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CHAPTER 1 POLYMERS BASED ON CASHEW NUT SHELL LIQUID AND CARDANOL

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CHAPTER 1

POLYMERS BASED ON CASHEW NUT SHELLLIQUID AND CARDANOL

1.1 INTRODUCTION

The present century is known as the century of polymers.

Without Polymers we cannot go ahead a single step in future. Our

day-to-day life requirement is fulfilled by polymeric products. Polymers

that are used in medical applications include naturally occuring materials

like natural rubber and cellulose. Synthetic bio-materials include silicone

rubber, polyvinylchloride, nylon, polytetrafluroethylene, polyethylene

terephthalate and polyurethanes.

Polyurethanes have a broad range of applications, including

machinery, transport, furnishings, textiles, paper making, packaging,

adhesives and sealants and medicine. The outstanding mechanica

properties and bio-compatibility of the polyurethanes make them some

of the most promising synthetic bio-materials.

Recently the use of renewable resources have gained

considerable importance as potential sources of energy and an

alternative energy sources to the ever preceding fossil based

derivatives. The recent need of high speed aviation radio engineering,

rocket technology and extreme conditions in space, magnetic belt and

radiation fluxes demanded new and heat resistant materials. So

polymer technology is now in search of novel materials which can

withstand prolonged exposure to high temperature.

Anacardium occidentale Linn. (Fam. Anacardaceae) commonly

known as "Mundri" in Tamil and "Kajutaka" in Sanskrit is cultivated in

plenty in the neighbouring Kanyakumari District (Fig. 1.1). After

r

2

removing the cashew nut, the shells are being wasted as a firewood

material in cottage industries. These cashew nut shells can be used as a

raw material for obtaining the most valuable Cashew Nut Shell Liquid

(CNSL) and also the monomer, cardanol for the synthesis of novel

polyurethanes.

Fig. 1.1 Cashew tree with cashew apple

1.1.1 Origin of the cashew tree

Cashew tree, native to Brazil is extensively cultivated in

Anadaman Islands, East Africa, Tanzania, Mozambique, Philippines and

other tropical countries" 2 . In India it is grown in the states of Kerala,

TamilNadu, Karnataka, Andhra Pradesh, Maharashtra, Orissa, West

Bengal, Assam and Goa. In Tamil Nadu, it is grown in Kanyakumari,

Pudukkottai and Cuddalore districts. Ohler has given an extensive

review' , ' on cashew growing with climate.

Cashew nut attached to a cashew apple as a grey coloured

kidney-shaped structure and is 2.5-4 cm long (Fig. 1.2). Cashew nut

consists of an ivory coloured kernel covered by a thin brown membrane

(testa) and enclosed by an outer brown porous shell that is the

mesocarp, which is about 3 mm thick and contains CNSL (Fig. 1.3). The

nut thus consists of the kernel (20-25%), the shell liquid (CNSL)

(20-25%) and the testa (2%), the rest being the shell. The kernels

freed from testa contain 1.6% water, 10% protein 5 , 57.4% fat, 5.3%

carbohydrate, 2.4% ash and 0.9% fibre6.

Fig. 1.2 Cashew apple with nut

Fig. 1.3 Cashew nut (with shell opened)

CNSL occurs as a reddish-brown liquid in the soft honey comb

structure of the shell of cashew nut. It is obtained in India as a

byproduct during isolation of the kernel by roasting the raw nuts in an

open or perforated rotating drum 7 . CNSL either leaks away or is burnt

in the fire. During this treatment the CNSL is polymerised.

1.1.2 Extraction of CNSL

Hot oil process8 and roasting process9' 10 are the two processes

which are used mainly in the extraction of CNSL

1.1.2.1 Hot oil process

This is the most common method of commercial extraction

largely used in Quilon and other areas in kerala. The raw nuts are

passed through a bath of hot CNSL (180200 0 C) itself, when the outer

part of the shell bursts open and releases CNSL (50% recovery).

Another 20% could be extracted by passing the spent shells through an

expeller and the rest by solvent extraction techniques". The expeller oil

however does not satisfy IS specifications and needs upgrading. This

can be done by acid washing followed by centrifugation and heating12.

Most industries follow the hot oil process, because it directly gives

cardanol due to decarboxylation of anacardic acid. Because of the

growing demand for cardanol or cardanol enriched CNSL, the hot oil

process has acquired reasonable significance.

1.1.2.2 Roasting process

In an Italian paten t13, the shells are scraped in rotary apparatus

with sand, steel and wool, heated to 100-300 0C for an hour and then

roasted to 400-700 0C in an inert atmosphere, when the oil again oozes

out.

^H

159

(i)

OH

H

-I15 29

(3)

5

1.1.2.3 Refining

CNSL contains sulphides, nitrogenous materials and minerals as

impurities, hence it needs refining. A number of acid treatment

methods, have been suggested for getting improved quality of CNSL'4'6

In these methods the crude CNSL is treated with aqueous solution of

acids such as hydrochloric, sulphuric, phosphoric and sulphates such as

sodium hydrogen sulphate. The refined CNSL is distilled under reduced

pressure. When steam is allowed to pass through sulphuric acid treated

CNSL followed by distillation, a decolourised form of CNSL is obtained.

1.1.3 Chemistry of CNSL

The principal components of natural CNSL are 3-pentadecenyl

phenol called cardanol (1), 3-pentadecenyl resorcinol called cardol (2),

3-pentradecenyl salicylic acid called anacardic acid (3) and 2-methyl-5-

pentadecenyl resorcinol called 2-methyl cardol (4).

