Page No.:70 2.1 2.1 2.1 2.1 Introduction Introduction Introduction Introduction Today, the high price of petroleum raw materials, scarcity of petroleum products and stringent environmental rules and regulations oblige synthetic polymer scientists to utilize natural renewable resources as their feed stocks for the development of polymers. These feed stocks are well accepted by chemists because of social, economical and environmental reasons. Fortunately, many researchers are now using renewable natural resources as their feed stocks in the development of many polymers.[1-2] Petrochemical resources (crude oil, natural gases and so on), used intensively in the worldwide chemical industry, are in fact limited resources and in a certain period of time will be depleted. The chemical industry is making big efforts to find alternatives to the petrochemical raw materials. One alternative represents the renewable resources which already play an important role in the development of the chemical industry. These renewable resources are relatively inexpensive, accessible, produced in large quantities (regeneratable every year and practically unlimited). [3-7] Owing to the increase in the cost and limited availability of petroleum sources recent trends of research is towards development of alternative polyols from renewable resources. The contribution of polyunsaturated vegetable oil and natural polyol based polyurethane are reported by several authors. [8-9] Vegetable oils and fats are very important resources for polyols. The vegetable oils such as soybean oil, castor oil, sunflower oil, palm oil, rapeseed oil, olive oil, linseed oil and so on, with a worldwide production of around 110 millions t/year (in 2000) [10-12] are used mainly in human food applications (76%), in technical applications (19.5% only 7.5% is converted into soaps, and 10.5% is used in oleochemical industry) and 1.5% in other applications. Soybean oil is the most important
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[19], Polycarbonate [20] etc are used for polyurethane
production. Among which compounds that have received most
attention are polyester and polyether based polyol. [20]
2.1.12.1.12.1.12.1.1 Polyols used for Renewable resourcesPolyols used for Renewable resourcesPolyols used for Renewable resourcesPolyols used for Renewable resources
In 1992, the total world’s production of vegetable oils
amounted to approximately 63 million metric tons (MMT), of
which 11.8 MMT found its way to industrial applications, mainly
to applications such as soaps and oleo chemicals. About 0.5
MMT was used in lubricants and coatings. [21] It was anticipated
that the total world’s production of oils and fats will rise to
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about 105 MMT per annum around the year 2010. [22] It is
expected that the use of vegetable oils, particularly in
lubricants, surfactants, coatings, genetic engineering and Bio-
degradable plastic [23] and bio-degradable binders for coatings
[24-25] will increase substantially.
The transformation of vegetable oils and other natural
products in polyols has opened up and is a very promising area
for new developments, such as genetic engineering to create new
triglycerides containing hydroxyl groups, synthesis of new
polyols by selective oxidation of vegetable oils (for example
microbial oxidation), new reactions for the transformation of
double bonds in polyols such as ozonolysis-reduction,
oxygenation reactions with molecular oxygen using special
complex catalysts (nickel complexes such as nickel
acetylacetonates), enzymic reactions, direct hydroxylation
reactions with heterogeneous catalysts (titanium silicalite) and
so on.[26]
For non-food applications, oleo chemical as well as fine-
chemical industries have expressed their interest in new fatty
acids with unusual properties and functionalities, since current
sources contain no more than approximately 10 different types
of fatty acid. Such usual fatty acids (Table: 1&2) could, on the
one hand, replace raw materials from petrochemical origin with
renewable resources and on the other hand, expand the existing
range of raw materials available and potentially lead to novel
products. Moreover, consumer products made from renewable
resources may also carry an appealing Environment-friendly or
“Green” label. Table: 1&2 gives an overview of a number of major
plant oils and their fatty acids that find use in coating
formulations together with some of their characteristics. The
major reactions of unsaturated triglyceride oils and derivatives
are depicted in Figure: 1.
Page No.:73
Table:Table:Table:Table:---- 1 1 1 1 Chemical Structures of fatty acids.Chemical Structures of fatty acids.Chemical Structures of fatty acids.Chemical Structures of fatty acids.
JATROPHA (Jatropha curcas L. ) Locally known as tuba-
tuba is one of the most promising sources of bio-fuel today.
About 30 percent of the tuba-tuba nut is composed of oil. This
oil can be easily processed into fuel that can replace or mixed
with petroleum based diesel to save on imported oil and most
importantly increase local employment and help the economy to
grow. The tuba-tuba has been planted for quite sometime but it
was mainly as fencing. It is also known in the Tagalog region as
“tubing bakod” and”sambo” while the Ilocanos call it “tawa-
tawa” while it is called “tagumbao” in Nueva Ecija and
Pangasinan. In the Cagayan Valley, it is known as “kalunay” and
“kasla” among the Ilonggos. In the Lanao region, it is known as
“tangantangan”.
Jatropha is a drought-resistant perennial shrub with an
economic life of up to 35 years and can even extend up to 50
years. The shrub has a smooth, gray bark which exudes a
whitish color, Watery latex when cut. The size of the leaves
ranges from 6-15 cm in length and width. It sheds Leaves in the
dry season and rejuvenates during the rainy season.
The flowers of Jatropha are formed terminally with the
female flowers usually slightly larger. It has two flowering peaks
which occur during the wet season. It is pollinated by insects
and each inflorescence yields fruits. Jatropha starts producing
seeds within 14 months from planting but reaches its maximum
productivity level after 4 to 5 years.
The seed matures when the capsules changes from green to
yellow about 2-3 months after flowering.
Jatropha is a potential source of biodiesel for local
production to replace a portion of the country’s dependence on
imported oil. The extracted oil from Jatropha can be used in
diesel engines (in lover blends with diesel fuel). Blending of fuel
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can be done up to 20 percent (B20) without engine modification.
Using Jatropha as biodiesel reduces greenhouse gas emissions.
Jatropha can be grown on marginal and degraded land, thus,
leaving prime agricultural lands for Food crops, and at the same
time restoring the fertility of these marginal lands.
