Thermal Behavior of Ricinodendron heudelotii oil polymer

1 23

Journal of Thermal Analysis andCalorimetryAn International Forum for ThermalStudies ISSN 1388-6150 J Therm Anal CalorimDOI 10.1007/s10973-015-4423-5

Thermal behavior of Ricinodendronheudelotii oil polymer

Edja F. Assanvo, Dilip Konwar & ShashiD. Baruah

1 23

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Thermal behavior of Ricinodendron heudelotii oil polymer

Edja F. Assanvo • Dilip Konwar • Shashi D. Baruah

Received: 4 July 2014 / Accepted: 9 January 2015

� Akademiai Kiado, Budapest, Hungary 2015

Abstract In this present study, the photopolymerization

of Ricinodendron heudelotii (R. heudelotii) oil have been

carried out with iron(III) tris(oxalato) ferrate(III) tetrahy-

drate (Fe[Fe(C2O4)3]�4H2O) as photoinitiator under UV

radiation of 254 nm at 40 �C in dimethyl sulfoxide. The

thermal decomposition of the R. heudelotii oil polymer is

studied using thermogravimetry and differential scanning

calorimetry methods. The R. heudelotii oil polymer

exhibits three stage decomposition patterns, and the main

decomposition occurs at the temperature range 300–

500 �C. The apparent activation energy (Ea) of the

decomposition has been calculated by three non-isothermal

methods of Flynn–Wall–Ozawa, Kissinger and modified

Coats–Redfern. The Johnson–Mehl–Avrami (n \ 1) model

was found to be the appropriate reaction model for the third

and main decomposition step. The model could be estab-

lished as f ðaÞ ¼ 0:52ð1� aÞ ½� lnð1� aÞ�ð�0:92Þ. The value

of pre-exponential factor (A) is also determined and was

found to be 4.11 9 1017 min-1.

Keywords Photopolymerization � Ricinodendron

heudelotii oil � UV radiation � Kinetic models � Activation

energy � Alpha-eleostearic fatty acid

Introduction

In this last decade, the use of vegetable oils and fatty acids

as starting raw renewable material is gaining more interest

in academy and industry. This interest is due to the

growing awareness on the environmental impact of petro-

leum-based polymeric material as well as the depletion of

the crude oil in one hand, and in the other hand, the ease

and availability of many chemical routes to modify and

functionalize the triglyceride unit of the vegetable oils to

synthesize polymeric materials, adhesives and composites

with specific properties and applications. Triglyceride

molecules are formed by three fatty acid chains joined to

glycerol by ester group. The fatty acid chain contains

varied number of carbon–carbon bonds generally from 14

to 22, with 0–3 double bonds per fatty acid unit. Plant oils

having triple conjugated carbon–carbon double bonds in

the fatty acid chain are more reactive and good potential

candidates for radical and addition polymerization to syn-

thesize bio-based material.

Ricinodendron heudelotii (R. heudelotii) is a fast

growing tree belonging to the Euphorbiaceae family. Its

distribution in Africa ranges from West Africa to Central

Africa and also found in Madagascar [1–3]. The total oil

content from the almonds of R. heudelotii tree varied from

45 to 67 %. R. heudelotii oil is a mixture of triglycerides

with unsaturated fatty acid chains. The oil is a good source

of a-eleostearic acid (51 %), a triple conjugated diene and

the iodine value in the range of 154–157 [1, 2]. Due to the

high level of polyunsaturated fatty acid, mainly a-eleo-

stearic acid (51 %) and linoleic acid (28 %) content and

iodine value, the R. heudelotii oil is a drying oil and

comparable to the Tung oil (Aleurites fordii) which con-

tains 80 % of a-eleostearic acid with iodine value 163–170.

Drying oils have the advantages of faster drying time by

autoxidation cross-linking reaction, higher water resistance and

higher hardness due to their high content of unsaturation [4].

Because of the similarity mentioned above between R. heu-

delotii oil and Tung oil, R. heudelotii oil can substitute Tung oil

as raw material for preparation of bio-based materials.

