Synthesis of biobased polyurethane from oleic and ricinoleic acids as the renewable resources via the AB-type self-condensation approach

Article abstract of DOI:10.1021/bm100233v

Polyurethane (PU) from methyl oleate (derived from sunflower oil) and ricinoleic acid (derived from castor oil) was synthesized using the AB-type self-polycondensation approach for the first time. In the present work, three novel AB-type monomers, namely, a mixture of 10-hydroxy-9-methoxyoctadecanoyl azide/9-hydroxy-10-methoxyoctadecanoyl azide (HMODAz), 12-hydroxy-9-cis- octadecenoyl azide (HODEAz) and methyl-N-11-hydroxy-9-cis-heptadecen carbamate (MHHDC) were synthesized from methyl oleate and ricinoleic acid using simple reaction steps. Out of these, HMODAz and HODEAz monomers were polymerized by the acyl-azido and hydroxyl AB-type self-condensation approach, while MHHDC monomer was polymerized through AB-type self-condensation via transurethane reaction. The acyl-azido and hydroxyl self-condensations were carried out at various temperatures (50, 60, 80. and 110 °C) in bulk with and without catalyst. A FTIR study of the polymerization, using HMODAz at 80 °C without catalyst, indicates in situ formation of an intermediate isocyanate group in the first 15?30 min, and further onward, the molar mass increases as observed by SEC analysis. In the case of the MHHDC monomer, a transurethane reaction was used to obtain a similar PU (which was obtained by AB-type acyl-azido and hydroxyl self-condensation of HODEAz) in the presence of titanium tetrabutoxide as a catalyst at 130 °C. HMODAz, HODEAz, MHHDC, and corresponding polyurethanes were characterized by FTIR, ¹H NMR, ¹³C NMR, and MALDI-TOF mass spectroscopy. Differential scanning calorimetric analysis of polyurethanes derived from HMODAz, HODEAz, and MHHDC showed two different glass transition temperatures for soft segments (at lower temperature) and hard segments (at higher temperature), indicating phase-separated morphology.

Full text of DOI:10.1021/bm100233v

1202
Biomacromolecules 2010, 11, 1202–1211
Synthesis of Biobased Polyurethane from Oleic and Ricinoleic
Acids as the Renewable Resources via the AB-Type
Self-Condensation Approach
Dnyaneshwar V. Palaskar,†,‡ Aure´lie Boyer,†,‡ Eric Cloutet,†,‡ Carine Alfos,§ and
Henri Cramail*,†,‡
Laboratoire de Chimie des Polyme`res Organiques, Universite´ de Bordeaux, ENSCBP, 16 Avenue
Pey-Berland, Pessac Cedex, F 33607 France, Laboratoire de Chimie des Polyme`res Organiques, CNRS,
Pessac Cedex, F 33607, France, and ITERG, 11 rue Gaspard Monge, Parc Industriel,
Pessac Cedex, F 33600, France
Received December 1, 2009; Revised Manuscript Received April 7, 2010
Polyurethane (PU) from methyl oleate (derived from sunflower oil) and ricinoleic acid (derived from castor oil)
was synthesized using the AB-type self-polycondensation approach for the first time. In the present work, three
novel AB-type monomers, namely, a mixture of 10-hydroxy-9-methoxyoctadecanoyl azide/9-hydroxy-10-
methoxyoctadecanoyl azide (HMODAz), 12-hydroxy-9-cis-octadecenoyl azide (HODEAz) and methyl-N-11-
hydroxy-9-cis-heptadecen carbamate (MHHDC) were synthesized from methyl oleate and ricinoleic acid using
simple reaction steps. Out of these, HMODAz and HODEAz monomers were polymerized by the acyl-azido and
hydroxyl AB-type self-condensation approach, while MHHDC monomer was polymerized through AB-type self-
condensation via transurethane reaction. The acyl-azido and hydroxyl self-condensations were carried out at various
temperatures (50, 60, 80. and 110 °C) in bulk with and without catalyst. A FTIR study of the polymerization,
using HMODAz at 80 °C without catalyst, indicates in situ formation of an intermediate isocyanate group in the
first 15-30 min, and further onward, the molar mass increases as observed by SEC analysis. In the case of the
MHHDC monomer, a transurethane reaction was used to obtain a similar PU (which was obtained by AB-type
acyl-azido and hydroxyl self-condensation of HODEAz) in the presence of titanium tetrabutoxide as a catalyst at
130 °C. HMODAz, HODEAz, MHHDC, and corresponding polyurethanes were characterized by FTIR, 1H NMR,
13C NMR, and MALDI-TOF mass spectroscopy. Differential scanning calorimetric analysis of polyurethanes
derived from HMODAz, HODEAz, and MHHDC showed two different glass transition temperatures for soft
segments (at lower temperature) and hard segments (at higher temperature), indicating phase-separated morphology.
of vegetable oils (from rapeseed, tung, linseed, canola, sun-
flower, and soybean) have been tested and reported for polyol
synthesis as polyurethane precursors. The use of enzymes or
chemicals to modify the structure of fatty acid and to introduce
functional groups to obtain functional monomers has been
known for a long time and, in some cases, particular vegetable
oils can be utilized directly as monomers. For example,
Ogunniyi15 and Ehrilich16 et al. reported that naturally hydroxy-
lated castor oil can be used to replace the petroleum-based polyol
to make polyurethane foams. Castor-oil-based polyurethanes
have also been used for artificial bones.17 Xiao et al. used
polyurethane based on castor oil as a component of semi-
interpenetrating polymer network (semi-IPNs) with nitroguar
gum.18 Castor-oil-based polyurethane composite proved also to
be a material useful as a “corrosion sensor”.19 Conveniently,
Cramail and co-workers describe the synthesis of monodisperse
PU nanoparticles by a miniemulsion technique in water as
dispersant medium using castor oil as a monomer.20 Polyester
diol based on ricinoleic acid was also prepared to be used for
conventional TPU applications. Nevertheless, it is expected that,
like conventional TPU systems, appropriate stabilizers would
promote even further thermal stability during melt processing.21a
On the other hand, it is important to mention that Matsumura
et al. utilized ricinoleic acid derived from castor oil as AB-
type monomer for lipase-catalyzed polyester synthesis.21b,c Lu
et al. used waterborne polyurethane made from rapeseed-oil-
based polyol to modify glycerol-plasticized starch and develop
Introduction
Polyurethanes are among the most important polymeric
materials, which exhibit versatile properties suitable for use in
many fields, such as footwear, machinery industry, coatings and
paints, rigid insulations, elastic fibers, soft flexible foam, and
medical devices.1 Additionally, the chemistry of PUs allows
for the synthesis of different types of polymeric materials such
as foams (flexible and rigid), thermoplastics (TPU), interpen-
etrating polymer networks (IPNs), and segmented PUs, depend-
ing on the polyols and isocyanates used as well as the method
of polymerization.