Aside from using the seed oil as biodiesel, the extracted oil
can also be used in making soap. The leaves can be used for
fumigating houses to expel bugs. The root extract can be used as
yellow dye while the bark extract as blue dye. The seeds when
pounded can be used for tanning while the roots, flowers and
latex of the tuba-tuba plant are said to have medicinal
properties.
With the ever increasing interest in biodiesel fuels, we may
be one day getting used to the idea that fuel for our vehicles was
harvested from local plantations instead of using imported oil.
[39-40]
Jatropha seed oil is extracted from the plant Jatropha
Curcas. The plant grows almost anywhere even on gravelly,
sandy and saline soils easily, which would otherwise lie waste. It
is a perennial plant which does not require much care and is
productive for 30-40 years. [41] Plantation of Jatropha is done in
the Tamilnadu, Andhra Pradesh, Bihar, Gujarat and certain
other plants of India.
The plant of Jatropha is a medium sized woody plant with
simple palmate or lobed leaves and umbel inflorescence. The
plant has brightly colored flower which makes it an ornamental
plant. The fruit tends to be capsular green when tender, yellow
when strong and dark brown when dry.
The oil content is 25-30% in seeds and 50-60% in the
kernel. [42] It contains 30-40% oleic acid and 35-40% linoleic
acid which the amount of linolenic acid is only 1-2.0%. There are
some chemicals elements in the seed, cursin, which are
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poisonous and render the oil not suitable human consumption.
Various methods for recovering of oil from seeds, including
extraction with organic solvents and water have been
investigated. The enzyme supported aqueous extraction offers a
nontoxic alternative to common extraction methods using
organic solvents with reasonable yields. [43]
The oil has a very high Saponification value and is being
extensively used for soap making in some countries. Also, the oil
is used as an illuminant in lamps as it burns without emitting
smoke. The latex of Jatropha curcus contains an alkaloid known
as Jatrophine which is belived to have anti – cancerous
properties. It is also used for skin diseases as an external
application. Jathropha curcus is also used for the preparation of
dye and alternative to diesel. [44] The oil is used as a thermal
stabilizer. [45] and as a biofuel. [46] staumann R, G.Foidl et al
produced biogas from Jatropha curcas press cake. [47]
� Structure of Jathropha oil:Structure of Jathropha oil:Structure of Jathropha oil:Structure of Jathropha oil: ----
Page No.:84
� Sesame Oil:Sesame Oil:Sesame Oil:Sesame Oil:
Sesame, Sesamum indicum L., is an ancient oil crop
supplying seeds for Confectionery purposes, edible oil, paste
(tahini), cake and flour. It is typically a crop of small farmers in
the developing countries. In 1993, all but 1000 half of the about
7 million has of sesame grown were in developing countries.
Sesame has important agricultural attributes: it is adapted to
tropical and temperate conditions, grows well on stored soil
moisture with minimal irrigation or rainfall can produce good
yields under high temperatures, and its grain has a high value
($Al000/t).
Sesame seed is believed to be one of the oldest seeds to
have been used as a condiment, as well as for the home-based
production of oil. Sesame oil is traditional cooking oil with a
long history, which is mainly cultivated in India and china but
also in Sudan and neighboring countries and in parts of Central
America (e.g. Mexico).It is derived from the seeds of the sesame
plant which is mainly cultivated in tropical and sub-tropical
areas with a dry and a rainy season. It requires a lot of water in
order to grow and ripen and a dry season during the harvesting.
It is an annual plant, growing on average between 50 to 250cm
high and is rich in flowers. Ideal growing temperatures lie
between 27 and 30°C. Harvesting is done by hand, with the
plants being cut manually and dried in the field. They are then
shaken so that the seeds fall out of the open pods. The
harvesting period in the Northern Hemisphere is between
October and December and, in the Southern Hemisphere, March.
The largest producers in Asia are China and India; in Africa it is
Sudan followed by Nigeria while, in Central America, it is Mexico
and Guatemala. [49]
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Sesame world production areas have remained generally
stable over the years, but in some countries the crop is being
marginalized. Competition from more remunerative crops and a
shortage of labour have pushed sesame to the less fertile fields
and to areas of higher risk. Left unchecked, sesame production
may decrease in the foreseeable future. This provides an
opportunity for Australia to produce larger quantities of high
quality sesame seed to replace ‘lost’ world production.
However, before sesame can realise its potential, extensive
research is needed to adapt the crop to mechanical agricultural
systems. Furthermore, as Australia is becoming more involved
with Asian regional activities, where much of the world’s sesame
is grown, Australia’s own agricultural self interest could be
combined with its international extension and aid programs by
taking the lead in a regional sesame research and development
project.
Sesame grows best on well drained soils of moderate
fertility. The optimum pH for growth ranges from 5.4 to 6.7.
Good drainage is crucial, as sesame is very susceptible to short
periods of water logging. Sesame is intolerant of very acidic or
saline soils. [49]
The response of sesame to both temperature and day
length indicates that it is well adapted to wet season production
in the tropics, or summer production in the warmer temperate
areas. While there is some variation between cultivars, the base
temperature for germination is about 16°C. In temperate areas,
soil temperatures determine the earliest date of sowing. The
Optimum temperature for growth varies with cultivar in the
range 27–35°C. Periods of high temperature above 40°C during
Flowering reduce capsule and seed development. Because sesame
is short day plant, with flowering initiated as day length declines
to a critical level, cultivars are developed for particular
latitudes.
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Sesame oil has an unsaponifiable fraction with a unique
composition. Sesamolin and sesamin may be found in
concentrations up to 1–1.5 %. They are reported to give a high
oxidation stability, especially at elevated temperatures.
Concentrates of these or straight sesame oil have been used as
an additive to increase the oxidation stability in frying oils.
