(OOC),
while of
thethe
amount
of
hydroxyl
formed in
polyol
was reported
as the
Photographs
hydroxyl
groups
formed
in
the
polyol
was
reported
as
the
OH
number.
Photographs
of
the
jatropha
oil andoil
the
resulting
polyol
are
shown
in
Figure
3.
Jatropha
oil
is
a
golden
yellow
oil,
while
the
and the resulting polyol are shown in Figure 3. Jatropha oil is a golden yellow oil, while thepolyol
oil
and
resulting
polyol are shown in Figure 3. Jatropha oil is a golden yellow oil, while the
is slightly
yellow.
polyol
isthe
slightly
yellow.
polyol is slightly yellow.
O
O
O
O
O
O
O
O
O
O
O
O
Jatropha oil
Jatropha oil
Temperature: 50°C /60 °C
Temperature:
50°C
/60/5h
°C
Time:
2h/ 3h /4h/
4.5h
Time: 2h/ 3h /4h/ 4.5h /5h
O
O
O
O
CHCOOH,
CHCOOH,
H
2O2
H2O2
O
O
O
O
O
O
O
O
O
O
O
O
O
O
Epoxidised jatropha
oil (EJO)
Epoxidised jatropha oil (EJO)
CH3OH,
CH
3OH,
H
2O
H2O
Temperature: 64 °C
Temperature:
Time:
30 min 64 °C
Time: 30 min
OH
OH
OCH3
OCH3
O
O
O
O
O
O
O
O
O
O
OH OCH3
OH OCH3
OCH3 OH
OCH3 OH
O
O polyol (JOL)
Jatropha oil-based
Jatropha oil-based polyol (JOL)
Figure 2. Synthesis of jatropha oil-based polyol via the epoxidation and oxirane ring opening method.
FigureFigure
2. Synthesis
of jatropha
polyolvia
via
epoxidation
and oxirane
ring opening
2. Synthesis
of jatrophaoil-based
oil-based polyol
thethe
epoxidation
and oxirane
ring opening
method. method.
Figure 3. Appearance of jatropha oil-based polyol (b); compared with the starting jatropha oil (a).
3. Appearance
of jatropha
oil-basedpolyol
polyol (b);
with
thethe
starting
jatropha
oil (a).oil (a).
FigureFigure
3. Appearance
of jatropha
oil-based
(b);compared
compared
with
starting
jatropha
Molecules 2017, 22, 551
Molecules 2017, 22, 551
4 of 17
4 of 17
2.1.2.1.
FTIR
Analysis
of JO,
EJO,
andand
JOL
FTIR
Analysis
of JO,
EJO,
JOL
The
FTIR
spectra
forfor
thethe
jatropha
oiloil
(JO),
epoxidised
jatropha
oiloil
(EJO),
and
jatropha
oil-based
The
FTIR
spectra
jatropha
(JO),
epoxidised
jatropha
(EJO),
and
jatropha
oil-based
polyol
(JOL)
areare
shown
in in
Figure
4. 4.
From
thethe
spectra
of of
thethe
jatropha
oil,oil,
thethe
absorbance
band
at at
polyol
(JOL)
shown
Figure
From
spectra
jatropha
absorbance
band
−
1
−1
3007
cmcmcorresponds
to the
double
bond
group.
TheThe
disappearance
of the
double
bond
and
3007
corresponds
to the
double
bond
group.
disappearance
of the
double
bond
and
− 1 the
−1 in
appearance
of of
new
peaks
at at
840
and
819
cmcm
spectra
of the
epoxidised
jatropha
oiloil
confirms
appearance
new
peaks
840
and
819
in the
spectra
of the
epoxidised
jatropha
confirms
thethe
conversion
of of
thethe
double
bond
to to
anan
epoxy
group
during
thethe
epoxidation
reaction.
After
thethe
conversion
double
bond
epoxy
group
during
epoxidation
reaction.
After
oxirane
ring
was
opened,
thethe
polyol
was
formed,
and
thisthis
was
confirmed
by by
thethe
existence
of aofbroad
oxirane
ring
was
opened,
polyol
was
formed,
and
was
confirmed
existence
a broad
1 , which
−1, −
absorbance
band
at 3425
cmcm
which
waswas
attributed
to the
hydroxyl
group
in the
JOLJOL
spectra.
absorbance
band
at 3425
attributed
to the
hydroxyl
group
in the
spectra.
1 attributed
−1 −
From
thethe
EJO
spectra,
thethe
weak
and
broad
shoulder
around
3425
cm
attributed
to the
OHOH
group
From
EJO
spectra,
weak
and
broad
shoulder
around
3425
cm
to the
group
was
observed,
instead
of of
a remarkable
peak,
as as
reported
in in
other
studies
[14,15].
This
indicates
thatthat
thethe
was
observed,
instead
a remarkable
peak,
reported
other
studies
[14,15].
This
indicates
minimum
side
reaction
associated
with
the the
ringring
opening
of epoxy
withwith
water/acid
during
epoxidation.
minimum
side
reaction
associated
with
opening
of epoxy
water/acid
during
epoxidation.
(a) JO
3007
1464
2922
722
1743
2853
1160
%T
(b) EJO 3h
840
819
(c) JOL 217
3425
4000
3500
3000
2500
2000
1500
1000
500
-1
Wavenumber (cm )
Figure
4. (Fourier
Transform
Infrared)
FTIRFTIR
spectra
of jatropha
oil (JO),
jatropha
oil (EJO),
Figure
4. (Fourier
Transform
Infrared)
spectra
of jatropha
oilepoxidised
(JO), epoxidised
jatropha
oiland
(EJO),
jatropha
oil-based
polyol (JOL).
and jatropha
oil-based
polyol (JOL).
2.2.2.2.
Effect
of Molar
Ratio,
Temperature,
and
Reaction
Time
onon
thethe
Oxirane
Oxygen
Content
Effect
of Molar
Ratio,
Temperature,
and
Reaction
Time
Oxirane
Oxygen
Content
Figures
5 5and
the oxirane
oxiraneoxygen
oxygencontent,
content,
OOC
relative
conversion
to
Figures
and66 present
present the
OOC
(%),(%),
andand
relative
conversion
to oxirane
oxirane
of
epoxidised
jatropha
oil
prepared
by
different
molar
ratios
of
formic
acid
to
the
oil
double
of epoxidised jatropha oil prepared by different molar ratios of formic acid to the oil double bond and
bond
and reaction
temperature.
The epoxidation
reaction
50 °C
was conducted
5 h, the
while
the
reaction
temperature.
The epoxidation
reaction
at 50 ◦ Catwas
conducted
over 5 over
h, while
reaction
reaction
at
60
°C
was
conducted
over
4
h.
Overall,
increasing
the
mole
ratio
of
formic
acid
to
the
oil
◦
at 60 C was conducted over 4 h. Overall, increasing the mole ratio of formic acid to the oil double
double
bond
from
0.4
to
0.6
increased
the
OOC
from
2.42%
to
4.49%
and
from
3.26%
to
4.64%
for
the
bond from 0.4 to 0.6 increased the OOC from 2.42% to 4.49% and from 3.26% to 4.64% for the reactions
reactions
conducted
50 °C
60 °C, respectively.
However,
the increase
in the
OOC becomes
less
◦ C, respectively.
conducted
at 50 ◦ Catand
60 and
However,
the increase
in the OOC
becomes
less significant
significant
when
there
is
a
20%
excess
of
formic
acid
in
the
mixture.
About
80%
relative
conversion
when there is a 20% excess of formic acid in the mixture. About 80% relative conversion to oxirane
to was
oxirane
was achieved
moleand
of acid
anddouble
the oilbond
double
bond
were equal.
achieved
when thewhen
molethe
of acid
the oil
were
equal.
Molecules 2017, 22, 551
5 of 17
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22,551
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55of
Figure 5. Effect of molar ratio and reaction temperature on the oxirane oxygen content (OOC) of
Figure
5. Effect
of molar
ratio
andreaction
reaction temperature
temperature on
oxygen
content
(OOC)
of of
Figure
5. Effect
of molar
ratio
and
onthe
theoxirane
oxirane
oxygen
content
(OOC)
epoxidisedjatropha
jatrophaoil.
oil.
epoxidised
epoxidised jatropha oil.
