The document summarizes research on the influence of the surfactant sorbitan monolaurate on the suspension polymerization of polyacrylic acid superabsorbent polymers. The study found that a weight ratio of acrylic acid to sorbitan monolaurate of 20/2 produced polymers with the highest swelling properties. Analysis using Fourier transform infrared spectroscopy and scanning electron microscopy showed the 20/2 sample had the best structure. Polymers made with a 20/3 ratio were found to have the most porous and compact morphology.
solubility enhancement and cosolvency by madhavishaikhazaroddin
“cosolvency and soluility enhancement” Pharmatech 2003, 160-166. They had developed simultaneous determination of sitagliptin phospate monohydrate and metformin by ultra performance liquid chromatographic (uplc)method.
Solid dispersion is an effective way of improving the dissolution rate of poorly water soluble drugs and hence its bioavailability. The water soluble carriers used in preparation of solid dispersion enhance the dissolution rate of the poorly water soluble drug. This work reflects the improvement of Dissolution Characteristics as well as Bioavailability of poorly aqueous soluble drug Hydrochlorothiazide. It belongs to BCS class 2 i.e. it has poor water solubility but good permeability.
solubility enhancement and cosolvency by madhavishaikhazaroddin
“cosolvency and soluility enhancement” Pharmatech 2003, 160-166. They had developed simultaneous determination of sitagliptin phospate monohydrate and metformin by ultra performance liquid chromatographic (uplc)method.
Solid dispersion is an effective way of improving the dissolution rate of poorly water soluble drugs and hence its bioavailability. The water soluble carriers used in preparation of solid dispersion enhance the dissolution rate of the poorly water soluble drug. This work reflects the improvement of Dissolution Characteristics as well as Bioavailability of poorly aqueous soluble drug Hydrochlorothiazide. It belongs to BCS class 2 i.e. it has poor water solubility but good permeability.
Cubosomal nanoparticles as an ocular delivery system of fluconazoleSidharth Mehta
The optimized cubosomal dispersion exhibited spherical nanosized particles and reasonable EE% along with higher
FCZ corneal permeation (twofold) as compared to that of FCZ solution.
Moreover, the in vivo study proved the efficacy and safety FCZ-loaded
cubosomal dispersion in treatment of induced keratomycosis
in rats compared to aqueous FCZ solution after topical ocular
application.
Based on the previous results, the use of
cubosomal dispersion as an ocular drug delivery system is
expected to improve antifungal activity of FCZ in treatment
of fungal keratitis.
Water treatment for irrigation and agriculture:
1) Repulsive effect on nematodes
2) High performance with brackish water
3) Savings of fertilizers and phytosanitary products
Solubilisation of Quinazoline drugs by using Beta cyclodextrin complex formationRavindra Zirmire
Solubility of the Quinazoline related drugs was enhanced by usind complex formation method,and the Physico chemical characterisation of these drugs was carried out by simplest methods as UV spectroscopy,TLC,FTIR Spectroscopy.
Cubosomal nanoparticles as an ocular delivery system of fluconazoleSidharth Mehta
The optimized cubosomal dispersion exhibited spherical nanosized particles and reasonable EE% along with higher
FCZ corneal permeation (twofold) as compared to that of FCZ solution.
Moreover, the in vivo study proved the efficacy and safety FCZ-loaded
cubosomal dispersion in treatment of induced keratomycosis
in rats compared to aqueous FCZ solution after topical ocular
application.
Based on the previous results, the use of
cubosomal dispersion as an ocular drug delivery system is
expected to improve antifungal activity of FCZ in treatment
of fungal keratitis.
Water treatment for irrigation and agriculture:
1) Repulsive effect on nematodes
2) High performance with brackish water
3) Savings of fertilizers and phytosanitary products
Solubilisation of Quinazoline drugs by using Beta cyclodextrin complex formationRavindra Zirmire
Solubility of the Quinazoline related drugs was enhanced by usind complex formation method,and the Physico chemical characterisation of these drugs was carried out by simplest methods as UV spectroscopy,TLC,FTIR Spectroscopy.
Surfactants and their applications in pharmaceutical dosage formMuhammad Jamal
This presentation is very much helpful for the medical students,pharmacists, researchers and other health care providers. i hope it will provide important information regarding surfactants and their applications in pharmaceutical dosage forms.