OH

15 H 29

6

OH

H 3 C

CHHO 15 29

(3) (2) (4)

1.1.4 Composition of CNSL

The composition of CNSL has been studied by various

investigators 1721 . Cold extracted CNSL consists mainly 90% anacardic

acid and 10% cardo1 2223 . Tyman showed that cold extracted CNSL

contains 82±1.05% anacardic acid, 13.8±0.17% cardol, 2.6±0.16%

2-methyl cardol and 1.6±0.17% cardanol by the use of gas-liquid

chromatographic methods 24 . During commercial extraction under hot

conditions the anacardic acid fraction of CNSL gets decarboxylated to

cardanol 25 . Commercial CNSL contains cardanol (83±0.51%) and cardol

(2.7±0.34%) as the major constituents. Murthy et al. 26 have reported a

higher content of cardanol (94.6%) and the absence of anacardic acid in

distilled CNSL. The phenolic composition of natural and technical CNSL

and IS specification for CNSL are presented in Tables 1.1 and 1.2.

7

Table 1.1

Phenolic composition of natural and

technical CNSL (Mozambique Origin)

Values are in %Component

Natural CNSL Technical CNSL

Cardanol 1.20 62.86Cardol 11.31 11.252-methyl cardol 2.04 2.08Anacardic acid 64.93 -Unknown phenolic compound 20.30 23.80

Table 1.2

I S specification for Cashew Nut Shell Liquid (CNSL)

Characteristics

Specific gravity 30/30° C

Viscosity at 30° C, Cp (max.)

Moisture % by weight (max.)

Matter insoluble in toluene °h by weight (max.)

Loss in weight on heating % by weight (max.)

Ash % by weight (max.)Iodine value (a) Wij's method

(b) catalytic methodPolymeric (a) Time, mm.

(b) Viscosity at 30°C(c) Viscosity after acid washinq at 30° C

Requirement

0.950-0.970

550

1.0

1.0

2.0

1.0250375430200

M[S1

1.2 APPLICATIONS OF CNSL

Compared with the conventional phenolic resins, CNSL

polymers have improved flexibility (due to the internal plasticization

effect of the long side chain) and hence better processability 27 . CNSL

forms the basic raw material for vast number of industrially imported

chemicals and chemical ingredients. A few of these include the use as

bactericides, fungicides, insecticides, dyestuffs etc 2829 . CNSL and its

derivatives have been found to be useful as ion exchangers 30 ' 31 , surface

active agents32 . The literature on CNSL is replete with innumerable

paten ts3336 , reports37 and reviews3840.

1.2.1 Use as friction materials

The major user of CNSL is the brake lining industry, which uses

mostly CNSL-modified phenolic resins and CNSL-based friction dust.

Brake linings and clutch facings based on CNSL resins have the property

of absorbing the heat generated by friction in the braking action while

retaining their braking efficiency longer. Brake linings and clutch facing

based on CNSL show very low fade characteristics and very high

recovery. CNSL-furfural reaction products show unusual evenness of

frictional characteristics over wide temperature ranges 4 ' (a significant

behaviour for a Friction material). A number of friction material

formulations based on CNSL polymer with improved abrasion resistance

have been patented 42-44. CNSL-based resins and cashew dust have been

used for preparing corrosion and skid-resistant friction materials4546.

1.2.2 Use as surface coatings

CNSL or its derivatives are used as anticorrosion primers, black

enamels and marine paints. Baking enamels were prepared by

condensing CNSL with formaldehyde in the presence of linseed oil and

turpentine. CNSL-formaldehyde condensation product in alkaline

medium on styrenation gives a resin which can be applied as a varnish

or pigmented to yield an enamel or paint. Varnishes resistant to water

and gasoline were prepared by incorporating sulphur in CNSL. Surface

coatings based on CNSL were prepared from formaldehyde, styrene,

hexamine and epichiorohydrin for the protection of bamboo surfaces47.

Insulating varnishes made by condensing CNSL with an alkyl ortho ester

can be used as such or after modification by cooking in drying oils.

Lacquers made from CNSL could be used for insulation, protective or

decorative coatings for furniture, buildings, and automobiles4849.

1.2.3 Use as Speciality Coatings

Specialty coatings for wooden surfaces of fishing boats have

been reported 5051 . CNSL-formalin reaction products give coatings with

improved heat resistance, flexibility and adhesion. Oil-modified alkyd

resins find wide use in surface coatings industry and printing inks.

Molten mixture of CNSL, asphalt, rubber and petroleum resin could be

used as a "rust-proof" tacky composition. Shellac-CNSL reaction

product can be used as a coating composition. CNSL distillation residue

10

is used as a coating for increasing the durability of light-roofing

corrugated sheets.

1.2.4 Use as adhesives and binder resins

CNSL - based adhesives have admirable properties to meet the

growing demand for quality and durability in timber and timber-based

products. The characteristics of saw dust boards improved markedly on

treatment with CNSL-based resins. Another new use for cashew phenol-

formaldehyde resin is in bamboo-based building boards. CNSL, modified

with furfural, aniline, xylol etc. also gives good plywood adhesives52.

CNSL-xylene-formaldehyde based compositions have been prepared as

binder resin for particle boards5354.

1.3 APPLICATIONS OF CARDANOL

The major constituent of CNSL which is separated after the

vacuum distillation is a meta-substituted phenolic compound called

cardanol. It can be converted into different varieties of polymeric

products which have a lot of industrial applications, such as surface

coatings, friction resistant components, laminates, moulding materials,

rubber compounding ingredients, ion exchange membranes, adhesives,

paints, varnishes, lacquers and binder resins5556.