Recently, intensive interest has been paid to the synthesis of
PU starting from natural resources like vegetable oils and natural
fats because of their important availability, sustainability,
biodegradability, and added values. It is well-known that the
products based on renewable resources are usually more eco-
compatible in comparison with petrochemical-based products.2–4
There have been many studies on the synthesis and character-
ization of a wide variety of polymers based on vegetable oils
in the recent years.5–12
Vegetable oils are triglycerides and often have at least one
unsaturated fatty acid in their chemical structure.13,14 Many types
* Corresponding author. E-mail: cramail@enscbp.fr.
† Universite´ de Bordeaux.
‡ CNRS.
§ ITERG.
10.1021/bm100233v
 2010 American Chemical Society
Published on Web 04/19/2010

Synthesis of Biobased Polyurethane
Biomacromolecules, Vol. 11, No. 5, 2010 1203
biodegradable films.22 Chang et al. added commercial soy flours
into water-blown rigid polyurethane foams to improve the
physical properties and lower the cost of these foams.23,24
Petrovic and co-workers have been doing extensive research in
the field and investigated the structure and properties of
vegetable-oil-based polyols, their applications in polyurethane
foams, and the foam’s biodegradation behavior and thermal
stability.25–27
temperature in THF with a setup consisting of a WATERS 880-PU
pump and a series of three microstyragel columns with pore sizes of
103, 105, and 106 Å. The elution of the filtered samples was monitored
using simultaneous UV and refractive index detections. The elution
times were converted to molar mass using a calibration curve based
on low dispersity (Mw/Mn) polystyrene (PS) standards. Infrared spectra
were obtained on a Bruker-Tensor 27 spectrometer using the attenuated
total reflection (ATR) mode. Matrix-assisted laser desorption ionization
time-of-flight mass spectrometry (MALDI-TOF MS) spectra were
performed by the CESAMO (Bordeaux, France) on a Voyager mass
spectrometer (Applied Biosystems). The instrument is equipped with
a pulsed nitrogen laser (337 nm) and a time-delayed extracted ion
source. Spectra were recorded in the positive-ion mode using the
reflectron and with an accelerating voltage of 20 kV. Polymer samples
were dissolved in THF at 10 mg mL-1. The dithranol matrix solution
was prepared by dissolving 10 mg in 1 mL of dichloromethane. A
methanol solution of cationization agent (NaI, 10 mg mL-1) was also
prepared. The solutions were combined in a 10:1:1 volume ratio of
matrix to polymer to cationization agent. Several microliters of the
obtained solution were deposited onto the sample holder and vacuum-
dried. Differential scanning calorimetry (DSC) thermograms were
measured using a DSC Q100 apparatus from TA Instruments. Polymer
samples were first heated from -100 to 200 °C and then the glass
transition temperatures were calculated from a second heating run. All
With the views on academic research considering this field,
our goal is to design new monomers and polymers using
vegetable oils as precursors. To our knowledge, while vegetable
oils have been studied as polyol precursors for PU synthesis,
there is no report on the AB-type self-condensation approach
to PU from vegetable oils. Recently, Hojabri et al. synthesized
1,7-heptane diisocyanate utilizing oleic acid as a renewable
source from sunflower oil, and from that PU was prepared with
petroleum- and canola-oil-based polyols, respectively. The
properties of PU obtained from fatty-acid derived diisocyanate
was comparable with PU obtained from petroleum-derived 1,6-
hexane diisocyanate.28 Isocyanates are highly reactive and toxic
chemicals, hence, nonisocyanate routes for PU synthesis are
required. Among the nonisocyanate routes to polyurethanes one
can cite the two most used: self-condensation approach in which
the AB-type monomer contains hydroxyl and acyl azide
groups29–31 and the other one is the ring-opening of cyclic
carbonate by amines.32 Kumar et al. showed that the acyl azide
route produces PU of moderately high molar mass, but highly
branched structures are also observed. Self-polycondensation
of an AB-type monomer makes the advantage of built-in
stoichiometric control for attaining high molar mass. Finally, it
is worth mentioning that the transurethane process is also
important in view of the nonisocyanate and nonsolvent route
to PU. For instance, Jayakannan and Deepa have reported PU
synthesis via a transurethane reaction of bisurethane and diol
in the presence of titanium tetrabutoxide as a catalyst.33
In this article, we wish to report the first example of vegetable-
oil-derived AB-type self-condensable monomers for the syn-
thesis of biosourced PU. The AB-type monomers described
below are composed of acyl-azide, hydroxyl, and methyl
urethane functionalities, namely, 10-hydroxy-9-methoxyocta-
decanoylazide/9-hydroxy-10-methoxyoctadecanoylazide(HMODAz),
12-hydroxy-9-cis-octadecenoyl azide (HODEAz), and methyl-
N-11-hydroxy-9-cis-heptadecen carbamate (MHHDC). Self-
condensation of HMODAz and HODEAz was carried out at
different temperatures, and the detailed reaction progress was
monitored by FTIR, 1H NMR, and SEC. MHHDC was polym-
erized by a transurethane polycondensation reaction in the
presence of titanium tetrabutoxide as a catalyst at 130 °C.
runs were performed at a rate of 10 °C min-1
.
1. Synthesis of AB-Type Monomers for Self-Condensation.
(i) Synthesis of 10-Hydroxy-9-methoxyoctadecanoyl Azide (HMODAz)
AB-Type Monomer (5). (a) Synthesis of Methyl cis-9,10-Epoxyoctade-
canoate (2). Methyl oleate (1; 5.0 g, 0.017 mol) and meta-chloroper-
benzoic acid (4.3 g, 0.025 mol) were dissolved into dichloromethane
(100 mL) and the reaction mixture was stirred at room temperature for
5 h. The reaction mixture was filtered, and the solution was washed
with aqueous saturated sodium bicarbonate (3 × 50 mL) and then with
water (3 × 50 mL). The organic layer was separated and dried with
anhydrous sodium sulfate. The solvent was removed by rotary
evaporator to obtain intermediate 2. Yield: 4.8 g (91%). IR: 1740
(COOCH3), 841 cm-1 (epoxy). 1H NMR (400 MHz, CDCl3): 0.87 (3H,
t, CH3, J ) 6.4 Hz), 1.20-1.70 (methylene protons), 2.29 (2H, t, CH2-
COOCH3, J ) 7.6 Hz), 2.99 (2H, epoxy ring proton), 3.66 (3H, s,
COOCH3).