E. F. Assanvo � D. Konwar � S. D. Baruah (&)

CSIR-North East Institute of Science and Technology,

Jorhat 785006, Assam, India

e-mail: [email protected]

123

J Therm Anal Calorim

DOI 10.1007/s10973-015-4423-5

Author's personal copy

The photoinitiated polymerization process is extremely

used in industry for the production of surface coatings and

other thin-layer material in the printing and coating

industries. Several applications of products obtained from

photoinitiated polymerization are in ultra-fast drying var-

nishes, printing, inks, coating for metal, wood, paper and

plastics, microelectronic, curing dental restoration, holog-

raphy and stereoslithography [5–7].

The UV-curable Tung oil alkyds were prepared and

functionalized with trimethylol propane trimethacrylate

(TMPTMA) onto a-eleosterate of Tung oil via Diels–Alder

cycloaddition [8]. This photo curable product exhibits fast

curing speed. Good coating materials based on maleated

alkyds have been synthesized [9, 10] with non-self-palm

stearin alkyds.

Recently, research on the industrial valorization of the

almonds of R. heudelotii and its domestication has been

initiated [1–3, 11]. But no work has been reported on the

kinetic analysis of the decomposition of photopolymer

derived from monomers obtained from R. heudelotii oil as

a source of renewable raw material. The study of thermal

degradation of polymeric material is very useful to

understand the thermal degradation processes and kinetic

model and mechanism, the thermal stability and cycling

and further application. The main objective of this work

was to study the kinetic behavior of thermal degradation of

bio-based polymers obtained by photopolymerization of R.

heudelotii oil as a monomer initiated by iron(III) oxalato as

photoinitiator. This complex has been successively used as

photoinitiator for photopolymerization of alkyl

(meth)acrylates [12].

Experimental

Materials

Oil from almonds of R. heudelotii obtained from Cote

d’Ivoire (Ivory Coast) has been extracted with the help of

soxhlet apparatus with hexane (Merck) as solvent for 6 h,

dried over anhydrous sodium sulfate (Rankem) and kept

under nitrogen at 4 �C for further use. Dimethyl sulphoxide

(Qualigens) was used after purification. The complex

Fe[Fe(C2O4)3]�4H2O was prepared as before [12].

Procedure and analysis

The photopolymerization reactions were conducted with the

help of an immersion well photochemical reactor (SAIC-

Chennai). The photochemical reactor was immersed in a

constant temperature thermostatic bath at 40 �C, and poly-

merizations were conducted by irradiating the ampoule at a

fixed distance from the photochemical reactor. The poly-

merization was carried out in the sealed ampoule after

purging the reactant with nitrogen to remove dissolved

oxygen. The reactants were irradiated by UV light produced

by the low-pressure lamp of 12 W which emits more than

90 % of its radiation at 254 nm. The lamp was located in a

double walled immersion well. Despite their low power

(12 W), the UV lamp produces over 3 9 1018 photons s-1

(measure by ferrioxalate actinometry in a quartz well),

which have a long life and a negligible warm-up time. After

desired time periods, the contents of the ampule were pre-

cipitated in hexane with trace quantities of hydroquinone.

The polymer was then filtered and dried in a desiccator. The

percent conversion and subsequently the rates of polymer-

ization, Rp, were calculated gravimetrically from the amount

of dried polymer formed and the initial mass of monomer in

the reaction. The polymerization reactions were repeated

thrice under similar conditions.

Thermal degradation of R. heudelotii oil polymer has

been studied using thermogravimetry (TG) analysis and

differential scanning calorimetry (DSC) methods. Differ-

ential scanning calorimetry (DSC) measurements were

performed on a Perkin Elmer Diamond DSC instrument in

nitrogen atmosphere with 2–5 mg of polymer samples in

aluminum pans at 20 �C min-1. The instrument was cali-

brated with indium for correction of heat of transition.

Thermal degradability and stability studies were performed

using TA series STD 2960 instrument in an argon atmo-

sphere at four different heating rates, i.e., at 20, 15, 10 and

3 �C min-1. DSC and TG runs were repeated thrice for

each sample. FTIR spectra were recorded on Perkin Elmer

IR 833 spectrophotometer using KBr for the polymer and

chloroform as solvent for the crude oil. The X-ray dif-

fractogram of the R. heudelotii oil polymer was obtained

by means of JDX-11P3A JEOL diffractometer using a Ni

filter with Cu-Ka radiation at 35 kV and 10 mA in the wide

angle range 2� \ h\ 60�.