SOLAR POWER VAPOUR ABSORPTION REFRIGERATION SYSTEMaj12345ay
USE OF SOLAR POWER IN REFRIGERATION SYSTEM
The power incident from the sun to the earth has very much amount of energy that the present consumption rate of all the commercial and general uses. We utilize only 0.1% of total incident sun energy on the surface of earth. Thus solar energy can fulfill our present as well as future needs of energy. That is a reason it called renewable sources of energy. It is also environmental clean source of energy and available at whole part of world where people live. Using of solar energy in the field of refrigeration and air conditioning system it become very economical.
In our project we provide solar heat in generator for heating purpose of vapor compression refrigeration system.
For past few decades, energy has played a prominent role in the development of technology and economy. Energy has now become inevitable factor for production as well. The objective of this project is to develop an environment friendly vapour absorption system. Vapour absorption system uses heat energy, instead of mechanical energy as in vapour compression system, in order to change the condition of refrigerant required for the operation of the cycle. R 717(NH3) and water are used as working fluids in this system. The basic idea of this project is derived from the solar heating panel to obtain heat energy, instead of using any conventional source of heat energy. In this project various observations are done by varying operating conditions related to heat source, condenser, absorber and evaporator temperatures. The drawback of this system is that, it remains idle in the cloudy weather conditions.
COMPONENTS USED IN SOLAR POWERED AQUA-AMMONIA VAPOUR ABSORPTION SYSTEM
• ABSORBER
• PUMP
• HEAT EXCHANGER
• GENERATOR
• SOLAR PANEL
• CONDENSER
• EXPANSION VALVE
• EVAPORATOR
• DC BATTERY
• FAN
MANUFACTURING EQUIPMENTS,EVALUATION &STABILITY ASPECTS OF MICROCAPSULESagar Savale
Microencapsulation is describe as a process of enclosing micron sized particles of solid or droplets of liquids or gases in an inert shell, which in turn isolates & protects from environment. The product is obtained by this process is called micro-particles, micro capsules, micro spheres.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Chemical and Physical properties of Cassava Starch-Cm-Chitosan-Acrylic Acid Hydrogel prepared from radiation –induced crosslinking
Gatot Trimulyadi Rekso
Center for Application of Isotopes and Radiation- National Nuclear Energy Agency
Jl. Lebak Bulus Raya No. 49, Jakarta-Selatan, Indonesia
Corresponding author; e-mail; gatot2811@yahoo.com ,
Fax: +62-21-.7513270, HP ; 08129419442
Synthesis, Characterization and Electrical Properties of Polyaniline Doped wi...IJERA Editor
The polyaniline were prepared by using different inorganic and organic acids via oxidative polymerization
method. The prepared samples were characterized by FTIR, the peaks are found to be at 507 cm˗1, 592 cm˗1, 798
cm˗1, 1138 cm˗1, 1244 cm˗1, 1302 cm˗1, 1471 cm˗1 and 1556 cm˗1. These predominant peaks may be
confirming the formation of polyaniline. The structural analysis was studied by employing XRD; found that
polyaniline is amorphous in nature. The SEM studies reveal that they are agglomerated, irregular and size of
these grain increases with increasing amount of polyaniline with different organic and inorganic acids. The dc
conductivity (dc) as a function of temperature (T) for polyaniline is studied in the temperature range from 30 to
1600C. At higher temperature it is found that conductivity increases because of hopping of polarons from one
localized states to another localized states. The ac conductivity of polyaniline was prepared by oxalic acid show
high conductivity at 106 Hz. This is due to the space charge polarization and electrode polarizations.
Present study aims to investigate the efficiency of newly synthesized adsorbent polyvinyl
alcohol-alginate bound nano magnetite microspheres modified with cetyltrimethyl ammonium bromide [PVAANM/CTAB]
in removal of anionic dye ‘Alizarin Red S’ from aqueous medium. The effect of agitation time,
influence of pH, amount of adsorbent, initial dye concentration and temperature were systematically studied by
batch sorption system. Various isotherms and kinetic models have been fitted with experimental data to evaluate
mechanism of adsorption. Characterization of the so-prepared adsorbent was accomplished by FTIR, XRD,
SEM and TEM analysis. The experimental data fitted very well with Freundlich and Temkin isotherm model.