Relative
Relativeconversion
conversionto
tooxirane
oxirane(%)
(%)
100.0
100.0
50⁰C,
⁰C,55hh
50
80.0
80.0
60.0
60.0
58.3
58.3
60⁰C,
⁰C,44hh
60
75.0
75.0
65.4
65.4
80.8
78.280.8
78.2
81.4
81.4
42.2
42.2
40.0
40.0
20.0
20.0
0.0
0.0
0.4
0.4
0.6
0.6
11
1.2
1.2
Molarratio
ratioof
offormic
formicacid
acidto
toC=C
C=C
Molar
Figure
Effect
of the
the
molar
ratio
andreaction
reactiontemperature
temperature on
on
relative
conversion
to oxirane
oxirane
of of
Figure
6. Effect
of the
molar
ratio
and
onrelative
relative
conversion
to oxirane
Figure
6.6. Effect
of
molar
ratio
and
reaction
temperature
conversion
to
of
epoxidised
jatropha
oil.
epoxidised
jatropha
epoxidised
jatropha
oil. oil.
The reaction
reaction at
at 60
60 °C
°C resulted
resulted in
in aa better
better OOC
OOC with
with aa reduced
reduced reaction
reaction time,
time, compared
compared to
to the
the
The
◦ resulted in a better OOC with a reduced reaction time, compared to
The
reaction
at 60
reaction
conducted
ataaC
lowertemperature.
temperature.ItItwas
wasinteresting
interestingthat
thataa4.3%
4.3%OOC
OOCwith
withaarelative
relativeconversion
conversion
reaction
conducted
at
lower
the reaction
conducted
at
a
lower
temperature.
It
was
interesting
that
a
4.3%
OOC
with
to
oxirane
of
75%
could
be
achieved
with
a
molar
ratio
of
0.6,
a
reaction
temperature
of
60
°C,
and
hof
of
to oxirane of 75% could be achieved with a molar ratio of 0.6, a reaction temperature of 60 °C, and aa4a4hrelative
reaction
time.
This
was
about
same
value
as
obtained
by
Goud
and
co-workers
[12]
with
the
application
conversion
to
oxirane
of
75%
could
be
achieved
with
a
molar
ratio
of
0.6,
a
reaction
temperature
reaction time. This was about same value as obtained by Goud and co-workers [12] with the application of
ofand
anion
ion
exchanger
or22time.
wt.%
%This
sulphuric
acidcatalyst
catalyst
after10
10
ofreaction
reaction
atGoud
50°C.
°C.The
Theresults
resultswere
were [12]
60 ◦ C,of
a 4exchanger
h of reaction
was about
same after
value
ashhobtained
by
and
co-workers
an
or
wt.
sulphuric
acid
of
at
50
comparable
with
the
findings
of
Hazmi
and
co-workers
[14]
for
5
h
epoxidation
assisted
by
more
with of
thean
findings
of Hazmi or
and
co-workers
[14] foracid
5 h catalyst
epoxidation
assisted
byreaction
more at
with comparable
the application
ion exchanger
2 wt.
% sulphuric
after
10 h of
concentrated
hydrogen
peroxidewith
(50%)the
ataafindings
temperature
of65
65°C
°C
and
higherformic
formic
acid
peroxide
(50%)
at
temperature
of
and
higher
50 ◦ C.concentrated
The results hydrogen
were
comparable
of Hazmi
and
co-workers
[14]acid
for loading.
5loading.
h epoxidation
Agreater
greaterconcentration
concentrationof
ofhydrogen
hydrogenperoxide
peroxide wasalso
also employedby
byMeyer
Meyerand
and co-workers[15]
[15]at
at
A
assisted by
more concentrated
hydrogen
peroxide was
(50%) atemployed
a temperature
of 65 ◦co-workers
C and higher formic
prolonged
reaction
times
of
up
to
10
h,
which
resulted
in
a
%OOC
of
4.75
at
a
temperature
of
50
°C.
prolonged reaction times of up to 10 h, which resulted in a %OOC of 4.75 at a temperature of 50 °C.
acid loading.
These results
results suggest
suggest that
that aa reaction
reaction temperature
temperature of
of 60
60 °C
°C can
can be
be employed
employed to
to achieve
achieve aa higher
higher
These
Aconversion
greater concentration
of ahydrogen
peroxide
waswithout
also employed
by Meyer
and
co-workers
to
oxirane
over
shorter
reaction
period
the
application
of
a
catalyst
or
more [15]
conversion to oxirane over a shorter reaction period without the application of a catalyst or more
at prolonged
reaction
times
of up to 10 h, which resulted in a %OOC of 4.75 at a temperature of
concentrated
hydrogen
peroxide.
concentrated
hydrogen
peroxide.
50 ◦ C. These results suggest that a reaction temperature of 60 ◦ C can be employed to achieve a higher
2.3.Effect
Effect
Oxiraneover
Oxygen
Contenton
onOH
OHNumbers
Numbers
JatrophaOil-Based
Oil-Based
Polyol(JOL)
(JOL)
conversion
toofof
oxirane
a shorter
reaction
period
without
the application
of a catalyst or more
2.3.
Oxirane
Oxygen
Content
ofofJatropha
Polyol
concentrated
hydrogen
peroxide.
A reaction
reaction
parameter
of 60
60 °C
°C and
and aa molar
molar ratio
ratio of
of 0.6
0.6 were
were selected
selected for
for the
the preparation
preparation of
of
A
parameter
of
epoxidisedjatropha
jatrophaoil
oilto
tobe
befurther
furtherconverted
convertedto
topolyol
polyolby
byoxirane
oxiranering
ringopening.
opening.For
Forthis
thispurpose,
purpose,
epoxidised
2.3. Effect of Oxirane Oxygen Content on OH Numbers of Jatropha Oil-Based Polyol (JOL)
A reaction parameter of 60 ◦ C and a molar ratio of 0.6 were selected for the preparation of
epoxidised jatropha oil to be further converted to polyol by oxirane ring opening. For this purpose, the
Molecules 2017, 22, 551
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6 of 17
6 of 17
6 of 17
the
JO
g.
77 shows
the
effect
of
times
with
amount
of JOof
scaled
up toup
400to
Figure
7 shows
the effect
varying
reactionreaction
times with
respect
the amount
amount
ofwas
JO was
was scaled
scaled
up
tog.400
400
g. Figure
Figure
shows
theof
effect
of varying
varying
reaction
times
with
respect
to
the
OOC.
Increasing
the
reaction
time
increased
the
OOC
in
the
epoxidised
JO.
It
can
be
to
the
OOC.
Increasing
the
reaction
time
increased
the
OOC
in
the
epoxidised
JO.
It
can
be
seen
respect to the OOC. Increasing the reaction time increased the OOC in the epoxidised JO. It canthat
be
seen
that
the
OOC
obtained
at
4
h
was
lower
than
the
results
found
in
the
previous
work,
in
which
aa
the
4 h was at
lower
thanlower
the results
found
in the
previous
in which
a small
scale
seenOOC
that obtained
the OOCat
obtained
4 h was
than the
results
found
in thework,
previous
work,
in which
small
scale
sample
was
used.
This
is
due
to
the
low
mass
transfer
coefficient
in
a
larger
scale
of
sample
was used.
This
is due
to This
the low
masstotransfer
coefficient
in a larger
scale ofinpreparation,
as the
small scale
sample
was
used.
is due
the low
mass transfer
coefficient
a larger scale
of
preparation,
as
the
other
factors
such
as
the
heat
transfer
area
are
not
well
considered.
At
this
stage,
other
factors
such
as
the
heat
transfer
area
are
not
well
considered.
At
this
stage,
all
the
epoxidised
JO
preparation, as the other factors such as the heat transfer area are not well considered. At this stage,
all
epoxidised
JO
to
by
oxirane
method
was
converted
to polyol
the oxirane
ring opening
using
methanol.
all the
the
epoxidised
JO was
wasbyconverted
converted
to polyol
polyol
by the
the method
oxirane ring
ring opening
opening
method using
using methanol.
methanol.
Figure
oil.
Figure 7.
7. Effect
Effect of
of reaction
reaction time
time on
on OOC
OOC of
of epoxidised
epoxidised jatropha
jatropha
jatropha oil.
oil.
The
relationship
between
%OOC
and
OH
number
is
in
Figure
8.
The relationship
relationship between
between %OOC
%OOC and
and OH
OH number
number is
is expressed
expressed in
in Figure
Figure 8.
8. As
As expected,
expected, higher
higher
The
expressed
As
expected,
higher
OH
numbers
of
polyol
were
obtained
by
increasing
the
%OOC.
Polyol
with
increasing
OH
numbers
OH
numbers
of
polyol
were
obtained
by
increasing
the
%OOC.
Polyol
with
increasing
OH
numbers
OH numbers of polyol were obtained by increasing the %OOC. Polyol with increasing OH numbers
from
138–217
mgKOH/g
successfully produced
from epoxidised
jatropha oil
with an
increase
from 138–217
138–217 mgKOH/g
mgKOH/g was
was
an OOC
OOC increase
increase
from
was successfully
successfully produced
produced from
from epoxidised
epoxidised jatropha
jatropha oil
oil with
with an
OOC
from
3.56
to
4.32.
