Synthesis and characterization of ricinoleamide-based polyurethane

Article abstract of DOI:10.1007/s11746-011-1867-z

Ricinus communis (RC) oil-based materials are currently receiving increasing attention because of economic and environmental concerns. In the present work, RC oil - a natural triol has been utilized for the development of an advanced polymeric material - poly(urethanericinoleamide) (PUR) through very simple synthesis and curing strategy, omitting derivatization steps or side reactions, chain extenders and crosslinkers. The synthesis of PUR was carried out in two steps. The first step is the introduction of an amide group in the RC oil (89.5% ricinoleic acid) via base catalyzed amidation, which results in N, N-bis (2-hydroxyethyl) ricinoleamide (HERA). The second step is urethanation of HERA by the reaction of toluene-2,4-diisocyanate (TDI) in minimal possible organic solvent by one-shot technique, which results in the formation of polyurethane along with amide linkages. The physico-chemical and spectral studies (FT-IR, ¹H-NMR and ¹³C-NMR techniques) confirm these two reactions and the structure of PUR. The resin was cured at ambient temperature without any cross linker. Solubility of the resin was investigated in different polar and non-polar solvents. Thermo-gravimetric analysis (TGA)/differential thermal analysis (DTA) and Differential Scanning Calorimetry (DSC) were used to determine the thermal stability and curing behavior of PUR. An ambient cured ricinoleamide modified polyurethane resin exhibited thermal resistance up to 200-220 °C. AOCS 2011.

Full text of DOI:10.1007/s11746-011-1867-z

J Am Oil Chem Soc (2011) 88:1989–1996
DOI 10.1007/s11746-011-1867-z
ORIGINAL PAPER
Synthesis and Characterization of Ricinoleamide-Based
Polyurethane
Mohammad Kashif
•
Eram Sharmin
•
Fahmina Zafar Sharif Ahmad
•
Received: 8 December 2010 / Revised: 25 May 2011 / Accepted: 26 May 2011 / Published online: 14 June 2011
Ó AOCS 2011
Abstract Ricinus communis (RC) oil-based materials are
currently receiving increasing attention because of eco-
nomic and environmental concerns. In the present work,
RC oil—a natural triol has been utilized for the develop-
ment of an advanced polymeric material—poly(urethane-
ricinoleamide) (PUR) through very simple synthesis and
curing strategy, omitting derivatization steps or side reac-
tions, chain extenders and crosslinkers. The synthesis of
PUR was carried out in two steps. The first step is the
introduction of an amide group in the RC oil (89.5%
ricinoleic acid) via base catalyzed amidation, which results
in N, N-bis (2-hydroxyethyl) ricinoleamide (HERA). The
second step is urethanation of HERA by the reaction of
toluene-2,4-diisocyanate (TDI) in minimal possible organic
solvent by one-shot technique, which results in the for-
mation of polyurethane along with amide linkages. The
temperature without any cross linker. Solubility of the resin
was investigated in different polar and non-polar solvents.
Thermo-gravimetric analysis (TGA)/differential thermal
analysis (DTA) and Differential Scanning Calorimetry
(DSC) were used to determine the thermal stability and
curing behavior of PUR. An ambient cured ricinoleamide
modified polyurethane resin exhibited thermal resistance
up to 200–220 °C.
Keywords Ricinus communis oil ꢀ Ricinoleamide ꢀ
Polyurethane ꢀ Spectral ꢀ TGA ꢀ Antimicrobial
Introduction
The strict environmental regulations imposed on the
industries by governments and international agencies all
over the world have focused the interests of scientists and
researchers towards the utilization of sustainable resources
for the preparation of eco-friendly polymeric materials.
Among the sustainable resources, vegetable oils (triglyc-
erides of fatty acids) are expected to be an ideal alternative
to petro-chemical feed stock [1]. They represent one of the
cheapest biological feed stocks available in large quantities
and their use as starting materials offers numerous advan-
tages, such as low toxicity, inherent biodegradability and
high purity [2]. They have several excellent properties that
can be utilized for the preparation of a number of value-
added polymers and other materials that have found vari-
ous applications in different fields. A variety of vegetable
oils such as Linseed, Tung, Soybean, Sunflower, Karanj,
Castor, etc., have been used for this purpose [3, 4].