In general polymers from cardanol are prepared by either

condensation with highly active aldehyde such as formaldehyde, furfural

etc. or by chain polymerization reaction through the unsaturation in the

11

side chain using acid catalysts. The hydrocarbon side chain itself by its

very presence imparts new properties such as internal plasticization,

flexibility etc. A study by Pillai et al .51-59 has shown that high

performance and speciality polymers could be produced from cardanol

by a variety of methods.

1.3.1 Use as adhesives and binder resins

Cardanol derivatives are extensively used in laminating industry

for reducing brittleness and improving the flexibility of laminates

produced by the co-condensation of phenol, CNSL and formaldehyde,

the resins improve resistance to heat, minimize age-hardening and

improve bonding of the reinforcement materials like paper, cloth and

glass fibre to the matrix. National Chemical Laboratory, Pune has

developed a process for the preparation of cardanol-based polyurethane

adhesives34 . No-bake core binders, used by metal casting industry, are

reported to have been prepared by reacting isocyanate with cardanol-

paraformaldehyde and cardanol alkyd resins60 . Aqueous emulsion of

cardanol is used for coating plywood for laminating purpose. Epoxy-

resins have been prepared by reacting cardanol -forma ldehyde resins

with epichiorohydrin. Major uses of the epoxides are: as protective

coating materials, auto primers, linings for cans, drums and pipes,

bonding and adhesive applications, potting and encapsulation of

electrical and electronic components and in electrical laminates6163.

12

Aggarwal and Satpute reported 64 the synthesis of cardanol- based epoxy

flexi bilizens for composite propellants.

1.3.2 Use in Moulding Compounds and Rubber

Cardanol-cresol formaldehyde resin is reported to give excellent

vulcanizate properties when suitably compounded with rubber. Modified

novolac resin from cardanol and paraformaldehyde on isocyanate

modification gave higher values of tensile strength, modulus and

hardness in natural rubber vulcanizates 65 . Cardanol when used as a

plasticizer in natural rubber improved its tear strength, solvent

resistance and ageing properties. Cardanol is used as a dispersant and

plasticizer66 . The esters and ethers from cardanol are used as

plasticizers (extenders) for the compounding of PVC 67. The monoester

of cardanol with fatty acids and phenyl ether have been synthesised and

have been investigated as extenders in PVC68. Cardanol or dimerised-

cardanol has been reacted with paraformaldehyde to give novolac

resins, which with epichlorohydrin produced epoxy novolac resins69.

These products are found useful as surface coating materials. The films

of the above product are very much flexible and water resistant.

Cardanol dialcohols prepared by Ghatge et al. have been used 70 to make

modified phenolic resins for utilization in synthetic and natural rubber.

Cardanol-based resoles and modified resoles have been synthesised and

utilized for the vulcanization of butyl rubber by Ghatge and Shindle71.

13

1.3.3 Use in textile industry

Cardanol is used for the synthesis of polyisocyanato phosphorus

compounds72 . These are used for making water repellant finishes to

c-01A4'Lcl

natural and synthetic textiles and paper. The phosptoius containing7kospho.-r1k- pfmc-o-peuf,ds iare used n polypropylenes for modification in heat and lightst o-6 L LL the poL- '' Ctcir pho$o--ustabiIfty 3 . Similarly pospheis polyisocyanates,, prepared from

cardanol are used in flame and glow resistance to cellulose textiles. Silk

and Art Silk Mills Research Association, India has recommended the+±L LLki-L, Lc1L

treated textile samples as useful in shower proof cloth72.A

1.3.4 Use as industrial chemicals

1.3.4.1 Bactericides, fungicides, insecticides, disinfectants

Chlorinated products of cardanol and hydrogenated cardanol

are found to possess pesticidal action34.

1.3.4.2 Emulsifiers and surface active agents

Cardanol, tetra -hydrocardanol and their ethers are suiphonated

under different conditions and neutralized with various bases to give

emulsifiers and surface active agents for a wide variety of application S34.

1.3.4.3 Anti oxidants

Cardanol and its derivatives are used as antioxidants. They are

also used as stabilizers against light, air and heat for several organic

materials, such as flavour-s 1 foods, lubricants, polymers and rubbers7475.

A new and efficient synthesis of ortho- and para-benzoquinones of

14

cardanol derivatives by the catalytic system MeRe0 3-H 202 has been

reported".

1.3.4.4 Stabilizers

Cardanol condensed with epichlorohydrin and polyepoxidised

resins are found to be good stabilizers for poly vinyl chloride7778.

1.3.4.5 Polymerisation

Oligomerisation of cardanol has been studied by Patni et al.79

Synthesis of a self-cross linkable polymer from cardanol and its curing

mechanism have been studied by Pillai et al80.

1.3.4.6 Curatives

Cardanol-based resols and isocyanate modified resols used for

the vulcanization of styrene-butadiene rubber were found to impart

superior physical properties to the vulcanizates. Poly aminophenol epoxy

resins impart good curing properties to rubber-8'.

1.3.4.7 Miscellaneous applications

Chen et al. 82 reported the synthesis of 6 titanate coupling

agents using cardanol which had high reactivity and good hydrolytic

stability. Ghatge et al. 83 reported the preparation of a self catalytic resin

from cardanol. Formaldehyde and diethanolamine which are blended

with polyethylene glycol and resultant blend on treatment with polymeric

diphenylmethane diisocyanate (MDI) yields urethane foams of different

densities.

15

1.4 CHEMISTRY OF POLYURETHANE

There are a number of methods leading to the

formulation of polyurethanes. But, the reaction of an isocyanate with an

alcohol, leading to polyurethane formation is the commercially important

method.

n OCNRNCO + n HOR'OH OCN(RNHCOOR')OH

Diisocyanate Polyol Polyurethane

Isocyanates which have highly unsaturated -N=C=O group can

react with themselves or with all compounds containing active hydrogen.

