Development of novel conductive copolymer based on furan with improved solubility and thermal properties

Article abstract of DOI:10.1016/j.molstruc.2020.129174

The aim of this paper is to synthesize a new conductive polymer poly(phenylazepane-2-one-furan) (Abbreviated as poly(PAF)), based on the alternation of furan and a synthesized monomer phenylazepane-2-one (PA). The reaction was carried out by cationic polymerization, using a prepared heterogeneous clay catalyst called Maghnite-H⁺. The structure of the polymer obtained was identified by different characterization methods such as UV-Visible spectroscopy, Fourier Transform Infra-Red spectroscopy, Differential Scanning Calorimetry and Proton/carbon Nuclear Magnetic Resonance. Thermal stability was evaluated by thermogravimetric analysis, showing that poly(PAF) is stable before 200 °C. The operating conditions were optimized at T = 25 °C and t = 4 h to obtain a yield of 90percent. The poly(PAF) obtained has a linear structure and a molecular mass M_n of 7300 g/mol, which makes it soluble in common organic solvents. The indirect band-gap was calculated by Tauc formula, its value was found 1.63 eV, showing that poly(PAF) behaves like a semiconductor. Ac electrical conductivity and dielectric properties of poly(PAF) have been investigated in detail in a wide range of frequencies at room temperature.

Full text of DOI:10.1016/j.molstruc.2020.129174

Journal of Molecular Structure 1225 (2020) 129174
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstr
Development of novel conductive copolymer based on furan with
improved solubility and thermal properties
Djamal Eddine Kherrouba,∗, Larbi Bouhadjarb, Malika Medjahdic
a Laboratoire de Chimie des Polymères, Université Ahmed Ben Bella d’Oran 1, BP 1524, El-Mnaouer, 31000 Oran, Algeria
b Faculté des Sciences de la Matière, Université Ibn Khaldoun de Tiaret, BP P78, Zaâroura, 14000 Tiaret, Algeria
c Laboratoire de structure, Elaboration et Application des Matériaux Moléculaires, Université Abd Elhamid Ibn Badis de Mostaganem, BP 27000, Algeria
a r t i c l e i n f o
a b s t r a c t
Article history:
The aim of this paper is to synthesize a new conductive polymer poly(phenylazepane-2-one-furan) (Ab-
breviated as poly(PAF)), based on the alternation of furan and a synthesized monomer phenylazepane-2-
one (PA). The reaction was carried out by cationic polymerization, using a prepared heterogeneous clay
catalyst called Maghnite-H+. The structure of the polymer obtained was identified by different character-
ization methods such as UV-Visible spectroscopy, Fourier Transform Infra-Red spectroscopy, Differential
Scanning Calorimetry and Proton/carbon Nuclear Magnetic Resonance. Thermal stability was evaluated
by thermogravimetric analysis, showing that poly(PAF) is stable before 200 °C. The operating conditions
were optimized at T = 25 °C and t = 4 h to obtain a yield of 90%. The poly(PAF) obtained has a lin-
ear structure and a molecular mass Mn of 7300 g/mol, which makes it soluble in common organic sol-
vents. The indirect band-gap was calculated by Tauc formula, its value was found 1.63 eV, showing that
poly(PAF) behaves like a semiconductor. Ac electrical conductivity and dielectric properties of poly(PAF)
have been investigated in detail in a wide range of frequencies at room temperature.
Received 12 May 2020
Revised 29 August 2020
Accepted 29 August 2020
Available online 31 August 2020
Keywords:
Furan
Band-gap
Conjugated polymer
Ac conductivity
Maghnite
© 2020 Elsevier B.V. All rights reserved.
1. Introduction
conjugated building material. Furan is a heterocyclic pentagonal
whose heteroatom is oxygen. Its resonance energy is 16 Kcal/mol;
In recent years, conductive polymers have become of great in-
terest in the electronics sector. They are macromolecules which
have the particularity of transporting charges (electrons or holes)
[1–4]. They were discovered in the 1970s by Shirakawa, Heeger and
MacDiarmid [5], when they showed the conductive property of the
first organic conductive polymer: polyacetylene. To be conducting,
a polymer must be conjugated, that is to say, that it must contain
alternating single bonds and double bonds. Conductive polymers
offer the advantage of the modular and flexible mechanical char-
acteristics of plastic materials, that conventional conductive mate-
rials do not possess [6–9]. They have many potential applications
such as flexible screens, lightweight batteries, corrosion protection
and electromagnetic shielding [10–12]. The main classes of intrin-
sically conductive polymers are polyacetylenes, polypyrroles, poly-
thiophenes, polyanilines and polyfurans. Compared to other poly-
mers, polyfurans have been less studied due to the difficulties of
their synthesis. Their electrochemical, spectroscopic and electronic
behavior has also been very little reported. Furan is obtained from
biomass; it is a biodegradable monomer, which makes it a green
it is weaker than pyrrole and thiophene, which explains its low
chemical stability and its sensitivity to light. Furan has a flat struc-
ture, the electron-free doublet present on the oxygen, can enter
into conjugation with the nucleus having two double bonds (π)
[13,14]. Furan polymerizes by binding to α position, losing protons
and obtaining a positively charged doped polymer. Electroneutral-
ity is ensured by the presence of negative counter-ions [15]. Proba-
bly, the difficulties in synthesizing furan-based monomers, as well
as the suspicion of high temperature thermal instability and the
insolubility in the common organic solvents have contributed to
the limited attention of this class of polymers [16–18].
Solid support reactions are advantageous in that they provide,
at least in part, the easy separation of the catalysts from the reac-
tion products. A simple filtration is enough to recover the solid cat-
alyst, after having fused or solvated the product obtained. It is now
believed that clays have acquired an important role in the cataly-
sis of different polymerization reactions and composite synthesis
[19–26]. In our study, we are particularly interested in montmoril-
lonite, knowing that we will use it as a solid catalyst. Montmoril-
lonite is a clay mineral characterized by a complex of three lay-
ers, separated by water molecules [27–29]. It can be activated by
submitting to hot digestion in strong mineral acid. Depending on
∗
Corresponding author.
E-mail address: djamaleddine.kherroub@yahoo.com (D.E. Kherroub).
https://doi.org/10.1016/j.molstruc.2020.129174
0022-2860/© 2020 Elsevier B.V. All rights reserved.