1
physico-chemical and spectral studies (FT-IR, H-NMR
1
3
and C-NMR techniques) confirm these two reactions and
the structure of PUR. The resin was cured at ambient
Electronic supplementary material The online version of this
article (doi:10.1007/s11746-011-1867-z) contains supplementary
material, which is available to authorized users.
M. Kashif ꢀ E. Sharmin ꢀ S. Ahmad (&)
Materials Research Laboratory, Department of Chemistry,
Jamia Millia Islamia, New Delhi 110025, India
e-mail: sharifahmad_jmi@yahoo.co.in
M. Kashif
e-mail: kashif_jmi25@yahoo.co.in
E. Sharmin
e-mail: eramsharmin@gmail.com
F. Zafar
Polyurethane is one of the important classes of polymers
that possess a unique structure and have versatile applica-
tions. They generally comprise soft segments (di-/poly-ol)
Department of Chemistry, Jamia Millia Islamia,
New Delhi 110025, India
e-mail: fahmzafar@gmail.com; fahm_zafar@yahoo.com
1
23

1
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J Am Oil Chem Soc (2011) 88:1989–1996
and hard segments (di-/poly-isocyanates). The desirable
properties of polyurethanes can be obtained by altering
these segments [5]. Vegetable oil-based polyols [6] can be
obtained by introducing several modifications such as
hydroxylation, ozonolysis, amidation, etc., and are
becoming important as an alternative to petro-based soft
segments [7, 8]. Commercially available natural polyol
such as Ricinus communis (RC) oil comprises about 90%
ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid) of the
total triglyceride fatty acids of the oil. It is considered as a
non-drying oil and has an effective hydroxyl functionality
of 2.7. It can be used directly as a raw material for the
preparation of polyurethanes without any further modifi-
cation [9]. It has potential for the syntheses of variety of
polyurethane products, ranging from coatings, cast elasto-
mers, thermoplastic elastomers, rigid foams, semi-rigid
foams, sealants and adhesives to flexible foams [7–9]. RC-
based polyurethane obtained from the direct utilization of
RC oil has advantages along with some disadvantages,
such as low functionality, low reactivity due to the sec-
ondary hydroxyl groups, thus leading to semi-flexible and
semi-rigid materials [7]. Therefore, several modifications
have been done to overcome these drawbacks [5–9].
thermometer and condenser) over a magnetic stirrer at
110 °C. Progress of the reaction was monitored by TLC
(Thin Layer Chromatography) [10]. After the completion
of the reaction (3 h), HERA was cooled down to room
temperature and purified with the help of a separatory
funnel through solvent and non-solvent methods [11].
In the purification step, firstly, HERA was dissolved in
a suitable solvent (diethyl ether or xylene) then treated
with a non-solvent (15% aqueous NaCl solution and
water, in which HERA does not dissolve), transferred to a
separatory funnel (to remove water) and left to stand for
some time. After some time, two layers were obtained—
one top solvent layer (HERA with solvent) and another of
aqueous layer (non-solvent). In the next step the solvent
layer is separated out with the help of the separatory
funnel and then dried over anhydrous sodium sulfate.
Finally, the solvent is evaporated off using a rotary vac-
uum evaporator to obtain the product HERA (yield
87 ± 1%).
-
1
FTIR (cm ): 3,369.3 (broad –OH), 3,010 (t, C=C–H),
2,923(t, –CH asym), 2,853 (t, –CH sym), 1,636.2 (t,
2
2
-
1
-1
[C=O amide), 1,078.9 cm and 1,052.9 cm (t, C–OH,
primary and secondary).