In the reaction with those compounds containing active hydrogen, the

hydrogen atom becomes attached to the nitrogen of the isocyanate and

the remainder of the active hydrogen compound becomes attached to

the carbonyl carbon. The most important groups that can react with the

isocyanates are the amino and hydroxyl groups (Eq. 1 - Eq. 5).

0

R-N=C=O + H-A R-NH-C-A

0

R-N=C=O + R'NH2 01 R-NH-C-NH-R'Urea

(Eq. 1)

(Eq. 2)

0

R-N=C=O + R'OH

R- NH-C-OR'

(Eq. 3)Urethane

16

0

R-N=C=O + HOH

R-NH-C-OH

RNH2 + CO2 (Eq. 4)

0

R-N=C=O + RNH2 R-NH-C-NH-R

(Eq. 5)

Urea

Secondary reactions that are important in the formation of

urethane polymers are those with urea (Eq. 6) and urethanes (Eq. 7):

0

R-N=C=O + R-NH-C-NH-R R-N-CONHR

CON HR

Biuret

(Eq. 6)

0

R-N=C=O + R-NH-C-OR'

R-N-COOR'

CON HR

Allophanate

(Eq. 7)

17

A further cross linking reaction which occurs under basic

conditions is the reaction of the isocyanate groups themselves to form

isocyanurate trimers.

0

RN R

3RNCOOC/ 0

Theories of network formation by additional cross linking of

polyurethanes due to biuret and allophanate formation have been

studied by Karel Dusek 84 . The reaction of isocyanates with polyols to

form polyurethanes85 proceeds readily under the influence of catalysts.

If the reactants are liquid then mixing at ambient temperature in the

correct ratio is all that is required. Sometimes post heating is carried

out to complete the reactions.

Development of polyurethanes is generally taken up by

appropriate selection of dihydroxy compound and polyol. Although

polyurethanes obviously contain urethane groups, they also contain

other groups such as ester/ether groups, aromatic ring/aliphatic long

chains etc that affects the properties of the polymers. Greater changes

in the properties of polyurethanes result from varying structure of the

major component of the polymer, the polyol and the dilsocyanate.

Variety of polyurethane 86-89 products can be developed by varying these

components.

18

1.4.1 Polyurethane foams

Urethane foams are formed from diisocyanateS and hydroxy-

terminated polyethers or polyesters. Linear or only slightly branched

polymers produce foams, whereas more highly branched polymers

produce rigid foams90 . Foams are produced by mixing all ingredients in

one step process. The reactions can be more readily illustrated if they

are in steps (the pre-polymer process). The first reaction is between

excess dilsocyanate and the hydroxyl containing polymer (Eq.8) to give

isocyanate terminated pre-polymer and excess diisocyanates. These

products are formed with water (Eq.9)

4(RNCO) 2+HO-w'-OH OCN-R-NHCOO--w'OOCNHRNO+ 2R(NCO)2

(Eq.8)

OCN-R-NHCOO OOCNH-R-NCO + 2R(NCO)2

H20

ifOOCNHR-NHCONH-R-NHCONHRNHCONHR w'-. + CO2t

(Eq.9)

Thus foams are the polymers containing the polyesters or

polyethers. Polyurethane foams are widely used and well known. They

are available in flexible, semi-rigid, and rigid foams in a number of

different densities. Various flexible foams are used as cushioning for

furniture, automobile seating, and mattresses. At higher densities, they

are cast or moulded into drawer fronts, doors, mouldings and complete

19

pieces of furniture. Flexible foams are open-celled structures that may

be used as artificial sponges. Semi rigid foams find use as energy-

absorbing materials in crash pads, arm rests and sun visors. Replicas of

wood carvings, decorative parts and mouldings are produced from high

density, self-skinning foams. The insulation value of these foams makes

them an ideal choice for insulating refrigerators and refrigerated trucks

and railroad cars.

Rigid polyurethane is a closed cellular material produced by the

reaction of toluene diisocyanate (TDI) with polyether and reactive

blowing agents such as monofluorotrichloromethane (fluorocarbon).

Diphenylmethane diisocyanate foams have better dimensional stability

than the other foams.

1.4.2 Polyurethane coatings

By proper formulation of various resins and isocyanates,

coatings could be produced that exhibit flexibility, improved resistance,

toughness, hardness, weatherability, chemical and abrasion resistance.

Poly functional polyester based on adipic acid, phthalic anhydride,

ethylene glycol, trimethylol propane etc. are generally used for the

preparation of two component polyurethanes91 . One component

polyurethane coatings have also been developed by reacting a stable

isocyanate terminated pre-polymers and a poly-functional polyether92.

Blocked isocyanate is used in the development of one component

urethane coatings. Urethane coatings prepared from toluene 2,4- and

20

2,6- dilsocyanates are found to exhibit excellent properties. However

they exhibit poor colour stability when exposed to ultra-violet

radiation 93 . Polyurethane coatings with outstanding light stability could

be produced by using aliphatic diisocyanates like hexamethylene

diisocyanate in the place of aromatic diisocyanates94.

1.4.3 Polyurethane elastomers

Solid polyurethane elastomers such as millable gums, cast

elastomers and thermoplastic polyurethanes have been prepared95.

Mutable gum is prepared usually with a hydroxyl component in slight

excess and cured by incorporating a polyisocyanate and heating under

pressure. Cast elastomers have been prepared by pre-polymer

technique 96 . The pre-polymer is formed by reacting a diisocyanate with

hydroxyl terminated polyester or polyether to form an isocyanate

terminated pre-polymer (Eq.10)

OCN-R-NCO + HO-R'-OH go OCN-R-NH-C-OR'-O-C--NH-R-NCO

11 il0 0 ........