(b) Synthesis of Methyl 10-Hydroxy-9-methoxyoctadecanoate/Methyl
9-Hydroxy-10-methoxyoctadecanoate (3/3′). Methyl cis-9,10-epoxyocta-
decanoate (2; 4.8 g, 0.015 mol), amberlyst 15 (0.05 g), and excess
methanol (100 mL) were refluxed for 12 h. The reaction mixture was
filtered and methanol was removed using a rotary evaporator. The
reaction mixture was dissolved into dichloromethane (100 mL) and
washed with water (3 × 50 mL). The dichloromethane solution was
separated and evaporated to obtain intermediate 3/3′ as a mixture of
regioisomers. Yield: 4.7 g (89%). IR: 3480 (OH), 1740 cm-1
1
(COOCH3). H NMR (400 MHz, CDCl3): 0.88 (3H, t, CH3, J ) 6.4
Hz), 1.20-1.70 (methylene protons), 2.29 (2H, t, CH2-COOH, J )
7.6 Hz), 2.99 (1H, dd, CH-OCH3, J ) 5.2, 10.8 Hz), 3.41 (3H, s, OCH3),
3.49 (1H, m, CH-OH), 3.66 (3H, s, COOCH3).
Materials and Methods
(c) Synthesis of 10-Hydroxy-9-methoxyoctadecanoic Acid/9-Hydroxy-
10-methoxyoctadecanoic Acid (4/4′). A mixture of regioisomer intermedi-
ates (3/3′; 4.0 g, 0.012 mol) was dissolved into 1 N methanolic
potassium hydroxide solution (100 mL) and refluxed for 12 h. The
methanol was removed from the reaction mixture and the crude product
was dissolved into 100 mL of water. The water solution was neutralized
with hydrochloric acid and the product was extracted with 3 × 50 mL
dichloromethane. The dichloromethane solution was washed with 3 ×
50 mL of water and dried on anhydrous sodium sulfate. The dichlo-
romethane solution was filtered and solvent was removed to obtain a
mixture of intermediates 4/4′. Yield: 3.50 g (91%). IR: 3435 (OH),
Materials. Methyl oleate (84.5%) and ricinoleic acid (88.5%) were
kindly provided by ITERG Pessac, France, and used as received
(detailed analysis carried out using AFNOR methods, NF EN ISO 5509
and NF EN ISO 5508, is presented in Supporting Information, Table
1). meta-Chloroperbenzoic acid (mCPBA), dibutyl tin dilaurate (DBT-
DL), titanium tetrabutoxide [Ti(n-BuO)4], sodium bicarbonate, 1 M
methanolic potassium hydroxide solution, 1 N hydrochloric acid, triethyl
amine, and sodium azide were purchased from Aldrich and used as
received. Ethyl chloroformate (Fluka), methanol, ethanol, tetrahydro-
furan dichloromethane (J. T. Baker), and anhydrous sodium sulfate were
purchased and used as received.
1
1709 cm-1 (COOH). H NMR (400 MHz, CDCl3): 0.86 (3H, t, CH3,
1
Analysis. H and 13C NMR spectra were recorded using a Bruker
AC-400 NMR at room temperature by dissolving the samples in CDCl3.
Size exclusion chromatography (SEC) analyses were performed at room
J ) 6.8 Hz), 1.20 to 1.70 (methylene protons), 2.34 (2H, t, CH2-COOH,
J ) 7.6 Hz), 2.98 (1H, dd, CH-OCH3, J ) 5.2, 11.2 Hz), 3.39 (3H, s,

1204 Biomacromolecules, Vol. 11, No. 5, 2010
Palaskar et al.
OCH3), 3.47 (1H, m, CH-OH). 13C NMR (400 MHz, CDCl3, ppm):
179.3 (COOH), 84.4 (CH-OMe), 72.2 (CH-OH), 58.3 (OCH3), 22-35
(alkyl chain protons), 13.9 (CH3).
for 12 h and dried under vacuum. The complete dried samples were
analyzed by H NMR and SEC.
1
(4) Polycondensation of MHHDC via Melt-Transurethane (9).
Into a 50 mL two-necked round-bottom flask equipped with a
magnetic stirring bar, vacuum adapter, and a nitrogen inlet were charged
methyl-N-11-hydroxy-9-cis-heptadecen carbamate (10; 1.0 g, 0.003 mol)
and titanium tetrabutoxide (0.035 g, 1 × 10-4 mol). The reaction
mixture was purged with nitrogen, followed by vacuum twice. The
reaction flask was kept in an oil bath at 130 °C for 4 h under a nitrogen
purge and then under vacuum at 130 °C for 2 h. Yield: 0.80 g (80%).
IR: 3338 (NH), 1695 (CO), 1526 (NH deformation), 1230 cm-1 (C-N).
1H NMR (400 MHz, CDCl3): 0.86 (CH3), 1.20-1.70 (methylene
protons), 3.13 (-CH2-NHCOO), 3.63 (OCH3), 4.86 (NH), 5.3-5.6
(CH)CH).
(d) Synthesis of 10-Hydroxy-9-methoxyoctadecanoyl Azide/9-Hydroxy-
10-methoxyoctadecanoyl Azide (HMODAz) AB-Type Monomer (5/5′). Into
a 100 mL round-bottom flask equipped with a magnetic stirring bar
and an addition funnel were charged a mixture of hydroxyl acid
intermediates 4/4′ (2.0 g, 0.006 mol), triethyl amine (1.8 g, 0.018 mol),
and THF/water mixture (7:3 v/v, 30 mL). The reaction mixture was
cooled to 0 °C and ethylchloroformate (1.96 g, 0.018 mol) was added
dropwise over a period of 10 min. The reaction mixture was stirred
for 2 h and then sodium azide (1.2 g, 0.018 mol) in water (7 mL) was
added dropwise for 10 min and stirred at 0 °C for 4 h. THF was
removed using a rotary evaporator and crude product was dissolved
into dichloromethane (100 mL). The dichloromethane solution was
washed with water (2 × 50 mL), dried over anhydrous sodium sulfate,
and filtered and the solvent was removed to obtain HMODAz as an oil
with a slightly yellow in color. Yield: 2.0 g (92%). IR: 3465 (OH),
Results and Discussion
(1). Synthesis and Characterization of HMODAz
AB-Type Monomer (5/5′). For the synthesis of PU via AB-
type self-condensation approach, the monomer should contain
at least one hydroxyl and one isocyanate group. In the present
work, HMODAz was designed as an AB-type self-condensable
monomer with one secondary hydroxyl group and one acyl azide
group as an isocyanate precursor.
1
2138 (N3), 1720 cm-1 (CO). H NMR (400 MHz, CDCl3): 0.87 (3H,
t, CH3, J ) 6.4 Hz), 1.20-1.70 (methylene protons), 2.32 (2H, t, CH2-
CON3, J ) 7.6 Hz), 2.98 (1H, dd, CH-OCH3, J ) 6, 11.6 Hz), 3.39
(3H, s, OCH3), 3.47 (1H, m, CH-OH). 13C NMR (400 MHz, CDCl3,
ppm): 180.1 (CON3), 84.1 (CH-OMe), 72.2 (CH-OH), 57.7 (OCH3),
21-37 (alkyl chain protons), 13.5 (CH3).