1
In the present work, we report the modification of RC oil
by amidation that yields triol [N, N-bis (2-hydroxyethyl)
ricinoleamide, HERA], which consists of two primary and
one secondary hydroxyl group along with an amide link-
age. HERA, considered as soft segment for polyurethane,
by the urethanation reaction with toluene-2,4-diisocyanate
H-NMR (CDCl /TMS, d, ppm): 5.5–5.3 {m, –CH=CH–
3
}, 5.26{s, –CH(OH)}, 4.85 (s, –CH –OH), 3.59 (s,
2
–CH(OH)}, 3.77 and 3.84 (t, –CH –N\), 3.56 and 3.49
2
(t, –CH –OH), 2.36 (m, –CH(OH) CH –), 2.2 {t, –CH –
2
2
2
C(=O)–N–}, 2.03(m, –CH –CH=CH–), 1.62 (m, –OCCH
2
2
CH ) 1.45 {m, =CHCH CH(OH)}, 1.30 (m, –CH –, fatty
2
2
2
(
TDI) yields polyurethane which has recurring amide
acid chain), 0.88 (t, –CH ).
3
1
3
linkages. It is expected that such modification can improve
the performance of RC oil based polyurethanes. Literature
survey reveals that no such work is reported on RC oil [9].
C-NMR (CDCl /TMS, d, ppm): 130–127.7(–HC=CH–;
3
olefin carbon), 71.4 {(–CH(OH)}, 59.376 (CH –OH),
2
47–40 (CH –N), 33.69 {CH –C(=O)–N–}, 29 (CH fatty
2
2
2
acid chain), 24.8 [CH CH C(=O)–N], 27.2 (CH –C=C–).
2
2
2
Materials and Methods
Synthesis of PUR (Urethanation of Ricinus communis
Oil Modified Monomer, HERA) (Table 1)
Chemicals
Pure HERA (1 mol) was reacted with different amounts of
TDI (0.8, 1 and 1.2 mol) in a minimal amount of EMK
(20 ml, for dilution and homogenous mixing of reaction
mixture) placed in a three-necked flat bottom flask fitted
with the dropping funnel, thermometer and condenser. The
reaction was carried out under a nitrogen environment
along with continuous stirring at room temperature. The
progress of the reaction was monitored by TLC (Thin
Layer Chromatography) [11] and hydroxyl value determi-
nation at regular time intervals. The reaction was stopped
on reaching the desired hydroxyl value of the product. The
solvent (EMK) was removed by a rotary vacuum evapo-
rator to obtain light yellow-colored liquid PUR (yield
96 ± 1%) designated as PUR-0.8, PUR-1 and PUR-1.2, the
numerals stand for the moles of TDI.
RC oil [Number average molecular weight (Mn): 930;
-
1
hydroxyl value: 160–168 mg KOH g
;
acid value:
-
.45 mg KOH g], sodium metal, diethyl ether, diethanol
1
2
amine (DEA), ethyl methyl ketone (EMK) (s.d. fine
chemical) and TDI (Merck India) of analytical grade were
used as such.
Synthesis of HERA (Amidation of Ricinus
communis Oil)
As reported in the literature [10], a calculated amount of
RC oil (0.1 mol), DEA (0.32 mol) and freshly prepared
sodium methoxide (0.007 mol) solution (in methanol) were
kept in a three-necked conical flask (fitted with a
1
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J Am Oil Chem Soc (2011) 88:1989–1996
1991
1
3
Table 1 Chemical composition for the synthesis of PUR
and C-NMR spectra were recorded on a JEOL GSX
00 MHz FX-1000 spectrometer using deuterated chloro-
3
Composition
HERA (mole)
TDI (mole)
[NCO]/[OH] ratio
form (CDCl ), as a solvent, and tetramethylsilane as an
3
PUR-0.8
PUR-1.0
PUR-1.2
1.0
1.0
1.0
0.8
1.0
1.2
1.6/3
2.0/3
2.4/3
internal standard.
Thermo-gravimetric analysis (TGA) and differential
thermal analysis (DTA) were performed using the SII
EXSTAR 6000, TG/DTA6300 (Japan) from 40 to 750 °C
in a nitrogen atmosphere at 10 °C min
Differential Scanning Calorimetry (DSC) was done with
-
1
heating rate.