Theory of thermal degradation and thermogravimetry

analysis

Thermogravimetry is a dynamic method in which the mass

loss of a sample is measured continuously as a function of

temperature at a constant heating rate. TG has been used

widely to study the kinetic degradation process of polymer,

it measures only the loss of volatile fragments of polymers,

caused by degradation, but cannot detect the intrinsic

chemical reaction. TG has been used widely to estimate the

kinetic of thermal degradation processes and to determine

the kinetic triplet parameters, activation energy (Ea), the

Arrhenius pre-exponential factor (A) and f(a) or g(a)

function [13–19].

E. F. Assanvo et al.

123


In general, the thermal degradation reaction of a solid

polymer can be shown as: Asolid ? Bsolid ? Cgas, where A

is the starting material, B the solid residue and C the gas

product. The kinetic of thermal degradation of polymer is

generally expressed by the typical kinetic equation.

dadt¼ kðTÞf ðaÞ ð1Þ

where dadt

is the decomposition rate, k is the decomposition

constant and f(a) is the conversion function.

The degree of conversion a or decomposition can be

calculated with this equation:

a ¼ w0 � wt

w0 � wf

ð2Þ

where a is the degree of conversion, w0, wt and wf are the

mass of the sample before degradation, at time t and after

complete degradation, respectively.

The decomposition constant k is given by the Arrhenius

equation.

kðTÞ ¼ Ae�Ea=RT ð3Þ

where A is the pre-exponential factor (s-1), Ea is the acti-

vation energy (kJ mol-1), R is the gas constant

(8.314 J mol-1 K-1) and T (K) is the absolute temperature.

By combining Eqs. 1 and 3, we obtain:

dadt¼ Ae�Ea=RTf ðaÞ ð4Þ

According to non-isothermal kinetic theory, the degree

of conversion a is expressed as a function of temperature.

The heating rate b can be expressed by:

b ¼ dT

dtð5Þ

Multiplying and dividing the left side of Eq. (4) by dT

dt,

we obtain:

dadT¼ ðA=bÞe�Ea=RTf ðaÞ ð6Þ

Equations (4) and (6) are the basis for calculation of

thermal degradation kinetic parameters.

Determination of the apparent activation energy (Ea)

In this paper, three methods for the determination of the

kinetic parameter for the decomposition of R. heudelotii oil

polymers at different heating rates have been used.

Kissinger method [20] is a differential method based on

the maximum temperature (Tm) of the first derivatives mass

loss curve at multiple heating rates.

The equation derived from this method is:

d ln b=T2m

� ��

dð1=TmÞ¼ �Ea

Rð7Þ

The activation energy can be obtained from the plot of

ln b=T2m

� �against 1,000/Tm for each stage of degradation,

and the slope of such line is equal to (-Ea/R).

Flynn–Wall–Ozawa (F–W–O) method [21, 22] is an

integral method. This method is iso-conversional method.

The final equation is:

log bð Þ ¼ logAE

R

� �� logðgðaÞÞ � 2:315� 0:4567

Ea

RT

ð8Þ

The activation energy can be determined from the slope of

the plot of log b against 1,000/T.

Modified Coats–Redfern method is a multiple heating

rate method of Coats–Redfern [23] equation. This method

is also integral method, and the final equation is:

lnb

T2 1� 2RTEa

� �

2

4

3

5 ¼ lnAR

E lnð1� aÞ

� � Ea

RTð9Þ

In this method, ln(b/T2) is plotted against 1,000/T, which

gives slope -Ea/R at different degree of conversion.

Determination of reaction model and pre-exponential

factor

Once the apparent activation energy has been determined,

the next step of the kinetic study consists of identifying an

appropriate kinetic model which corresponds to the

experimental data obtained from TG results. Malek

[24, 25] suggested an algorithm based on the shape of

characteristic functions y(a) and z(a). These functions are

obtained by transformation of TG data.

For non-isothermal experiments conditions, these func-

tions are:

yðaÞ ¼ dadt

� �exp

Ea

RT

� �¼ Af ðaÞ ð10Þ

zðaÞ ¼ dadt

� �T2 ¼ f ðaÞgðaÞ ð11Þ

The value of amax,z at the maximum of z(a) is characteristic

of the kinetic model, while the shape of the y(a) at amax,y is

identical to the kinetic model f(a). The explicit formulae

and properties of the y(a) and z(a) for a specific kinetic

reaction model are given in Table 1.