2
D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
the conditions of this digestion (duration, the concentration of the
acid bath and temperature), the catalytic properties are improved.
The hydronium ions inserted between the montmorillonite sheets
will be the active sites responsible for the catalytic aspect [30]. X-
ray diffraction analysis can confirm the intercalation of hydronium
ions, showing an increase in the interfoliar space corresponding to
the plane (001) of the montmorillonite.
This work focuses mainly on the synthesis of a new con-
ductive polymer, obtained from furan and synthesized monomer
(phenylazepane-2-one);
a conductive polymer with improved
Physico-chemical properties, allowing it to replace conven-
tional conductive polymers. The copolymerization of furan with
phenylazepane-2-one was to impart the solubility aspect and the
thermal stability to the material obtained. The initiation of the
copolymerization reaction was carried out cationically by heteroge-
neous catalysis based on montmorillonite type clay (Maghnite-H+).
This ecological catalyst was prepared and studied in the polymer
chemistry laboratory of Ahmed Ben Bella University in Oran, Alge-
ria. This new strategy was largely consistent with the principles of
green chemistry.
2. Experimental section
2.1. Materials
ε-caprolactam, phenol, furan, acetic anhydride, dimethylsulfox-
ide, N,N-dimethylformamide, tetrahydrofuran, sulfolane, toluene,
methanol and dichloromethane were purchased from Aldrich
Chemical Co. X-ray powder diffraction analysis (XRD) of Magh-
nite and prepared Maghnite (Maghnite-H+) was recorded using
Bruker X-Ray diffractometer at the rate of 2° min−1 in the 2θ range
of 2.0 − 80° Various methods of analysis were used to identify
and characterize the polymer obtained such as FT-IR spectroscopy
(Perkin-Elmer System), UV–Vis spectroscopy (OPTIZEN 2120), 1H
NMR and 13C NMR (300 MHz Bruker). The thermogravimetric anal-
ysis (ATG) was performed by Labsys Evo Setaram with a heating
rate of 10 °C/min. The DSC analysis was carried out on a Setaram
92 DSC apparatus under a helium flow rate of 20 ml/min, the sam-
ple (4.9 mg) to be analysed was preheated before registering the
spectrum. The rate of heating was 10 C/min. The Ac electrical con-
ductivity and the dielectric measurements of the poly(PAF) were
determined by two-probe method at 1 V, in a frequency range
from 20 Hz to 10 MHz, using a GW-Instek 821−LCR-Meter bridge
with PC.
Fig. 1. The synthetic route of Poly(PAF).
cipitate in powder form was recovered by filtration, dried under
vacuum and weighed. The yield of the reaction was about 86%.
2.4. Polymer synthesis
The copolymerization of furan and synthesized phenylazepane-
2-one took place in solution under inert atmosphere (nitrogen), us-
ing Maghnite-H+as a catalyst. Maghnite-H+ was dried at 100 °C for
one hour before being used. The role of Maghnite-H+ was dehy-
drogenation of furan (1 g) and phenylazepane-2-one (3.05 g) dis-
solved in dichloromethane. The reaction synthesis was carried out
during 3 h at 25 °C. Finally and after removing Maghnite-H+ from
the mixture by filtration, methanol was added slowly to the mix-
ture with gentle stirring to precipitate the polymer. The copolymer
obtained was dried under vacuum at room temperature overnight.
The yield of the reaction was about 89%. This previously described
procedure was repeated several times at different temperatures,
times and catalyst contents. Fig. 1
2.2. Catalyst preparation
Maghnite-H+ was prepared by treating the raw-Maghnite with
a solution of sulfuric acid 0.25 M, at room temperature over two
days until saturation was achieved. The cation-exchanged Maghnite
was: filtered, resuspended in deionized water continuously until
no sulfate ions were detected in the filtrate by BaCl2, isolated by
filtration, dried in an oven at 105 °C and then finely ground. The
clay cation exchange capacity (CEC) was found to be 84 meq/100 g
of dried Maghnite-H+ [7].
2.3. Monomer synthesis
Phenylazepane-2-one was prepared by the reaction of capro-
lactam with phenol. So in a three-neck flask, 5 g of caprolactam
was solubilized over toluene. After stabilizing the temperature at
70 °C, 4.25 g of phenol and 4.6 g of acetic anhydride were added
to the flask. Then, 0.1 g of the previously prepared Maghnite-H+
was added to the reaction mixture. The mixture was left for 2 h
with gentle stirring. At the end of the reaction, a light yellow pre-
3. Results and discussion
3.1. XRD characterization of Maghnite-H+
The X-ray powder diffraction patterns of raw-Maghnite and
Maghnite-H+ (Fig. 2) showed the presence of other crystalline
phases in addition to montmorillonite, such as mica, calcite and