The synthesized PUR were dissolved in the solvent
EMK) and filtered, repeatedly for purification. The solvent
(
SII EXSTAR 6000, DSC620 (Japan) from 30 to 400 °C in
a nitrogen atmosphere at 10 °C min heating rate.
-
1
was removed from the filtrate with the help of rotary
vacuum evaporator to obtain pure PUR-0.8, PUR-1 and
PUR-1.2, which were taken for characterization. This
operation was performed to remove any impurity (gel
fraction, if any), which was not obtained here.
Results and Discussion
-
1
FTIR (cm ): 3,290.9 (weak, residual –OH), 3,339 (t,
N–H of urethane), 3,069 (t, Ar C=C–H), 3,010 (t, C=C–
H), 1,716 (t, [C=O urethane), 1,636.2 (t, [C=O amide),
Generally, synthesis and application of polyurethanes
requires volatile organic compounds (VOC), through
cumbersome multistep processes. In the present work,
synthesis and curing of ricinoleamide based polyurethane
was achieved at room temperature. The overall process,
which almost reduces use of VOC to 50%, is simple and
environmentally friendly.
2
,923(t, –CH asym), 2,853 (t, –CH sym), 2,273 (t, free
2
2
NCO), 1,605, 744.5 (t, and bending, Ar–C=C), 1,622
[C=O, amide), 1,228 (t, NCOO–), 697 (bending, N–H
urethane).
(
1
H-NMR (CDCl /TMS, d, ppm): 5.53–5.35 (q,
3
–
CH=CH–)[h], 5.29 and 4.85 (s, low intensity, –OH)[k, a],
Synthesis (Fig. 1)
4
.01–4.43 (m, –CH O C (=O)NH– and –CH O C (=O)NH–,
2
0
urethane)[n, p], 3.77 and 3.9 (t, –CH –N\)[c, c ], 3.5
Figure 1 a shows the synthesis of PUR from RC oil. The
amidation of the oil was carried out without VOC by the
reaction of diethanolamine at 110 °C in the presence of
sodium methoxide (acts as a catalyst) that results in the
formation of HERA. The amidation reaction proceeds
through the base-catalyzed nucleophilic acyl substitution
2
(
(
(
(
(
t, low intensity,–CH –OH)[b], 3.6 (t, –CHOH)[j], 2.4
2
t, –CH (C=O)N\}[d], 2.33 {t, =CHCH CH(OH)}[i], 2.2
2
2
s, –CH of TDI)[t], 2.02 (m, –CH –CH=CH–)[g], 1.61
3
2
m, –OCCH CH )[e], 1.44 (m, –CH(OH) CH –)[l], 1.31
2
2
2
0
m, –CH –, fatty acid chain)[f, f ], 0.88 (t, –CH )[m].
2
3
13
C-NMR (CDCl /TMS, d, ppm): 173.2 ([C=O ami-
bimolecular (S 2) reaction mechanism while urethanation
N
3
de)[c], 149–152 ([C=O urethane and free –NCO)[q, n],
30, 126(–HC=CH–; olefin carbon)[h, i], 127–132 (aro-
was carried out in a minimal possible amount of solvent via
the addition reaction between the primary and the sec-
ondary –OH group of HERA and the NCO– group of TDI
(in different mole ratios) that result in the formation of
PUR [12, 13]. It was found that the addition of TDI above
1.2 mol caused the formation of lumpy aggregates result-
ing in PUR that are too viscous [12].
1
matic ring carbons)[r, s, t, u, v, w], 65–69(–CH –O and
2
0
–
CH–O–)[a , p], 71.4, 59.376 (residual, CH–OH and CH –
2
0
OH)[k, a], 50–55 (CH –N)[b, b ], 36–20 (chain CH )[j, d, l,
2
2
f, m, g, e, n], 18.5 (CH attached to aromatic ring)[x], 14
3
(
–CH )[o].