(ii) Synthesis of 12-Hydroxy-9-cis-octadecenoyl Azide (HODEAz)
AB-Type Monomer (8). The procedure for the synthesis of HODEAz
is similar to HMODAz synthesis except ricinoleic acid was used. Yield:
90%. IR: 3400 (OH), 3008 ()C-H), 2133 (N3), 1720 cm-1 (CO). 1H
NMR (400 MHz, CDCl3): 0.87 (3H, t, CH3), 1.20-1.70 (methylene
protons), 2.31 (2H, t, CH2-CON3), 3.58 (1H, m, CH-OH), 5.3-5.6
(CH)CH). 13C NMR (400 MHz, CDCl3, ppm): 180.5 (CON3), 132.9
and 125.3 (CHdCH), 71.3 (CH-OH), 42.8 (CH2CON3), 36.7 and 35.2
(CH2-CH(OH)-CH2), 21-37 (alkyl chain protons), 13.5 (CH3).
(iii) Synthesis of Methyl-N-11-hydroxy-9-cis-heptadecene Carbamate
(MHHDC), AB-Type Monomer for Transurethane Process (10). Into a
100 mL round-bottom flask equipped with a magnetic stirring bar and
refluxed condenser were charged 12-hydroxy-9-cis-octadecenoyl azide
(8; 2.0 g, 0.006 mol) and dry methanol (50 mL). The reaction mixture
was refluxed for 4 h, and after that, the excess of methanol was removed
on a rotary evaporator. The crude urethane product was dissolved into
dichloromethane (100 mL), washed with water (2 × 50 mL), dried
over anhydrous sodium sulfate, and filtered, and the solvent was
removed to obtain the carbamate product (10). Yield: 1.85 g (92%).
IR: 3600-3400 (OH), 3334 (NH), 3008 ()C-H), 1703 cm-1 (CO).
1H NMR (400 MHz, CDCl3): 0.87 (3H, t, CH3, J ) 6.6 Hz), 1.20-1.70
(methylene protons), 3.14 (2H, dd, CH2-NHCOO-, J ) 6.4, 12.8 Hz),
3.59 (1H, m, CH-OH), 3.64 (3H, s, NHCOO-CH3), 4.63 (1H, NH-
COO), 5.3-5.6 (CH)CH). 13C NMR (400 MHz, CDCl3, ppm): 157
(NHCOO-), 133 (CHdCH), 71.4 (CH-OH), 51.8 (NHCOOCH3),
24-37 (alkyl chain carbons).
HMODAz as an AB-type monomer was synthesized in four
step reactions (Scheme 1), and the structure of all the intermedi-
1
ates were confirmed by FTIR and H and 13C NMR spectros-
copy. FTIR analysis of methyl oleate (1) shows a band at 1654
cm-1 due to the presence of vinylic double bond (CdC) and a
band at 1740 cm-1 due to the presence of an ester bond, while
a CdCsH stretching vibration band is observed at 3005 cm-1
(Figure 1). Further, the structure elucidation of methyl oleate
1
was carried out by H NMR spectroscopy in which vinylic
protons appeared at 5.32 ppm and methyl ester protons at 3.65
ppm. In the first step, methyl oleate (1) was epoxidized using
meta-chloroperbenzoic acid reagent to yield intermediate (2).
FTIR spectrum of intermediate 2 shows the absence of a band
at 3005 cm-1 due to CdCsH group. The appearance of a new
1
peak in H NMR spectrum due to epoxy ring protons (Hc) at
2.9 ppm and absence of vinylic protons at 5.32 ppm confirms
the epoxidation of the vinylic bond. The second step consists
of the epoxide ring-opening of 2 using methanol in the presence
of acid catalyst amberlyst 15 to obtain a mixture of two
regioisomers (3/3′) containing a secondary hydroxyl group.
Further onward, for the simplicity of the reaction schemes, we
write one isomer structure in the scheme as well as in the figures
1 and 2. The ring-opening of epoxide was confirmed on the
basis of an appearance of a band at 3480 cm-1 due to hydroxyl
group and a band at 1100 cm-1 due to ether bond in the IR
1
spectrum (Figure 1). The H NMR spectrum of a mixture of
(2) AB-Type Self-Condensation of HMODAz (5/5′) and
HODEAz (8). Into a 50 mL two necked round-bottom flask equipped
with a magnetic stirring bar and a nitrogen inlet were charged HMODAz
(2.0 g, 0.005 mol) and kept in an oil bath at different temperatures
(50, 60, 80, and 110 °C) for various times. Yield: 1.80 g (90%). IR:
3338 (NH), 1695 (CO), 1526 (NH deformation), 1230 cm-1 (C-N).
1H NMR (400 MHz, CDCl3): 0.87 (CH3), 1.20-1.70 (methylene
protons), 3.18 (-CH2-NHCOO), 3.39 (OCH3), 4.88 (NH).
regioisomers (3/3′; Figure 2) shows significant three new peaks
at 2.99, 3.41, and 3.49 ppm that correspond, respectively, to
CH to which the methoxy group is attached, methoxy protons,
and CH to which hydroxyl group is attached along with other
peaks. In the third step, methyl ester hydrolysis of intermediate
3/3′ using methanolic potassium hydroxide was carried out to
obtain corresponding hydroxy acid 4/4′. The FTIR spectrum of
hydroxy acid 4/4′ shows a broad band due to acid hydroxyl at
(3) Progress of AB-Type Self-Condensation Monitored by
3435 cm-1 and disappearance of the ester band at 1740 cm-1
.
1
FTIR, H NMR Spectroscopy, and SEC. Into a 50 mL two-necked
Moreover, the disappearance of a peak at 3.66 ppm correspond-
ing to methyl ester protons (COOCH3) in H NMR spectrum
of intermediate 4/4′ confirms the formation of carboxylic acid.
A peak for carboxylic acid 4/4′ appeared at 179.3 ppm in 13C
NMR spectrum. In the last step, hydroxy acid 4/4′ was converted
into hydroxyl acyl azide monomer 5/5′ using a reported
round-bottom flask equipped with a magnetic stirring bar and a nitrogen
inlet, were charged HMODAz (5/5′; 2.0 g, 0.005 mol) and kept in an
oil bath at 80 °C for 24 h. Aliquots (15 mg) were taken out after 15,
45, 60, and so on, minute reaction time intervals and immediately
analyzed by FTIR spectroscopy. After FTIR analysis, samples were
reacted with an excess of ethanol into a nitrogen atmosphere at 40 °C
1

Synthesis of Biobased Polyurethane
Biomacromolecules, Vol. 11, No. 5, 2010 1205
Scheme 1. Synthesis of HMODAz (5/5′) Derived from Methyl Oleate and Corresponding Polyurethane (6)
method.35,36 Hydroxy acid was reacted with ethyl chloroformate
in the presence of triethyl amine to form in situ mixed anhydride
and subsequently reacted with sodium azide to afford acyl azide
HMODAz. The structure of hydroxyl azide 5/5′ was confirmed
by FTIR and 1H and 13C NMR spectroscopy. The IR spectrum
shows a strong absorption band at 2138 cm-1 due to the
asymmetric stretching vibration of the azide group (N3) and also
a shift of the carbonyl group band from 1709 to 1720 cm-1
due to formation of the more electron withdrawing azide group
than the carboxylic acid precursor. The presence of a hydroxyl
group could not interfere with the reaction of ethyl chlorofor-
mate, as noticed by FTIR spectroscopy (because if there was
the reaction, a carbonate band in the FTIR should appear). A
peak of the methylene group attached to an azide group (CH2-
position.34 In comparison with methyl oleate as a starting
material for PU synthesis by the self-condensation approach,
ricinoleic acid is advantageous due to the hydroxyl group
naturally being present in the fatty ester backbone, thus, reducing
the number of chemical reactions to obtain an acyl-azide
hydroxy AB-type monomer.