The determination of the pre-exponential factor (A) is

the last step of the kinetic analysis, once the reaction model

has been identified to obtain the kinetic triplets [Ea, A and

f(a)]. The pre-exponential factor is determined from the

Malek equation [24].


123


A ¼ �bEa

RT2maxf 0ðamaxÞ

expEa

RTmax

� �ð12Þ

Tmax, amax denote to the maximum peak on DTG curve,

and f0(amax) is the derivative value of amax from f(a)

function.

Results and discussion

A typical plot of rate of polymerization (Rp) and % con-

version of R. heudelotii oil against reaction time with

Fe[Fe(C2O4)3]�4H2O as photoinitiator is shown in Fig. 1.

The reaction is very sensitive of the composition of the

reaction mixture. The differential rates of polymerization

were computed by the method of ratio variation.

The FTIR spectrum of R. heudelotii oil and its polymer

are shown in Fig. 2. The spectrum of R. heudelotii oil

showed a sharp shoulder peak at 3,011 cm-1, and this

corresponded to trans–trans conjugated unsaturations. The

presence of trans–trans conjugation in the a-eleostearic

acid chain was observed by the strong peaks at 992 cm-1.

The peaks at 965 and 725 cm-1 were assigned to the

presence of cis-unsaturations in the eleostearic chain. The

0.65

0.60

0.55

0.50

0.45

0.40

0.35

2 4 6 8 10 12

Time/h

Deg

ree

of c

onve

rsio

n/%

10

8

6

4

2

0

Rp

× 1

05/m

ol L

–1 s

–1

Fig. 1 Degree of polymerization (solid line) and rate of polymeriza-

tion, Rp (dotted line) of R. heudelotii oil in the function of reaction time

at 40 �C in DMSO under argon atmosphere [Rh oil] = 1.00 mol L-1;

[Fe(III)] = 5 9 10-4 mol L-1

4,000 3,500 3,000 2,500 2,000 1,500 1,000 500

Wavenumber/cm–1

% T

30111744 16

4315

88

1163

1737

1122

R. h

eude

lotii

Oil

R. heudelotii Oil polymer

Fig. 2 FTIR spectra of R. heudelotii oil crude oil and R. heudelotii

oil polymer

Table 1 The basic kinetic models and properties of y(a) and z(a) functions

Kinetic models Symbol f(a) y(a) z(a)

Johonson–Mehl–Avrami JMA (n) n(1 - a) [-ln(1 - a)](1-1/n) n \ 1: concave

n = 1: linear

n [ 1: convex

0.632

Phase-boundary controlled reaction (contracting

area, i.e., tridimensional shape or one-halforder

kinetics)

R2, F1/2 2(1 - a)1/2 Convex 0.750

Phase-boundary controlled reaction (contracting

volume, i.e., tridimensional shape or two-third-

order kinetics)

R3, F2/3 3(1 - a)2/3 Convex 0.704

Two-dimensional diffusion (tridimensional

particle shape) Valensi equation

D2 1/[-ln(1 - a)] Concave 0.834

Three-dimensional diffusion (tridimensional

particle shape) Jander equation

D3 3ð1�aÞ2=3

2½1�ð1�aÞ1=3 �Concave 0.704

Three-dimensional diffusion (tridimensional

particle shape) Ginstling–Brounshtein

D4 3

2½ð1�aÞ�1=3�1�Concave 0.776

Sestak Breggren (autocatalytic model) SB (m, n) (a)m (1 - a)n 0 \ am \ ap amax depends on

exponents


123


FTIR spectrum shows a strong characteristic band at

1,744 cm-1 which corresponded to stretching vibration of

ester carbonyl group C=O, in the R. heudelotii oil, while a

shifted weak peak is observed in the case of R. heudelotii

oil polymer at 1,737 cm-1. The second difference is

observed at 1,643 and 1,588 cm-1 which can be assigned

to –C=C–C= conjugated double bonds stretch in the R.

heudelotii oil were absent in the polymer spectrum indi-

cating that all the double bonds in the R. heudelotii oil have

been consumed. This reaction of the double bonds can be

verified also by the disappearance of the stretching vinyl

group sp2 H–C= at 3,011 cm-1 on the R. heudelotii oil

polymer spectrum.