(Eq.10)

The pre-polymer is then further reacted with an active

hydrogen compound such as glycol, diamine or tn-functional polyol such

as trimethylol propane. Chain extension using the glycol takes place with

the formation of urethane groups as shown in Eq.11.

OCN-R-NCO + H0-R"-OH '. OCN-R-NH-C-O-R"-O-C-NH-R-NCO

0 0(Eq.11)

21

When diamines are used as the chain extender, substituted

urea linkages are formed. (Eq.12)

OCN-R-NCO + H 2 N-R"-NH 2 30. OCN-R-NH-C-NH-R"-H-C-NH-R-NCO

11 110 0

(Eq.12)

Polyurethane elastomers have remarkable resistance to

solvents including gasoline, aliphatic hydrocarbons and aromatic

hydrocarbons'. Polyurethane elastomers have a wide number of

applications that include flexible coupling connectors, earth removing

equipment and farm machinery. They are used for conveyor rollers,

drive sprockets, cable jacketing and bumpers; common uses of cross

linked thermosetting elastomers include shoe heels, 0-rings, pump

impellers and tread stock for tires98.

1.4.4 Polyurethanes in bio-medical applications

Polyurethanes have got an ample number of bio-medical

applications99 . Polyurethanes have been used in the artificial heart'°°,

hollow fibre dialysers as a potting medium for embedding the fibres in

the outer casing 101 , heat exchanger component of oxygenators'° 2 , breast

implant devices 103 and implants in dentistry, urology, cardiology and

wound dressings. Several groups of workers have investigated the

potential applications of polyurethanes as components in sensors

inc!uding glucose sensors 104 and as ion selective membranes in

potentiometric sensors. In addition, because of their diverse properties,

L-xylene diisocyanate (9).

?H3

NCO

FtJco

CH 3

OCN NCO

(5) (6)

22

they have also been investigated for in use as nerve guides, artificial

corneas, and intraocular lens '°5 , in vertebral discs106 , sutures, repair of

cartilage defects, foam casts, tympanic membranes and nipple

prosthesis'° 7 . Polyurethanes are also used to support or assist in medical

imaging and surgery. Polyurethane resins are used to make "belly

boards" to enhance CT scanning of pelvic malignancies108.

1.5 RAW MATERIALS FOR POLYURETHANE SYNTHESIS

Generally, polyurethanes are synthesised using appropriate

materials, diisocyanates and polyols.

1.5.1 Diisocyanates

The commercially available diisocyanates are 2,4- toluene

diisocyanate (5), 2,6- toluene diiscocyante (6), 4,4'-diphenylmethane

diisocyanate (7), hexamethylene diisocyanate (8) and tetramethyl

OCN-_K) —CH 2 NCO

(7)

—CCH3

CH

LLjC—NCO

C H3

H(CH2)6

(8)

NCOOCN

(9)

23

1.5.2

Polyols

The commonly used polyols are poly (oxytetramethylene) glycol

(10), 1,2,6- hexane triol (11), sorbftol (12), trimethylol propane (13),

propylene glycol (14), ethylene glycol (15) and 1,3 butylene glycol

(16).

H (O-CH 2 -CH 2 -CH 7 -CH 2 ), OH

(10)

OH

HO-CH2-CH-CH2-CH2-CH2-CH2--j

(11)

OH H OH OH CH2OH

HOCH c-c- C— C---CH2OH CH3CH2— —CH 2OH

H OH H H CH2OH

(12) (13)

24

HO-CH2-Ch-OH HO-CH2-CH2-OH

CH3 (15)

(14)

HO-CH2-CH2-CH-CH3

[111.(16)

1.5.3 Diols / Diamines

The commonly used dios are ethylene glycol (15), 1,4- butane

diol (17), 1,6- hexane dio! (18) and xylene a, a'- diol (19).

HO-CH2-CH2-CH2-CH2-OH HO-CH2-(CH2)4-CH2-OH

(17) (18)

CHOH

áCH2OH

(19)

25

The commonly used diamines are 4,4'-diamino diphenyl

methane (20), 3,3'-dichloro-4,4'- diamino diphenylmethane (21),

benzidine (22), 3,3' dimethyl benzidine (23) and p-phenylene diamine

(24).

H2 N—Q._ C NH2 2 HN— CH2 2

(20) (21)

CH

2 Nd2 H2N-NH

(22) (23)

NH7óNH2

/4/ VIP

(24)

26

1.6 SCOPE OF THE PRESENT WORK

In recent years, emphasis has been given on effective

utilization of naturally available and renewable resources for the

development of raw materials for various polymer based products.

Cashew Nut Shell Liquid (CNSL), and one of its ingredients, cardanol can

be successfully exploited for the development of phenolic resins for the

manufacture of different industrial products. The multi functional role of

cardanol and cardanol pre-polymers has been well documented in the

literature in the last few years and it has left many options open to

derive useful products out of this agricultural by-product. The phenolic

nature of cardanol has prompted different researchers to react it with

formaldehyde or with other aldehydes to produce numerous resinous

materials just like those produced from phenol. An umpteen number of

literature has been cited in the previous sections of this chapter

highlighting the utilization of o- and p- functionality of cardanol. Besides,

cardanol has an acidic-phenolic hydroxyl group and a long meta-

substituted unsaturated hydrocarbon side chain which can be exploited

fruitfully, for carrying out further chemical reactions, leading to new

polymers.

