MECHANOCHEMICAL ACTIVATION OF DISPERSED LAYER
COMPOSITES ON THE BASIS OF TALC AND A SERIES OF
BIOLOGICAL ACTIVE SPECIES
Lugovskoy S, Lugovskoy A, Zinigrad M.
Ariel University Center of Samaria, Ariel, Israel
Abstract. Interaction of mineral talc as an inert carrier with bioactive species
(salicylic acid, glycerin, olive oil) was studied by IR Spectroscopy. Substitution of the
silicate hydroxyls by organic acid or alcohol moieties occurs for all the species
studied. Dispersed layered composites, built from the silicate (talc) matrix, to which a
bio-active component is bound, are formed in this interaction in the time scale of 1 
а  5 minutes. The formation of new materials viz. layered dispersed mechanocomposites proceeds due to etheri- or esterification of the basic active sites on the
silicate surface with acids or alcohols.
INTRODUCTION
The mechanochemical approach to the solid-phase synthesis of organic
compounds has some advantages as compared to the conventional “wet” chemical
methods. It allows the elimination of the dissolution stage and therefore excludes the
problem of wastes containing organic pollutants, which enables the development of
environmental friendly synthetic technologies. So, B. X. Wang and X. P. Zhao
demonstrated that the interaction between kaolinite and glycerin occurs via the
reaction of layered kaolinite hydroxyls and those of glycerin [1]. Mechanochemical
milling was also used for the immobilization of organic acids by esterification and
etherification [2], as well as for performance of a series of mechanochemical acidbase reactions for obtaining hybrid organic-organometallic materials [3]. Margetić has
studied a "Highspeed vibrational milling" (HSVM) method on various groups of
chemical reactions, such as Diels-Alder and 1,3-dipolar cycloadditions, Reformatsky,
Prato and Bingel reactions and others [4]. Polycondensation of salicylic acid with
formaldehyde in the course of mechanochemical processing was investigated by our
group [5].
Our research demonstrated that the interaction in the course of the
mechanochemical activation of solid bio-active materials with talc occurs via the
reaction of talc hydroxyls with the hydrogen atoms of the biological agents.
EXPERIMENTAL
Salicylic acid (Aldrich, 99.0+%), glycerin (Aldrich, , 99+%) and food grade
olive oil were taken as model bio-active materials and mixed in mass ratio 1:10 to 1:4
with talc (powder, 350 mesh) prior to mechanochemical activation. The
mechamochemical activation was performed on a Planetary Ball Mill PM-100
(Retsch), drum rotation velocities 100-650 rpm and corresponding jar rotation
velocities 200-1300 rpm. Agate milling jars 125 mL and 10 mm agate milling balls
were used.
Infrared spectra were measured on FTIR System Spectrum BX (Perkin Elmer)
with the use of standard KBr tablet samples.
2-145
RESULTS AND DISCUSSION
Mechanochemical Activation (MCA) of the individual reagents
The process of mechanochemical activation of talc and the individual
bioactive agents was preliminarily studied in order to understand the processes taking
place in the course of joint activation of the organic molecules with the layered
silicate.
The structure of talc is built of silicon-oxygen tetrahedrons. A talc layer is
formed of two SiO4-tetrahedron lattices facing by their apexes one towards another,
and a lattice of magnesium oxide octahedrons between the silica lattices. Van der
Waals forces bind the layers together.5
octahedron
tetrahedron
O
Si
OH
Mg
Fig. 1. Talc Structure.
IR absorbance spectra of raw and activated talc were studied formerly [6,7,8].
Our experiments demonstrated that no significant changes of talc structure occur in
the course of the first 10-20 seconds of activation. Apparently, only inter-layer Van
der Waals bonds are broken during the initial stage of activation due to severe
displacement deformation, while stronger intra-layer bonds remain intact (Fig 2.).
We assume that the number of acidic and basic sites grows in the course of
MCA. On the reaction of the acidic groups with basic sites, water molecules are
formed, whose presence is proven by the characteristic valent and deformational
vibrations in the spectra of talc after 30 second and longer activation. Activation for 5
minutes results in complete destruction of talc crystal structure (Fig 2.). IR spectra of
such samples demonstrated only broad bands of an amorphous product and water
assumedly weakly polarized by magnesium cations [9].
Therefore, the MCA of talc for less than 30 second causes its dispersion
without significant changes of the crystalline structure.
MCA of mono-carbon acids
In the process of MCA of all mono-carbon acids, IR absorbance assigned to
valent OH vibrations is observed as a broad band having some unclear maxima in the
range 2500-3350 cm-1 [7]. The main maximum is observed at about 3000 cm-1, and a
2-146
sharper secondary peak appears at about 2650 cm-1 and is considered characteristic.
This broad band at 3000 cm-1 was assigned to the ν-OH bond vibration masked by the
very intensive band of valent vibrations of СН3- and СН2-moieties having pronounced
maxima at 2955, 2920, 2870 and 2850 cm-1 [8].