The XRD patterns (Fig. 3) of the R. heudelotii oil

polymer sample exhibit a single broad peak at 2h = 19.74�indicating an amorphous solid state of the polymer. This

may be due to the glassy state and transparent appearance

of the R. heudelotii oil-based polymer.

The DSC profile of R. heudelotii oil polymer in nitrogen

in Fig. 4 shows a broad exotherm between 85.85 and

219.37 �C with DH = -390.30 Jg-1. The degradation

temperature range (Trange), heat of fusion (DHf) = -0.3831

kJ mol-1, activation energy of the reaction

(Ea) = 135.16 ± 3.829 kJ mol-1 and order of decompo-

sition (n) = 2.125 ± 0.057 of the sample were obtained by

using the DSC kinetic software of Perkin Elmer. The cal-

culation is based on the multi-linear regression of the rate

equation which is expressed as: ln[b(da/dt)] = ln (Z) -

Ea/RT ? n�ln(1 - a), where b is the scanning rate, a is the

degree of conversion, Z is the pre-exponential constant and

T is the absolute temperature in K.

The TG (Fig. 5a) curves show that the R. heudelotii oil

polymer decomposes with formation of approximately

10 % residue. The derivative curves (DTG) in Fig. 5b,

show the increase in maximum decomposition temperature

with the increased heating rates. The DTG curves show

three main decomposition stages. The first stage from 100

to 200 �C, second stage from 200 to 300 �C and the third

stage from 300 to 500 �C, and the major decomposition

appears at this third stage. The three stages of decompo-

sition have been also reported for other polymers based on

vegetable oils including Tung oil by Larock et al. [26, 27].

The first stage of decomposition at lower temperature is

due to the evaporation of the unreacted free R. heudelotii

oil and water in the polymer. The second stage corresponds

to the cross-linked polymer decomposition and the third,

and the main stage is due to the decomposition of

more stable cross-linked polymer formed in the second

stage [26, 27].

The activation energies (Ea) calculated with F–W–O,

Kissinger and modified Coats–Redfern methods are

reported in the Table 2. The Ea values from F–W–O and

Kissinger methods show good agreement, but the values

obtained from modified Coats–Redfern method were

higher. The linear plot of a Kissinger method for the third

stage of decomposition is depicted in Fig. 6.

Figure 7a–c show iso-conversional plots of F–W–O

method of R. heudelotii oil polymer for the three stages of

decomposition. The fitted lines are nearly parallel, indi-

cating that either the decomposition reaction consists of a

single mechanism (parallel lines) or at least two steps and

complexity of the mechanism (not parallel lines) [13, 14].

In order to analyze more deeply the decomposition mech-

anism, we investigated on the relationship of the activation

energy (Ea) as a function of the degree of conversion (a).

Figure 8 and Table 2 show clearly that the Ea values at

each stage of decomposition are increasing function of the

degree of conversion. This dependence of the Ea values

3,000

2,400

1,800

1,200

600

010 20 30 40 50 60 70

Angle 2θ

Inte

nsity

cou

nt/a

.u.

19.74

Fig. 3 X-ray diffraction diffractogram of R. heudelotii oil polymer

16

12

8

4

0

Hea

t flo

w/m

WE

xo

50 75 100 125 150 175 200 225

Peak = 143.21 °C

Onset = 85.85 °C

End = 219.37 °C

Temperature/°C

Fig. 4 DSC curve of the R. heudelotii oil polymer in nitrogen

atmosphere at heating 10 �C min-1


123


with the degree of conversion indicates a complex reaction

mechanism exists for the thermal decomposition of R.

heudelotii oil polymer, the occurrence of parallel, consec-

utive or competing reaction [13, 14].

The procedure proposed by Malek et al. [24, 25] was

used to determine the kinetic model best fitted to the

experimental data of non-isothermal degradation of R.

heudelotii UV polymer. The normalized plots of y(a) and

z(a) from 0 to 1 are shown in Fig. 9. It is observed that the

curves have not demonstrated any significant variation

with a given b value, except for the corresponding to

20 �C min-1, which was slightly shifted to high a value,

but it exhibited the same shape profile as others plots. It

has been shown from Fig. 9 and Table 3 that,

amax,y = 0.60 and amax,z = 0.632. The y(a) function shows

the concave behavior, whereas amax,z = 0.632 which are

describable by the reaction model Johnson–Mehl–Avrami

(JMA) (n \ 1) in which the representative f(a) function is

as follows:

f ðaÞ ¼ nð1� aÞ ½� lnð1� aÞ�ð1�1=nÞ ð13Þ

The value of n can be calculated from amax,y using

Eq. (14) according to Svoboda et al. [28]

n ¼ 1

1� ln 1� amax;y

� � ð14Þ

By applying Eq. (14), the value of n was calculated as

0.52.