For the synthesis of 12-hydroxy-9-cis-octadecenoyl azide AB-
type monomer (8), a reported method was used.35,36 Ricinoleic
acid was reacted with ethyl chloroformate in presence of triethyl
1
CON3) appears at 2.32 ppm in the H NMR spectrum of 5/5′,
and the 13C NMR spectrum shows a peak at 180.09 ppm for
the carbonyl attached to an azide group, confirming the
transformation from carboxylic acid to an acyl-azide group.
(2) Synthesis and Characterization of 12-Hydroxy-
9-cis-octadecenoyl Azide (HODEAz) AB-Type Monomer (8).
Ricinoleic acid is a potential important hydroxyl containing C18
fatty acid with a cis-configuration double bond in the ninth
Figure 1. FTIR spectra of intermediates based on methyl oleate: (a)
methyl oleate, (b) 2, (c) 3/3′, (d) 4/4′, and (e) HMODAz (5/5′).
Figure 2. 1H NMR spectra of intermediates based on methyl oleate,
2, 3/3′, 4/4′, and HMODAz (5/5′): solvent, CDCl3; T ) 25 °C.

1206 Biomacromolecules, Vol. 11, No. 5, 2010
Palaskar et al.
Scheme 2. Synthesis of HODEAz (8) and MHHDC (10) Derived from Ricinoleic Acid and Corresponding Polyurethane (9) by (a) Acyl
Azido and Hydroxyl AB-Type Self Condensation Approach and (b) Transurethane Reaction Approach
amine to form in situ a mixed anhydride, and then it was
subsequently reacted with sodium azide to afford acyl azide 8
(Scheme 2). The structure of HODEAz (8) was confirmed by
cis-octadecenoyl azide (8) and obtained in quantitative yield
(Scheme 2). The formation of 10 was easily confirmed by FTIR
spectroscopy (Figure 5). In the spectrum, a band of azide at
2238 cm-1 vanished and a carbonyl band was shift to 1702 cm-1.
A band appeared at 3334 cm-1, confirming the presence of the
N-H bond of urethane. In the 1H NMR spectrum of 10, a signal
1
FTIR and H and 13C NMR spectroscopy. The FTIR spectrum
shows a strong absorption band at 2133 cm-1 due to asymmetric
stretching vibration of azide group (N3) and also a shift of the
carbonyl group band from 1707 to 1720 cm-1 due to the
formation of a more electron withdrawing azide group (Figure
3). In addition, a band due to the CdCsH stretching vibration
appeared at 3008 cm-1. In the 1H NMR spectrum of HODEAz
(8), a triplet peak of the methylene group attached to an azide
group (CH2-CON3) appears at 2.31 ppm and vinylic protons
(CHdCH) appear at 5.2-5.60 ppm (Figure 4). 13C NMR
spectrum shows a peak at 180.53 ppm for the carbonyl carbon
attached to an azide group, confirming the carboxylic acid to
acyl azide transformation.
(3) Synthesis and Characterization of Methyl-N-
11-hydroxy-9-cis-heptadecen Carbamate, AB-Type Monomer
for Transurethane Process (10). An AB-type self-condensable
monomer specially dedicated to transurethane reaction namely,
methyl-N-11-hydroxy-9-cis-heptadecen carbamate (10) was
designed from ricinoleic acid as a biobased source. It was
synthesized by refluxing excess methanol with 12-hydroxy-9-
Figure 4. 1H NMR spectra of HODEAz (8) and PU (9; solvent, CDCl3,
T ) 25 °C).
Figure 5. FTIR spectra of (a) methyl-N-11-hydroxy-9-cis-heptadecen
carbamate (10) and polyurethane (9), obtained by a transurethane
reaction.
Figure 3. FTIR spectra of ricinoleic acid (7), HODEAz (8), and PU
(9).

Synthesis of Biobased Polyurethane
Biomacromolecules, Vol. 11, No. 5, 2010 1207
Figure 6. 1H NMR spectra of methyl-N-11-hydroxy-9-cis-heptadecen
carbamate (10) and ricinoleic acid derived biobased polyurethane (9),
obtained by transurethane reaction.
Figure 7. FTIR spectra of HMODAz (5/5′) polymerization samples
taken at different intervals.
ization. It was found that all the temperatures used for
polymerizations were useful. There was a crucial effect of
temperature on the decomposition of acyl azide as well as
polymerization rate observed by FTIR analysis. An increase in
the reaction temperature leads to an increase in the acyl azide
decomposition, as already observed by Theato and co-workers,37
yielding a faster rate of polymerization. Hence, compared to
run 1, which was carried out at 50 °C, run 4 (vii; Table 1) carried
out at 80 °C shows a higher molar mass for similar time
reactions.
Table 1. Experimental Conditions and Results for Polymerization
of HMODAz (5/5′) and HODEAz (8)
SECa
run
AB-type monomer T (°C) time (h) Mn
Mw
Mw/Mn
1
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HMODAz
HODEAz
HODEAz
HODEAz
50
50
60
60
80
80
80
80
80
80
80
80
110
60
80
80
20
5
8
23
1
2
3
5
7
9
23
6
4
24
10
24
3210 4880
2720 4280
1040 1620
2475 3780
740 1740
1640 3240
2510 4820
2610 3880
3510 6030
3660 6340
6390 10450
8890 18740
3500 6310
5300 7770
6210 9330
6880 10030
1.5
1.6
1.6
1.5
2.3
2.0
1.9
1.5
1.7
1.7
1.6
2.1
1.8
1.5
1.5
1.5
2b
3 (i)
3 (ii)
4c (i)
4 (ii)
4 (iii)
4 (iv)
4 (v)
4 (vi)
4 (vii)
5b
6
7
8
9
For further analysis of the reaction progress, polymerization
1
was carried out at 80 °C and monitored by FTIR, H NMR
spectroscopy, and SEC. The monomer (5/5′) initially forms in
situ isocyanate by the decomposition of acyl azide group via
Curtius rearrangement38a and then isocyanate functions react
with the hydroxyl group to form urethane. It is known that the
reactivity of isocyanates are high toward the hydroxyl group,
and hence, to stop the further increase in molar mass, aliquots
taken at different intervals were reacted with an excess of
ethanol after IR spectroscopic analysis and used for further SEC
and 1H NMR analyses. Figures 7 and 8 show, respectively, FTIR
and 1H NMR spectra of polymerization progress, while Figure
9 shows SEC traces along the polymerization progress upon
heating at 80 °C. The band at 2138 cm-1 (Figure 7) due to
presence of acyl azide groups (CON3) converts into a new band
attributed to isocyanate functions located at 2270 cm-1. The
absorption band at 3341 cm-1 is observed due to the formation
of N-H urethane bonds. Aliquots taken after 15 min of reaction
show almost complete transformation of acyl azido group into
isocyanate function on the basis of FTIR spectrum (Figure 7).
