Monoacryloyl esters of carbohydrates: Synthesis, polymerization and application in ceramic technology

Article abstract of DOI:10.1016/j.carbpol.2014.05.023

The article presents the interdisciplinary research among organic synthesis, chemistry of polymers and ceramic technology. It presents the synthesis of monoacryloyl esters of fructose and glucose that is 1-O-acryloyl-d-fructose and 3-O-acryloyl-d-glucose,

Full text of DOI:10.1016/j.carbpol.2014.05.023

Carbohydrate Polymers 111 (2014) 610–618
Contents lists available at ScienceDirect
Carbohydrate Polymers
journal homepage: www.elsevier.com/locate/carbpol
Monoacryloyl esters of carbohydrates: Synthesis, polymerization and
application in ceramic technology
a,∗
b
a
Paulina Wiecinska , Tadeusz Mizerski , Mikolaj Szafran
a
Warsaw University of Technology, Faculty of Chemistry, Department of Chemical Technology, 3 Noakowskiego St., 00-664 Warsaw, Poland
Warsaw University of Technology, Faculty of Chemistry, Department of Organic Chemistry, 3 Noakowskiego St., 00-664 Warsaw, Poland
b
a r t i c l e i n f o
a b s t r a c t
Article history:
The article presents the interdisciplinary research among organic synthesis, chemistry of polymers and
ceramic technology. It presents the synthesis of monoacryloyl esters of fructose and glucose that is 1-
O-acryloyl-d-fructose and 3-O-acryloyl-d-glucose, conditions of their polymerization and application in
shaping of advanced ceramic powders by the so called gelcasting method. The paper presents the influ-
ence of carbohydrate esters on the viscosity of Al2O3 suspensions and microstructure of final ceramic
samples. The results showed that synthesized esters of saccharides can play the role of organic monomers
able to polymerize in situ and self-cross-linking compounds in gelcasting. The paper presents the pro-
posed structure of polymeric network which is formed from acryloyl ester of glucose during gelcasting
process. The paper describes rheological behaviour of slurries composed of synthesized substances and
A2O3 powders, wetting angles of alumina substrate by synthesized compounds, differences in glass
transition temperatures of polymers and the microstructure of obtained final ceramic samples.
Received 7 February 2014
Received in revised form 17 April 2014
Accepted 3 May 2014
Available online 23 May 2014
Keywords:
Monoacryloyl esters
Fructose
In situ polymerization
Gelcasting
Ceramics
©
2014 Elsevier Ltd. All rights reserved.
1
. Introduction
(De Hazan, Heinecke, Weber, & Graule, 2009; Lewis, 2000; Zhang &
Binner, 2008). Only such suspensions can lead to achieve homoge-
nous final ceramic elements of good properties.
Advanced ceramic materials currently represent a wide group
of materials (for example: Al O , ZrO , Si N , BaTiO , Ni-Al O )
One of the willingly applied colloidal processes is gelcasting,
which combines conventional shaping from ceramic slips with
polymer chemistry (Omatete, Janney, & Nunn, 1997; Santacruz,
Nieto, Binner, & Moreno, 2009). Gelcasting allows to obtain high-
quality, complex-shaped ceramic elements by means of an in situ
polymerization, through which a macromolecular network is
created to hold ceramic particles together. There exist some com-
mercially available monomers commonly applied in gelcasting
process, such as acrylamide, 2-hydroxyethyl acrylate, acrylic acid,
etc. (Ma, Huang, Yang, Le, & Sun, 2006; Ma, Xie, Miao, Huang,
& Cheng, 2002) but they present excessive toxicity and must be
used together with external cross-linking monomers. Gelcasting
process can be performed also with the use of polysaccharides
and proteins as gelling agents, which are non-toxic and environ-
mentally friendly. The most often applied gelling agents are agar
(Olhero, Tari, Coimbra, & Ferreira, 2000) agarose (Santacruz, Nieto,
& Moreno, 2005), cellulose acetate (Mueller, Yu, & Willert-Porada,
2006), chitosan (Bengisu & Yilmaz, 2002), gelatin (Tulliani, Bartuli,
Bemporad, Naglieri, & Sebastiani, 2009), etc. Significant disadvan-
tages of applying polysaccharides and proteins in gelcasting are
relatively long gelation time or necessity to dissolve the above
2
3
2
3
4
3
2
3
which are becoming widely used as the materials for electronics,
dental implants, cutting tools, abrasive elements of high quality,
materials used in nuclear industry and medicine. In order to fabri-
cate the above products, it is necessary to use ceramic powders
of suitable properties; nevertheless the important stage of the
production is shaping of the material. Colloidal processing plays
nowadays the leading role in fabrication of advanced ceramics,
mainly because it meets the demands of ceramic industry which is
looking for cheap and environmentally friendly technologies. Col-
loidal suspensions are the basis for many shaping techniques of
ceramics such as: slip casting (Suarez et al., 2009; Tallon Galdeano,
Limacher, & Franks, 2010), gelcasting (Young, Omatete, Janey, &
Menchhofer, 1991), electrophoretic deposition (Sakka, Suzuki, &
Uchikoshi, 2008; Uchikoshi, Suzuki, Okuyama, Sakka, & Nicholson,
2
004), direct coagulation casting (Graule, Gauckler, & Baader, 1996)
or freeze casting (Dash, Li, & Ragauskas, 2012). The main challenge
of colloidal methods lies in achieving time-stable, low viscosity
suspensions having high solid loading of well dispersed particles
◦
compounds at the raised temperature (for example 60–70 C for
agaroids as reported by Millan, Nieto, and Moreno (2002). This
∗ Corresponding author. Tel.: +48 22 2347413; fax: +48 22 628 27 41.