The sorption kinetics follows pseudo second order kinetic model. PVA-ANM/CTAB has been found an effective,
economic, eco-friendly and efficient adsorbent as it showed ≥ 98% removal at pH 8 and could be regenerated
by acetic acid and reused.
PREPARATION AND ANALYSIS OF NOVEL HYDROGELS PREPARED FROM THE BLEND OF GUAR G...msejjournal
This research work deals with the preparation of a series of hydrogels using renewable resources, in order
to decrease the adverse impact on the environment, and understand their swelling behavior. Hydrogels
were synthesized using guar gum and chitosan with glutaraldehyde as the cross-linking agent, protonated
with 98% conc. sulphuric acid. Concentration of chitosan was varied as 0, 12.5, 25, 37.5 and 50% (w/w) in
guar gum, while that of glutaraldehyde was varied as 0, 1.5, 3 and 6% (w/w) of the total quantity of guar
gum and chitosan. Prepared hydrogels were characterized for moisture content, equilibrium water
absorbency, re-swelling capacity, swelling ability in acidic (pH = 3) and basic (pH = 11) pH distilled
water, equilibrium saline water absorbency and Fourier transform infrared spectroscopy. It was
determined that moisture content, equilibrium water absorbency and equilibrium saline water absorbency
decreased with increased concentration of chitosan and glutaraldehyde, but they still had water swelling to
be classified as hydrogel. Re-swelling capacity of the hydrogels decreased with increased cycles of reswelling. Prepared hydrogels maintained high water swelling in acidic pH distilled water as compared to
basic pH distilled water. This hydrogels can be utilized as eco-friendly water manageable materials.
In this research in order to produce blood sugar biosensor, an appropriate
membrane for glucose oxidase immobilization by using nanofibers created from
polymers of polyacrylic acid and starch are studied. They are biocompatible and
biodegradable respectively and were prepared by electro-spinning method for
nanofiber fabrication. Dimethylformamide and distilled water were used as solvent for
PAA and starch respectively to get a homogeneous solution. Because nanofibers made
of polyacrylic acid-starch face with enzymes, due to its extremely high hydrophilic
‘OH’ groups may lose their cohesion, crosslinking as chemical surface modification
and for better enzyme immobilization, non-thermal plasma surface modification using
atmospheric pressure Dielectric Barrier Discharge (DBD) were used. Crosslinking was
carried out by APTMS and Glutaraldehyde (GA). The effect of electro-spinning process
variables on morphology of nanofibers was examined by Scanning Electron
Microscopy (SEM). Nanofibers structure and chemical composition to demonstrate
the successful linking and immobilization of enzymes in the composite membrane was
obtained by Fourier Transform Infrared spectroscopy (FTIR) and improved thermal
stability of nanofibers in presence of enzyme and surface modifications was
determined by Thermal Gravimetric Analysis (TGA).
Production of Amphiphilic Surfactant Molecule From Saccharomyces Cerevisiae M...inventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Plotting of ternery phase diagram for preparation of SMEDDS
21 jan12 180323_dewi sondari
1. Influence of Surfactant Sorbitan Monolaurate to Suspension Polymerization of Polyacrylic Acid Superabsorbent (Dewi Sondari)
Akreditasi LIPI Nomor : 536/D/2007
Tanggal 26 Juni 2007
INFLUENCE OF SURFACTANT SORBITAN
MONOLAURATE TO SUSPENSION POLYMERIZATION OF
POLYACRYLIC ACID SUPERABSORBENT
Dewi Sondari, Nuri Astrini, Lik Anah and Agus Haryono
Research Center for Chemistry (P2K) - LIPI
Kawasan Puspiptek Serpong 15314, Tangerang
e-mail : sondaridewi@yahoo.com
ABSTRACT
INFLUENCE OF SURFACTANT SORBITAN MONOLAURATE TO SUSPENSION
POLYMERIZATION OF POLYACRYLIC ACID SUPERABSORBENT. A superabsorbent polymer has
been prepared by suspension polymerization reaction using acrylic acid, sodium hydroxide, cyclohexane,
potassium persulfate as initiator and sorbitan monolaurate as surfactant. The effect of different weight ratio of
acrylic acid/sorbitan monolaurate 20/1, 20/2 and 20/3 were investigated based on its swelling properties,
chemical structure by using Fourier Transform-Infra Red (FTIR) Spectroscopy and the surface morphology
by Scanning Electron Microscopy (SEM). The molecular weight of polyacrylic acid superabsorbent was
determined by intrinsic viscosity measurements in 2 M aqueous sodium hydroxide at 25 oC. The study showed
sample with weight ratio of acrylic acid/sorbitan monolaurate = 20/2 have best swelling properties.