The aliquots after FTIR analysis were reacted with ethanol and
analyzed by 1H NMR spectroscopy, which shows a peak at 4.06
ppm (Hg) due to methylene group protons attached to urethane
group (Figure 8).
a Based on PS calibration, b Reaction in presence of DBTDL (0.1 wt
c
% on HMODAz) as catalyst. Runs 4(i) to 4(vii) carried out for FTIR, 1H
NMR and SEC studies.
for methyl group protons (Hf) attached to urethane bond
appeared at 3.65 ppm, while a signal for methylene protons (Hd)
attached to the NH bond appeared at 3.14 ppm (Figure 6). A
signal appeared at 4.63 ppm corresponding to the protons (He)
of the NH group, while the other protons are matching well
with the expected structure. The carbamate formation was also
confirmed by the 13C NMR spectrum, the carbonyl carbon
appearing at 157 ppm.
(4) Self-Polycondensation of HMODAz, Characterization,
and Reaction Progress Monitored by FTIR, 1H NMR
spectroscopy, and SEC. Self-polycondensation of acyl azide and
hydroxyl groups was adapted as an approach for the synthesis
of polyurethane. The advantages of this approach are (i) the
reaction proceeds smoothly by simple heating of the monomer
in a one-pot reaction, and (ii) there is no need for optimization
of the molar ratios between OH and CO-N3. Self-condensation
of novel HMODAz AB-type monomer was carried out at
different temperatures, such as 50, 60, 80, and 110 °C. Table 1
shows the detailed reaction conditions and results of polymer-
FTIR spectra of aliquots taken along the polymerization
reaction allowed us to observe evolution of characteristic bands,
such as, isocyanate band at 2270 cm-1, which decreases in
intensity, N-H band from polyurethane at 3338 cm-1, which
increases in intensity, the band at 1526 cm-1 due to N-H
bending vibration, and the band of the carbonyl group of acyl
azide at 1720 cm-1 shifts to lower frequency (1695 cm-1) due
to formation of the urethane bond.

1208 Biomacromolecules, Vol. 11, No. 5, 2010
Palaskar et al.
Table 2. Experimental Conditions and Results for Transurethane
Polycondensation of MHHDC (10)
SECa
run catalyst
T (°C) time (h)
Mn
Mw
Mw/Mn
1
Ti(n-BuO)4
130
130
130
130
130
150
5
6
6
5
6
6
3840
6950
5480
9850
1.4
1.4
2
Ti(n-BuO)4
no
3b
4c
5d
6
catalyst
Ti(n-BuO)4
Ti(n-BuO)4
Ti(n-BuO)4
4510
5370
5000 10120
9020
9290
2.0
1.7
2.0
a Based on PS calibration. b No polymer. c Oligomers obtained from
acyl-azido and hydroxyl self-condensation approach (Mn, 3430; Mw, 5870;
Mw/Mn, 1.7). d Oligomers obtained from acyl-azido and hydroxyl self-
condensation approach (Mn, 5100; Mw, 7820; Mw/Mn, 1.5).
Table 1. The molar mass of the polyurethane synthesized at
60 °C was found to be less compared with self-condensation
carried out at 80 °C, which indicates that 80 °C is a better
temperature for the formation of an in situ isocyanate intermedi-
ate as well as polycondensation.
PU (9) formation was confirmed by FTIR, 1H NMR, and 13
C
NMR spectroscopy. The conversion of acyl azide group into
intermediate isocyanate via “Curtius rearrangement” and fol-
lowed by condensation with the secondary hydroxyl group was
confirmed on the basis of bands observed at 3334 and 1691
cm-1 due to the urethane N-H stretching vibration and the CdO
stretching vibrations of the PU (Figure 3). The vinylic double
bond in the PU remains intact, showed by the dC-H bond
stretching vibration band at 3010 cm-1. Urethane formation was
also confirmed by 1H NMR spectroscopy, with the peak
corresponding to methylene protons attached to acyl azide group
in the monomer HODEAz (8) is shifted to downfield due to
urethane formation as well a new peak appearing in the range
of 4.6 to 4.8 ppm due to NH protons of the urethane group
(Figure 4). 13C NMR spectrum shows an urethane carbonyl
function at 156.57 ppm confirming self-condensation.
Figure 8. 1H NMR spectra of HMODAz (5/5′) polymerization samples
at different intervals (quenched with ethanol).
(6) Self-Polycondensation of MHHDC via Melt-Transure-
thane Reaction. Transurethane is a condensation between
bisurethane (A-A) and diol (B-B) in the presence of catalyst
and, similarly, it can be AB-type self-condensation in the
presence of catalyst.33 Transurethane polycondensation was
carried out on MHHDC at 130 °C in the presence of titanium
tetrabutoxide as catalyst in two stages (Scheme 2). In the first
stage, the reaction was performed at 130 °C by stirring under
nitrogen flow for 2 h to obtain oligomers and in the second
stage reaction was carried out at 130 °C under vacuum for 3 h
for further condensation. It was also possible to carry out
transurethane reaction at 150 °C to achieve slightly better results.
Figure 9. SEC traces of HMODAz (5/5′) polymerization samples as
a function of time.
Similar kind of observations was seen in 1H NMR spectra of
aliquots. The intensity of a peak at 4.06 ppm due to methylene
protons attached to the carbamate group (NH-COO-CH2CH3)
as an end-group decreases with time (15 min, 1 h, 3 h, etc.)
due to an increase in molar mass of polyurethane (Figure 8).
There were also increases in the peak intensities at 4.80 ppm
due to NH protons of urethane groups and the peak at 3.16
ppm due to methylene protons attached to the urethane group
of polyurethane (-CH2-NH-COO-).
SEC results reveal that an aliquot after 15 min shows
formation of traces of di-, tri-, and tetramer along with the
isocyanate monomer (Figure 9). As the time of polymerization
increases the intensities of SEC peaks corresponding to oligo-
mers reduce and SEC peaks shift to higher molar mass showing
polycondensation mechanism. The self-condensation (Run 5)
in presence of DBTDL as a catalyst was faster than self-
condensation without catalyst (Run 4 (v), 7 h) on the basis of
molar mass obtained by SEC.