D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
3
+
Fig. 2. X-ray powder diffraction of raw-Maghnite and Maghnite-H 0.25 M.
quartz. Under the effect of the acid treatment of raw-Maghnite, the
mica and calcite contents were reduced; this was deduced from
the decrease in the intensity of the corresponding peaks located
at 19.74, 62.14° for mica, and 20.81, 39.61° for calcite. The removal
of most of the quartz located at 20.81 and 26.54° is probably due
to the mechanical treatment of raw-Maghnite by the sedimenta-
tion process. The increase in basal spacing corresponding to the
˚
space of montmorillonite layers; from 10.5 A in raw-Maghnite to
+
˚
15.02 A in Maghnite-H was reflected by the shift of the montmo-
rillonite peak towards the small values of θ (8.41 to 5.87°). This is
explained by the replacement of interlamellar ions such as Mg2+
and Ca2+ by gigantic hydronium ions of the relatively large molec-
ular radius. In general, we note that acid treatment of Maghnite
increased basal spacing of montmorillonite, but did not affect the
original Maghnite structure, which was confirmed by the absence
of the appearance or disappearance of peaks in XRD spectrum of
Maghnite-H+.
3.2. Characterization
Fig.
3 shows the optical absorption spectrum of dissolved
Fig. 3. UV–visible spectrum of poly(PAF).
poly(PAF) in DMSO. The color of the polymer solution was
greenish-yellow. The adsorption spectrum makes appear three ab-
sorption bands located at 330, 364 and 423 nm assigned to; the
π–π∗ transition of the C = C chromophore present in the aro-
matic benzene and furan rings, the n–σ∗ transition of the non-
bonding electronic level in nitrogen atom and the n–π∗ transi-
tion of the carbonyl groups of caprolactam respectively. The ex-
istence of bands at high wavelength values is due to the exten-
sive conjugation of the polymer chain. This curve obtained by UV-
Visible spectroscopy makes it possible to calculate the absorption
coefficient, which is a necessary parameter in order to then deter-
mine the optical band-gap of our synthesized material.
the PA and 1.62, 2.54 and 3.35 ppm for the poly(PAF) are assigned
to caprolactam ring protons. The peaks Hc (2H, d) at 6.66 ppm,
Ha (1H, t) at 6.70 and Hb (2H, t) at 6.74 ppm for PA and Hc’ (2H,
s) at 6.46 and Ha’ (1H, s) at 6.74 ppm for poly(PAF) correspond to
phenyl ring protons. The disappearance of the peak Hb in the spec-
trum of the polymer and the conversion of Ha and Hc into singular
gave the reason to conceive that the attachment of the furan ring
on the phenyl ring was at the carbon atom in meta-position. The
furan ring protons Hg (2H, d) appear at 6.87. The appearance of the
Hg peak as a doublet peak shows that the attachment to the furan
cycle was in atoms 1 and 4. The small peaks Hh at 7.13 ppm and
Hi at 7.90 ppm are attributed to phenyl and furan ring protons, re-
spectively, at the end of the polymer chain. The number average
The 1H NMR spectra of synthesized monomer and polymer
were obtained to identify and confirm their chemical structure.
Fig. 4 shows the superposition of the 1H NMR spectra of PA (a)
and poly(PAF) (b). The resonances at 1.69, 2.54 and 3.33 ppm for