Sesame oil is also mainly used for human consumption but
a small percentage is used in the soap, cosmetic and skin care
industries. The market for sesame oil is mainly located in Asia
and the Middle East where the use of domestically produced
sesame oil has been a tradition for centuries. Oriental sesame oil
has a dark Colour and characteristic, nutty odour, which is
developed by roasting the seeds before extracting the oil. [50]
M.Bhattacharjee, et. al. was study to evaluate the
performance of sesame oil as an alternative of soybean and
linseed oil in the formulation of offset printing ink. Three sets of
rosin modified phenolic resin based varnish were made for offset
ink applications (sheet fed ink) using linseed, Soya, and sesame
oil as vegetable sources. Three offset cyan inks were made with
these three varnishes and were critically evaluated the
performance of the inks. Sesame oil showed significant
advantages on the controlled rheological properties with good
print and post print properties in comparison with other
conventional oils like Soya and linseed. Sesame oil produced a
superior quality of printed specimen with less hazards in the
runnability in the machine. So sesame oil can be successfully as
an alternative vegetable oil printing ink formulation. [51]
Page No.:87
2.22.22.22.2 Literature ReviewLiterature ReviewLiterature ReviewLiterature Review
Since the present study aimed for the synthesis and
characterization of renewable resources based Modified polyol
the literature survey on various aspects of their synthesis,
characterization and applications pertaining to surface coatings
are discussed in the following section.
2.2.12.2.12.2.12.2.1 Synthesis of Polyol base on renewable Synthesis of Polyol base on renewable Synthesis of Polyol base on renewable Synthesis of Polyol base on renewable
resourcesresourcesresourcesresources
V. C. Patel, et. al. synthesized Alkyd resin based on
Jathropha and rapeseed oils using glycerol, phthalic, and maleic
anhydride to obtain the resins suitable for electrical
applications. These resins were characterized for the physical
and electrical properties. Varnishes were prepared using these
resins and characterized as per standard methods. [52]
analysis (TGA) and X-ray diffraction studies. TGA of the
polyurethanes indicated a higher thermal stability of 2450C in
nitrogen atmosphere at 30% decomposition. [67]
A. R. Fornof. et. al. studied the effect of time and
temperature on the air oxidation of soybean oil in the absence of
catalysts or added initiators was investigated. It was possible to
divide the air oxidation of soybean oil into three regimes. The
first regime of air oxidation resulted in insignificant change in
the hydroxyl number. During this regime, it was proposed that
natural antioxidants, which are present in raw soybean oil, were
consumed and peroxide formation occurred. A drastic increase in
hydroxyl number due to the formation and subsequent
decomposition of peroxides marked the second regime of air
Page No.:90
oxidation. In the third regime of air oxidation, free radical
crosslinking of the soybean oil occurred, and an insoluble gel
was formed. [68]
Dunlap. et. al. investigated the condensation reaction
between polycarboxylic acid based oil and diols was studied and
various parameters affecting this reaction such as type and
concentration of catalyst, reaction temperature and mole ratio of
the reactants. The authors also investigated the preparation and
reaction kinetics of fatty acid polyol from linseed oil and usage
of metal acetate as catalyst. [69]
Eef. A. Oostveen. et. al. developed durable and sustainable
coatings and additives for thermoset and thermoplastic materials
based on renewable resources. Authors presented Phthalate free,
high solid alkyd resins based on inventive combination of
sucrose, fatty acids, and renewable cross-linkers. They prepared
reactive diluents, water –borne alkyd emulsion and plasticizers.
[70]
P. K. Arndt. et. al. reported a new degradation method
(pivaloylysis) and prepared cellulose oligomers and reported
series of structural modifications of cellulose oligomer.[71]
Bustos G. et. al. hydrolysed sugar cane bagasse under
different concentration of Hydrochloric acid (2% - 6%), Reaction
time (0-300 min) and Temperature (100-128 oC) and rationalized
the products and suggested optimal condition as 128 oC, 2 %
HCl and 51.1 min.[72]
Gladys Sanchez. et. al. hydrolysed the hemicellulose and
cellulose parts in the straw material Paja Brava (Sturdy grass)
by using dilute sulfuric acid at 0.5 to 1 Wt % at 170 and 230 oC.
[73]
Since the days of Cross and Bevan, Many other methods of
treatments of wood and plants have been developed. Two of these
methods are by W.G. Van Beckum [74] (Chlorination followed by
ethanol amine extraction) and G. Jayme [75] (Treatment with
acidify Sodium Chloride at pH 3-4)
Page No.:91
Frenny. et. al. treated wood successively with chlorine and
then with aqueous potassium hydroxide and prepared a crude
cellulose. They found that the crude cellulose actually contain
large amount of non cellulosic polysaccharides termed β and γ-
cellulose, which are now included under the general terms hemi
cellulose. [76]
Jurgen Metzer. et. al focused on the conservation and
management of resources for the newer developments, to which
the scientists will make considerable contribution and encourage
the environmentally sound use of renewable natural resources.
In this contribution, author highlighted the chemical uses of fats
and oils as renewable stocks. [77]
2.2.22.2.22.2.22.2.2 Characterization of Polyol base on renewable Characterization of Polyol base on renewable Characterization of Polyol base on renewable Characterization of Polyol base on renewable
resourcesresourcesresourcesresources
N. Dutta et. al. synthesized three different polyester resins
from a purified Vegetable oil (Nahar Seed oil). The various
physical properties of the oil like iodine value, Saponification
value, specific gravity, moisture content, have been determined.
The monoglyceride have been obtained from the oil by
alcoholysis method. The synthesized resins have been
characterized by physico-chemical properties. [78]
S. Dutta. et. al. synthesized series of polyurethane resins
with varying NCO/OH resins from the monoglycerides of Mesua
Ferra L. seed oil, poly(ethylene glycol) and toluene diisocyanate
in the presence of dibutyltindilaurate as the catalyst. And
characterized the physical properties such as hydroxyl value,
acid value, Saponification value, iodine value, specific gravities
and isocynate value has been studied. [79]
B. Lin. et. al. synthesized Soybean oil based polyols (5-OH
polyol, 10-OH polyol and 15-OH polyol) from Epoxidized soybean
oil. The melting peak of polyols and the relationship between
melting peak and the number-average functionality of hydroxyl
Page No.:92
in polyols were investigated by differential scanning calorimetry
(DSC). The thermal decomposition of polyols and some of their
thermal properties by thermogravimetric (TG) and derivative
Thermogravimetric (DTG) were also studied. The thermal
stability of polyols in a nitrogen atmosphere was very close
hence they had a same base plate of triglyceride for polyols. [80]
Suresh S. Narine. et. al. prepared rigid polyurethane (PU)
foams using three North American seed oil as starting materials.