E-mail address: pwiecinska@ch.pw.edu.pl (P. Wiecinska).
http://dx.doi.org/10.1016/j.carbpol.2014.05.023
0
144-8617/© 2014 Elsevier Ltd. All rights reserved.

P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
611
affects considerably on deterioration of the rheological proper-
ties of suspensions through water evaporation. What is more, it
complicates the process of shaping from a technological point
of view.
The interesting alternative for commercial acrylic monomers
and polysaccharides could be specially designed and synthesized
compounds on the basis of carbohydrates which will be able to
polymerize in situ. The obtained polymeric network would be able
to hold ceramic particles together. Authors elaborated the synthesis
of new compounds on the basis of glucose and fructose named 3-O-
acryloyl-d-glucose and 1-O-acryloyl-d-fructose. These compounds
should be able to maintain a stable ceramic suspension and poly-
merize in situ at room temperature. It is worth mentioning that the
chemical structure of monosaccharides derivatives, i.e. the location
of acryloyl group in a molecule, may have a big influence on the rhe-
ological properties of ceramic suspensions and polymerization rate.
Mono-, disaccharides as well as carbohydrate polymers have been
recently found to lie in area of researchers’ interest as processing
agents in ceramic technologies (Li & Akinc, 2005; Schilling, Sikora,
Tomasik, Li, & Garcia, 2002; Srinivasan, Jayasree, Chennazhi, Nair,
Fig. 1. Chemical structure of synthesized compounds: (a) 3-O-acryloyl-d-glucose,
(
b) 1-O-acryloyl-d-fructose.
solution, was the initiator of polymerization. Redistilled water was
used as a solvent.
2.2. Characterization techniques
Reactions were followed by thin layer chromatography (TLC) on
silica gel 60F254 (Merck), as eluent heptane-acetone mixture 2:1
was used, for development 1%aq solution of KMnO4 and 1% alco-
1
holic solution of 12MoO3·H3PO4 × H2O were used. The HNMR and
13
CNMR spectra were recorded on Gemini 200, Varian. The solvent
residual peaks of D2O and CDCl3 were used as internal standards.
Infrared spectra were recorded using a Biorad FTIR Spectrometer
FTS165 on KBr pellet.
&
Jayakumar, 2012; Tallon Galdeano & Franks, 2011; Yar, Acar,
Yurtsever, & Akinc, 2010).
The paper shows the synthesis of 1-O-acryloyl-d-fructose and 3-
O-acryloyl-d-glucose, then the polymerization conditions of above
compounds and the proposed structure of nascent polymeric
network. Authors discuss also the influence of the synthesized com-
pounds on the properties of alumina slurries and sintered ceramic
samples.
2.3. Synthesis of monoacryloyl esters of carbohydrates
The synthesis route is shown in the example of 1-O-acryloyl-
d-fructose (Fig. 2). The aim of the synthesis was to obtain, from
d-fructose, an organic monomer in which one of the hydroxyl
groups is replaced by acryloyl group which enables free radi-
cal polymerization of the molecules. The synthesis of the new
monomer was carried out in three stages. In the first stage 2,3:4,5-
di-O-isopropylidene-d-fructopyranose (DIPF) was obtained in
order to block four from the five free hydroxyl groups in a fruc-
tose molecule (Fig. 2a). This stage was performed on the basis of
procedure described by Glen, Myers, and Grant (1951).
2
. Experimental procedure
2.1. Materials
The reagents for the organic synthesis have been purchased
from the following suppliers: d-fructose (POCh, Poland, >98%),
acryloyl chloride (Sigma–Aldrich, 96%), methylene chloride (POCh,
Poland, puriss), N,N-dimethylaniline (Merc, for synthesis) MgSO4
I stage. d-fructose (27.0 g, 0.150 mol), anhydrous acetone
(142.5 g, 2.455 mol), anhydrous ZnCl2 (36.0 g, 0.264 mol) and
polyphosphoric acid (1.5 g, 0.005 mol P4O10 added to 3.0 g,
3
(
(
POCh, Poland, puriss), H SO4 (POCh, Poland, puriss), PbCO3
POCh, Poland, puriss), anhydrous acetone (POCh, Poland, puriss),
0.026 mol 85% phosphoric acid) were placed in the 500 cm flask
2
◦
and mixed for 26 h at 25 C. Then 70 g, 0.875 mol of 50% NaOHaq
anhydrous ZnCl2 (POCh, Poland, puriss), 85% phosphoric acid
POCh, Poland, puriss), P O (POCh, Poland, puriss), 1,2:5,6-di-O-
isopropylidene-d-glucofuranose (Biosynth, Switzerland, >95%).
The reagents for the in situ polymerization of synthesized com-
pounds and shaping of alumina by gelcasting are described below.
solution was added. The obtained precipitate was filtered off and
the dark brown solution was discoloured by active carbon. Then
acetone was evaporated, 50 ml of water was added and extrac-
tion by using 20 ml of heptane was carried out 5 times. The
(
4
10
obtained extract was dried by MgSO . After filtering off MgSO ,
4
4
The first used ceramic was ␣-Al O3 of symbol Nabalox 713-10
dichloromethane was distilled. Then 200 ml of 0.05 M H SO4 was
2
2
(
Nabaltec, Germany) of mean particle size D5 = 0.70 ␮m, specific
added and mixed for 8 h. The reaction mixture was extracted by
20 ml portions of dichloromethane, rinsed by saturated solution
of NaHCO3 and dried. After few hours the crystals of the product
0
2
surface area 8.0 m /g measured by BET on ASAP 2020 V3.01H
(
pycnometer on AccuPyc II 1340 Pycnometer (Micromeritics, USA).