1
The obtained polymer was characterized by IR, H NMR, and
SEC. Table 2 shows reaction conditions and results of tran-
surethane polycondensation. It was observed that the transure-
thane reaction was only possible in presence of titanium
tetrabutoxide, as shown by the experiment performed in the
absence of catalyst (Table 2, run 3).
In another two reactions, an attempt was made to synthesize
PU by transurethane reaction using the PU oligomers obtained
from acyl-azido and hydroxyl AB-type self-condensation ap-
proaches. For this purpose, isocyanate-terminated PU oligomers
were synthesized and reacted with excess of methanol to
obtained PU oligomers resembling the structure with MHHDC.
These oligomers were characterized by IR, 1H NMR, and SEC.
Further, the transurethane polycondensation was carried out in
presence of titanium tetrabutoxide under vacuum at 130 °C to
obtain high molar mass PU. As it can be seen in Table 2 (run
4), Mw increases from 5870 to 9020 g/mol after a transuretha-
(5) Self-Polycondensation of HODEAz (8) and
Characterization of PU (9). As previously described, self-
polycondensation of HODEAz was carried out at 60 and 80 °C
in bulk reaction without catalyst (Scheme 2). Polyurethanes
obtained were characterized by SEC and results are given in

Synthesis of Biobased Polyurethane
Biomacromolecules, Vol. 11, No. 5, 2010 1209
nization reaction and low molar mass oligomers vanished as
observed in SEC traces (Figure 10).
Figure 5b shows FTIR of polyurethane synthesized by
transurethane polycondensation. IR spectrum of PU is similar
to monomer (10) except the hydroxyl band that is shifted to
3337 cm-1. 1H NMR spectrum of PU (9) confirms the structure
of polyurethane by transurethane reaction (Figure 6). Transure-
thane reaction was also confirmed on the basis of a decrease of
intensity of OCH3 protons (Hh′) of chain end-group due to molar
mass increase compare with signal intensity of -CH2NHCOO-
protons at 3.13 ppm. At this reaction temperature, the presence
of double bond in the polymer suggests that no side reactions
have occurred.
Figure 10. SEC traces of (a) PU oligomers obtained from acyl-azido
and hydroxyl AB-type self-condensation approach, and (b) PU
obtained by transurethane reaction on oligomers.
(7) MALDI-TOF Mass Spectroscopy Analysis. Low molar
masses of these PU obtained by both methods made us analyze
whether macrocycles were formed. Indeed, it is known that AB-
type monomers can form macrocycles during polymerization.38b–e
A typical MALDI-TOF MS spectrum is shown in the Figures
12 and 13 for PU obtained by transurethane process (run 1,
Table 2). It should be noted that these spectra are very
complicated, probably due to the monomer source as well as
the polydispersity of PU,33 whatever the matrix used, for
Figure 11. PU with linear structure (a) and macrocyclic structure (b).
Figure 12. MALDI-TOF mass spectrum of PU (run 1, Table 2).
Figure 13. MALDI-TOF mass spectrum of PU (run 1, Table 2) in the mass range 1126-1332.

1210 Biomacromolecules, Vol. 11, No. 5, 2010
Palaskar et al.
masses of all the PU formed by both the processes were
observed and explained by the formation of macrocycles. Two
glass transition temperatures due to soft and hard segments,
respectively, were observed for all PU synthesized from methyl
oleate and ricinoleic acid. DSC analysis revealed that both PU
obtained from ricinoleic acid by different methods had nearly
the same Tg.
Acknowledgment. The authors are thankful to the CNRS,
the French Ministry of Education, and the Aquitaine Council.
Supporting Information Available. Methyl oleate and
ricinoleic acid composition analysis using AFNOR methods,
NF EN ISO 5509 and NF EN ISO 5508. 13C NMR spectra of
10-hydroxy-9-methoxyoctadecanoic acid/9-hydroxy-10-meth-
oxyoctadecanoic acid (4/4′), 10-hydroxy-9-methoxyoctadecanoyl
azide/9-hydroxy-10-methoxyoctadecanoyl azide (HMODAz) (5/
5′), 12-hydroxy-9-cis-octadecenoyl azide (HODEAz) (8), and
methyl-N-11-hydroxy-9-cis-heptadecen carbamate (MHHDC)
(10). MALDI-TOF mass spectrum of PU (run 8 and run 4 (v),
Table 1) and PU (run 6, Table 2). This material is available
free of charge via the Internet at http://pubs.acs.org.
Figure 14. DSC traces of PU obtained by polymerization of HMODAz
(5/5′) derived from methyl oleate (run 4 (vii), Table 1), PU obtained
by polymerization of HODEAz (8) derived from ricinoleic acid (run 9,
Table 1), and PU obtained by polymerization of MHHDC (10) derived
from ricinoleic acid (run 2, Table 2).
example, dithranol, trans-3-indoleacrylic acid, or trans-2-[3-
(4-tert-butylphenyl)-2-methyl-2-propenylidene]-malononitrile.
Figures 12 and 13 show several series of signals but one of
the major series of signals have an interval of 295.3 which
corresponds to molar mass of major repeating unit of the
polymer. Peaks at m/z (1 + 295.3n + 31 + Na+) ) 941.04 (n
) 3), 1236.38 (n ) 4), 1532.66 (n ) 5), and so on correspond
to the PU with a linear structure (Figure 11a). Another series
of peaks found at interval of 295.3 at m/z (295.3 n + Na+) )
909.02 (n ) 3), 1204.34 (n ) 4), 1500.64 (n ) 5) matches
with PU macrocycles having a structure presented in Figure
11b. MALDI-TOF MS analysis of PU obtained by acyl azido-
hydroxyl self-condensation of HMODAz (5/5′) and HODEAz
(8) were also carried out, and the results also revealed PU having
a linear structure and partly formed macrocycles (see Supporting
Information for MALDI-TOF MS spectra, Figures 5-11).
(8) Differential Scanning Calorimetry Analysis. Figure 14
shows DSC thermograms for the PU derived from HMODAz
(5/5′), HODEAz (8), and MHHDC(10) by self-condensation
approach at a heating rate of 10 °C/min. Two different glass
transition temperatures were observed for all PU derived from
methyl oleate and ricinoleic acid based monomers. The
observed glass transition temperature at lower temperature
results due to soft segments and at higher temperature due
to hard ones. HMODAz derived PU showed Tgs at -22 and
27 °C. In case of PU synthesized from HODEAz, Tgs
observed at -53 and 26 °C, while MHHDC-derived PU
exhibited Tgs at -44 and 26 °C.
References and Notes
(1) Woods, G. The ICI Polyurethanes Book, 2nd ed.; Wiley: New York,
1990.
(2) Stalmans, M.; et al. Tenside, Surfactants, Deterg. 1995, 32, 84–108.