Polyol with terminal primary hydroxyl groups synthesized from
canola oil by ozonolysis and hydrogenation based technology,
commercial commercially available soybean based polyol and
crude castor oil were reacted with aromatic diphenylmethane
diisocyanate to prepare the foams. Their physical and thermal
properties were studied and compared using dynamic mechanical
analysis and thermogravimetric analysis techniques, and their
cellular structures were investigated by scanning electron
microscope. [81]
Azam Mukhtar. et. al. studied the fatty acid composition of
tobacco seed oil revealed that the oil is rich in unsaturated fatty
acids, having linoleic acid (71.63%), oleic acid (13.46%) and
Palmitic acid (8.72%) as the most abundant unsaturated and
saturated fatty acids respectively. So the tobacco oil was
characterized as semi-drying type on the basis of fatty acid
composition. The synthesis of alkyd resin was carried out by
alcoholysis or monoglyceride process using an alkali refined
(TMA), modulated differential scanning calorimetry (MDSC), and
thermogravimetric analysis (TGA), and measurements were taken
of tensile properties. The effect of dangling chains on network
properties was assessed. The formation of hydrogen bonds was
observed by FTIR. [97]
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2.2.32.2.32.2.32.2.3 Applications of RenewaApplications of RenewaApplications of RenewaApplications of Renewable Resources based ble Resources based ble Resources based ble Resources based
MaterialsMaterialsMaterialsMaterials
Sandip D. et. al. synthesized Polyester polyols using
vegetable oil fatty acids having different characteristics (mainly
in terms of hydroxyl functionality) and epoxy resin, using
triethylamine as a catalyst. Polyols were characterized by the
FTIR spectroscopy. Polyurethane adhesives were synthesized
from it and used in bonding rubber. Treatment of sulphuric acid
on the non-polar styrene butadiene rubber (SBR) surface was
studied for the bond strength improvement via an increase in
wettability of the rubber surface. Wettability was found by
measuring the contact angle using Goniometer. Bond strength
was evaluated by 1800C T-peel test. The surface modification
and mode of bond failure were studied by Scanning Electron
Microscopy (SEM). The synthesized polyurethane adhesives were
compared with the commercial adhesive. [98]
A.I. Aigbodion, et. al. prepared Rubber seed oil (RSO) and
its derivatives, heated rubber seed oil (HRSO) and alkyd resins
were evaluated as binders in air drying solvent and waterborne
coatings. HRSO was obtained by heating RSO at 3000C until the
desired viscosity. Acid value of RSO (53) is somewhat high. The
major saturated fatty acids are Palmitic (10.2%) and Stearic
(8.7%) while the main unsaturated fatty acids are oleic (24.6%),
linoleic (39.6%) and linolenic (16.3%). Naturally, RSO is semi-
drying and heating enhances its drying ability. GPC analysis
reveals that RSO consists of a rather high molecular weight
fraction that is rarely found in commonly known vegetable oils.
The average molecular weight of RSO is higher than that of
HRSO with the latter narrower in molecular weight distribution.
Low molecular weight species constitute greater proportion of
the alkyds and their number average molecular weights range
between 1379 and 3304 which are comparable to those of
commercial alkyds. The narrower the size distribution the better
the quality of these alkyds as binders. Physico-chemical
Page No.:97
properties of solvent-borne alkyds vary with oil length (OL) and
they are optimum at 50% OL. Water-borne alkyds investigated
show that the sample with lower oil content contains lower
volatile organic content. All the alkyd samples and HRSO are
fairly resistant to water and alkali while they are virtually
unaffected by acid and salt solutions. However, samples IV and
V (water-borne alkyds) are more resistant than their solvent-
borne counterparts (samples I–III) but exhibited lower
scratch/gouge pencil hardness. [99]
John Argyropoulos, et. al.synthesized the hydroformylation
of seed oil based fatty acid methyl esters leads to aldehyde
intermediates that can be hydrogenated to give novel seed oil
based monomers. In this study, the seed oil based monomers
were polymerized with low molecular weight diols to produce
novel aliphatic polyester polyols with very low viscosities. The
seed oil polyester polyols provide environmentally friendly
(green) coating formulations with low volatile organic compound
emissions which lead to coatings with superior physical
properties, such as exceptional hydrolytic resistance and
flexibility. From these polyester polyols, waterborne
polyurethane dispersions were also developed with excellent
stability resulting in coatings with superior physical properties
(i.e., good toughness and abrasion resistance), and exceptional
hydrolytic and acid resistance. [100]
J. van Haveren, et. al. studied Due to limited fossil
resources and an increased need for environmentally friendly,
sustainable technologies, the importance of using renewable feed
stocks in the paint and coatings area will increase in the
decades to come. This paper highlights some of the perspectives
in this area. Alkyd resins for high-solid paints and reactive
diluents, completely based on commercially available renewable
resources, were prepared and characterized. Alkyd resins based
on sucrose and unsaturated fatty acids or oils showed a low
intrinsic viscosity, making them suitable to be used in high-solid
alkyd paints. Reactive diluents based on similar starting
Page No.:98
materials showed excellent properties with regard to thinning
behavior and effect on drying characteristics. Powder coating
polyester resins were synthesized, starting from isosorbide and
diacids. Polyester resins with glass transition temperatures up
to 700C were obtained. Incorporation of small amounts of other
diols and trifunctional components was found to improve color
and coating properties. In order to create completely renewable
resin systems, the development of renewable drying agents for
alkyds and crosslinkers for powder coatings is in progress. [101]
(PU) foam from palm oil-derived polyol. The polyol was
synthesized by transesterification reaction of palm oil and
pentaerythritol using calcium oxide as a catalyst. The obtained
palm oil-based polyol was reacted with commercial polymeric
diphenylmethane diisocyanate in the presence of water (blowing
agent), N,N dimethylcyclohexylamine (catalyst) and
polydimethylsiloxane (surfactant) to produce rigid PU foam. The
effects of the amount of the catalyst and surfactant on foam
properties (i.e. density, compressive strength and thermal
behaviors) were studied. [112]
Manawwer Alam, et. al. made to develop the room
temperature cured polyesteramide resin by condensation
polymerization reaction between fatty amide diol (N, N-bis 2-
hydroxy ethyl linseed oil fatty amide) obtained from oil of linseed
(Linum Ussitatissimum seeds) and pyridine dicarboxylic acid
(PyA) to develop pyridine polyesteramide (Py-PEA), which was
further treated with toluene-2,4-diisocyanate (TDI), in different
weight percentages to develop a series of pyridine poly(urethane
esteramide) resins (Py-UPEA). The structural elucidation of Py-
PEA and Py-UPEA were carried out by FT-IR, 1H-NMR and C-NMR
spectroscopic techniques. Physico-chemical characterizations of
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these resins were performed by standard laboratory methods.