The secondary band at about 2650 cm-1 is attributed to the interaction of OHvibrations with the vibrations of dimers at lower frequencies. Bands at 940 and 1430
cm-1 are attributed to the deformation OH-vibrations, and the latter band is also caused
by the valent C-O vibration. Antisymmetric vibrations of C=O are assigned to the
band at 1710 cm-1 and the shoulder at 1690 cm-1 [6].
IR spectra of salicylic acid in the process of MCA were described previously by
us. [5]. From the comparison of the IR spectra of the salicylic acid before and after the
activation it is obvious that hydrogen bonds are not broken in the course of the activation.
Therefore, the crystal structure of the acid is not affected by the activation and no
destruction of acid dimer takes place.
Presumably, mechanochemical activation causes dislocation deformation along
slip planes while relatively stronger hydrogen bond structure is preserved. The weaker
interlayer bonds are broken in the activation process and are quickly restored soon
after.
MCA of individual glycerin and olive oil was not performed, because these
substances are liquid.
MCA of salicylic acid
IR spectra of salicylic acid in the process of MC activation were described
elsewhere [12]. From the comparison of the IR spectra of the salicylic acid before and
after the activation it is obvious that hydrogen bonds are not broken in the course of the
activation. Therefore, the crystal structure of the acid is not affected by the activation and
no acid dimer destruction takes place.
Presumably, mechanochemical activation causes dislocation deformation
along slip planes while relatively stronger hydrogen bonds structure is preserved. The
weaker interlayer bonds are broken in the activation process and are quickly restored
soon after.
MC activation of the system “talc-glycerin”
Glycerin normally forms clusters [10] due to the formation of relatively stable
hydrogen bonds that is confirmed by the ОН valent vibration absorbance at 34503250 cm-1 in the IR spectrum (Fig. 2). The position of the absorbance bands of OH
vibrations evidences that the glycerin molecules are orientated in the direction
facilitating the formation of hydrogen bonds, which is typical for alcohols. We
attribute the observed band having two maxima at 1475 cm-1 and 1465 cm-1 to mixed
 ОН +  СН2 vibrations of glycerin, whereas the band at 1060 cm-1 is assigned to 
С-О [11].
2-147
а)
b)
55sec
Talc
Absorbance
Absorbance
10min
155sec
Glycerin
10min
Glycerin
4000
3600
3200
, cm
55sec
155sec
Talc
2800
1800
2400
1600
1400
, cm
-1
1200
-1
с)
55sec
Absorbance
10 min
Talc
155sec
Glycerin
1400
1200
1000
 cm
800
600
-1
Fig. 2. IR absorption spectra of glycerin and talc before and after the activation
measured in the range of 3800-2600 cm-1 (а), 1900-1200 cm-1 (b), 1400-600 cm-1
(c).
After 55 second MC activation of talc-glycerin system significant changes in
IR absorbance spectrum take place in the range of 3600–3100 cm-1 (Fig. 3а), where
glycerin  ОН и  ОН bands are observed. A broad band having its maximum at 3430
cm-1 appears after 3 minutes of activation (Fig. 2a). The bands with maxima at ~3430
см-1 can be assigned to valent and deformation water molecules vibrations13
evidencing the formation of water in the course of MC activation of talc with
glycerin. The decent of valent (3750-3600 cm-1) and deformation (915 and 940 cm-1)
bands of talc OH-groups is also observed.
No significant change takes place for the main vibrations of the tetrahedron and
octahedron lattices of talc layers (1150-950 and 800-700 cm-1), [12,13], except only a
slight decrease of the intensity of the as Si-O-Si antisymmetric vibration band at 1115
cm-1. Therefore, the crystal structure of talc remains intact.
We attribute the change of absorptions in the range of 3600-3100 cm-1, the
decrease of intensities of internal and external talc OH-groups, accompanied by the
change of the band at 1500-1400 cm-1 and the appearance of water molecule OHvibrations to the mechanochemical interaction of glycerin with talc basic surface sites.
Etherification of talc and glycerin hydroxyls results in the formation of a
mechanochemical composite, in which silicate surface metal ions are chemically
bound to alkyls via oxygen bridges similar to alkoxides.
2-148
Therefore, the performed study demonstrates that polyatomic alcohol
hydroxyls can take part in mechanochemical interactions with surface atoms of
natural silicate.
MCA of the system “talc – olive oil”
Olive oil contains unsaturated fat acid moieties viz. 75% of oleic, 13% of
linoleic and 0.55% of linolenic acids. In the course of mechanochemical activation of
talc with the oil (Fig. 4 a-c) IR spectra demonstrate the decrease of C=O and O-H
valent vibrations of carboxyls (1710 and 2700-2400 cm-1), appearance of water valent
and deformation vibrations (broad bands having weak maxima at 3600 and 1630 cm-1)
and appearance of new absorption bands in the characteristic range of carboxylate
ions (1590 and 1460 cm-1) [9]. Simultaneously, talc band intensities decrease,
particularly those of valent and deformation vibrations of surface talc hydroxyls
(3695, 3670, 3650 and 940 сm-1).