Key words : Superabsorbent polymer, Suspension polimerization, SEM, FT-IR, Surfactant
ABSTRAK
PENGARUH SURFAKTAN SORBITAN MONOLAURAT TERHADAP POLIMERISASI
SUSPENSI SUPERABSORBEN ASAM POLIAKRILAT. Polimer superabsorben telah dibuat secara reaksi
polimerisasi suspensi menggunakan asam akrilat, sodium hidroksida, sikloheksan, potassium persulfat sebagai
inisiator, dan sorbitan monolaurat sebagai surfaktan. Pengaruh dari berbagai rasio berat asam akrilat/sorbitan
monolaurate = 20/1, 20/2 and 20/3 telah dipelajari berdasarkan sifat mengembang (swelling properties),
struktur kimia yang dianalisis menggunakan spektroskopi Fourier Transform-Infra Red (FT-IR) dan morfologi
permukaan yang diamati menggunakan Scanning Electron Microscope (SEM). Berat molekul superabsorben
poliasam akrilat dihitung dengan cara mengukur kekentalan intrinsik dalam larutan natrium hidroksida 2M
pada suhu 25 oC. Hasil penelitian menunjukkan sampel dengan perbandingan berat asam akrilat/sorbitan
monolaurat = 20/2 mempunyai nilai sifat mengembang yang terbesar.
Kata kunci : Polimer superabsorben, Polimerisasi suspensi, SEM, FT-IR, Surfaktan
INTRODUCTION
Superabsorbent polymers can be described as For superabsorbent polymers used as medical
polymer having a network structure and a moderate and sanitation materials, they must have high absorption
degree of cross-linking. They can absorb a large amount rates and low residual levels of toxic chemicals. Usually,
of water, considerably more than their dry mass. The the porous superabsorbent polymers are prepared by
amount of the water absorbend can be in a range of adding chemical reagents to produce bubbles in the
hundreds to thousands time to that of the polymer. These polymer [1].
polymers have been extensively used as absorbents in Recent developments were also suggest the
personal care products, such as infant diapers, feminine production of super-absorbent polymers from acrylic
hygiene products, and incontinence product. They have acid and a cross-linker by solution or suspension
also received considerable attention for a variety of more polymerization. The type and quantity of cross-linker
specialized applications, including matrices for enzyme control both the swelling capacity and gel modulus. The
immobilization, bioabsorbents in preparative synthesis and the use of cross-linker polyacrylate super-
chromatography, materials for agricultural mulches, and absorbents have been a popular topic in the polymer
matrices for controlled release devices [1]. technology research and development [2].
21
2. Jurnal Sains Materi Indonesia Edisi Khusus Desember 2008, hal : 21 - 24
Indonesian Journal of Materials Science ISSN : 1411-1098
In general, the functions of the surfactant used samples have been averaged over 3 independent
in the polymerization, are that the polymerization measurements.
mixture forms a stable emulsion, the surfactant does The water uptake is expressed in terms of
not retard the polymerization reaction, and uniform swelling ratio (Q, g/g) was calculated by:
polymer particles are formed without coagulation nor
separation [3]. Q = (Wt - Wo - Wn) / Wo
In this study, we investigated influence of
surfactant sorbitan monolaurate to polyacrylic acid Where :
superabsorbent properties into suspension W n = Weight of nylon cloth
polymerization. Wo = Weight of dry hydrogel
W t = Weight of swollen hydrogel
EXPERIMENTAL METHODS
FT-IR Spectrum and SEM Analysis
Materials Infrared absorption spectra of polyacrylic
Acrylic acid purity 99,8% was purchased from superabsorbent was studied by FT-IR using IR
Aldrich (Singapore), sodium hydroxide, cyclohexane Prestige-21 Shimadzu (Shimadzu Co., Japan). The
were reagent grade from E-Merck, Potassium persulfate polymers were mixed with KBr and pressed to a plate for
pure grade was purchased from E-Merck, and Sorbitan measurement. All of the spectra were measured 16 scans
Monolaurate was purchased from Aldrich. at a resolution of 4 cm-1. A background spectrum
containing no sample was substracted from all spectra.