These
values
are
comparable
with
other
vegetable
oil
based
polyols
synthesised
from
from
3.56
to
4.32.
These
values
are
comparable
with
other
vegetable
oil
based
polyols
synthesised
from
from 3.56 to 4.32. These values are comparable with other vegetable oil based polyols synthesised
soybean
oil,
castor
oil,
linseed
oil,
and
palm
oil
[16–18].
The
OH
numbers
will
determine
the
amount
of
soybean
oil, castor
oil, linseed
oil, andoil,
palm
oilpalm
[16–18].
OH numbers
determine
the amountthe
of
from
soybean
oil, castor
oil, linseed
and
oil The
[16–18].
The OH will
numbers
will determine
diisocyanate
required
for
polyurethane
synthesis.
Depending
on
the
application,
vegetable
oil-based
diisocyanate
required
for
polyurethane
synthesis.
Depending
on
the
application,
vegetable
oil-based
amount of diisocyanate required for polyurethane synthesis. Depending on the application, vegetable
polyols
relatively
high OH
are
desired for
of rigid
polyurethane
[19].
polyols with
with
relatively
OH numbers
numbers
are generally
generally
for production
production
rigid
polyurethane
[19].
oil-based
polyols
withhigh
relatively
high OH
numbersdesired
are generally
desiredoffor
production
of rigid
However,
polyols
with
low
OH
numbers
are
advantageous
in
terms
of
bio-based
content,
as
they
However, polyols
with low OH
numbers
are OH
advantageous
in advantageous
terms of bio-based
content,
as they
polyurethane
[19]. However,
polyols
with low
numbers are
in terms
of bio-based
require
less
diisocyanate
as
aa hard
segment
in
the
polyurethane
[20].
The
combination
of
the
OH
require
less
diisocyanate
as
hard
segment
in
the
polyurethane
[20].
The
combination
of
the
OH
content, as they require less diisocyanate as a hard segment in the polyurethane [20]. The combination
numbers
and
hard
segment
content
was
reported
as
a
key
role
in
controlling
the
structure
and
the
numbers
and
hard
segment
content
was
reported
as
a
key
role
in
controlling
the
structure
and
the
of the OH numbers and hard segment content was reported as a key role in controlling the structure
thermophysical
and
mechanical
properties
of
the
polyurethane
film
[16–20].
thermophysical
and mechanical
properties
of the polyurethane
film [16–20].
and
the thermophysical
and mechanical
properties
of the polyurethane
film [16–20].
Figure
Figure 8.
8. Effect
Effect of
of %OOC
%OOC of
of EJO
EJO on
on the
the OH
OH number
number
of
JOL.
number of
of JOL.
JOL.
Molecules 2017, 22, 551
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7 of 17
7 of 17
Molecular Weight
Weight and Rheology of Epoxidised Jatropha Oil (EJO)
2.4. Molecular
The molecular weights of the jatropha oil (JO) and epoxidised jatropha oil (EJO) were determined
using gas permeation chromatograpy (GPC). The analysed GPC results (Table 2) for JO and the three
4 h,
and
4.54.5
h, are
presented
as number
average
(Mn )(M
and
EJOs produced
produced at
atvarious
variousreaction
reactiontimes,
times,3 3h,h,
4 h,
and
h, are
presented
as number
average
n)
weight
average
(Mw )(M
molecular
weight.
A higher
polydispersity
index
(PDI)
was was
observed
for EJO
and
weight
average
w) molecular
weight.
A higher
polydispersity
index
(PDI)
observed
for
3 h and
EJOEJO
4 h,4indicating
a broad
whichisisaatypical
typical
characteristic
EJO
3 h and
h, indicating
a broadmolecular
molecularweight
weight distribution,
distribution, which
characteristic
of
of jatropha
(JO).
The
EJO
producedusing
usinga alonger
longerreaction
reactiontime
timeshowed
showedaa significantly
significantly higher
jatropha
oiloil
(JO).
The
EJO
4.54.5
produced
of 1457
1457 with
with aa narrow molecular
molecular weight
weight distribution
distribution (Figure
(Figure 9),
9), suggesting
suggesting the
the formation
formation of
of a
Mnn of
dimer. Dimerisation
Dimerisation(or
(oroligomerisation)
oligomerisation)isisanan
epoxy
ring
opening
side
reaction
that
occurs
when
epoxy ring opening side reaction that occurs when the
the epoxy
group
reacts
with
acid
water,followed
followedbybythe
thedimerisation
dimerisationof
ofthe
the already
already formed
epoxy
group
reacts
with
thethe
acid
or or
water,
first step, the attack of aa proton
proton on an
an epoxy
epoxy group
group leads
hydroxyl compound. In the case at issue the first
to the formation of hydroxyl and acetyl or formyl groups. If the reaction stops at that stage, a polyol
A hydroxyl
hydroxyl group may react further with an epoxy group to give internal
is formed (Figure 10) [21]. A
ethers or oligomeric
ethers
(dimers)
formation
of of
epoxidised
jatropha
oil
oligomeric ethers (dimers)[21].
[21].The
Theschematic
schematicofofdimer
dimer
formation
epoxidised
jatropha
is shown
in Figure
11. In11.
addition
to increasing
molecular
weight,weight,
dimerisation
typically
will cause
oil
is shown
in Figure
In addition
to increasing
molecular
dimerisation
typically
willa
significant
increaseincrease
of viscosity[21].
cause
a significant
of viscosity[21].
Table 2. Molecular weight of epoxidised jatropha oil.
Table
Sample
Sample
n
MM
n
JO
JO
EJO 3EJO
h 3h
EJO 4EJO
h 4h
EJO 4.5
h 4.5 h
EJO
MwM w
1630
1630
1666
1666
1516
1516
1566
1566
1083
1083
995
995
834
834
1457
1457
PDI =PDI
Mw=
/M
Mnw /M n
1.51
1.51
1.67 1.67
1.82 1.82
1.07 1.07
5
EJO 4.5h
dwt/d(logM)
4
3
2
1
0
500
1000
1500
2000
2500
3000
3500
Molecular weight (Daltons)
Figure 9. The
The molecular
molecular weight
weight distribution of EJO 4.5 h.
The functionalisation of double bonds to the epoxy groups leads to a significant increase in
The functionalisation of double bonds to the epoxy groups leads to a significant increase in
viscosity. As shown in Figure 12, the viscosity of EJO 4.5 h at 25 °C◦ is 180 mPas, while the viscosity of
viscosity. As shown in Figure 12, the viscosity of EJO 4.5 h at 25 C is 180 mPas, while the viscosity
the starting jatropha oil is 55 mPas. Both JO and EJO 4.5 h exhibit Newtonian behaviour in the
of the starting jatropha oil is 55 mPas. Both JO and EJO 4.5 h exhibit Newtonian behaviour in the
measured shear rate ranges. Increasing the temperature causes a significant reduction of viscosity, as
measured shear rate ranges. Increasing the temperature causes a significant reduction of viscosity,
shown in Figure 13. Although having a dimer structure, the viscosity of the EJO 4.5 h is still low and
as shown in Figure 13. Although having a dimer structure, the viscosity of the EJO 4.5 h is still low and
comparable to completely epoxidised soybean oil (ESO), as reported by Petrovic and co-workers [21].
comparable to completely epoxidised soybean oil (ESO), as reported by Petrovic and co-workers [21].
It is worth noting that a low viscosity ESO produced commercially has been receiving attention for
It is worth noting that a low viscosity ESO produced commercially has been receiving attention for
use as a reactive diluent to reduce the viscosity of a petroleum-based epoxy, thus improving the
use as a reactive diluent to reduce the viscosity of a petroleum-based epoxy, thus improving the
processibility of the resin [22].
processibility of the resin [22].
8 of 17
Molecules 2017, 22, 551
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8 of 17
8 of 17
8 of 17
1 11
RR
R
OO
O
2 22
HH
H
2 22
1 11
RR
R
HH
H
OO
O
OO
O
CC
C
HH
H
2 22
2 22
2 22
1 11
2 22
OO
O
2 22
HH
H
RR
R
HH
H
OO
OHH
H
OO
C
OCC
HH
H
C
OO
OCC
HH
H
1 11
HH
H
OO
O
OO
O
OO
O
CC
C
HH
H
OO
ORR
R
RR
R H
H
H
C
2 22 CC
OHH
HH
H
H OO
CC
C
OCC
C OO
HH
H
CC
C OO
C
OCC
HH
H
RR
R
O
O
O
RR
R
1 11
RR
R
+ ++
HH
H
2 22
RR
R
1 11
RR
R
HH
H
CC
C
OO
O
HH
H
CC
C
2 22
RR
R
RR
R
O
O
O
HH
H
CHH
H
HH
HHH
H CC
C
C
C
O
OO
OCC
C OO
HH
H
HH
H OO C
C
O C
OO
C H
OCC
H
H
HH
H
Molecules 2017, 22, 551
Figure 10. Side reaction of epoxy groups [21].