The second alumina powder used in the research was high purity
␣
Micromeritics, USA) and density 3.92 g/cm3 measured by helium
◦
appeared. Melting point was 93–97 C.
II stage. In the second stage esterification reaction was
carried out to obtain 1-O-acryloyl-2,3:4,5-diisopropylidene-d-
fructopyranose (1-Akr-DIPF) (Fig. 2b). DIPF (39.0 g, 0.15 mol),
N,N-dimethylaniline (26.0 g, 0.165 mol) and methylene chloride
(225 ml, 3.514 mol) were placed in the 500 cm3 two-necked flask
equipped with condenser and dropping funnel. Acryloyl chloride
(13.9 g, 0.154 mol) was added from dropping funnel during 7 min to
the boiling reaction mixture. Then, the mixture was boiled for 20 h,
stirred on a magnetic stirrer. The content of the flask was poured
into water (750 ml) placed in separating funnel. Lower layer was
separated and washed with 450 ml of 3% solution of sulfuric acid
and with 750 ml of water. The solution was dried with magnesium
sulfate and evaporated. Then 90 ml of hexane was added. After 24 h
the precipitate was filtered off and dried on air.
-Al O of symbol TM-DAR (Tamei Chemicals, Japan) of an average
2 3
3
particle size 0.21 ␮m (calculated from BET), density 3.80 g/cm and
a specific surface area 14.1 m /g.
2
Two synthesized esters of carbohydrates and a commercially
available 2-hydroxyethyl acrylate, HEA (Fluka, >97%) were tested
as monomers in the gelcasting process of alumina powders. Both
esters named 3-O-acryloyl-d-glucose (3-acr-G) and 1-O-acryloyl-
d-fructose (1-acr-F) were synthesized in a three step synthesis
elaborated by authors described in the following paragraph. The
chemical structures of synthesized compounds are shown in Fig. 1.
Diammonium hydrocitrate, DAC (POCh, Poland, puriss) and cit-
ric acid, CA (Sigma, puriss) were used as dispersing agents in
ꢀ
ꢀ
the Al O ceramic slurries. N,N,N ,N -tetramethylethylenediamine,
2
3
TEMED (Fluka, >98%) played the role of activator and ammonium
III stage. In the third stage four hydroxyl groups were unlocked
persulfate (Aldrich, ≥98%), used in the form of 1 wt.% aqueous
by hydrolysis (Fig. 2c). 1-Akr-DIPF (28.0 g, 0.089 mol) and H SO4
2

6
12
P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
Fig. 2. Synthesis of 1-O-acryloyl-d-fructose: (a) stage I: synthesis of 2,3:4,5-di-O-isopropylidene-d-fructopyranose, (b) stage II: synthesis of 1-O-acryloyl-2,3:4,5-
diisopropylidene-d-fructopyranose, (c) stage III: synthesis of 1-O-acryloyl-d-fructose.
Table 1
(
224 ml, 0.02 M) were placed in the flask (equipped with condenser
Values of wetting angle and glass transition temperature of examined compounds.
and mechanic stirrer) and heated from room temperature up to
◦
1
10 C on the oil bath. Additionally, 0.05 g of phenothiazine was
Monomer
Wetting angle of
alumina surface ( )
Glass transition
temperature of
polymer [ C]
◦
added to prevent polymerization during heating. After 25 min the
reaction mixture got clear and colourless. The reaction progress
was monitored by thin layer chromatography (TLC). The TLC-plates
were developed by the mixture heptane–acetone (2:1). The dif-
◦
3-O-acryloyl-d-glucose
11
20
29
46
5.5
−19.0
−27.4
–
1-O-acryloyl-d-fructose
2-Hydroxyethyl acrylate
ference between R values for the substrate and the products is
f
Water
relatively large (the disappearance of substrate is easy to observe)
and the difference of Rf values for partially hydrolysed product
(
monoisopropylidene derivative) and the final compound is small,
derivatives of carbohydrates were measured. For comparison the
measurements were also done for 2-hydroxyethyl acrylate, com-
monly used in ceramic technology. Wetting angle of compounds
was measured by applying a drop of monomer on polished alumina
substrate and then taking a picture. On the resulting photographs
the tangent to the droplet surface at the point of contact between
the phases was drawn and the angle was measured. The glass
transition temperature (Tg) was measured by differential scanning
calorimetry (DSC) on Perkin-Elmer Pyris 1. First, polymeric tapes
were obtained from monomers by free radical polymerization. The
polymerization was carried out with the use of TEMED and ammo-
nium persulfate as redox initiator. The Tg was marked by reading
the temperature at the point of inflection in the curve of heat capac-
ity changes as a function of temperature. The measurements were
but it is sufficient to determine the moment when the reaction com-
pletes. Therefore, on the basis of TLC measurements, after ca. 3 h
3
0 min the reaction was completed. The mixture was cooled and
.5 g of lead carbonate was added in one portion in order to neu-
2
tralize the acidic solution. The mixture was stirred during 5 min,
then filtered and concentrated on air.