The surface morphology was observed using scanning
Methods
electron microscopy (SEM).
Synthesis of Superabsorbent Polymers Polyacrylic
Acid Measurement of Molecular Weight by
Intrinsic Viscosity
In 200 mL flask, acrylic acid having a purity of
99.8% by weight was placed. While cooling it, 76.5 g of For the determination of viscosity-average
22.6% by weight aqueous sodium hydroxide solution molecular weight (Dalton), the polyacrylic acid was
was dropped thereinto with stirring to neutralize dissolved in 2 M aqueous sodium hydroxide. Five
the acrylic acid. Then, potassium persulfate was added different dilute solutions were used to do the
and stirring was continued at room temperature to experiments on measurement of intrinsic viscosity (η).
dissolve it. The Mark-Houwink equation relating to intrinsic
213 g of cyclohexane and sorbitan monolaurate viscosity with empirical viscometer constant
were charged into a 500 mL flask equipped with a reflux K = 0.0422 (mL/g) and a = 0.64 for polyacrylic acid was
condenser, and the surfactant was dissolved at room used to calculate the molecular weight using this
temperature with stirring. The aqueous solution equation [4].
of partially neutralized acrylic acid salt was dropped to
be suspended therein. Polymerization reaction was RESULTS AND DISCUSSION
carried out for 3 hours while keeping the bath temperature
at 70 oC [3]. Swelling Studies
With the aim of investigating the effect of
Swelling Analysis surfactant on the material’s sorption properties an
equilibrium swelling measurements in distilled water were
The water absorption capability of hydro-gel performed on hydrogel samples, obtained from three
were measured by tea bag method using nylon cloth [5].
The hydrogel (approximately 500 mg ) is weighed 250
and poured into the bag. The open side of the bag 225
200
is closed. The bag was then immersed into the 175
Swelling ratio
20/1 ratio
distilled water to swell. After a suitable period of time, 150
20/2 ratio
125
the bag was taken out from the water. The bag was 100
20/3 ratio
20/2>20/3=20/1
then hanged for 15 minutes to let the excess water to 75
50
dripp off and then weighed to determine the amount of
25
distilled water absorbed by the hydro-gel. Equilibrium 0
swelling measurements in distilled water were carried 0 20 40 60 80 100 120
Tim e (m inute)
out for all samples using an electronic microbalance
(AdamAAA250L) with an accuracy of ±10-4 g. Reported Figure 1. Swelling ratio in distilled water vs time of
values of equilibrium water uptakes for each different various weight ratio of acrylic acid/sorbitan monolaurate
22
3. Influence of Surfactant Sorbitan Monolaurate to Suspension Polymerization of Polyacrylic Acid Superabsorbent (Dewi Sondari)
different weight ratio of acrylic acid/sorbitan (20/1, 20/2
and 20/3). The resulted swelling ratios are shown in
Figure 1.
Figure 1 shows that the water uptake capability
of hydrogel was influenced by sorbitan monolaurate
content. Higher swelling capacity will be produced when
weight ratio of acrylic acid/sorbitan monolaurate = 20/2
was put into reaction. The influence of sorbitan
monolaurate as the surfactant forms a stable suspension.
A stable polymer will be obtained when the amount of
surfactant, which is added, is optimum, in which the Figure 3. Scanning Electron Micrograph of the hydrogel
polymer product will be less harder and water swelling surface with weight ratio of acrylic acid/sorbitan
monolaurate 20/1
capacity will be higher. In the other hand, the increase of
surfactant amount, the formed polymer during the
polymerization becomes a block and has such a low
water absorption.
Optimizing the amount of added surfactant to
polymerization mixture, result in a more stable
suspension. This formed polymer particle sizes are small
and uniform, so that, increases the water absorption
capability. When the particle sizes were smaller, the
surface area is better, and then the better surface area
will be have better water absorption.