3
In the formation of PUR, a different amount of TDI was
used. However, PUR-1 was to found to be the optimum
composition. Thus, it was subjected to characterization as
described in the proceeding section.
Characterization
Standard laboratory methods of TLC was used to monitor
the progress of the reactions [11].
Generally, in polyurethane chemistry a particular ratio
of functional groups is used: [–N=C=O]/[OH] groups and
this ratio is close to 1 or a maximum 1.1; the best properties
are when one equivalent weight of isocyanate reacts with
one equivalent weight of polyol. In other words, the best
properties are obtained when the NCO/OH ratio is equal to
one (to get the highest molecular weight). Nevertheless, for
some applications, it is required to be below the stoichi-
ometry as in the polyurethanes described here. Thus, this
ratio may be altered according to the end use application
Solubility of the resin was tested in various polar and
non-polar solvents by taking 50 mg of resin in 10 ml of
different solvents in a closed test tube and set aside for a
day. Physico-chemical tests such as hydroxyl value, spe-
cific gravity and refractive index were performed by stan-
dard laboratory methods [11].
FT-IR spectra of resins were obtained with a Perkin-
Elmer 1750, FTIR spectrophotometer (Perkin Elmer
1
Instruments, Norwalk, CT) using an NaCl cell. H-NMR
1
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1
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J Am Oil Chem Soc (2011) 88:1989–1996
Fig. 1 Synthesis of PUR
through amidation and
urethanation reactions
-
1,241, 1,164 and 1,097 cm ) of RC oil disappeared with
1
requirement of polyurethanes, i.e., to prepare high or low
molecular weight polyurethane. In this case, at each ratio,
we have an excess of hydroxyl groups (Table 1), which
based on general principles of polyaddition reactions lead
to low molecular weight PUR, which may find applications
as coating and adhesive materials [14].
the appearance of new bands at 1,622, 1,078.9,
-
1,052.9 cm for amide carbonyl, primary and secondary
1
alcoholic groups (C–O stretching), respectively, as well as
-
the presence of a broad band at 3,369 cm instead of
1
-
3,422.1 cm confirming the amidation of RC oil. In PUR
1
-
spectra, the hydroxyl band of HERA (3,369.3 cm )
1
It is worth mentioning that the urethanation reaction was
carried out by using a ‘‘one-shot’’ technique. In this method,
all the ingredients (HERA and TDI) are mixed simulta-
neously and the resulting mixture is allowed to polymerize
directly. The advantage of using this method is that no
intermediate prepolymer preparation is necessary [15].
-
1
diminished and was centered at 3,290.9 cm . The presence
-
of new bands at 3,339 cm (N–H stretching of urethane
1
-
1
linkages), 1,716 cm
(urethane carbonyl stretching),
-
1
1,228 cm (NCOO– stretching), 2,273 (free NCO stretch-
ing), and 697 (N–H of urethane) [13, 16, 17] as well as bands
at 3,069, 1,605.5, and 744.5 for aromatic ring of TDI confirm
1
Spectral Analysis
the urethanation of HERA. H-NMR (Fig. 3) spectra of pure
PUR-1 shows the characteristic peaks at 4.01–4.43 ppm
FTIR spectra (Fig. 2): It is observed in the spectra of HERA
that the characteristic bands of ester carbonyl (at 1,745,
{m, –CH O C (=O)NH– and –CH OC(=O)NH–,urethane}[n,
2
p], 2.2 ppm (s, –CH3 of TDI)[t], and 6.9–7.38 ppm
1
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J Am Oil Chem Soc (2011) 88:1989–1996
1993
Fig. 2 FTIR spectra of RC oil
(
(
a), HERA (b) and pure PUR-1
c)
1
3
(
aromatic peaks)[r, s, q] while C-NMR (Fig. 4) spectra of
pure PUR-1 shows the spectral peaks at 149–152 ppm
[C=O urethane and free –NCO)[q, n], 127–132 ppm
bands of TDI based polyurethanes [13, 17]. Closer exami-
1
nation of H-NMR spectra of HERA and PUR-1 reveals that
(
pure PUR-1 shows suppressed characteristic peaks of –OH,
(
aromatic ring carbons)[r, s, t, u, v, w], 65–69 ppm (–CH –O
0
–CH–OH and CH –OH compared to HERA (sect. 2.1)
2
2
and –CH–O–)[a , p] and 18.5 ppm (CH attached to aro-
3