There is an ample scope for extending the hydroxyl

functionality by reacting with epichiorohydrin and hydrolyzing the epoxy

resin to a high molecular weight nucleophilic compound containing

flexible as well as rigid molecular structures. Such a nucleophilic high

27

molecular weight compound can react with an isocyanate group which is

an electrophile to give urethane. Therefore, by carefully synthesising the

high molecular weight nucleophilic compound with various molecular

size, functionality and stereo regularity, it is possible to develop

polyurethanes having wide range of physico-chemical and mechanical

properties as well as high performance characteristics.

The currently available polyurethanes do not meet all the

requirements of long term reliability under various ageing conditions.

Polyurethanes having a synergistic structural architecture which can

meet various requirements such as physico-chemical, mechanical and

thermal properties, stability against thermal, hydrolytic and oxidative

degradations, stability under ageing conditions such as low and high

temperature ageing, chemical environment etc., need to be developed.

Cardanol-based active hydrogen compound containing various chemical

groups is a choice of raw material for the development of such

polyurethanes, as the systematic attempts are rather scanty. Further,

the fact that CNSL is a renewable natural resource abundantly available

at a low cost, adds to the scope of such an endeavor. The synthesis and

characterisation of polyurethanes based on cardanol is an attempt in this

direction.

1.7 OBJECTIVES OF THE PRESENT WORK

(I) To synthesise and characterise cardanol-formaldehyde high

ortho novolac resins.

(ii) To synthesise and characterise high molecular weight

multinuclear compound with hydroxyalkyl nucleophilic end

group using cardanol -forma ldehyde high ortho novolac resins.

(iii) To synthesise polyurethanes using various dilsocyanates and

cardanol-formaldehyde resins / hydroxyalkylated cardanol-

formaldehyde resins and to evaluate the material properties.

(iv) To synthesise polyurethanes using various dilsocyanates and

cardanol-formaldehyde resins / hydroxyalkylated cardanol-

formaldehyde resins and commercially available polyol,

polypropylene glycol 2000 (PPG-2000) and to evaluate the

material properties.

(v) To evaluate the energy of activation of the newly developed

polyurethanes using Coats Redfern equation and also to

perform regression analysis of a few candidate polyurethanes.

(vi) To evaluate the performance of the newly developed

polyurethanes under various ageing conditions and also to test

the biodegradability of the synthesised polyurethanes.

29

1.8 REFERENCES:

1. I.H.P. Tyman, Chem.soc..Rev.,8, 499 (1979).

2

R.J. Wilson, 'The Market for cashew nut kernels and cashew

nut shell liquid'., Tropical products Institute, London (1975).

3

J.H. Ohier, Tropical Abstracts.., 22, 4 (1967).

4

S. Singh, S. Krishnamurthy and S.L. Katyal 'Fruit culture

India'., ICAR, New Delhi (1967).

5. G.Lossner, Beitr, 'Trop. Subtrop. Landwirt Tropen

Veterinaermed'., 9, 131 (1971).

6. J.H.P. Tyman and S.K. Lam, Lipids., 13, 525 (1978).

7. A.R.R. Menon, J.D. Sudha, C.K.S. Pillai and A.G. Mathew, J.Sci.

Ind. Res., 44, 324 (1985).

Ii'

S.A. Compagine coloniale due Angoche Swiss pat., 311, 789

(1956).orL pLcbrv o phri

9. W. Knop and A. Scheib, 'chemistry and Application of-Phenolic7L 0 \ j-rvl'i-- r -.o p H.s cu-cL opLCI crn2'

resins polymer properties and Applicat-lons'., Springer Ve rI u g,

Berlin (1979).

10. C.K.S. PiIlai, Pop.plast &packaging., March issue (1997).

11 D.C.Russel, 'FAQ Agricultural Service Bulletin'., (FAO, Rome),

73-75 (1969).

30

12. A.G.Mathew, C.Balachandran, C.Krishnaswamy, and

H.Sreemulanathan, Proceedings of the Third Annual

Symposium on plantation crops-placrosym 111., edited by

K.V. George (Central plantation crops Research Institute,

Kasaragode) (1980).

13. G.Natta and R.Ripa monti, Ital.pat., 476,540 (1952).

14. S. Caplan, U.S. Pat., 2559, 593 (1951).

15. British Resin products Ltd. Br. Pat., 664169 (1952).

16. S.H. Park and C.K. Lee, Kungnip Kongop Yonguso pago., 21,

81 (1971).

17. A.A. Durrani, J.Chem. Technol. Biotechnol., 32, 681 (1982).

18. A.K. Misra, Chem. Age. India., 27, 944 (1976).

19. P.H. Gedam, P.S. Sampathkumaran and M.A. Sivasamban, Ind.

J. Chem., 10, 388 (1972).

20. R. Paramashivappa, P.P. Kumar, P.J. Vithayathil, and A.S. Rao,

J. Agric Food Chem., May; 49(5): 2548-51, (2001).

21. P.Phani Kumar, R. Paramashivappa, P.J. Vithayathil, P.V. Subba

Rao and A.J.Srinivasa Rao, Agric Food Chem., July 31; 50(16):

4705-8 (2002).

22. G.D. Gokhale, M.M. Patel and R.C. Shah, Curr. Sci., 9, 362

(1940).

23 S.Ruhemann and S.Skinner, J.Chem.Soc., 51,663 (1887).

24 J.H.P. Tyman, Anal. Chem., 48(1), 30(1976).

31.

25. K. M. Nair, E.V.V. Bhaskar Rao, K.K.N. Nambiar, and

M.C.Nambiar, Eds., cashew (Anacardium occidentale-L)

Monograph on plantation., C. P.C. R.I. Kasargode, Kerala,(1979).