In case of the synthesis of 3-O-acryloyl-d-glucose, the first
stage of the synthesis could be omitted, because 1,2:5,6-di-O-
isopropylidene-d-glucofuranose was commercially available. The
procedure in the second and the third stage was analogous to
the synthesis of fructose ester. 3-O-acryloyl-d-glucose has been
obtained in a crystalline form and used in further research as
received. 1-O-acryloyl-d-fructose is a resin like substance, there-
fore was used in the form of a 50% aqueous solution in order to
◦
◦
made in the temperature range from −100 C to 100 C at heating
1
13
◦
facilitate its dosage. The HNMR, CNMR and FTIR spectra of 1-O-
rate 20 C/min. The results of wetting angle and glass transition
acryloyl-d-fructose are presented in Figs. 3 and 4.
temperature measurements are presented in Table 1.
2.4. Measurements of wetting angle and glass transition
2.5. Preparation of ceramic suspensions and shaping
temperature
Alumina aqueous suspensions with investigated monoacryloyl
esters of carbohydrates (which played the role of organic monomer
able to polymerize in situ) were prepared in redistilled water
at room temperature. First, the dispersant used as a mixture of
diammonium hydrocitrate and citric acid was dissolved in water
In order to examine the new compounds as monomers (binders)
in fabrication of alumina ceramic by using the in situ polymeriza-
tion, the wetting angle of alumina substrate and the glass transition
temperature of polymers obtained from synthesized monoacryloyl

P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
613
Fig. 3. (a) 1HNMR and (b) 13CNMR spectra of 1-O-acryloyl-d-fructose.
followed by monomer and activator. The composition of prepared
ceramic suspensions is given in Table 2. Alumina powder was then
added and the suspensions were mixed in an alumina jar in a plan-
etary ball mill PM100 (Retsch) for 90 min with a speed of 300 RPM.
Next the slurries were deaerated for 20 min under reduced pressure
in a vacuum desiccator supplied with magnetic stirrer. After that
the initiator of polymerization was added and the slurry was mixed
for additional 5 min. Slurries with applied monomers are able to
gelate at room temperature. The mixture was then cast into identi-
cal PVC moulds of internal diameter 20 mm and height 5 mm. After
a thick gelled bodies were obtained, specimens were unmoulded
◦
◦
and dried for 24 h at 50 C. The sintering process (1600 C, 1 h for
◦
Al O Nabalox and 1550 C, 1 h for Al O TM-DAR) of ceramic sam-
2
3
2
3
ples obtained by gelcasting was then conducted in Carbolite furnace
Fig. 4. FTIR spectrum of 1-O-acryloyl-d-fructose.

6
14
P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
Table 2
soluble in water, whereas the polymer is completely insoluble. Sec-
ondly, 1HNMR spectra of product (measured a couple of days after
The composition of prepared ceramic suspensions with the use of Al2O3 Nabalox,
monoacryloyl esters of carbohydrates and 2-hydroxyethyl acrylate.
the synthesis) reveal no signals in region of ı = 1/3 (for the poly-
mer and the oligomers the signals of CH2 CH2 groups should
be visible in the mentioned region). Accuracy of those measure-
ments allows us to suppose that the content of oligomers would
be less than 5%. Finally, in case of 3-O-acryloyl-d-glucose, authors
obtained in last experiments the crystalline monomer in 81% yield.
The filtrate still contained the monomer (which is visible in HNMR
spectrum).
Table 1 lists the values of wetting angle of alumina substrate
and glass transition temperature of polymers obtained from exam-
Monomer
3-O-
acr-G
1-O-
acr-F
HEA
Concentration of Al2O3 [vol%]
Concentration of Al2O3 [wt.%]
55.0
82.7
3.0
0.14
0.10
1.0
50.0
79.7
3.0
0.14
0.10
1.0
55.0
82.7
3.0
0.14
0.10
1.0
Monomer content [wt.% wrt Al2O3 powder]
Dispersant DAC content [wt.% wrt Al2O3 powder]
Dispersant CA content [wt.% wrt Al2O3 powder]
Activator TEMED content [wt.% wrt monomer]
Initiator ammonium persulfate [wt.% wrt monomer]
1
0.4
1.0
0.5
ined compounds. The best wettability of ceramic substrate exhibits
in air. SEM images of ceramic samples in a green state and after
sintering were done on Ultra Plus (Zeiss, Germany).
◦
3
-O-a cryloyl-d-glucose (wetting angle 11 ). Very good wettabil-
◦
ity exhibits also fructose ester (wetting angle 20 ). The wetting
angle of commercial monomer 2-hydroxyethyl acrylate was 29 .
Rheological properties of synthesized esters and 2-
hydroxyethyl acrylate (used comparatively) were determined
on Kinexus Pro rheometer (Malvern Instruments, UK) in the paral-
lel plate geometry with a gap of 0.5 mm. The shear rate increased
◦
Nevertheless all investigated monomers much better wet alumina
◦
than water (wetting angle 46 ). A low value of wetting angle
can be related to the development of adhesive coating around
ceramic grains. This can facilitate the formation of polymeric net-
work which increases the mechanical strength of a ceramic sample.
High mechanical strength of ceramic elements in green state is a
very important factor in terms of machining and transportation of
ceramic samples before sintering process.
−1
from 0.1 to 35 s . Parallel plate geometry requires small sample
volume (ca. 2 ml). The influence of the synthesized compounds
on the viscosity of ceramic suspensions was examined by using
Brookfield RVDV + II – Pro Viscometer (Brookfield Engineering
Laboratories Inc., USA) in the coaxial cylinders geometry. The
−
1
−1
shear rate increased from 0.1 to 35 s and back to 0.1 s . For this
measurement a spindle S34 was used. In case of coaxial cylinders
sample volume is 20 ml; however measurements of ceramic
slurries in parallel plate geometry would cause problems with
water evaporation.