at 5.26 ppm [–CH(OH)], 4.85 ppm and (–CH –OH),
2
matic ring)[x]. These spectral bands are the characteristic
3.59 ppm [CH(OH)], 3.56 and 3.49 ppm (–CH –OH), while
2
1
23

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J Am Oil Chem Soc (2011) 88:1989–1996
1
3
C-NMR spectral analysis of pure PUR-1 also support the
Physico-chemical Properties and Solubility
suppression of the characteristic peaks of –CH–OH and
CH –OH of HERA (sect. 2.1) at 71.4 ppm (–CH–OH) and
2
The data for physico-chemical properties of HERA and
different compositions of PUR are given in Table 2. It
reveals that the percent hydroxyl content of PUR decreases
gradually from PUR-0.8 to PUR-1.2, that is, with increases
in the amount of TDI. The trend can be attributed to the
consumption of hydroxyl groups of HERA during uretha-
nation reaction with TDI. The specific gravity and refrac-
tive index of PUR increase with the increased content of
5
9.376 ppm (CH –OH). The suppression of these peaks can
2
be correlated to the consumption of –OH, –CH–OH and
CH –OH of HERA with –NCO of TDI in the formation of
2
polyurethane.
These spectral studies are correlated to the formation of
PUR, through the addition reaction of –OH groups of
HERA and –NCO of TDI [13, 17].
1
Fig. 3 H NMR spectra of pure
PUR-1
13
Fig. 4 C NMR spectra of
pure PUR-1
1
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J Am Oil Chem Soc (2011) 88:1989–1996
1995
Table 2 Physico-chemical tests of HERA and different compositions
of PUR
these chemical reactions are collectively responsible for the
three dimensional optimum cross linked structure of PUR.
Resin code
HERA
438.9
PUR-0.8
154.05
PUR-1
PUR-1.2
62.7
Thermal Analysis
Hydroxyl value
mg KOH g
109.725
-1
)
(
The thermal stability of PUR-1 is shown in Fig. 5. It reveals
that the degradation of PUR-1 was observed in the range of
Specific gravity
(
0.8654
1.6120
0.8912
1.6230
0.8965
1.636
0.8987
1.639
-1
g ml
)
150–390 °C. This may be correlated to the decomposition
Refractive index
of urethane bonds followed by the volatilization of the
decomposition products. It is reported that polyurethanes
generally exhibit relatively low thermal stability due to the
presence of labile urethane groups. The onset of this bond
dissociation occurs around \300 °C through the dissocia-
tion of isocyanate and alcohol, the formation of primary
amine and olefins, or the formation of secondary amines
TDI attributed to the inclusion of increased urethane con-
tent in the polymer backbone.
The solubility test reveals that all PUR compositions
(
before curing) are completely soluble (100%) in EMK,
chloroform, carbon tetrachloride, DMF (Dimethylformam-
ide), DMSO (Dimethyl sulfoxide), THF (Tetrahydrofuran)
and diethyl ether while they have 20% solubility in methyl
alcohol, ethyl alcohol, and insoluble in water. The higher
solubility of these resins in polar and non-polar solvents
that result in the loss of CO from the urethane bond,
2
depending upon the type of isocyanate and polyol employed
[18]. The decomposition of the urethane bond in PUR-1
takes place at quite high temperatures due to any allo-
phanate and biuret linkages formed during the curing
reaction, they reopen quite readily on heating at a relatively
high temperature as they are most thermolabile [18]. The
degradation in the range of 390–410 °C may be correlated
to the decomposition of the amide bond, aromatic ring and
aliphatic alkyl chain of the fatty acid followed by the vol-
atilization of the decomposition products, respectively. The
polyol used in this study is based on HERA. So, the main
chain cleavage may result in the formation of 16-undeca-
noic acid and heptanal as evident by the thermal degrada-
tion of ricinoleic acid [19]. Derivative TGA curves (DTG)
of PUR-1 shows almost single step thermal degradation,
which matches with TGA of the same. This step incurs
about 85 wt% loss correlated to a cross-linked, homogenous
except H O and alcohol is due to the presence of long fatty
2
acid hydrocarbon chains and polar groups of the resin.