100 200 300 400 500

Temperaure/°C100 200 300 400 500

Temperaure/°C

100

80

60

40

20

0

Mas

s/%

20 °C

15 °C

10 °C

3 °C

(a) 1,000

800

600

400

200

0

Der

ivat

ive

mas

s/%

°C

–1

15 °C

10 °C

3 °C

20 °C(b)Fig. 5 TG (a) and DTG

(b) curves of R. heudelotii

polymer at heating rates of 3,

10, 15 and 20 �C min-1 in

argon atmosphere

Table 2 Activation energies for different decompositions steps of R. heudelotii oil-based polymer

Conversion a Flynn–Wall–Ozawa Coats–Redfern modified Kissinger

Ea/kJ mol-1 r2 Ea/kJ mol-1 r2 Ea/kJ mol-1 r2

First stage

0.03 70.08 0.9950 80.12 0.9958

0.04 74.03 0.9940 84.55 0.9950

0.05 83.70 0.9988 94.94 0.9980

Mean 75.93 86.53 76.06 0.9995

Second stage

0.1 100.94 0.9971 114.08 0.9975

0.15 111.30 0.9978 125.64 0.9980

Mean 106.12 119.86 96.88 0.9975

Third stage

0.2 141.78 0.9930 158.41 0.9938

0.3 175.93 0.9987 195.30 0.9988

0.4 197.88 0.9997 218.91 0.9998

0.5 207.05 0.9989 228.87 0.9990

0.6 212.99 0.9969 235.37 0.9972

0.7 225.71 0.9956 249.00 0.9960

0.8 219.85 0.9954 243.16 0.9958

Mean 197.31 218.43 193.74 0.9999


123


The reaction kinetic model for the degradation of R.

heudelotii polymer in a value range of 0.2 B a B 0.9 could

be established as:

f ðaÞ ¼ 0:52ð1� aÞ ½� lnð1� aÞ�ð�0:92Þ ð15Þ

For JMA model, (1–1/n) = 1 represents random distri-

bution, (1–1/n) [ 1 for ordered distribution and (1–1/n) \ 1

indicating a clustered distribution [15], therefore the R.

heudelotii UV polymer degrades in a clustered distribution

way as the value of (1–1/n) = -0.92 \ 1.

The calculated f0(amax) and the pre-exponential factor

(A) are given in Table 3. From the Table 3, the average

value of the pre-exponential factor A for the degradation of

–10.0

–10.4

–10.8

–11.6

–11.2

–12.01.42 1.44 1.46 1.48 1.50

1000/Tm/K–1

In/β

/T2 m

Fig. 6 Plot of Kissinger method of R. heudelotii oil polymer for the

third stage of decomposition

1.4

1.2

1.0

0.8

0.6

0.4

log

β

1.4

1.2

1.0

0.8

0.6

0.4

log

β

1.4

1.2

1.0

0.8

0.6

0.4

log

β

1000/T/K–11.4 1.5 1.6 1.7 1.8 1.9 2.0

0.80.70.60.50.4

0.20.3

2.32 2.40 2.48 2.56 2.64

1000/T/K–1 1000/T/K–11.86 1.92 1.98 2.04 2.10 2.16

0.030.040.05

0.150.1

(a) (b)

(c)