The glass transition temperature of all polymers is below room
temperature. This means that in conditions of gelcasting process
which is carried out at room temperature polymers have elastic
properties. These properties are largely responsible for vesting the
ceramic products required mechanical strength before the sinter-
◦
ing process. The highest Tg value amounting 5.5 C has polymer
3
. Results and discussion
obtained from 3-O-acryloyl-d-glucose, the lowest has commercial
◦
polyhydroxyethyl acrylate (−27.4 C). Nevertheless all investigated
3.1. Properties of monoacryloyl esters of carbohydrates
compounds have beneficial elastic properties for application in
shaping of ceramic materials.
Fig. 1 shows the molecular structure of 3-O-acryloyl-d-glucose
and 1-O-acryloyl-d-fructose respectively. The acryloyl group in the
molecule of 1-O-acryloyl-d-fructose is substituted at the first car-
bon in the fructose ring unlike 3-O-acryloyl-d-glucose, where the
OH group at third carbon in the glucose ring has been replaced.
This was due to differences in the spatial structure of d-glucose
and d-fructose. It means that in case of d-glucose the OH group
at third carbon could not be blocked by isopropylidene groups
and therefore underwent esterification reaction, whereas the spa-
tial structure of d-fructose let to leave OH group at first carbon
not blocked. The use of compounds with different spatial struc-
ture allowed estimating the impact of different configuration of
hydroxyl and acryloyl groups on the properties of colloidal alumina
suspensions (such as viscosity of slurries) and ceramic samples,
what is the important aspect in ceramic technology.
3.2. Application of monoacryloyl esters of carbohydrates as
organic monomers in gelcasting process
The synthesis of monoacryloyl esters of carbohydrates was ini-
tially performed for certain application in ceramic technology. First
of all viscosity measurements of ceramic suspensions and fabri-
cation of Al O3 elements by using the in situ polymerization was
2
done. Table 2 presents the composition of prepared ceramic sus-
pensions. One of the advantages of gelcasting process is a possibility
to control the time, after which the gelation occurs, by adding a
suitable amount of activator and initiator of polymerization. For
this reason the quantities of the activator (TEMED) and initiator
of polymerization (ammonium persulfate) have been experimen-
tally chosen in order to assure at least 15 min delay time before
the slurry starts to polymerize. The amount of activator in ceramic
slurries was constant for all suspensions and fixed as 1.0 wt.% based
on monomer content. The quantity of initiator was individually
matched in order maintain 15 min idle time. For this reason the
optimum amount of initiator added to the ceramic slurry with 3-O-
acryloyl-d-glucose was about 0.4 wt.%, for 1-O-acryloyl-d-fructose
1.0 wt.% and for commercially available 2-hydroxyethyl acrylate
0.5 wt.%. This indicates that the chemical structure of monoacry-
loyl derivatives of carbohydrates may have the influence on the
polymerization rate and the amount of the initiator needed to start
the polymerization.
1
Fig. 3a presents HNMR spectrum of synthesized 1-O-acryloyl-
d-frucose: wide multiplet at 3.6 ppm (10H) corresponds to protons
of OH and CH bonds, multiplet at 6.2 (1H) corresponds to protons
of vinyl group. 1-O-acryloyl-d-fructose was the mixture of ␣ and
␤
anomers. Fig. 3b presents 13C NMR spectrum of synthesized 1-
O-acryloyl-d-frucose: 61.9; 65.4; 74.2; 72; 81.9; 97.8 ppm–signals
from C atoms of saccharide fragment; 126.5; 133.7 ppm – signals
of C atoms of vinyl group; 168.1 ppm – signal of C atom of car-
bonyl group. Fig. 4 shows FTIR spectrum of 1-O-acryloyl-d-fructose:
−
1
O
1
H stretching (wide peak 3349 cm ), C O stretching (1722 and
− −1 −1
1
714 cm ), C C (1658 cm and 920 cm ), aliphatic C H stretch-
−
1
−1
−1
ing (2938 cm ), CH2 (1410 cm ), O H bending (1297 cm ),
Fig. 5 presents flow curves and viscosity curves of synthesized
esters of carbohydrates and 2-hydroxyethyl acrylate used compar-
atively. 3-O-acryloyl-d-glucose is a solid, therefore 50% aqueous
solution has been prepared in order to examine the rheological
properties of this substance. In case of 1-O-acryloyl-d-fructose a
fully crystallized product was not obtained, therefore again 50%
−
C
O (1154 cm 1).
One of the most important points during the synthesis is to
receive the pure monomer, with as low as possible oligomer
and polymer impurities. The evidence for receiving the expected
monomer is that the product (high viscosity liquid) is very well

P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
615
Fig. 5. (a) Flow curves and (b) viscosity curves of synthesized esters of carbohydrates and 2-hydroxyethyl acrylate.
aq solution has been also prepared. On the basis of rheological
measurements it can be stated that the lowest viscosity has 2-
hydroxyethyl acrylate, it is a Newtonian fluid. Slight shear thinning
behaviour is observed for the 1-O-acryloyl-d-fructose. The viscosi-
ties of 1-O-acryloyl-d-fructose, 3-O-acryloyl-d-glucose solutions
Fig. 7 presents the proposed chemical structure of polymer
formed from 3-O-acryloyl-d-glucose. There are hydrogen bonds
marked with red. The main polymeric chains are formed owing to
the presence of double bond between carbons in acryloyl group.