Figure
10.
Side reaction
reaction of
epoxy
groups
Figure 10.
10. Side
Side
of epoxy
epoxy groups
groups [21].
[21].
Figure
reaction of
[21].
O
O
O
O
OO
O
O
O
O
O O
O O
O
O
O
O
O
O
O
O
OO
O
O
O
O
OO
O
O
O
O
O
O
O
O
O
O
OO
O
O
O
O
O O
O O
O
O
O
O
O
O
O
O
O O
OO
O
O
OO
O
O
O
O
O
O
+
+
+
O
O
O
RO
RO
RO
O
O
O
OH
OH
OH
O
O
O
O
O
O
O
O
O
O
O
O
RO
RO
RO
O
O
O
O
O
O
OH
OH
OH
O
O
O
O
O
O
Figure 11. Schematic representation of dimer formation.
Figure 11.
11. Schematic
Schematic representation
representation of dimer formation.
Figure
of dimer formation.
Viscosity
(Pa.s)
Viscosity
(Pa.s)
Viscosity
(Pa.s)
0.25
0.25
0.25
JO
JO
EJO 4.5 h
JO
EJO 4.5 h
EJO 4.5 h
0.20
0.20
0.20
0.15
0.15
0.15
0.10
0.10
0.10
0.05
0.05
0.05
0.00
0.00
0.00
10
10
10
100
100
Shear100
rate (1/s)
Shear rate (1/s)
Shear rate (1/s)
1000
1000
1000
Figure 12. Viscosity curve of jatropha oil (JO) and epoxidised jatropha oil (EJO) at 25 °C.
Figure
12. Viscosity
Viscosity curve
curve of jatropha oil (JO) and epoxidised jatropha
jatropha oil
oil (EJO)
(EJO) at
at 25
25 °C.
Figure 12.
of jatropha oil (JO) and epoxidised jatropha oil
(EJO) at
25 ◦°C.
C.
Molecules 2017, 22, 551
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9 of 17
Figure
13. Viscosity
of jatrophaoil
oil(JO)
(JO)and
and epoxidised
epoxidised jatropha
(EJO)
at various
temperatures.
Figure
13. Viscosity
of jatropha
jatrophaoiloil
(EJO)
at various
temperatures.
2.5. Molecular
Weight,
Physicochemicaland
andRheological
Rheological Properties
Oil-based
Polyol
(JOL)
2.5. Molecular
Weight,
Physicochemical
PropertiesofofJatropha
Jatropha
Oil-based
Polyol
(JOL)
The molecular weight of JOL is presented in Table 3. It is obvious that the molecular weight is
The molecular weight of JOL is presented in Table 3. It is obvious that the molecular weight is
higher than the starting EJO. With Mn increased from a range of 834–1457 for EJO to 1439–2129 for
higher
than the starting EJO. With Mn increased
from a range of 834–1457 for EJO to 1439–2129 for
JOL, it is believed that oligomerisation
also occurred during the ring opening step with methanol.
JOL, The
it is newly
believed
that
oligomerisation
also
occurred
during
theepoxy
ring opening
with
methanol.
formed OH groups tend to react with the
existing
groups tostep
form
a higher
The newly
formed
OHdimer
groups
tend to react
with the existing
epoxy
groupsin
toJOL
form
a as
higher
molecular
molecular
weight
or oligomer.
Oligomerisation
is more
pronounced
217
a result
of
weight
or oligomer.
Oligomerisation
is more
pronounced
in JOL
217 as a result
of reported
the relatively
thedimer
relatively
high epoxy
content of the starting
EJO.
The formation
of oligomers
was also
Caillol
and co-workers
[23] for
soybean
oil-based polyol
(44–63%was
oligomers)
produced
ring and
high by
epoxy
content
of the starting
EJO.
The formation
of oligomers
also reported
byby
Caillol
opening
with
carboxylic
acid.
co-workers [23] for soybean oil-based polyol (44%–63% oligomers) produced by ring opening with
carboxylic acid.
Table 3. Molecular weight of JOL.
Molecular
weight
of PDI
JOL.= Mw/Mn
Sample Table 3.M
n
M
w
JOL 161
1572
2121
1.35
Sample JOL 188
M1439
n
2110 M w
1.47 PDI = M w /M n
2129
2231 2121
1.05
JOL 161 JOL 217
1572
1.35
JOL 188
1439
2110
1.47
JOL 217
2231in Table 4. The polyols
1.05 produced were
Other physico-chemical
properties2129
of the JOL are given
slightly yellow in colour, and all of them were liquid at room temperature. A polyol of industrial
importance is commonly required to have low viscosity and a high hydroxyl value. From our
Other
physico-chemical properties of the JOL are given in Table 4. The polyols produced were
previous work, waterborne polyurethane film synthesised from JOL 138 was soft and tacky with
slightly yellow in colour, and all of them were liquid at room temperature. A polyol of industrial
poor structural rigidity [20]. For this reason, only JOL 161, JOL 188, and JOL 217 were analysed in
importance
commonly
low viscosity
and a viscosity
high hydroxyl
value. From
our as
previous
terms ofisviscosity
and required
rheology.to
Inhave
polyurethane
production,
is an important
criterion
it
work,determines
waterborne
polyurethane
film
synthesised
from
JOL
138
was
soft
and
tacky
with
poor
structural
the ease of pouring and pumping the polyol into the machine to be mixed with
rigidity
[20]. For this
only
161,
188, andof
JOL
analysed
viscosity
diisocyanates
[18].reason,
As shown
in JOL
Figure
10,JOL
the viscosity
the217
JOLwere
increased
from in
430terms
to 940ofmPas
and rheology.
polyurethane
production,
viscosity
an important
determineswith
the ease
when the In
OH
number increased
from 161
to 217ismgKOH/g.
The criterion
viscosity as
is itcomparable
soybean
oil-based
polyol
a lower
OH number,
a viscosity
of 2500 to 35,000
mPas
was
of pouring
and
pumping
the [24,25].
polyol With
into the
machine
to be mixed
with diisocyanates
[18].
As shown
in
reported
for
polyol
derived
from
crude
palm
oil
[18].
A
commercial
polyol
is
available
in
various
Figure 10, the viscosity of the JOL increased from 430 to 940 mPas when the OH number increased
ranges
from as low
230 mPas
to above 10,000
depending
onpolyol
the OH[24,25].
number,
from viscosity
161 to 217
mgKOH/g.
Theasviscosity
is up
comparable
with mPas,
soybean
oil-based
With a
functionality, production routes, and its vegetable oil origin types [26].
lower OH number, a viscosity of 2500 to 35,000 mPas was reported for polyol derived from crude palm
The JOL exhibits Newtonian behaviour similar to the rheological behaviour of the starting EJO,
oil [18]. A commercial polyol is available in various viscosity ranges from as low as 230 mPas up to
as shown in Figure 14. With increasing temperature, the viscosity decreased significantly (Figure 15).
aboveBased
10,000
the OH number,
functionality,
routes,
and its vegetable
onmPas,
these depending
results, the on
processing
temperature
of the JOLproduction
could be easily
correlated
with
oil origin
types
[26].
viscosity.
For
example, the JOL has to be heated to a temperature above 70 °C to achieve a viscosity
The
JOL
exhibits
Newtonian
similar
to the rheological
behaviour
of the
of less
than
100 mPas
(see inset behaviour
in Figure 15).
In waterborne
polyurethane
production,
the starting
reaction EJO,
as shown
in Figure
14. With
increasing
temperature,
the viscosity decreased significantly (Figure 15).
temperature
is usually
in the
range of 65
°C to 90 °C [16,27,28].
Based on these results, the processing temperature of the JOL could be easily correlated with viscosity.
For example, the JOL has to be heated to a temperature above 70 ◦ C to achieve a viscosity of less than
100 mPas (see inset in Figure 15). In waterborne polyurethane production, the reaction temperature is
usually in the range of 65 ◦ C to 90 ◦ C [16,27,28].
Molecules
2017, 22,
551
Molecules
Molecules 2017,
2017, 22,
22, 551
551
10 of 17
17
10
10 of
of 17
Table
4.
Physicochemical
properties
of
the
JOL.
Table
4. Physicochemical
Physicochemical properties
properties of
of the
the JOL.
JOL.
Table 4.