Fig. 7 Iso-conversion plot of

F–W–O method of R. heudelotii

oil polymer at varying of degree

of conversions a for first stage

(0.03, 0.04 and 0.05), b second

stage (0.1 and 0.15) and c third

stage (0.2, 0.3, 0.4, 0.5, 0.5, 0.6,

0.7 and 0.8) of decomposition

220

200

180

160

140

0.2 0.3 0.4 0.5 0.6 0.7 0.8α

Act

ivat

ion

ener

gy/k

J m

ol–1

Fig. 8 Relationship of activation energy Ea versus degree of

conversion (a) of the third stage of decomposition of R. heudelotii

oil polymer for F–W–O method


123


the R. heudelotii UV polymer was found to be

A = 4.11 9 1017 min-1. Thus, having the kinetic triplets

[Ea, A and f(a)], the final kinetic equation which describes

the degradation of the R. heudelotii UV polymer in the

third and main degradation step is established by:

bdadT¼ 4:11� 1017 exp

�197:31

RT

� �

� 0:52ð1� aÞ ½� lnð1� aÞ�ð�0:92Þh i ð16Þ

Conclusions

Ricinodendron heudelotii oil polymer was synthesized

using photoinitiated polymerization with complex of iro-

n(III) tris (oxalato) ferrate(III) tetrahydrate as photoiniti-

ator. The R. heudelotii oil polymer undergoes three stages

decomposition process, and the main decomposition occurs

at a temperature range between 300 and 500 �C. Three

non-isothermal methods based on equations of F–W–O,

Kissinger and modified Coats–Redfern have been used to

evaluate the activation energy of thermal decomposition. It

was found that the apparent activation energy varies with

the degree of conversion indicating that the R. heudelotii

oil polymer decomposes with a multiple reaction step

mechanism process. By applying the suggested Malek

procedure, JMA (n \ 1) model was found to be the best

fitted reaction model of the decomposition of R. heudelotii

oil polymer and established as f ðaÞ ¼ 0:52ð1� aÞ½� lnð1� aÞ�ð�0:92Þ

. The pre-exponential factor A =

4.11 9 1017 min-1 was also calculated. According to the

results, R. heudelotii oil polymer is thermally stable and

can be used as raw material for the formulation of biode-

gradable polymer.

Acknowledgements The authors wish to thank Dr. D. Ramaiah,

Director, CSIR-NEIST, Jorhat for permission to publish the results.

EFA expresses his heartfelt thanks to CSIR-India and TWAS-Italy for

award of the CSIR-TWAS fellowship (FR Number: 3240239552) for

postgraduate studies at CSIR-NEIST, Jorhat.

References

1. Marshall E, Newton AC, Schreckenberg K. Commercialisation of

non-timber forest products: first steps in analysing the factors

influencing success. Int For Rev. 2003;2:128–37.

2. Tchiegang C, Kapseu C, Njouenkeu R, Ngassoum MB. Ricino-

dendron heudelotii (Bail.) kernels: a novel ingredient for tropical

food agro-industries. J Food Eng. 1997;32:1–10.

3. Kapseu C, Tchiegang C. Chemical properties of Ricinodendron

heudelotii (Bail.) seed oil. J Food Lipids. 1995;2:87–98.

4. Huang Y, Pang L, Wang H, Zeng Z, Yang J. Synthesis and

properties of UV-curable tung oil based resins via modification of

Diels–Alder reaction, nonisocyanate polyurethane and acrylates.

Prog Org Coat. 2013;76:654–61.

5. Odian G. Principle of polymerization. 4th ed. New York: Inter-

science; 2004.

6. Fouassier JP, Allonas X, Burget D. Photopolymerization reaction

under UV lights: principal, mechanisms and examples of appli-

cations. Prog Org Coat. 2003;47:16–36.

7. Yusuf YJ, Steffen J, Nicholas JT. Photoinitiated polymerization:

advances, challenges, and opportunities. Macromolecules.

2010;43:6245–60.

8. Mark DS, Kent RM, Thanamongkolitt N. Synthesis of UV-cur-

able Tung oil based alkyd. Prog Org Coat. 2012;73:425–34.

9. Seng NG, Desmond TCA. Novel approach to convert non-self-

drying palm stearin alkyds into environment friendly UV curable

resins. Prog Org Coat. 2012;73:409–14.