The hydrogen bonds are created between glucose units in the
main polymeric chain and between neighbouring chains. Hydrogen
bonding in the polymer is probably analogous to those in cellu-
lose structure. The similar structure and hydrogen bonding can
be formed in the polymeric network of 1-O-acryloyl-d-fructose.
Thus the polymers developed from carbohydrate esters are cross-
linked owing to the presence of hydrogen bonds unlike commercial
acrylic monomers such as presented in the paper 2-hydroxyethyl
acrylate. Acrylic monomers in ceramic technology are always
used together with the external cross-linking agent, for example
−
1
and 2-hydroxyethyl acrylate at shear rate 5.0 s were 135 mPas,
4 mPas and 7 mPas, respectively. It means that viscosities of the
2
monomers are very low. In the successive measurements rheologi-
cal properties of ceramic suspensions composed of alumina powder
and examined substances were measured.
Fig. 6 shows flow curves and viscosity curves of ceramic slurries
with the synthesized monoacryloyl derivatives of carbohydrates
and with the commercially available 2-hydroxyethyl acrylate. The
measurements were performed for slurries of 50 vol% (79.7 wt.%)
solid loading. The lowest viscosity had slurry with commercial 2-
ꢀ
N,N -methylenebisacrylamide or poly(ethylene glycol) diacrylate.
−
1
hydroxyethyl acrylate, the apparent viscosity at shear rate 5.0 s
The use of external cross-linking agents ensures high mechanical
strength of ceramic bodies in green state. The polymers based on
monoacryloyl carbohydrates combines advantages of both polysac-
charides and acrylic polymers. They are environmentally friendly
and opposite to polysaccharides can gel at room temperature. Addi-
tionally they do not strongly increase the viscosity of ceramic
suspensions and on the contrary to acrylic monomers they do not
need the use of external cross-linking agent. As a result both the
amount of organic additives needed in the suspension and the
amount of gases released to the atmosphere during binder burnout
are reduced.
Authors have investigated the influence of three monoacryloyl
esters of carbohydrates on the polymerization idle time of alumina
powder Nabalox 713-10 and on density and mechanical strength of
ceramic samples in a green state (Szafran, Wiecinska, Szudarska, &
Mizerski, 2013). The analyzed esters were 3-O-acryloyl-d-glucose,
1-O-acryloyl-d-fructose and 6-O-acryloyl-d-galactose. The results
showed that polymerization rate and mechanical strength of
ceramic samples is different for each ester. Additionally, syn-
thesized monoacryloyl esters of carbohydrates ensure higher
mechanical strength of ceramic green bodies than for example
commercially available 2-hydroxyethyl acrylate (Bednarek, Sakka,
Szafran, & Mizerski, 2010). This indicates that there is a need to
recognize the differences between described in this paper carbo-
hydrate esters (taking into consideration their spatial structure,
viscosity, glass transition temperature of polymers, etc.) in order to
estimate what type of acryloyl ester would be the most favourable
in ceramic technology.
was 1.13 Pas. Slightly higher viscosity amounting 1.56 Pa s had
slurry with 3-acr-G. The highest viscosity 4.03 Pas had suspensions
with 1-acr-F, nevertheless it was still low enough to fill precisely
casting moulds. All investigated ceramic suspensions are shear
thinning fluids.
On the basis of flow curves, yield points (that is stresses at
which a solid material begins to flow) of slurries can be determined.
The lowest yield point 2.4 Pa was observed for the slurry with 2-
hydroxyethyl acrylate, higher yield point 4.1 Pa was noted for slurry
with 3-acr-G and the highest stress at which slurry begins to flow
was observed for the suspension with 1-acr-F (12.5 Pa). For that
reason the maximal solid content which ensures good fluidity of
slurries with 1-acr-F was fixed at 50 vol%, while for slurries with
two other monomers the solid content could be raised to 55 vol%,
as indicated in Table 2.
The differences in viscosities of suspensions can be explained in
two ways. Firstly, viscosities of pure monomers may affect viscosi-
ties of ceramic slurries. As shown in Figs. 5 and 6 the lowest viscosity
has 2-hydroxyethyl acrylate and alumina slurry containing this
monomer, the highest viscosity has 1-O-acryloylo-d-glucose and
corresponding alumina slurry. The slurry with 2-hydroxyethyl
acrylate has the lowest viscosity probably due to the fact that HEA
is a liquid, therefore the total amount of liquid phase in suspensions
is higher than in case of carbohydrates esters. On the other hand,
the differences in viscosities of pure monomers are insignificant,
while of slurries are considerable. The second explanation of this
phenomenon is that the position and orientation of hydroxyl and
acryloyl groups in a molecule have an influence on the viscosity of
ceramic slurries. In this case, more favourable chemical structure
has 3-acr-G than 1-acr-F. The influence of the conformation and
structure of saccharides on the viscosity of nanoalumina suspen-
sions have been discussed by Falkowski, Szafran, and Temeriusz
Ceramic samples have been obtained by gelcasting method
which is schematically presented in Fig. 8. The basic stage of
shaping is the preparation of time-stable ceramic suspension of
low viscosity and high concentration of solid phase. In gelcasting
process, at the beginning a composition of ceramic powder, disper-
sant, organic monomer, activator and initiator of polymerization is
(
2008).