Thermal analyses of these resins were accomplished by
thermogravimetric analysis (TGA) and differential scanning
calorimetry (DSC) techniques. Coatings of Py-UPEA were
prepared on mild steel strips to evaluate their physico-
mechanical and chemical/ corrosion resistance performances
under various corrosive environments. It was found that among
all these systems, the sample having 14 wt% loading of TDI
showed the best physico-mechanical and corrosion resistance
performances. Thermal stability performance suggests that the
system could be safely used up to 200°C. [113]
2.32.32.32.3 Synthesis of Modified Polyols from Synthesis of Modified Polyols from Synthesis of Modified Polyols from Synthesis of Modified Polyols from
Having understood the synthesis of various Modified
polyols from renewable resources like Dehydrated Castor oil,
Jathropha oil and Sesame oil and their applications in diverse
range of industrial products, it was thought to derive the polyols
from other sources to be used for surface coatings. Thus in the
present study, the Modified polyols are derived by reacting non-
traditional oils like Dehydrated castor Oil (DCO), Jathropha Oil
(JO), Sesame oil (SO) with hydroxyl compounds viz. Ethylene
Glycol (EG), Dipropylene Glycol (DPG), Glycerine and Trimethylol
Propane (TMP). The synthesis involved the alcoholysis reaction
between the above moieties. Thus the series of Modified polyols
are prepared by varying the type and amount of each ingredient.
The resulting Modified polyols are characterized for various
physico-chemical characteristics essentially significant in
context to their utilization in surface coatings. The instrumental
techniques like IR and GC were also employed.
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2.42.42.42.4 Experimental workExperimental workExperimental workExperimental work
2.4.1 2.4.1 2.4.1 2.4.1 Synthesis of Modified PolyolsSynthesis of Modified PolyolsSynthesis of Modified PolyolsSynthesis of Modified Polyols
2.4.1.12.4.1.12.4.1.12.4.1.1 Materials and MethodsMaterials and MethodsMaterials and MethodsMaterials and Methods
In the present study, Dehydrated Castor Oil was obtained
from Usha Coating, Vitthal Udhyognagar, Vallabh Vidyanagar,
and Gujarat. Sesame Oil was procured form local market and
Jathropha oil was obtained from Bio-diesel Research Centre,
Agriculture University, Anand (Gujarat). The Fatty acid
composition and its Characterization of oils (physical properties)
are shown in Table: 3-8.
Trimethylolpropane (TMP), Glycerol, was obtained from
Himalaya Resins, Halol. Gujarat. And Ethylene glycol and
Dipropylene glycol were obtained from Samir-Tech. Chem. Pvt.
Ltd. Baroda, Gujarat, India. Lithium hydroxide (LiOH) and
Methyl ethyl ketone was procured from Chitichem Corporation,
Baroda.
Reactive diluents like Trimethylol propane trimethacrylate
(TMPTMA) and Photointiator like Benzophenone was procured
from Merck, USA. Dimethylethnolamine was obtained from
S.D.fine chemical, Baroda.
2.4.1.2 Synthesis of Modified Polyols based on 2.4.1.2 Synthesis of Modified Polyols based on 2.4.1.2 Synthesis of Modified Polyols based on 2.4.1.2 Synthesis of Modified Polyols based on
Polyols were prepared via alcoholysis of triglyceride oil by
proprietary method [114-116].
Alcoholysis of Dehydrated castor oil, Jathropha oil and
Sesame oil with Ethylene Glycol, DiPropyleneGlycol, Glycerin,
Trimethylol propane was carried out separately in the presence
of powdered LiOH (catalyst) with the mole ratio of 1:0.75, 1:1,
1:2 (Oil:Polyol) by following process. The reaction was carried
out under nitrogen atmosphere in a 500 ml four-necked flask
Page No.:105
equipped with a thermometer, a mechanical stirrer, heating
arrangement, Dean and Stark assembly and condenser. The oil
and polyol in stoichiometric ratio along with the catalyst (LiOH)
were charged in the flask and heated to a temperature of 250-
260oC. The progress of alcoholysis was checked at regular time
intervals, and practically the endpoint was taken as the point at
which solubility in alcohol was reached. At this stage heating
was stopped and the reaction mixture allowed to cool to room
temperature. The reaction scheme explaining the above reaction
is depicted as Scheme: 1. The compositions tried in preparing
the series of modified polyols are as described in Table: 9-11.The
resulting polyols were characterized as per the standard
methods.
2.52.52.52.5 CharacCharacCharacCharactttteeeerization of Modified Polyols based rization of Modified Polyols based rization of Modified Polyols based rization of Modified Polyols based
on renewable resourceson renewable resourceson renewable resourceson renewable resources
All the above prepared Modified polyols based on renewable
resources were free flowing liquids. The Characterization was
emphasized particularly on the properties, which have direct
relevance to their application in polyurethane synthesis.