26. B.G.K. Murthy, M.A. Sivasam ban and J.S. Agarwal, Ind. J.chem.,

3, 33, (1965).

27. Cashew nut shell liquid patents - USA vol.1 (Cashew Export

promotion Council, Ernakularn) (1964).

28. M.T. Harvey, U.S. Pat .,2, 36712 (1944).

29. Harvel Corp, Br.pat .,627, 926(1949).

30. H.A. Shah and S.L. Batna, J.Appl Chem., 3, 335 (1953).

31. N. Krishnaswamy, K.P. Govindan, and R.N. Pandya, Chem.

md., (London), 1456 (1957).

32. K.G. Kurda and M.R. Kamath, Br. Pat., 591, 906 (1947).

33. Cashew nut shelf liquid patents - UK, Indian and Japan, vol.

II, cashew nut Export promotion council, Ernakularn (1964).

34. Cashew nut shell liquid - Extraction and uses- a survey of

world patents up to 1976, Cashew Nut Export Promotion

Council, Emakulam (1978).

35. Indian cashew nut shell liquid - A Versatile Industrial Raw

Material of Great promise -- Regional Research Laboratory,

Trivandrum and Cashew Nut Export promotion council, Ernakularn

(1978).

36. Production and utilization of cashew nut shell liquid in India

Cashew Nut Export promotion Council, Cochin (1977).

32

37. A. K. Mishra and G.N. Pandey, J.AppI.Polym.Sci., 26, 361

(1984).

38. C.K.S. Pillai, Pop. Plast & Packaging., November Issue (1993).

39. P.H.Gedam and P.S. Sampath Kumaran Prog.Org.Coatings., 14,

115 (1986).

40. B.G.K. Murthy and M.A. Sivasamban, Cashew causenic., 1, 8

(1979).

41. B.Golding, Furfural-phenol condensation in polymers and

Resins., (D. Van Nostrand co Inc, New Jersey) 255 (1959).

42. J.C. Adelmann, U.S. pat., 3959194 (to Johos-Manville Corp), 25,

May (1976), Chemical Abstracts, 8547987 x (1976).

43. Jap. Pat., 57123279 (to Hitachi Chemical Co. Ltd) 31, July 1982,

Chemical Abstracts, 98, 36677p (1983).

44. Jap. Pat., 57121080 (to Sumitomo Electric Industries Ltd), 28

July 1982, Chemical Abstracts 98, 36679r (1983).

45. Akebono Brake Kogyo, Jap Pat., 82108269 (1982), Chemical

Abstracts 97220904r (1982).

46. Hitachi Chemical Corporation Jap. Pat., 5881237 (1983),

Chemical Abstracts 100, 8075g (1984).

47. Indian Jr. Of. Chem. Technology.,, 4, p145-149 (1997).

48. Chemical Abstracts 95, 152239j (1981).

49. V. Madhu Sudhan, B.G.K. Murthy & M.A. Sivasamban, Cashew

Causerie., vi (2), 12-16 (1984).

33

50. M.R.Jayanth, S.P. Potnis and J.S.Aggarwal, J. colour sc., 16,

7-10 (1976).

51. R. Balasubramanian, and A.G. Gopala Krishna Pillal,on-tkQ-• - r4 SJdL aon-the—of-cashew - nu Shell quid-as

ou Q rtx-L c'w woorv c, .Q00±'a, surface coating material on- wooden- fishidg Boats, incw rut kll )U ,-c' vj&e cz- f-i-ote vv

Cashew nut Shell Liquid fr Maclie paints and protective

coatins (Central Institute of Fisheries Technology, Cochin)

p 15-19 (1979).

52. C.P. Dhamaney, Paint India., 28(9) (1978) 28(12) (1978)

32-33, 26(9) (1976) 19; 28 (10) (1978) 27-28; 29 (2) (1979)

27-28 & 29 (2) (1979) 5-8.

53. C.P. Dhamaney, J.colour,sci.., 16(3) 25-27 (1977) Paint India.,

30 (4) 7-8 (1980); 27(3) 19-21 (1977).

54. A.J. Hawkes, A.A. Durrani and J.P. Tyman, Eur..pat.Appin.,

15761; 17 Sep., 1980; Chemical Abstracts 93 240530m

(1980).

55. M.S. Ramaiah, V. Madhusudhanam, M.B. Naidu and M.A.

Sivasamban, Paint manuf., 43(11), 36 (1973).

56. British Resin products Ltd. Br. Pat., 742286 (1955).

57. C.K.S. Pillai et al, Rubber Plast.Annual II., (1987).

58. C.K.S. Piilai, RubbReptr.., 12, 145 (1988).

59. C.K.S. Pillai, V.S. Prasad, J.D. Sudha, S.C. Bera and A.R.R.

Menon, J.AppI.Polym.Sci.., 41, 247 (1990).

60. S.S. Mahajan and R.S. Khisti, Res & md., New Delhi, 29, 26-28

(1984).cLcrv 7J.w) rttt >k2iL Lq A v-rcôdci= I

61. Lndian Cashew nut-Shell-liquid - A-versatile industrial-raw-ti-L of Jj rr

rnaterial or gieat promise (Regional Research Laboratory,

Trivandrum, cashew Export promotion Council, Cochin (1983).

62. Chemical Abstracts 90, 123147u (1979); Chemical Abstracts

91, 124955p (1979).

63. Chemical Abstracts 97, 25197k (1982).

64. J.P. Aggarwal and R.S. Satpute, J.Macromol.Sci, pure and

AppI.Chem., 30, 19 (1993).