6
16
P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
Fig. 6. (a) Flow curves and (b) viscosity curves of Al2O3 Nabalox suspensions with examined monomers.
prepared in aqueous medium and poured into the moulds. Then the
entire system gel in situ around the particles, creating the network
that holds the ceramic grains together. Thus the desired shape of
the product is retained. Before the addition of the initiator of poly-
merization the suspension is degassed because oxygen is a well
known inhibitor of radical polymerization. When gelation process
is finished, the obtained green body can me unmoulded, dried and
sintered. During sintering process all organic additives are burned
out, nevertheless they are very important processing agents in the
whole shaping process.
Decomposition of the organic additives used in ceramic tech-
nology is usually investigated by thermal analysis (DTA/TG
measurements). Authors have examined thermal decomposition of
synthesized monoacryloyl esters of carbohydrates in comparison
to commercial substances by using thermal analysis coupled with
mass spectrometry (Bednarek & Szafran, 2012). The results showed
that during thermal decomposition of polymers formed from 1-O-
acryloyl-d-fructose and 3-O-acryloyl-d-glucose no harmful gases
are released to the atmosphere. These substances decompose with
the release of H O and CO . While the application of commercial
2
2
Fig. 7. Proposed structure of polymer formed from 3-O-acryloyl-d-glucose, hydrogen bonds between glucose units are marked with red. (For interpretation of the references
to color in this figure legend, the reader is referred to the web version of this article.)

P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
617
Fig. 8. Scheme of fabrication of ceramic elements by using the in situ polymerization.
monomers such as acrylamide and cross-linking substances e.g.
ꢀ
N,N -methylenebisacrylamide results in releasing of harmful NOx.
The presented in Fig. 9a SEM micrograph of Al O TM-DAR green
2
3
body shows that the obtained by gelcasting ceramic specimens are
homogenous. Polymeric bridges, formed due to the in situ poly-
merization of 3-O-acryloyl-d-glucose, between ceramic grains are
marked with red. It is much easier to recognize polymeric bridges
on SEM when ceramic powder of finer particles is used, therefore for
the microstructure observations Al O TM-DAR was chosen instead
2
3
of Al O Nabalox. Based on SEM image of sample after the sintering
2
3
process (Fig. 9b) one can observe the high degree of densification
what is substantial in ceramic technology. Carbohydrate polymers
which had formed during gelcasting process did not disturb the
sintering process. The detailed properties of ceramic specimens in
green and sintered state obtained with the use of 3-O-acryloyl-d-
glucose we described elsewhere (Bednarek et al., 2010; Falkowski,
Bednarek, Danelska, Mizerski, & Szafran, 2010).
4. Conclusions
The synthesis of monoacryloyl esters of carbohydrates
3
-O-acryloyl-d-glucose
and
1-O-acryloyl-d-fructose
was
ꢀ
ꢀ
described. The compounds can polymerize by using N,N,N ,N -
tetramethylethylenediamine and ammonium persulfate as redox
initiating system. Acrylol esters of carbohydrates have been used
as organic monomers in fabrication of Al O ceramics by gelcasting
2
3
technique. The obtained polymers are characterize by low glass
transition temperature what is very beneficial for ceramic appli-
cations. They have also very good wettability of ceramic substrate.
Viscosities of alumina suspensions composed of synthesized
compounds are low, what ensures obtaining high quality ceramic
parts. SEM images of alumina bodies in green and sintered state
showed that the application of new compounds allows to obtained
homogenous ceramic bodies. The synthesized compounds are
therefore the good alternative for the commercially available
Fig. 9. SEM images of Al2O3 TM-DAR samples obtained by gelcasting with the use
of 3-O-acryloyl-d-glucose (a) green body and (b) sintered sample.

6
18
P. Wiecinska et al. / Carbohydrate Polymers 111 (2014) 610–618
acrylic monomers such as 2-hydroxyethyl acrylate used in the
fabrication of ceramic elements by using the in situ polymerization,
mainly because they do not need the use of external cross-linking
agent.
Millan, A. J., Nieto, M. I., & Moreno, R. (2002). Thermogelling polysaccharides for
aqueous gelcasting – Part I: A comparative study of gelling additives. Journal of
the European Ceramic Society, 22, 2209–2215.
Mueller, A., Yu, F., & Willert-Porada, M. (2006). Cellulose acetate based gelcast-
ing process for Gd-containing ceramic bodies. Journal of the European Ceramic
Society, 26, 2743–2751.
Olhero, S. M., Tari, G., Coimbra, M. A., & Ferreira, J. M. F. (2000). Synergy of polysaccha-
ride mixtures in gelcasting of alumina. Journal of the European Ceramic Society,
Acknowledgement
2
0, 423–429.
Omatete, O. O., Janney, M. A., & Nunn, S. (1997). Gelcasting: From laboratory devel-
This work has been supported by the Ministry of Science and
Higher Education of Poland (Grant no. IP2011 002171).
opment toward industrial production. Journal of the European Ceramic Society,
1
7, 407–413.
Sakka, S., Suzuki, T. S., & Uchikoshi, T. (2008). Fabrication and some properties of
textured alumina-related compounds by colloidal processing in high-magnetic
field and sintering. Journal of the European Ceramic Society, 28, 935–942.
Santacruz, I., Nieto, M. I., & Moreno, R. (2005). Alumina bodies with near-to-
theoretical density by aqueous gelcasting using concentrated agarose solutions.
Ceramics International, 31, 439–445.
Santacruz, I., Nieto, M. I., Binner, J., & Moreno, R. (2009). Gel casting of aqueous
suspensions of BaTiO3 nanopowders. Ceramics International, 35, 321–326.