OH
OH Number
Number
OH Number
Sample (mgKOH/g)
(mgKOH/g)
(mgKOH/g)
JOL
138
JOL 138
138
138
JOL
138
138
JOL
161
JOL 161
161
161161
JOL 161
JOL
188
JOL 188
188
188188
JOL 188
JOL
217
217
JOL 217
JOL 217
217217
Sample
Sample
Acid
Acid Value
Value
Acid Value
(mgKOH/g)
(mgKOH/g)
(mgKOH/g)
29.92
29.92
29.92
26.09
26.09
26.09
26.66
26.66
26.66
15.95
15.95
15.95
EW
EW **
EW *
407
407
Physical
Density
Physical
Density
**
** Density
Physical
3
Appearance
(kg/m
3)
f **
)
Appearance
(kg/m
(kg/m3 )
Appearance
--liquid
liquid
- 4.51
- 965.5
liquid liquid
4.51
965.5
4.51
965.5
liquid liquid
4.82
971.9
liquid
4.82 4.82 971.9971.9
liquid liquid
8.24
975.5
8.24 8.24 975.5975.5
liquid liquid
liquid
407348
348348
298
298298
259259
259
** Equivalent
weight,
**
functionality.
* Equivalent weight,
weight, **
Equivalent
**functionality.
functionality.
1.4
1.4
JOL
JOL 161
161
JOL
JOL 188
188
JOL
JOL 217
217
EJO
EJO 4.5h
4.5h
Viscosity(Pa.s)
(Pa.s)
Viscosity
1.2
1.2
1.0
1.0
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0.0
0.0
10
10
100
100
Shear
Shear rate
rate (1/s)
(1/s)
1000
1000
Figure
14. Viscosity
curves of
jatropha oil-based
polyol
with
different
OH
numbers
at
25
Figure
oil-based polyol
polyol with
with different
different OH
OH numbers
numbers at
at 25
25 ◦°C.
°C.
Figure 14.
14. Viscosity
Viscosity curves
curves of
of jatropha
jatropha oil-based
C.
As
As shown
shown in
in Figure
Figure 16,
16, the
the viscosity
viscosity plotted
plotted against
against the
the reciprocal
reciprocal temperature
temperature obeyed
obeyed the
the
As
shown
in
Figure
16,
the
viscosity
plotted
against
the
reciprocal
temperature
obeyed
the
Arrhenius
Arrhenius dependence
dependence (Equation
(Equation 1):
1):
Arrhenius dependence (Equation (1)):
E
(1)
=
(1)
(1)
η=
= ηo e RT
reference
viscosity,
the
viscous-flow
activation
energy,
the
gas
constant,
and
T
where
where
is is
the
gas
constant,
and
T is
is aa reference
reference viscosity,
viscosity,EE
Eisis
isthe
theviscous-flow
viscous-flowactivation
activationenergy,
energy,R R
R
is
the
gas
constant,
and
T
where ηη
ηooo is
is
absolute
temperature
From
slopes
of
straight
lines,
activation
energy
of
the
absolute
temperature
(K).(K).
From
thethe
slopes
of these
straight
lines,
the the
activation
energy
of flow
can
is the
the
absolute
temperature
(K).
From
the
slopes
of these
these
straight
lines,
the
activation
energy
of flow
flow
can
be
is
in
be
and and
this this
is presented
in Table
5. 5.
cancalculated,
be calculated,
calculated,
and
this
is presented
presented
in Table
Table
5.
of
250
ss−1
−1s..− 1 .
Figure 15.
Viscosityof
ofjatropha
jatrophaoil-based
oil-basedpolyol
polyol(JOL)
(JOL)at
varioustemperatures
temperaturesat
shearrate
rate
250
15. Viscosity
Viscosity
of
jatropha
oil-based
polyol
(JOL)
atatvarious
various
temperatures
atataa ashear
shear
rate
ofof
250
Molecules 2017, 22, 551
Molecules 2017, 22, 551
11 of 17
11 of 17
9
8
7
ln η
6
JO
EJO 4.5 h
JOL 161
JOL 188
JOL 217
5
4
3
2
1
2.6
2.8
3.0
3.2
3.4
3.6
1/T *1000
Figure 16. The viscosity–temperature relationship for jatropha oil-based polyols (JOLs).
(JOLs).
The viscous-flow
viscous-flow activation
activation energies
energies for
for jatropha
jatropha oil
oil and
and EJO
EJO are
are also
also included.
included. The
The activation
activation
The
energy of
of flow
flow is
is related
related to
to the
the flexibility
flexibility of
of the
the molecular
molecular chains
chains and
and the
the interaction
interaction between
between
energy
molecules
[29].
The
activation
energies
of
the
polyols
were
significantly
higher
than
those
of
EJO and
and
molecules [29]. The activation energies of the polyols were significantly higher than those of EJO
jatropha
oil.
These
confirmed
the
hydrogen
bonding
present
in
all
the
JOLs,
increasing
according
to
jatropha oil. These confirmed the hydrogen bonding present in all the JOLs, increasing according
hydroxyl
numbers.
The
activation
energy
values
soy
to
hydroxyl
numbers.
The
activation
energy
valuesobtained
obtainedare
arecomparable
comparabletotothose
those values
values of
of soy
polyols
reported
by
Dai
and
co-workers
[25].
Vegetable
oil
contains
a
cis
C=C
double
bond
that
polyols reported by Dai and co-workers [25]. Vegetable oil contains a cis C=C double bond that created
a defect
in theofpacking
of the triglycerides.
The lower
viscosity
of the
oil to
is
acreated
defect in
the packing
the triglycerides.
The lower viscosity
of the
vegetable
oil isvegetable
comparable
comparable
to animal
fat [30].energy
The activation
energy
of jatropha
oilreported
is similar
that reported
animal
fat [30].
The activation
of jatropha
oil is similar
to that
fortosoybean
oil [29].for
soybean oil [29].
Table 5. Viscosity at 45 ◦ C and activation energy of viscous flow (Ea ) for the jatropha oil-based polyols.
Table 5. Viscosity at 45 °C and activation energy of viscous flow (Ea) for the jatropha oil-based polyols.
Sample
Sample
JO JO
EJO
EJO
JOL 161
JOL JOL
161 188
JOL JOL
188 217
JOL 217
◦
Viscosity at 45 C (mPas)
Activation Energy (kJ/mol)
Viscosity
at 45 °C (mPas)
Activation
Energy (kJ/mol)
25.7
28.7 28.7
25.7
77.2
32.3
77.2
32.3
154.8
39.1
154.8 241.0
39.1
40.5
241.0 289.0
40.5
46.0
289.0
46.0
2.6. Monitoring Polyurethane Synthesis by FTIR
2.6. Monitoring Polyurethane Synthesis by FTIR
The polyurethane synthesis was monitored by FTIR analysis, as shown in Figure 17. At 1 h of
− 1FTIR
Thetime,
polyurethane
synthesis was
monitored
by
shown
in Figure
17. At
1 h of
reaction
a strong absorbance
peak
at 2270 cm
was analysis,
observed,aswhich
indicated
a high
amount
−1 was observed, which
−
1
reaction
time,
a
strong
absorbance
peak
at
2270
cm
indicated
a
high
amount
of free isocyanate. The formation of an absorbance peak at 3324 cm confirmed the formation of
of free isocyanate.
The formation
of an
absorbance
peak at and
3324polyol
cm−1 confirmed
the formation
of
urethane
by the reaction
of dimethylol
propionic
acid (DMPA)
with isophrene
diisocyanate
urethane
by
the
reaction
of
dimethylol
propionic
acid
(DMPA)
and
polyol
with
isophrene
diisocyanate
(IPDI). At the early stage of polymerisation, it is believed that the DMPA reacted rapidly with IPDI
(IPDI).
At the
stage of
of the
polymerisation,
it is believed
that the DMPA reacted rapidly with IPDI
due
to the
highearly
reactivity
primary hydroxyl
in the structure.
due to
the
high
reactivity
of
the
primary
hydroxyl
in
the
structure.
The consumption rate of free isocyanate is high during the first two hours of reaction and becomes
The
consumption
rate toofa free
isocyanate
is high
during
theand
first
of reaction
and
slower
as time
proceeds due
decreasing
amount
of NCO
groups
thetwo
lowhours
reactivity
of secondary
becomes
slower
time
proceeds
to a decreasing
amount
of NCO(HEMA)
groups and
lowtoreactivity
OH
groups
in theas
JOL.
After
3 h of due
reaction,
hydroxyethyl
methacrylate
wasthe
added
end-cap
of
secondary
OH
groups
in
the
JOL.
After
3
h
of
reaction,
hydroxyethyl
methacrylate
(HEMA)
was
the terminal NCO groups. After 3 h and 35 min, the NCO peak almost disappeared, thus indicating
added
to
end-cap
the
terminal
NCO
groups.