Curing of Film
The solution of PUR in EMK was applied on mild steel
strips. It was cured at ambient temperature without any
modifier. The curing time for PUR was found to be
1
0–20 min. The curing process of PUR resin occurs
through the chemical reaction of free –NCO of PUR with
atmospheric moisture and –OH of the other chains after the
solvent evaporation. This chemical reaction is followed by
other characteristic reactions that are the formation of
urethane, amine, urea, allophanate and biuret [13]. All
Fig. 5 TGA and DTA
thermogram of PUR-1
1
9
8
7
6
5
4
3
2
00.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
10.00
5
0
.00
.00
-
5.00
-
-
10.00
15.00
10.0
.0
0
2
00.0
400.0
Temperature °C
600.0
1
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J Am Oil Chem Soc (2011) 88:1989–1996
the University Grant Commission (UGC). SAP for TGA and DSC
facilities.
Conflict of interest None.
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15–140 °C (centered at 129.5 °C) followed by an exo-
therm attributed to the reaction of the remaining unreacted
groups in the PUR-1 backbone. TGA/DTG thermograms do
not show significant decomposition in the former temper-
ature range. After 230 °C, a strong exothermal reaction is
observed due to the degradation of the PUR-1 backbone.
The temperature range between 300–420 °C shows a
maximum weight loss in the TGA/DTG thermogram.
7
8
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(1996) Vogel’s textbook of practical organic chemistry, 5th edn.
Prentice Hall, New York, ISBN 0582462363
The non-edible and non-drying RC oil was utilized for the
preparation of environmentally friendly, room-temperature
cured, ricinoleamide-modified polyurethane using a one-
shot technique in a minimal amount of organic solvent. The
synthesis and curing strategy were very simple omitting
derivatization steps or side reactions (at optimum loading
of TDI), crosslinkers, and chain extenders. The synthesized
polymer shows moderate antibacterial activity. Thermal
degradation of the resin was more or less similar to virgin
polyurethane, indicating that this modification of RC oil
has not influenced the thermal stability. The resin can
safely be used up to 200–220 °C. It can be utilized for eco-
friendly adhesives, protective paints and coating material.
The application studies of ricinoleamide-modified poly-
urethane as an advanced coating material will be published
soon.
12. Sharmin E, Ashraf SM, Ahmad S (2007) Epoxidation, hydrox-
ylation, acrylation and urethanation of Linum usitatissimum seed
oil and its derivatives. Eur J Lipid Sci Technol 109:134–146
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ization, antibacterial and corrosion protective properties of
epoxies, epoxy-polyols and epoxy-polyurethane coatings from
linseed and Pongamia glabra seed oils. Int J Bio Macromol
4
0:407–422
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6. Lu Y, Larock RC (2009) Soybean oil based waterborne poly-
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Acknowledgments Dr. Fahmina Zafar and Dr. Eram Sharmin are
thankful to the Council of Scientific and Industrial Research (CSIR)
India for a Senior Research Associateship (SRA) and a Research
Associateship (RA) against Grants No: 13(8385-A)/Pool/2010 and
19. Szycher M (1999) Szycher’s Handbook of polyurethane, 2nd edn.
CRC Press, Sterling Biomedical, Inc, Lynnfield MA, Michael
Szycher, Cardio-Tech International, Woburn, Massachusetts
9
/466(0102) 2K8-EMR-I, respectively. The authors also acknowledge
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