2.5.12.5.12.5.12.5.1 Colour and Clarity (Visual)Colour and Clarity (Visual)Colour and Clarity (Visual)Colour and Clarity (Visual)
The polyols were taken in 100 ml glass cylinder. The visual
appearance of the liquid was checked as a clear (transparent), or
translucent or opaque and accordingly reported. The colour of
polyols was reported in the Gardner 1933 tube colour standard
scale in the range of numbers 1-18. The results are given in
In this test, a liquid (polyol) stream is allowed to flow
downward in the ring shaped zone between the glass wall of a
sealed tube and the rate of rise of air bubble is noted. The rate
at which bubble rises is direct measure of kinematic viscosity.
The rate of bubble rise is compared with a set of calibrated
bubble tubes containing silicon oils of known viscosities. The
results are given in Table: 9-11. [117]
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2.5.32.5.32.5.32.5.3 Hydroxyl Value Hydroxyl Value Hydroxyl Value Hydroxyl Value
Hydroxyl value can be defined as “Number of milligram of
KOH equivalent to the acetic acid which combines with one gram
of the hydroxyl containing sample.” It was performed according
to ASTM Standard [114] Detail procedure is as under…
About 1 gm of the sample (W) was weighed accurately in
glass capsule and charged in the flat bottom flask. 15-20 ml of
predistilled n-butanol was added as diluent. Exact amount of
acetylating mixture (pyridine: acetic anhydride; 3:1) was added
to the flask containing the above mixture. It was stirred
vigorously. Flask was then equipped with condenser and the
mixture was refluxed gently for 1-1.5 hours. It was slowly cooled
down and 15 ml of water was added from the top of the
condenser, so that unreacted acetic anhydride gets converted
into acetic acid. Excess of acetic acid was back titrated using
standardized alcoholic KOH (S). [118]
Blank (B) was performed following the same procedure
without sample.
Hydroxyl value of the polyol was calculated by using
following equation:
56.11 (B-S) x NKOH
W
Where, B = Blank Reading, ml of standard KOH soln.
S = Sample Reading, ml of standard KOH soln
W = Weight of the sample in gm
And N = Normality of KOH Solution
With the help of hydroxy value, the average molecular
weight of sample calculated by the fol lowing formula,
2 X 56.1 X 1000Mol.wt. = ---------------------
Hydroxy value
H y d r ox y l V a l u e =
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2.5.42.5.42.5.42.5.4 Iodine ValueIodine ValueIodine ValueIodine Value
Iodine value is defined as “The weight of Iodine in grams
absorbed per 100 gms of sample under specified conditions”. It
is the measure of proportion of unsaturated constituents present
in the sample.”
It was performed according to IS method [119]. Detail
procedure is as given below…
1 gm of resin (W) was weighed in the glass capsule and
carefully introduced in the Iodine flask (250 ml). CCl4 (25 ml)
was added to dissolve the sample. Exactly 25 ml of Wij ’s solution
was pipetted using Propipetter and added to the Iodine flask.
The flask was stoppered and set aside for the one hour in the
dark. After this 15 ml of 10% KI solution along with 100 ml of
distilled water added to the flask. The liberated Iodine was
titrated against 0.1 N Na2S2O4 solution (Standardize) using
starch solution as an indicator. Burette reading was noted when
colour changes from blue to colourless (S ml). A blank
determination was carried out at the same time (B ml) without
addition of sample.
Iodine value of the polyol is calculated using following
equation:
IV W
NSBx )(69.12 −=
Where, B = Blank Reading, ml of standard Na2S2O4 solution
S = Sample Reading, ml of standard Na2S2O4 solution
W = Weight of the sample in gm
And N = Normality of Na2S2O4 solution.
Page No.:108
2.5.52.5.52.5.52.5.5 Preparation of Fatty Acid Methyl EsterPreparation of Fatty Acid Methyl EsterPreparation of Fatty Acid Methyl EsterPreparation of Fatty Acid Methyl Ester
Approximately 1 gm of oil sample was taken in a 100 ml of
standard joint round bottom flask and to it 10 ml of 0.5%
methanolic KOH solution was added. Water condenser was
attached and refluxed for 2 hrs at 70oC-80oC on water bath. The
content of the flask was than neutralized with 0.1 N HCl
solutions. The material was then transferred to a separating
funnel and the methyl ester extracted by using hexane as
solvent. The hexane layer was washed twice with distilled water
to remove the inorganic materials. The hexane distilled out
under vacuum and the methyl ester thus prepared was checked
for its purity on TLC plate. To check the purity of methyl ester,
glass plate having dimension 10 cm × 20 cm coated with silica
gel G (Mesh size:350) was used. After spotting of the sample
(Prepared methyl ester) and the standard methyl ester the plate
was developed with the following solvent system: Hexane-
diethylether, 99:1(v/v). After development, the plate was dried
and visualized under Iodine vapour. One single spot of same R f
value for prepared and standard fatty acid methyl ester indicates
that the methyl ester thus prepared were pure.
The product was thus ready for injection in Gas
Chromatography.
2.5.62.5.62.5.62.5.6 GGGGas Chromatography of prepared fatty acid as Chromatography of prepared fatty acid as Chromatography of prepared fatty acid as Chromatography of prepared fatty acid
methyl estermethyl estermethyl estermethyl ester
Gas chromatography of the methyl ester was carried out in
Perkin-Elmer gas chromatograph (Model: Auto system XL) using
BP 225 capillary column (Length: 25 meter, Inner Diameter:
0.250mm, Thickness: 0.25 micron) where fused silica was the
stationary phase. The mobile phase was hydrogen gas (Flow rate:
9 psi). Injection port and detector temperature were 250oC and
300oC respectively. The Gas Chromatograph was run in non-
Page No.:109
isothermal condition where the Initial Temperature was 65oC and
it was held for 5 minutes, then the temperature was raised to
220oC (Final Temperature) at 10oC/min and it was held for 20
minutes. Each time the sample (0.2 µL, dissolved in Chloroform)
was injected through micro syringe and the peaks obtained were
identified by comparing the relative retention time of these peaks
with those of standard fatty acid methyl esters. The fatty acid
compositions and Gas Chromatography Spectra were reported in
Table: 3-8 and Figure: 2-4.