(3) Patel, M. K.; Thei, A.; Worrell, A. Resour. ConserV. Recycl. 1999,
25, 61–78.
(4) Steber, J. TextilVeredlung 1991, 26, 348–354.
(5) Miyagawa, H.; Misra, M.; Drzala, L. T.; Mohanty, A. K. Polymer
2005, 46, 445–453.
(6) Lligadas, G.; Ronda, J. C.; Galia, M.; Biermann, U.; Metzger, J. O. J.
Polym. Sci., Part A: Polym. Chem. 2006, 44, 634–645.
(7) Lu, Y.; Larock, R. C. Biomacromolecules 2008, 9, 3332–3340.
(8) Ionescu, M.; Petrovic, Z. S.; Wan, X. J. Polym. EnViron. 2007, 15,
237–243.
(9) Lu, Y.; Larock, R. C. Biomacromolecules 2007, 8 (10), 3108–3114.
(10) Lu, Y.; Larock, R. C. Biomacromolecules 2006, 7 (9), 2692–2700.
(11) Wang, H. J.; Rong, M. Z.; Zhang, M. Q.; Hu, J.; Chen, H. W.; Cziga´ny,
T. Biomacromolecules 2008, 9, 615–623.
(12) Satheesh Kumar, M. N.; Manjula, K. S. S. J. Appl. Polym. Sci. 2007,
105, 3153–3161.
(13) Hill, K. Pure Appl. Chem. 2000, 72, 1255–1264.
(14) Petrovic, Z. Polym. ReV. 2008, 48, 109–155.
(15) Ogunniyi, D. S. Bioresour. Technol. 2006, 97, 1086–1091.
(16) Ehrilich, A.; Smith, M. K.; Patton, T. C. J. Am. Oil Chem. Soc. 1959,
36, 149–154.
(17) Sakamoto, W. K.; Kanda, D. H. F.; Andrade, F. D. A.; Das-gupta,
D. K. J. Mater. Sci. 2003, 38, 1465–1470.
(18) Fan, Q.; Xiao, C. Polym. Compos. 2008, 758–767.
(19) Alam, J.; Riaz, U.; Ahmad, S. Polym. AdV. Technol. 2008, 19, 882–
888.
(20) Zanetti-Ramos, B. G.; Lemos-Senna, E.; Soldi, V.; Borsali, R.; Cloutet,
E.; Cramail, H. Polymer 2006, 47, 8080–8087.
Conclusions
(21) (a) Xu, Y.; Petrovic, Z.; Das, S.; Wilkes, G. L. Polymer 2008, 49,
4248–4258. (b) Matsumura, S.; Takahashi, K. Macromol. Chem. Rapid
Commun. 1986, 7, 369–373. (c) Ebata, H.; Toshima, K.; Matsumura,
S. Macromol. Biosci. 2007, 7, 798–803.
(22) Lu, Y.; Tighert, L.; Berzin, F.; Rondot, S. Carbohydr. Polym. 2005,
61, 174–182.
(23) Chang, L.; Xue, Y.; Hsieh, F. J. Appl. Polym. Sci. 2001, 80, 10–19.
(24) Chang, L.; Xue, Y.; Hsieh, F. J. Appl. Polym. Sci. 2001, 81, 2027–
2035.
(25) Shogren, R. L.; Petrovic, Z.; Liu, Z.; Erhan, S. Z. J. Polym. EnViron.
2004, 12, 173–178.
Three new AB-type self-condensable monomers, namely, 10-
hydroxy-9-methoxyoctadecanoyl azide/9-hydroxy-10-methoxy-
octadecanoyl azide (HMODAz) (5/5′), HODEAz (8), and
MHHDC (10) were synthesized from methyl oleate (sunflower
oil) and ricinoleic acid (castor oil), respectively, using simple
reaction steps. Self-condensation of HMODAz was studied at
50, 60, 80, and 110 °C, while self-condensation of HODEAz
(8) was carried out at 80 °C. The acyl azide group of AB-type
monomer decomposes to form in situ isocyanate as an inter-
mediate within 15-30 min at 80 °C. Further, the isocyanate
containing AB-type intermediate condenses each other to form
polyurethane. Transurethane reaction was carried out on MH-
HDC to obtain similar PU to the one formed by AB-type self-
condensation of HODEAz (8). The comparatively low molar
(26) Zlatanic, A.; Lava, C.; Zhang, W.; Petrovic, Z. S. J. Polym. Sci., Part
B: Polym. Phys. 2004, 42, 809–819.
(27) Javni, I.; Pertovic, Z. S.; Guo, A.; Fuller, R. J. Appl. Sci. 2000, 77,
1723–1734.
(28) Hojabri, L.; Kong, X.; Narine, S. S. Biomacromolecules 2009, 10 (4),
884–891.

Synthesis of Biobased Polyurethane
Biomacromolecules, Vol. 11, No. 5, 2010 1211
(29) Kumar, A.; Ramakrishnan, S. Chem. Commun. 1993, 1453–1454.
(30) Kumar, A.; Ramakrishnan, S. J. Polym. Sci., Part A: Polym. Chem.
1996, 34, 839–848.
(31) Ranganathan, T.; Ramesh, C.; Kumar, A. Chem. Commun. 2004, 154–
(36) Ghatge, N. D.; Vernekar, S. P.; Wadgaonkar, P. P. Makromol. Chem.
Rapid Commun. 1983, 4 (5), 307–311.
(37) Klinger, D.; Chang, J. Y.; Theato, P. Macromol. Rapid Commun. 2007,
28, 718–724.
(38) (a) Scriven, E. F.; Turnbull, K. Chem. ReV. 1988, 88, 297–368. (b)
Tsarevsky, N. V.; Sumerlin, B. S.; Matyjaszewski, K. Macromolecules
2005, 38, 3558–3561. (c) Laurent, B. A.; Grayson, S. M. J. Am. Chem.
Soc. 2006, 128, 4238–4239. (d) Misaka, H.; Kakuchi, R.; Zhang, C.;
Sakai, R.; Satoh, T.; Kakuchi, T. Macromolecules 2009, 42, 5091–
5096. (e) Binauld, S.; Boisson, F.; Hamaide, T.; Pascault, J.;
Drockenmuller, E.; Fleury, E. J. Polym. Sci., Part A: Polym. Chem.
2008, 46, 5506–5517.
155.
(32) Ochiai, B.; Satoh, Y.; Endo, T. J. Polym. Sci., Part A: Polym. Chem.
2001, 39, 4091–4100.
(33) Deepa, P.; Jayakannan, M. J. Polym. Sci., Part A: Polym. Chem. 2008,
46, 2445–2458.
(34) Borsotti, G.; Guglielmetti, S.; Battistel, E. Tetrahedron 2001, 57,
10219–10227.
(35) Ghatge, N. D.; Jadhav, J. Y. J. Polym. Sci., Polym. Chem. Ed. 1983,
21, 1941–1950.
BM100233V