Figure 4. Scanning Electron Micrograph of the hydrogel
surface with weight ratio of acrylic acid/sorbitan
FT-IR and SEM Analysis monolaurate 20/2
The infrared spectroscopy was used to determine
the type of bonds present in the hydrogel. The infrared
spectra in Figure 2 indicate that the hydrogel is containing
carboxyl group (-COOH). Spectra peak at 1734 cm-1 and
800 cm-1 arised from symmetric stretching vibration of
C=O, and –C-C respectively.
Another new peak is at 2852 cm-1 and 2924 cm-1
arised from stretching vibration of –C-H. The
polymerization between acrlylic acid using potassium
persulfate as initiator was showed by disappearance
of spectrum peak at 3100-3000 cm-1 from double bond Figure 5. Scanning Electron Micrograph of the hydrogel
of -HC=CH-. surface with weight ratio of acrylic acid/sorbitan
monolaurate 20/3
sample 4
sample 5
SML 2x
%T
Samples with different surfactant amounts
were collected, and their surface morphologies
were investigated by SEM. A series of SEM
micrographs of polyacrylic acid hydrogel with various
surfactant are shown in Figure 3, 4, and 5.
A From SEM analysis, it can be shown
that morphology of the hydrogel surface
B micrograph (weight ratio acrylic acid/sorbitan
monolaurate 20/1 and 20/2) were less porous and
compact compared with SEM image of 20/3 sample
C
in Figure 5. It is obviously illustrated in Figure 5
that 20/3 sample has more porous and compact
morphology.
4000
SML 2x
3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600
1/cm
The surfactant of sorbitan monolaurate
Wave number (cm-1 )
influenced to the formed polymer particle size. An
Figure 2. Infrared spectra of the polyacrylic acid
optimum surfactant amount will provide a more porous
superabsorbent with various weight ratio acrylic acid/
sorbitan monolaurate. (A) 20/1; (B) 20/2 and (C) 20/3 and compact of polymer structure.
23
4. Jurnal Sains Materi Indonesia Edisi Khusus Desember 2008, hal : 21 - 24
Indonesian Journal of Materials Science ISSN : 1411-1098
Molecular Weight Determination by Intrinsic [5]. Y. ZHAO, H. SU, L. FANG and TAN, Polymer, 46
Viscosity (2005) 5368-5376
The molecular weight of polyacrylic acid
superabsorbent polymer were reported in Table 1.
Table 1. Molecular weight of the polyacrylic acid superabsorbent
polymer
Weight ratio acrylic acid/ Molecular
No
sorbitan monolaurate weight
1 20/1 135,397
2 20/2 191,594
3 20/3 217,274
Molecular weight depends on polymer chain,
longer polymer chain will be produced when less initiator
was put into reaction and depend on the amount of
monomer. The functions of the sorbitan monolaurate as
surfactant used in the polymerization, are that the
polymerization mixture forms a stable suspension, the
surfactant does not retard the polymerization reaction,
and uniform polymer particles are formed without
coagulation nor separation.
CONCLUSIONS
Superabsorbent polymer has been prepared by
suspension polymerization reaction using acrylic acid
and sorbitan monolaurate as surfactan. Sample with
weight ratio of acrylic acid/sorbitan monolaurate = 20/2
have best swelling properties.
The morphology of polymer made of acrylic acid/
sorbitan monolaurate with weight ratio of 20/3 has porous
and compact structure more than others.
ACKNOWLEDGEMENTS
The authors are thankful for the financial
supported by DIPA thematic from Indonesian Institute
of Sciences (LIPI)
REFERENCES
[1]. CHEN, Y., LIU, Y.F., and TAN, H.M., Preparation
of macroporous cellulose-based superabsorbent
polymer through the precipitation method,
BioResources, 3 (1) (2008) 247-254
[2]. Absorbent Polymers: AMCOL International, http:/
/www.amcol.com/fctbook/absor.htm, (1996)
[3]. United States Patent. 4,340,706. July. 20, 1982.
Alkali metal acrylate or ammonium acrylate polymer
axcellent in salt solution-absorbency and process
for producing same, (1982)
[4]. BRANDRUP, J., IMMERGUT, E.H., and GRULKE,
E.A., Polymer Handbook, fourth edition, A Wiley-
Interscience Publication, Canada.
24