2.5.72.5.72.5.72.5.7 IR IR IR IR ––––SpecSpecSpecSpectroscopytroscopytroscopytroscopy
IR spectrum of polyols is considered to be one of the useful
methods of characterization. In principle, it provides qualitative
and quantitative information about the structural details of the
polyols under examination. IR spectra are measured either by
making pallet with KBr or in the form of solution with suitable
solvent or by putting a drop of a sample between two KBr prisms
if sample is liquid. One of the most popular applications of IR
spectra is detection of functional group in the polymer chain.
In recent years, with the introduction of commercial
Fourier Transformation Infra Red (FTIR) spectrometer, that are
operatable over the entire IR frequency range, many application
of IR analysis that were impossible or at least difficult using
conventional dispersive instruments are now readily
accomplished [120].
The IR-Spectra [121] were scanned on Nicholet FTIR-
spectrophotometer in the range of 4000–400cm -1. The liquid
sample was taken on KBr- cell (The crystal of potassium
bromide). The representative spectra of oil and polyol are shown
in Figure: 5-16.
Page No.:110
2.62.62.62.6 Result and DiscussionResult and DiscussionResult and DiscussionResult and Discussion
2.6.12.6.12.6.12.6.1 Colour and ClarityColour and ClarityColour and ClarityColour and Clarity
The colour of liquid Modified polyols (Table: 9-11) derived
from (Dehydrated Castor oil, Jathropha oil, and Sesame oil) are
little darker then their parent oils. This may be due to partial
oxidation of fatty acid components during the hydrolysis
The viscosity of liquid Modified polyols derived (Table: 9-
11) from Dehydrated Castor oil, Jathropha oil, and Sesame oil
can be compared and visualized on the bases of hydrogen
bonding and number of free hydroxyl groups. The hydroxyl
values of DCE-3, DCD-3, DCG-3, DCT-3, JE-3, JD-3 JG-3, JT-3
and SE-3, SD-3, SG-3, ST-3 are higher than those of other
description codes and that is mainly due to their tendency to
form intermolecular hydrogen bonding compared to the
corresponding ones. At the same time since TMP & Glycerine is
slightly more bulkier then Ethylene Glycol and
Dipropyleneglycol. It also affects the tendency of hydrogen
bonding of these said compounds.
2.6.32.6.32.6.32.6.3 Hydroxy ValueHydroxy ValueHydroxy ValueHydroxy Value
Hydroxyl values of the entire range of Modified polyols
prepared have been experimentally determined and the results
are reported in Table: 9-11. The renewable resources like
Dehydrated Castor oil, Jathropha oil, and Sesame oil based
Modified polyols, with increase in hydroxyl group content,
showed an increase in hydroxyl value of the polyols. At the same
time in almost all the polyols synthesized, the experimental
hydroxyl values are found to be slightly lower than the
theoretically calculated values. This can be attributing to the
following reasons.
Page No.:111
a) There may be a possibility of a side reaction such as
etherification of polyol under the conditions of
processing [123].
b) Polyol may have undergone an addition reaction with
carbon – carbon double bond to give a hydroxyl acid
[124].
The above side reactions would consume hydroxyl groups
without loss of carboxyl groups. This might result in the
reduction in experimental hydroxyl values.
2.6.42.6.42.6.42.6.4 IodineIodineIodineIodine Value Value Value Value
Iodine Value of all liquid Modified polyol is represented in
Table: 9-11. From the results it appears that the degree of
unsaturation of fatty acid chain is not significantly altered.
Based on the iodine values of the corresponding oil, it has been
found to be very close to the experimentally determined value.
These results are consistent with the proposed mechanism for
polymerization for alkyd [125], where, unsaturation of fatty acid
is not believed to be taking part in the reactions. The
unsaturated fatty acid system might have undergone
polymerization to form dimer by mechanism as suggested by
Harrision et al [126]. However, such reaction would not occur
due to the lower processing temperature and in the absence of
any catalyst and in the inert atmosphere.
2.6.52.6.52.6.52.6.5 Gas ChromatographyGas ChromatographyGas ChromatographyGas Chromatography
The oils used for the present work were characterized for
their fatty acid composition using gas chromatography. The
chromatograms of Dehydrated Castor oil, Jathropha oil and
Sesame oil are shown in Figure: 2-4. The fatty acid compositions
of each of the oil used in the present work are shown in Table:
3,5&7.
Page No.:112
2.6.62.6.62.6.62.6.6 Infrared spectral studyInfrared spectral studyInfrared spectral studyInfrared spectral study
Figure: 5-16 represents the IR–Spectra of Renewable
resources like oil (Dehydrated castor oil, Jathropha oil and
Sesame oil) and Modified polyol, derived from it.
The peak at 3400 cm -1 is more sharp and longer in polyol
than in parent oil which confirms the presence of free hydroxyl
groups upon alcoholysis of oil with polyhydroxy compound. The
peak at 1750 cm -1 also becomes sharp and longer in polyol than
for oil which also confirms the alcoholysis (Tran-esterification)
reaction of oil with polyhydroxy compound
Strong and sharp band at 1150 cm -1 can well be assigned
to C-O stretching of secondary -C-OH group along with the band
at 1350 cm -1 due to bending of C-OH group in the polyol.
Similarly strong band at 1050 cm -1 and at 1350 cm -1 can be
assigned to O-H bending vibrations and C-O stretching
vibrations of primary alcohol groups –CH2OH present in polyols.
The absorption bands at 1580-1600 cm -1 can be attributed
to diene type of unsaturation present in oil as well as polyols
and the strong bands at 1700 cm -1 of course to carbonyl group of
esters.