After
3
h
and
35
min,
the
NCO
peak
almost
disappeared,
that most of the isocyanate groups were involved in polymerisation. An absorbance peak at 1707 cm− 1
thus indicatingwith
that carbonyl
most of the
isocyanate
groups
in polymerisation.
An absorbance
corresponded
group
stretching,
andwere
the involved
–NH bending
observed at 1531
cm− 1 was
−1 corresponded with carbonyl group stretching, and the –NH bending observed
peak
at
1707
cm
evidence of polyurethane formation.
at 1531 cm−1 was evidence of polyurethane formation.
Molecules 2017, 22, 551
12 of 17
Molecules 2017, 22, 551
12 of 17
100 (b)
95
100
90
95
85
90
85
12 of 17
% Transmittance
% Transmittance
% Transmittance
% Transmittance
(a)
100
Molecules 2017, 22, 551
98
100 (b)
(a)
JPU 1 h
JPU 2 h
JPU 2 h 45 min
JPU 3 h 35 min
JOL
N=C=O
JPU 1 h
JPU 2 h
JPU 2 h 45 min
2320
2280
2240
JPU 3 h 35 min
-1
Wavenumber
(cm
)
JOL
N=C=O
2320
2280
2240
100
(c)
Wavenumber (cm-1)
2200
2200
96
98
94
96
4000
94
4000
O-H
JPU 1 h
JPU 2 h
JPU 2 h 45 min
JPU 3 h 35 min
N-H
JOL
O-H
JPU 1 h
JPU 2 h
3800
3600
3400
3200
JPU 2 h 45 min
-1
JPU 3 h 35 min
N-H)
Wavenumber (cm
JOL
3800
3600
3400
3200
3000
3000
Wavenumber (cm-1)
90
% Transmittance
% Transmittance
100
80
90
70
(c)
N-H
JPU 1 h
80
JPU 2 h
60
N-H
JPU 2 h 45 min
70
JPU 3 h 35 min
JOL 1 h
C=O
JPU
50
JPU 2 h
60
JPU 2 h 45 min
1800 1750 1700 1650 1600 JPU
1550
1500
3 h 35
min 1450
-1
C=O
Wavenumber (cmJOL
)
50
Figure
FTIR spectra
of (a)
isocyanate
group1650
in polyurethane,
(b)
the hydroxyl
andthe
urethane
groupand
1800
1750
1700
1600 in
1550
1500
1450 (b)
Figure
17.17. FTIR
spectra
ofthe
(a)
the
isocyanate
group
polyurethane,
hydroxyl
-1
in polyol and polyurethane respectively, and (c) Wavenumber
the carbonyl(cm
and
urethane
group
in
polyurethane.
)
urethane group in polyol and polyurethane respectively, and
(c) the carbonyl and urethane group
in polyurethane.
Figure 17. FTIR spectra of (a) the isocyanate group in polyurethane, (b) the hydroxyl and urethane group
2.7. Physical Properties of the Aqueous Polyurethane (JPU) Dispersion
in polyol and polyurethane respectively, and (c) the carbonyl and urethane group in polyurethane.
The Properties
aqueous JPU
synthesised in
this Dispersion
work has a solid content of 25 wt. % and
2.7. Physical
of thedispersion
Aqueous Polyurethane
(JPU)
2.7. Physical
Properties
the Aqueous
Polyurethane
(JPU)
Dispersion
appears
milky
white inofcolour.
The dispersion
has
a low
viscosity of 12.5 mPas, with a zeta potential
aqueous
JPU 18
dispersion
synthesised
in this work
hasdispersion,
a solid content of
25 wt. % and
appears
ofThe
−56.6
mV.
Figure
shows
a
particle
size
distribution
of
the
demonstrates
theand
low
The aqueous JPU dispersion synthesised in this work
has a solidwhich
content
of 25 wt. %
milky
white
in
colour.
The
dispersion
has
a
low
viscosity
of
12.5
mPas,
with
a
zeta
potential
of
particle
size
with
a
modal
peak
at
13.5
nm.
From
the
point
of
view
of
colloidal
stability,
the
dispersion
appears milky white in colour. The dispersion has a low viscosity of 12.5 mPas, with a zeta potentialis
−56.6
mV.asFigure
18 shows
a particle
sizethan
distribution
of the
dispersion,
which
demonstrates
the low
stable
the average
particle
is less
100 nm [31].
particle size
is andemonstrates
important
parameter
of −56.6
mV.
Figure 18
showssize
a particle
size distribution
of The
the dispersion,
which
the low
particle
size size
with
a
modal
peak
at
13.5
nm.
From
the
point
of
view
of
colloidal
stability,
the
dispersion
inparticle
deciding
the
industrial
applications
of
a
waterborne
polyurethane
dispersion
[32],
in
which
with a modal peak at 13.5 nm. From the point of view of colloidal stability, the dispersion isa
small
particle
size is particle
essential
for deep
of[31].
the
dispersion
into
aissubstrate
[33]. parameter
is stable
as
the
average
is
than100
100nm
nm
[31].
The
particle
isimportant
an important
parameter
stable as the average
particlesize
size
is less
lesspenetration
than
The
particle
sizesize
an
in deciding
the industrial
applications
of aofwaterborne
polyurethane
dispersion
in deciding
the industrial
applications
a waterborne
polyurethane
dispersion[32],
[32],ininwhich
whichaasmall
particle
size
is essential
for deepfor
penetration
of the of
dispersion
into into
a substrate
[33].
small
particle
size is essential
deep penetration
the dispersion
a substrate
[33].
Figure 18. Particle size distribution of the JPU dispersion.
Figure
Particlesize
size distribution
distribution ofofthe
dispersion.
Figure
18.18.Particle
theJPU
JPU
dispersion.
Molecules 2017, 22, 551
13 of 17
3. Materials and Methods
3.1. Materials
Reagent grade hydrogen peroxide 30% and methanol were supplied by Merck (Darmstadt,
Germany). Isophrene diisocyanate (IPDI), dimethylol propionic acid (DMPA), n-methyl pyrollidone
(NMP), hydroxyethyl methacrylate (HEMA), phtalic anhydride, and dibutyltin dilaurate (DBTDL)
were supplied by Sigma Aldrich (Milwaukee, WI, USA). Ethyl methyl ketone (MEK), triethylamine
(TEA), formic acid, magnesium sulphate anhydrous, pyridine, and sodium hydroxide were reagent
grade, supplied by Classic Chemicals (Shah Alam, Malaysia). The crude jatropha oil was supplied by
Biofuel Bionas Sdn Bhd, Kuala Lumpur, Malaysia. It is a non-food grade material and was used as
received. All chemicals were used without further purification.
3.2. Preparation of Jatropha Oil-Based Polyol (JOL)
Polyols were synthesised by a two-step process; namely epoxidation followed by oxirane ring
opening (Figure 2).
3.2.1. Epoxidation
The reaction parameters for the epoxidation step are presented in Table 6. The epoxidation
parameters are divided into three groups; reaction temperature at 50 ◦ C with varied molar ratio,
reaction at 60 ◦ C with varied molar ratio, and the molar ratio fixed in 1:0.6:1.7 with varied reaction
times. Briefly, a mixture of jatropha oil and formic acid was placed in a 1 L flask and heated to 40 ◦ C
under continuous stirring. Hydrogen peroxide 30% was then added dropwise for 30 min before
increasing the temperature to a specified reaction temperature. After a prescribed time, the mixture
was cooled to room temperature. The aqueous layer was discarded, and the remaining acid was
removed by washing the oil layer with an excessive amount of water. Magnesium sulphate was then
added to the EJO as a drying agent.
Table 6. Reaction parameters for the epoxidation step and the acid values of epoxidised jatropha
oil (EJO).
No.
Molar Ratio a
Reaction Temperature (◦ C)
Reaction Time (h)
Acid Value (mgKOH/g)
1
2
3
4
5
6
7
8
9
10
11
1.0:0.4:1.7
1.0:0.6:1.7
1.0:1.0:1.7
1.0:0.4:1.7
1.0:0.6:1.7
1.0:1.0:1.7
1.0:1.2:1.7
1.0:0.6:1.7
1.0:0.6:1.7
1.0:0.6:1.7
1.0:0.6:1.7
50
50
50
60
60
60
60
60
60
60
60
5
5
5
4
4
4
4
2
3
4
4.5
14.49
14.76
16.27
15.10
15.20
16.40
14.43
15.95
a
Double bond: Formic acid: Hydrogen peroxide.