65. N.D Ghatge and N.N. Maldar, Rubb..Reptr., 6(1), 13-17 (1981).

66. K. Prabhakaran, Asha Narayanan, C. Pavithran J.Euro. Ceramic

Society., 21, 2873-2878 (2001).

67. P.T.I Science Service., 5, July 16-31 (1990).

68. N.D. Ghatge and S.V. Vailva, Die Aggewandte Macromoleculare

chemie., 43, 1 (1975).

69. N.D. Ghatge and D.R. Pati!, IndJ.Tech., 18,203 (1980).

70. N.D. Ghatge, B.M. Sinde and A.S. Mand patil, Rubber News.,

(India) 17 (1) 38 (1978).

71. N.D. Ghatge and B.M. Shinde4, J. Elastomerics., w (2), 48

(1979).

72. N.D. Ghatge and S.D. Yadav, colourage. Annual., 160 (1971).

73. U.S. Pat., 2, 898, 180 (1959).

35

74. A.R.R. Menon, C.K.S. Pillal and G.B. Nando, .7.AppI.Polym.Sci.,,

51, 2157 (1994).

75. E.L. Short, V. Tychopoulous and J.H.P. lyman .7.Chem.Tech.

Biotechnol., 53, 389 (1992).o, V Q ci ô y' Q M Cc, 1 eJt&. C - i-4 Q'} CA-CA* ). - LLpper76. , 7.Chem.ioc., Perkin Trans., I, 581-586 (2000).

77. E.Neuse and J.D. van Schalkwyk, SAfr.J.Sci., 72(8) 223 (1976).78. S.P.Vernekar, Indian.J.,Technol., 18,170-2(1980).

79. M.K. Trivedi, M.J. Patni and Lavleen Bindal, Ind,J.Technol,, 27,

281-284 (1989).

80. George John and C.K.S. Piliai, J. Polym. Sc., 31, 1069-1073(1993).

81. Chemical Abstracts s5, 178528w (1976).

82. Chen.Tianein, Linchan Huaxue Yu.Gongye., 6(3), 9 (1986).83. N.D. Ghatge, K.B. Gujar and S.S. Mahajan, Ind.J, Technol., 23

(5), 195 (1985).

84. Karel Dusek, Polymer Bulletin., 17, 481-488 (1987).

EMS J.Kenneth,V. Wynne, .J. Makal, and vUk, Polymer Reprints.,43(2)

791 (2002).

T.Lashanda ,James-Korley,S. Gregory, Pollock, Nikola Kojic, Man

sze Ko,H. Gareth. Mckinley and T. Paula, Hammond, Polymer

Reprints,, 43(2), 474 (2002).

87. T.Lashanda, James-Korley and T.Paula. Hammond, Polymer

Reprints., 43(1), 662 (2002).

36

88. Hongtu Li Jinghui Sun Hongwen Zhang Mingzhi Wu Jingyuan

Wang, Fangping Qiu Polymer Reprints., 43(2), 1065 (2002).

89. Alberto Mariani and Stefano Flori, Laura Ricco and Saverlo Russo,

Polymer Reprints., 43(2), 875 (2002).

90. G.F. Boumann in 'Polyurethane Technology', Interscience pub,

New York P 95 (1969) M. Kittel, Adhesion 21, 162 (1977).

91. H.L. Heiss, J.H. Saunders, M.E. Morris, B.R. Davis and E.E.

Hardy, Ind..Eng.Chem., 46, 1498 (1954).

92. R.L. Jacobs and J.W. Long, J. Elast.plast., 11, 15 (1979).

93. T.C. Patton in 'Polyurethane technology' C.P.F. Bruins Ed,

Interscience press New Delhi, p 215 (1969).

94. Farben fabriken,A.G. Bayer, Products for surface coatings,

Desmodur, Desmophan Ed. 1.6 p 14 (1966).

95. M.W. Riley, Mater.Design Eng., 50 (4)92 (1959).

96. E. Muller, Rubber plastics Age., 39(3) 195 (1958).

97. K.A. Pigot, R.J. Cote, K.Ellegast et al. Rubber Age., 91, 629

(1962).

98. L.Terry, Richardson and Erik Lokensgard in 'Industrial plastics,

Theory and Applications' Delmer publishers, Inc. (1983).

99. Nina M.K.Lamba, Kimberly A.Woodhouse and Stuart L.Cooper in

'Polyurethanes in Biomedical Applications', CRC Press, USA

(1998).

100. J.W.Boretos, W.S. Pierce, R.E.Baier, A.F. Leroy and H.J.Donachy,

J. Biomed..Mater.Res, 9, 327 (1975).

37

101. F.F. Lee, C.J. Durning and E. F. Leonard, Trans.Am..

Soc.Artif. Intern. Organs.,, 31, 526 (1985).

102. M.F. Roester,C.BulI and M.T. lonesus Cardiovasc.Surg., 21, 271

(1980).

103. F. R. Ashley, Plastic Reconstr.Surg., 45, 421 (1970).

104. T.Sternberg, M.B. Barrau, L. Gangiotti and D.R. Thevenot,

Bio sensors., 4, 27 (1988).

105. W.L. Jongebloed, G.Vander veen, D.Kalicharan and J.G.F. Worst,

Blo materials., 15, 766 (1994).

106. C.K. Lee, N.A. Langrana, J.R. Parsons and M.C.Zimmerman,

Spine., 16, 253 (1991).

107. G.G. Hallock, Ann.Plast.Surg., 24, 80 (1990).

108. T.G. Shanahan, M.P. Mehta, K.L. Berteirud and T.J.Kinsteila,

Int.J.Radiat.Oncol,Biol.Phys., 19, 469 (1990).