The unsaturation is also confirmed by the presence of -C-H
bending vibrations due to -CH=CH- group at 1420 cm -1 both in
oil and polyol.
2.72.72.72.7 SummarySummarySummarySummary
The Modified polyols were prepared successfully from
Renewable resources like (Dehydrated castor oil, Jathropha oil
and Sesame oil) by reacting with EG, DPG, Glycerin and TMP
and are all in liquid form having enough number of hydroxyl
groups required for further reaction with diisocyanates for the
synthesis of urethane acrylate oligomers. The instrumental and
physico-chemical characterization of these polyols revealed their
excellent suitability for utilization in synthesis of urethane
acrylate oilgomers to be used for UV-curable coating
compositions.
Page No.:113
Page No.:114
Figure: 2 Figure: 2 Figure: 2 Figure: 2 Gas Chromatography of Dehydrated Gas Chromatography of Dehydrated Gas Chromatography of Dehydrated Gas Chromatography of Dehydrated
Castor oilCastor oilCastor oilCastor oil
Page No.:115
Figure: 3 Figure: 3 Figure: 3 Figure: 3 Gas Chromatography of Jathropha oilGas Chromatography of Jathropha oilGas Chromatography of Jathropha oilGas Chromatography of Jathropha oil
Page No.:116
Figure: 4 Figure: 4 Figure: 4 Figure: 4 GGGGas Chromatography of Sesame oilas Chromatography of Sesame oilas Chromatography of Sesame oilas Chromatography of Sesame oil
Page No.:117
Table:Table:Table:Table:----3333 Fatty acid composition of Dehydrated Fatty acid composition of Dehydrated Fatty acid composition of Dehydrated Fatty acid composition of Dehydrated
Castor oilCastor oilCastor oilCastor oil
Dehydrated Castor oil Sr No. Name C-Group
Theoretical GC
1 Palmitic Acid C16 (1-3) % 1.6
2 Stearic Acid C18 (1-3)% 1.5
3 Oleic Acid C18:1 (3-5) 3.8
4 Linoleic Acid C18:2 (45-49)% 48
5 Linolenic Acid C18:3 (3-6)% 5.01
6 Arachidic Acid C20 (0.4-1) 0.9
Table:Table:Table:Table:----4 4 4 4 Physical Properties of Dehydrated Physical Properties of Dehydrated Physical Properties of Dehydrated Physical Properties of Dehydrated
Castor OilCastor OilCastor OilCastor Oil
Sr No.
Characteristics Specification Results
1 Refractive Index (1.4805-1.4825) 1.4820
2 Relative density@ 250C (0.925-1.115) 1.1171
3 Color ( Gardner) (5-15) (5-15)
4 Acid Value (mg KOH/gm),max (2-5) 1.8
5 Iodine Value (125-145) 142.2
6 Saponification Value (188-195) 182
Table:Table:Table:Table:----5 5 5 5 Fatty acid composition of Jathropha oilFatty acid composition of Jathropha oilFatty acid composition of Jathropha oilFatty acid composition of Jathropha oil
Jathropha oil Sr No. Name C-Group
Theoretical GC
1 Palmitic Acid C16 (14.1-15.3) % 15.2
2 Stearic Acid C18 (3.7-9.8)% 8.5
3 Oleic Acid C18:1 (34.3-45.8)% 43.20
4 Linoleic Acid C18:2 (29.0- 44.2)% 40.45
5 LinolenicAcid C18:3 (0-0.3)% 0.1
6 ArachidicAcid C20 (0- 0.3)% 0.2
Page No.:118
Table:Table:Table:Table:----6 6 6 6 Physical Properties of Jathropha oilPhysical Properties of Jathropha oilPhysical Properties of Jathropha oilPhysical Properties of Jathropha oil
Sr No. Characteristics Specification Results
1 Refractive Index (1.355-1.485) 1.422
2 Relative density@ 250C (0.925-1.00) 1.0171
3 Color ( Gardner) (9-15) 10
4 Acid Value (mg KOH/gm),max (5-9) 6.2
5 Iodine Value (135-145) 132
6 Saponification Value (180-195) 190.1
Table: Table: Table: Table: ---- 7 7 7 7 Fatty acid composition of Sesame oilFatty acid composition of Sesame oilFatty acid composition of Sesame oilFatty acid composition of Sesame oil
Sesame oil Sr No. Name C-Group
Theoretical GC
1 Palmitic Acid C16 (7-9)% 9.1
2 Stearic Acid C18 (4-5)% 4.3
3 Oleic Acid C18:1 (37-49)% 45.4
4 Linoleic Acid C18:2 (35-47)% 40.4
5 LinolenicAcid C18:3 (3-6)% 4.09
6 ArachidicAcid C20 (0.4-1) 0.8
Table:Table:Table:Table:----8 8 8 8 Physical Properties of Sesame OilPhysical Properties of Sesame OilPhysical Properties of Sesame OilPhysical Properties of Sesame Oil
Sr No. Characteristics Specification Results
1 Refractive Index (1.470-1.474) 1.472
2 Relative density@ 250C (0.925-0.990) 1.0171
3 Color ( Gardner) (12-15) 14
4 Acid Value (mg KOH/gm),max 2 1.8
5 Iodine Value (103-116) 112
6 Saponification Value (188-195) 192.5
Page No.:119
Table: Table: Table: Table: ---- 9 9 9 9 Characterization of Dehydrated Castor Characterization of Dehydrated Castor Characterization of Dehydrated Castor Characterization of Dehydrated Castor
oil based Modifiedoil based Modifiedoil based Modifiedoil based Modified Polyols Polyols Polyols Polyols
Table: Table: Table: Table: ---- 10 10 10 10 Characterization of Jathropha oil based Characterization of Jathropha oil based Characterization of Jathropha oil based Characterization of Jathropha oil based
Table: Table: Table: Table: ---- 11 11 11 11 Characterization of Sesame oil based Characterization of Sesame oil based Characterization of Sesame oil based Characterization of Sesame oil based