3.2.2. Oxirane Ring Opening
The reactions were carried out in a four-necked flask equipped with a mechanical stirrer,
condenser, dropping funnel, and thermometer. For this reaction, the molar ratio of methanol to
water is 5:1, while the amount of water is 10% (w/w) of epoxidised jatropha oil. Briefly, a calculated
amount of methanol, water, and sulphuric acid catalyst (0.3 wt. %) were poured into a 1 L flask and
heated to 64 ◦ C under continuous stirring. Epoxidised jatropha oil was then added, and the reactions
proceeded for 30 min, followed by adding sodium bicarbonate to quench the reaction. After being
Molecules 2017, 22, 551
14 of 17
cooled to room temperature, the deposit was discarded. Methanol and water were removed by vacuum
distillation.
Only
to
Molecules 2017,
22,the
551 third series of epoxidised jatropha oil was selected to be further converted
14 of 17
polyol using the same oxirane ring opening conditions. Four types of polyol with different hydroxyl
10
1.0:0.6:1.7
60
4
numbers were produced.
11
1.0:0.6:1.7
60
4.5
15.95
Double bond:
Formic acid: Hydrogen peroxide.
3.3. Preparation of Aqueous Polyurethane
Dispersion
a
The
reactions were
carried
out in a four-necked
3.3. Preparation
of Aqueous
Polyurethane
Dispersion flask equipped with a mechanical stirrer, dropping
funnel, condenser, and thermometer. The jatropha oil-based polyol (JOL 161) and DMPA (dissolved
The reactions were carried out in a four-necked flask equipped with
a mechanical stirrer,
in NMP)
werefunnel,
charged
into theand
flask
and heatedThe
to ajatropha
temperature
of polyol
80 ◦ C (JOL
for 30161)
min.
mixture
dropping
condenser,
thermometer.
oil-based
andThe
DMPA
◦ C and the IPDI was slowly dropped for 30 min. DBTDL was used as a catalyst.
was then
cooled
to
60
(dissolved in NMP) were charged into the flask and heated to a temperature of 80 °C for 30 min. The
The reaction
wasthen
reheated
a temperature
ofdropped
80 ◦ C for
h,min.
followed
theused
addition
mixture was
cooled and
to 60reached
°C and the
IPDI was slowly
for330
DBTDLby
was
as a of
HEMA
for a The
chain
termination
step. About
20 g of
MEK was added
batch
to reduce
catalyst.
reaction
was reheated
and reached
a temperature
of 80 °C
for 3by
h, batch
followed
by the the
addition
of system
HEMA for
a chain
termination
step. About
20 gg).
of The
MEKreaction
was added
by batch
to the
viscosity
of the
(the
total amount
of MEK
was 100
wasbatch
complete
when
reducespectra
the viscosity
of the
system
(the total
amount
of MEK
g). The reaction
was
complete that
ATR-FTIR
showed
that
the NCO
peak
at 2270
cm− 1was
had100
disappeared,
thus
indicating
−1 had
the ATR-FTIR
spectra showed
that the NCO
2270 to
cm40
disappeared,
thus
◦ C and
all thewhen
diisocyanate
was consumed.
The reactants
werepeak
then at
cooled
neutralised
by the
indicating that all the diisocyanate was consumed. The reactants were then cooled to 40 °C and
addition of TEA (1.2 equiv. per DMPA), followed by dispersion at high speed with distilled water to
neutralised by the addition of TEA (1.2 equiv. per DMPA), followed by dispersion at high speed
produce the JPU dispersions with a solid content of ∼25 wt.% after removal of the MEK under vacuum.
with distilled water to produce the JPU dispersions with a solid content of ∼25 wt.% after removal of
The formulation
of waterborne
is shownofinwaterborne
Table 7, using
NCO/OH
of 0.8/1.0,
while
the chemical
the MEK under
vacuum. TheJPU
formulation
JPU is
shown in Table
7, using
NCO/OH
of
reaction
is
shown
in
Figure
19.
0.8/1.0, while the chemical reaction is shown in Figure 19.
H3CO
OH
O
O
O
OCH3
O
O
CH3
CH3
OCH3
+
CH3
O C N
+
HO
OH
N C O
O
COOH
IPDI
O
DMPA
JOL
O
DBTDL ( catalyst )
O
HO
CH2
O
HEMA
CH3
N
O
O
H3CO
O
O
O
O
OCH3
O
O
TEA
N
H
OCH3
H
N
O
O
O
COO
O
N
H
NH
O
Water
O
O
Aqueous polyurethane dispersion
Figure 19. Synthesis of aqueous polyurethane dispersion.
Figure 19. Synthesis of aqueous polyurethane dispersion.
O
H
N
O
O
O
CH2
CH3
Molecules 2017, 22, 551
15 of 17
Table 7. The recipe of aqueous polyurethane (JPU) dispersions.
Ingredient
Functional Group
Mass (g)
Mol
JOL
DMPA
HEMA
IPDI
OH
OH
OH
NCO
60.0
7.3
4.3
29.0
0.172
0.111
0.033
0.260
3.4. Characterisation
The oxirane oxygen content measurement of the epoxidised jatropha oil was determined according
to AOCS Tentative Method Cd 9-57, revised in 1963. The theoretical maximum oxirane oxygen content,
OOCt was determined to be 5.74% according to Equation (2):
OOCt = {( IV0 /2Ai )/[100 + ( IV0 /2Ai ) A0 )]} × A0 × 100
(2)
where IV0 (96.06) is the initial iodine value of the oil, Ai (126.9) is the atomic weight of iodine, and A0
(16.0) is the atomic weight of oxygen [13].
The oxygen oxirane content was used to determine the relative conversion to oxirane, according
to Equation (3):
Relative conversion to oxirane = OOCc /OOCt
(3)
where OOCc is an experimental oxirane oxygen content.
The determination of the hydroxyl number of the jatropha-based polyol followed ASTM D4274-99
Test Method C (reflux phthalation) standard practice. The equivalent weights (EW) of the polyols were
calculated using Equation (4) [18]:
EW =
(Molecular weight of KOH × 1000)
OH number
=
56100
OH number
(4)
The acid number measurements of the epoxidised jatropha oil and the polyol were determined
according to ASTM D4662-03 Test Method A standard practice.
The FTIR spectra were recorded on a Perkin-Elmer Spectrum 2000 spectrometer (Perkin Elmer,
Norwalk, CT, USA), equipped with a horizontal germanium attenuated total reflectance (ATR)
accessory. The spectra were recorded in the range of 4000–500 cm− 1 with a nominal resolution
of 4 cm− 1 .
The molecular weight of the samples was determined using Gel Permeation Chromatography
(Waters Co., Milford, MA, USA) with a series of Styragel® columns. Calibration was performed using
a polystyrene standard, whereby tetrahydrofuran (THF) was used as the eluent with a flow rate of
1.0 µL/min at 35 ◦ C. The sample injection volume was 50.0 µL.
The rheological properties of the samples were analysed on an ARG2 rheometer (TA Instruments,
DE, USA). The rheometer was equipped with a 40 mm 2◦ cone, and the gap between the truncated tip
of the cone and the bottom Peltier plate was maintained at 56 µm.
The particle size of the polyurethane dispersions was measured by a Zetasizer Nano-S (Malvern
Instruments, Herrenberg, Germany). Approximately 0.1 mL of the polyurethane dispersion was
diluted with 3 mL distilled water and measured at 25 ◦ C.
4. Conclusions
Jatropha oil-based polyols were successfully synthesised by epoxidation and an oxirane ring
opening method, and the physicochemical properties of the products were reported. The epoxidation
reaction parameters such as temperature, the oil double bond to formic acid molar ratio, and time
showed a significant effect on the conversion of the double bond to an oxirane group. About 75%
conversion was obtained at a temperature of 60 ◦ C, a molar ratio of 1:0.6, and a 4 h reaction time,
Molecules 2017, 22, 551
16 of 17
which is equivalent to 4.30% OOC of epoxidised jatropha oil (EJO). Furthermore, a series of JOLs with
a hydroxyl number of 138–217 mgKOH/g was successfully prepared after the oxirane ring opening of
the EJO produced at a reaction time of 2.25 to 4.5 h. The resulting JOLs exhibited Newtonian behaviour,
with a low viscosity of 430–970 mPas, and molecular weight of 1349–2129 g/mol. Polyurethane was
successfully synthesised from JOL, as monitored by FTIR. The corresponding polyurethane dispersion
had average small particle size, indicating good colloidal stability.
Acknowledgments: The authors gratefully acknowledge the Ministry of Higher Educations Malaysia
for the financial support provided for this work (FRGS-Malaysia’s Rising Star Awards, Code:
UPM/700-2/1/FRGS/GSP/5524868). The authors would also like to thank the Malaysian Nuclear Agency
for the use of their facilities and instruments.