1.0

0.8

0.6

0.4

0.2

0.0

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9α

1.0

0.8

0.6

0.4

0.2

0.0

0.2 0.4 0.6 0.8α

20 (°C)

15 (°C)

10 (°C)

3 (°C)

20 (°C)

15 (°C)

10 (°C)

3 (°C)

z(α

)

y(α

)

(a) (b)Fig. 9 The plots of the

characteristic functions, a y(a)

and b z(a)

Table 3 Values of amax,y, amax,z, amax, f0(amax) and A at different

heating rate (b) for the degradation of R. heudelotii UV polymer

b/�C min-1 amax,y amax,z amax f0(amax) A 9 10-17/min-1

3 0.57 0.610 0.60 -1.12 3.17

10 0.58 0.620 0.60 -1.12 3.80

15 0.58 0.620 0.59 -1.12 3.99

20 0.67 0.6900 0.65 -0.92 5.50

Average 0.60 0.632 0.61 -1.07 4.11


123


10. Desmond TCA, Seng NG. Environment friendly UV-curable

resins from palm stearin alkyds. J Appl Polym Sci. 2012;125:

306–13.

11. Fotso Nehemie DT, Mbouna D, Denis ON. Regeneration in vitro

du Ricinodendron heudelotii. Cahier Agric. 2007;16:31–6.

12. Baruah SD, Goswami A, Dass NN. Photoinitiation of methyl

methacrylate with a novel iron(III) oxalate complex. Polym Bull.

1995;35:561–6.

13. Vyazovkin S, Burnham AK, Criado JM, Perezmaqueda LA. IC-

TAC Kinetics Committee recommendations for performing

kinetic computations on thermal analysis data. Thermochim Acta.

2011;520:1–19.

14. Vyazovkin S, Sbirrazzuoli N. Isocoversional Kinetic Analysis of

Thermally Stimulated Processes in Polymers. Macomol Rapid

Commun. 2006;27:1515–32.

15. Yan QL, Zeman S, Svoboda R, Elbeih A. Thermodynamic

properties, decomposition kinetics and reaction models of

BCHMX and its Formex bonded explosive. Thermochim Acta.

2012;547:150–60.

16. Jankovic B, Mentus S, Jankovic M. A kinetic study of the thermal

decomposition process of potassium metabisulfite: estimation of

distributed reactivity model. J Phys Chem Solids. 2008;69:

1923–33.

17. Khachani M, El Hamidi A, Halim M, Arsalane S. Non-isothermal

kinetic and thermodynamic studies of the dehydroxylation pro-

cess of synthetic calcium hydroxide Ca(OH)2. J Mater Environ

Sci. 2014;5:615–24.

18. Yang HC, Lee MW, Hwang HS, Moon JK, Chung DY. Study on

thermal decomposition and oxidation kinetics of cation exchange

resins using non-isothermal TG analysis. J Therm Anal Calorim.

2014;. doi:10.1007/s10973-014-3853-9.

19. Sherchenkov A, Kozyukhin S. Estimation of kinetic parameters

for the phase change memory materials by DSC measurements.

J Therm Anal Calorim. 2014;. doi:10.1007/s10973-014-3899-8.

20. Kissinger HE. Reaction kinetics in differential thermal analysis.

Anal Chem. 1957;29:1702–6.

21. Ozawa T. Thermal analysis—review and prospect. Thermochim

Acta. 2000;355:35–42.

22. Flynn JH. A general differential technique for the determination

of parameters for d(a)/dt = f(a)A exp(-E/RT)—energy of acti-

vation, pre-exponential factor and order of reaction (when

applicable). J Therm Anal. 1991;37:293–305.

23. Coats AW, Redfern JP. Kinetic parameters from thermogravi-

metric data. Nature. 1964;201:68–9.

24. Malek J. The kinetic of analysis of non-isothermal data. Ther-

mochim Acta. 1992;200:257–69.

25. Malek J. The kinetic analysis of crystallization processes in

amorphous materials. Thermochim Acta. 2000;355:239–53.

26. Larock RC, Fengkui L. Synthesis, structure and properties of new

tung oil-styrene-divinylbezene copolymers prepared by thermal

polymerization. Biomacromolecules. 2003;4:1018–25.

27. Suresh SN, Xiaohua K, Leila H. Fatty acid-derived diisocyanate

and bio-based polyurethane product from vegetable oil: synthesis,

polymerization and characterization. Biomacromolecules.

2009;10:884–91.

28. Svoboda R, Malek J. Interpretation of crystallization kinetics

results provided by DSC. Thermochim Acta. 2011;526:237–51.


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http://dx.doi.org/10.1007/s10973-014-3853-9

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Thermal Behavior of Ricinodendron heudelotii oil polymer

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