Simultaneously, talc bands intensity decreases, particularly of valent and
deformation vibrations of surface talc hydroxyls (3695,3670, 3650 and 940 сm-1).
а)
b)
oil1(T-oil)correct.spc
oil2(oil-T)correct.spc
65sec
95sec
635sec
1235sec
65sec
Absorbance
Absorbance
20min
10min
95sec
oil
10min
20min
oil
95sec
65sec
4000
3000
2000
, cm
1000
3000
2600
2200
, cm
-1
1800
-1
c)
oil1(T-oil)correct.spc
oil2(oil-T)correct.spc
65sec
95sec
635sec
1235sec
65sec
Absorbance
20min
10min
95sec
oil
2000
1500
1000
, cm
500
-1
Fig. 3. IR absorption spectra of olive oil and talc before and after the activation
measured in the range of 4000-500 cm-1 (а) and narrow ranges of 3000- 1500 cm-1
(b) and 2000-600 cm-1 (c)
2-149
We believe that the strong chemical bonding of talc to acids occurs due to the
interaction of acid protons with talc hydroxyls. This is confirmed by the appearance of
new absorption bands characteristic for the ionized carboxyls [7] in the IR spectrum
of the reaction product.
We assign these changes to the neutralization of hydroxyls of talc, which are
formed in the course of mechanochemical activation, by acid protons formed in
mechanochemical hydrolysis of the oil. Carbon acid anions are therefore bound to
cationic sites of talc.
CONCLUSIONS
The proposed mechanochemical synthesis can be used as a "clean" and
environmental friendly method of synthesis of organic and composite materials. It
allows getting rid of the dissolution stage and therefore of the problem of solventcontaining wastes. Because no solvents or catalysts are used, the obtained materials
can be further used without additional purification. The performed study
demonstrated the possibility of obtaining composite materials based on natural
silicates and containing polyatomic alcohols by the fast and clean mechanochemical
method. Such materials serve as active agents for various cosmetic and drug
compositions.
Only dispersion of talc occurs during first 20 second of mechanochemical
treatment. For longer activation times, talc Me-OH bonds are broken and talc layer
lattice is destructed. Acidic and basic surface sites are formed and water is produced
on their recombination. Mechanochemical activation of silicates (talc) with alcohols
occurs via the reaction of basic active sites on the silicate surface with alcohol
hydroxyls. Mechanochemical activation of talc with organic acids occurs via the
reaction of talc hydroxyls with acid protons and formation of water.
The nature of bond in the product of mechanochemical activation is
determined by the nature of reacting functional groups.
REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
Wang B. X., Zhao X. P (2002) Electrorheological behavior of kaolinite–polar
liquid intercalation Composites
Journal of Materials Chemistry, DOI:
10.1039/b201592g, 12: 1865–1869
Grigorieva TF, Vorsina IA, Barinova AP and Lyakhov NZ (2004)
Mechanocomposites as new materials for solid-phase cosmetics. Chemistry for
Sustainable Development 12 (2): 139-146
Braga D, Maini L, Polito M, Mirolo L and Grepioni F (2003) Reversible solidstate reaction between 18-Crown[6] and M[H2PO4] (M 5 K, Rb, Cs) and an
investigation of the decomplexation process . Chem. Eur. J. 9: 4362-4365
Margetić D (2005) Mehanokemijske Organske bez koristenja otapala. Kemija u
industriji (Zagreb) 54 (7-8): 351-358
Svetlana Lugovskoy, Marina Nisnevitch, Michael Zinigrad, David Wolf.
Mechanochemical synthesis of salicylic acid–formaldehyde chelating copolymer. Clean Techn Environ Policy (2008) 10(3) p 279–285
Farmer V.C. (1977) The Infrared Spectra of Minerals, L, 770
Grigorieva T.F., Vorsina I.A, Barinova A.P., Boldyrev V.V. (1996) Solid-state
interaction of kaolinite and acids during joint mechanical activation. J. Materials
Synthesis and Processing, 4 (5): 299-305
Roscioli J. R., Hammer N. I., Johnson M. A. (2006) Infrared spectroscopy of
2-150
9.
10.
11.
12.
13.
water cluster anions, (H2O)n=3-24- in the HOH bending region: Persistence of
the double H-bond acceptor (AA) water molecule in the excess electron binding
site of the class I isomers J. Phys. Chem. A, 110 (24): 7517-7520
Bellami LJ (1975) Infrared spectra of complex molecules, John Wiley and
Sons, New York
Anoma Mudalige and Jeanne E. Pemberton (2007) Raman spectroscopy of
glycerol/D2O solutions. Vibrational Spectroscopy 45(1): 27-35
Nakanishi K (1965) Infrared Spectra and Structure of Organic Compounds, Mir,
Moscow, USSR
Leiserowitz L (1976) Molecular packing modes. Carboxylic acids . Acta
Crystallog. B32 (3): 775-802
Handke M., Jastrzębski W., Mozgawa W. (2004) Vibrational spectra of
aluminosilicate structural clusters J. Mol. Struct., 704(247):1-3
2-151