Author Contributions: S.S., L.C.A., E.R.J., and M.B. conceived and designed the experiments; S.S, E.R.J., and S.M.
performed the experiments; S.S., M.M.A., D.R.A.B., and M.Z.S. analyzed the data; L.C.A. and M.Z.S. contributed
reagents and equipment; and S.S. and L.C.A. wrote the paper.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Ferreira, P.; Pereira, R.; Coelho, J.F.J.; Silva, A.F.M.; Gil, M.H. Modification of the biopolymer castor oil with
free isocyanate groups to be applied as bioadhesive. Int. J. Biol. Macromol. 2007, 40, 144–152. [CrossRef]
[PubMed]
Boruah, M.; Gogoi, P.; Adhikari, B.; Dolui, S.K. Preparation and characterization of Jatropha Curcas oil based
alkyd resin suitable for surface coating. Prog. Org. Coat. 2012, 74, 596–602. [CrossRef]
Patel, V.C.; Varughese, J.; Krishnamoorthy, P.A.; Jain, R.C.; Singh, A.K.; Ramamoorty, M. Synthesis of alkyd
resin from jatropha and rapeseed oils and their applications in electrical insulation. J. Appl. Polym. Sci. 2008,
107, 1724–1729. [CrossRef]
Kong, X.; Liu, G.; Curtis, J.M. Characterization of canola oil based polyurethane wood adhesives. Int. J.
Adhes. Adhes. 2011, 31, 559–564. [CrossRef]
Silva, B.B.R.; Santana, R.M.C.; Fortem, M.M.C. A solventless castor oil-based PU adhesive for wood and
foam substrates. Int. J. Adhes. Adhes. 2010, 30, 559–565. [CrossRef]
Aung, M.M.; Yaakob, Z.; Kamarudin, S.; Abdullah, L.C. Synthesis and characterization of Jatropha (Jatropha
curcas L.) oil-based polyurethane wood adhesive. Ind. Crops. Prod. 2014, 60, 177–185. [CrossRef]
Saravari, O.; Praditvatanakit, S. Preparation and properties of urethane alkyd based on a castor oil/jatropha
oil mixture. Prog. Org. Coat. 2013, 76, 698–704. [CrossRef]
Harjono, S.P.; Alim, M.Z. Synthesis and application of jatropha oil based polyurethane as paint coating
material. Makara. J. Sci. 2012, 16, 134–140.
Sarin, R.; Sharma, M.; Sinharay, S.; Malhotra, R.K. Jatropha-Palm biodiesel blends: An optimum mix for Asia.
Fuel 2007, 86, 1365–1371. [CrossRef]
Tan, S.G.; Chow, W.S. Biobased epoxidized vegetable oils and its greener epoxy blends: A review. Polym. Plast.
Technol. Eng. 2010, 49, 1581–1590. [CrossRef]
Goud, V.V.; Dinda, S.; Patwardhan, A.V.; Pradhan, N.C. Epoxidation of Jatropha (Jatropha curcas) oil by
peroxyacids. Asia-Pac. J. Chem. Eng. 2010, 5, 346–354. [CrossRef]
Goud, V.V.; Patwardhan, A.V.; Dinda, S.; Pradhan, N.C. Kinetics of epoxidation of jatropha oil with
peroxyacetic and peroxyformic acid catalysed by acidic ion exchange resin. Chem. Eng. Sci. 2007, 62,
4065–4076. [CrossRef]
Sinadinović-Fišer, S.; Janković, M.; Borota, O. Epoxidation of castor oil with peracetic acid formed in situ in
the presence of an ion exchange resin. Chem. Eng. Process Process Intensif. 2012, 62, 106–113. [CrossRef]
Hazmi, A.S.A.; Aung, M.M.; Abdullah, L.C.; Salleh, M.Z.; Mahmood, M.H. Producing Jatropha oil-based
polyol via epoxidation and ring opening. Ind. Crops Prod. 2013, 50, 563–567. [CrossRef]
Meyer, P.; Techaphattana, N.; Manundawee, S.; Sangkeaw, S. Epoxidation of soybean oil and jatropha oil.
Thammasat Int. J. Sci. Tech. 2008, 13, 1–5.
Lu, Y.; Larock, R.C. Soybean-oil-based waterborne polyurethane dispersions: Effects of polyol functionality
and hard segment content on properties. Biomacromolecules 2008, 9, 3332–3340. [CrossRef] [PubMed]
Molecules 2017, 22, 551
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
17 of 17
Garrison, T.F.; Kessler, M.R.; Larock, R.C. Effects of unsaturation and different ring-opening methods on the
properties of vegetable oil-based polyurethane coatings. Polymer 2014, 55, 1004–1011. [CrossRef]
Ahmad, S. Palm-based polyols and polyurethanes. Technology 2002, 24, 1–29.
Petrovic, Z. Polyurethanes from vegetable oils. Polym. Rev. 2008, 48, 109–155. [CrossRef]
Saalah, S.; Abdullah, L.C.; Aung, M.M.; Shlleh, M.Z.; Biak, D.R.A.; Basri, M.; Jusoh, E.R. Waterborne
polyurethane dispersions synthesized from jatropha oil. Ind. Crops Prod. 2015, 64, 194–200. [CrossRef]
Petrovic, Z.S.; Zlatanic, A.; Lava, C.C.; Sinadinovic-Fiser, S. Epoxidation of soybean oil in toluene with
peroxoacetic and peroxoformic acids-kinetics and side reactions. Eur. J. Lipid. Sci. Technol. 2002, 104, 293–299.
[CrossRef]
Miao, S.; Wang, P.; Su, Z.; Zhang, S. Vegetable-oil-based polymers as future polymeric biomaterials.
Acta Biomater. 2014, 10, 1692–1704. [CrossRef] [PubMed]
Caillol, S.; Desroches, M.; Boutevin, G.; Loubat, C.; Auvergne, R.; Boutevin, B. Synthesis of new polyester
polyols from epoxidized vegetable oils and biobased acids. Eur. J. Lipid. Sci. Technol. 2012, 114, 1447–1459.
[CrossRef]
Zhang, J.; Tang, J.J.; Zhang, J.X. Polyols prepared from ring-opening epoxidized soybean oil by a castor
oil-based fatty diol. Int. J. Polym. Sci. 2015, 2015, 1–8. [CrossRef]
Dai, H.; Yang, L.; Lin, B.; Wang, C.; Shi, G. Synthesis and characterization of the different soy-based polyols
by ring opening of epoxidized soybean oil with methanol, 1,2-ethanediol and 1,2-propanediol. J. Am. Oil
Chem. Soc. 2009, 86, 261–267. [CrossRef]
Desroches, M.; Escouvois, M.; Auvergne, R.; Caillol, S.; Boutevin, B. From vegetable oils to polyurethanes:
Synthetic routes to polyols and main industrial products. Polym. Rev. 2012, 52, 38–79. [CrossRef]
Bullermann, J.; Friebel, S.; Salthammer, T.; Spohnholz, R. Novel polyurethane dispersions based on renewable
raw materials—Stability studies by variations of DMPA content and degree of neutralisation. Prog. Org.
Coat. 2013, 76, 609–615. [CrossRef]
Ni, B.; Yang, L.; Wang, C.; Wang, L.; Finlow, D.E. Synthesis and thermal properties of soybean oil-based
waterborne polyurethane coatings. J. Therm. Anal. Calorim. 2010, 100, 239–246. [CrossRef]
Blayo, A.; Gandini, A.; Nest, Le, J.-F. Chemical and rheological characterizations of some vegetable oils
derivatives commonly used in printing inks. Ind. Crops Prod. 2001, 14, 155–167. [CrossRef]
Guo, A.; Cho, Y.; Petrović, Z.S. Structure and properties of halogenated and nonhalogenated soy-based
polyols. J. Polym. Sci. Part A Polym. Chem. 2000, 38, 3900–3910. [CrossRef]
Tielemans, M.; Roose, P.; Groote, De P.; Vanovervelt, J.-C. Colloidal stability of surfactant-free radiation
curable polyurethane dispersions. Prog. Org. Coat. 2006, 55, 128–136. [CrossRef]
Hercule, K.M.; Yan, Z.; Christophe, M.M. Preparation and characterization of waterborne polyurethane
crosslinked by urea bridges. Int. J. Chem. 2011, 3, 88–96. [CrossRef]
Asif, A.; Shi, W.; Shen, X.; Nie, K. Physical and thermal properties of UV curable waterborne polyurethane
dispersions incorporating hyperbranched aliphatic polyester of varying generation number. Polymer 2005,
46, 11066–11078. [CrossRef]
Sample Availability: Samples of the compounds jatropha oil, epoxidised jatropha oils and polyols are available
from the authors.
© 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
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(CC BY) license (http://creativecommons.org/licenses/by/4.0/).