Schilling, C. H., Sikora, M., Tomasik, P., Li, C., & Garcia, V. (2002). Rheology of
alumina-nanoparticle suspensions: Effects of lower saccharides and sugar alco-
hols. Journal of the European Ceramic Society, 22, 917–921.
Srinivasan, S., Jayasree, R., Chennazhi, K. P., Nair, S. V., & Jayakumar, R. (2012).
Biocompatible alginate/nano bioactive glass ceramic composite scaffolds for
periodontal tissue regeneration. Carbohydrate Polymers, 87, 274–283.
Suarez, G., Sakka, Y., Suzuki, T. S., Uchikoshi, T., Zhu, X., & Aglietti, E. F. (2009). Effect of
starting powders on the sintering of nanostructured ZrO2 ceramics by colloidal
processing. Science and Technology of Advanced Materials, 10, 1–8.
Szafran, M., Wiecinska, P., Szudarska, A., & Mizerski, T. (2013). New multifunc-
tional compounds in gelcasting process – Introduction to their synthesis and
application. Journal of the Australian Ceramic Society, 49(1), 1–6.
References
Bednarek, P., Sakka, Y., Szafran, M., & Mizerski, T. (2010). Gelcasting of alumina with a
new monomer synthesized from glucose. Journal of the European Ceramic Society,
30, 1795–1801.
Bednarek, P., & Szafran, M. (2012). Thermal decomposition of monosaccharides
derivatives applied in ceramic gelcasting process investigated by the coupled
DTA/TG/MS analysis. Journal of Thermal Analysis and Calorimetry, 109, 773–782.
Bengisu, M., & Yilmaz, E. (2002). Gelcasting of alumina and zirconia using chitosan
gels. Ceramics International, 28, 431–438.
Dash, R., Li, Y., & Ragauskas, A. J. (2012). Cellulose nanowhisker foams by freeze
castin. Carbohydrate Polymers, 88, 789–792.
De Hazan, Y., Heinecke, J., Weber, A., & Graule, T. (2009). High solids loading ceramic
colloidal dispersions in UV curable media via comb-polyelectrolyte surfactant.
Journal of Colloid and Interface Science, 337, 66–74.
Falkowski, P., Bednarek, P., Danelska, A., Mizerski, T., & Szafran, M. (2010). Applica-
tion of monosaccharides derivatives in colloidal processing of aluminum oxide.
Journal of the European Ceramic Society, 30, 2805–2811.
Falkowski, P., Szafran, M., & Temeriusz, A. (2008). Effect of different subtitutent
groups in monosaccharide ring on viscosity of nanometric alumina suspension.
In Global Roadmap for Ceramics – ICC2 Proceedings Verona.
Glen, W., Myers, G., & Grant, G. (1951). Monoalkyl hexoses: Improved procedures
for the preparation of 1- and 3-methyl ethers of fructose, and of 3-alkyl ethers
of glucose. Journal of Chemical Society, 20, 2568–2572.
Graule, T. J., Gauckler, J. L., & Baader, F. H. (1996). Direct coagulation casting – A
new green shaping technique: 1. Processing principles. Industrial Ceramics, 16,
Tallon Galdeano, C., Limacher, M., & Franks, G. (2010). Effect of particle size on the
shaping of ceramics by slip casting. Journal of the European Ceramic Society, 30,
2819–2826.
Tallon Galdeano, C., & Franks, G. V. (2011). Recent trends in shape forming from col-
loidal processing: A review. Journal of the Ceramic Society of Japan, 119, 147–160.
Tulliani, J., Bartuli, C., Bemporad, E., Naglieri, V., & Sebastiani, M. (2009). Preparation
and mechanical characterization of dense and porous zirconia produced by gel
casting with gelatin as a gelling agent. Ceramics International, 35, 2481–2491.
Uchikoshi, T., Suzuki, T. S., Okuyama, H., Sakka, Y., & Nicholson, P. S. (2004). Elec-
trophoretic deposition of alumina suspension in a strong magnetic field. Journal
of the European Ceramic Society, 24, 225–229.
Yar, Y., Acar, F. Y., Yurtsever, E., & Akinc, M. (2010). Reduction of viscosity of alu-
mina nanopowder aqueous suspensions by the addition of polyalcohols and
saccharides. Journal of the American Ceramic Society, 93(9), 2630–2636.
Young, A. C., Omatete, O. O., Janey, M. A., & Menchhofer, P. A. (1991). Gelcasting of
alumina. Journal of the American Ceramic Society, 74(3), 612–618.
3
1–35.
Lewis, J. A. (2000). Colloidal processing of ceramics. Journal of the American Ceramic
Society, 83(10), 2341–2359.
Li, C., & Akinc, M. (2005). Role of bound water on the viscosity of nanometric alumina
suspensions. Journal of the American Ceramic Society, 88(6), 1448–1454.
Ma, J., Xie, Z., Miao, H., Huang, Y., & Cheng, Y. (2002). Gelcasting of ceramic sus-
pension in acrylamide/polyethylene glycol systems. Ceramics International, 28,
8
59–864.
Ma, L. G., Huang, Y., Yang, J. L., Le, H. R., & Sun, Y. (2006). Control of the inner
Zhang, Y., & Binner, J. G. P. (2008). Effect of dispersants on the rheology of aqueous
silicon carbide suspensions. Ceramics International, 34, 1381–1386.
stresses in ceramic green bodies formed by gelcasting. Ceramics International, 32,
9
3–98.