4
D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
Fig. 4. 1H NMR spectra of PA (a) and poly(PAF) (b).
1626 cm−1 is assigned to C = C stretching vibration of the phenyl
ring. The peak at 1530 cm−1 is assigned to the C = C stretching
vibration bands of the furan rings. The peak at 1453 cm−1 is as-
molecular weight (Mn) of poly(PAF) was calculated after integra-
tion, by comparing the signal areas corresponding to the protons
of the furan ring in the repeating unit (Hg) (56 times larger) to
that of the terminal group (Hi), After division taking into account
the number of existence of each proton per molecule, Mn is about
7300 g/mol.
–
signed to the conjugated C N stretching. The mid-intensity band at
1259 cm−1 corresponds to the valence vibration of the C N bond.
–
The peak at 1051 cm−1 is assigned to the C C stretching vibration
–
bands. A distinct peak at 736 cm−1 is due to the C–H out-of-plane
vibration. The IR spectrum was in good agreement with the pro-
posed structure.
In order to complete the structural study of synthesized prod-
ucts, 1H NMR analysis was supported by 13C NMR analysis to
identify and confirm the carbon-carbon bonds. Fig. 5 shows the
13C NMR spectra of the monomer (curve above) and the poly-
mer (curve below). The carbons of the phenyl ring are observed
at 122.80, 128.86, 117.07 and 141.73 ppm for the monomer (C1, C2,
C3 and C4) and at 122.85, 135.99, 116.73 and 141.76 ppm for the
polymer (C’1, C’2, C’3 and C’4). The displacement of the C2 peak
from 128.86 in the monomer to 135.99 in the polymer indicates
the conversion of the secondary carbon to a tertiary carbon, due
to the creation of a new bond with the furan carbon. The signals
appeared at 172.45, 50.65, 34.56, 29.92, 24.20 and 29.21 ppm for
the monomer (C5, C6, C7, C8, C9 and C10), and at 172.79, 50.78,
34.66, 29.98, 24.91 and 29.21 ppm for the polymer (C’5, C’6, C’7,
C’8, C’9 and C’10) are assigned to carbon atoms belonging to the
caprolactam ring. The attachment of the furan ring gave rise to
the birth of two peaks C11 and C12 located respectively at 137.09
and 119.25 ppm. The two small peaks α and β seen at 128.52 and
121.37 ppm are, respectively, assigned to the carbons of furan and
phenyl rings at the ends of the polymer chain. These results are to
a large extent compatible with those obtained by 1H NMR analysis.
Fig. 6 shows the IR absorption spectrum of poly(PAF) from
which we will cite the main peaks. The small peak at 3058 cm−1
3.3. Thermal properties
Fig. 7 shows the TGA, DTG and DSC thermograms of poly(PAF)
obtained in a helium atmosphere, at a heating rate of 10 °C/min.
This polymer shows good thermal stability up to a temperature of
around 200 °C, beyond this temperature; the polymer begins to
undergo thermal decomposition in a single main stage. This re-
sult showed a significant improvement in degradation temperature
compared to other pure synthesized polyfurans; 150 °C [31], 160 °C
[32], polyfuran composites doped by tin oxide particles 180 °C
[32] and similar to that of crosslinked polyfuran copolymerized
with epoxide 200 °C [33]. The DSC curve shows a small temper-
ature variation at about 162 °C, which represents the glass transi-
tion temperature of the polymer, as well as an endothermic peak
at about 260 °C due to melting phenomenon. In the temperature
range between 450 and 570 °C, several endothermic and exother-
mic effects are noticed in the DSC signal, due to the pyrolytic de-
composition of the polymer.
3.4. Conductivity measurements
–
is attributed to the aromatic C H. The two mid-intensity bands at
2925 and 2854 cm−1 correspond, respectively, to the symmetric
−1
Fig. 8a shows the evolution of ac electrical conductivity (σac),
the real part of the permittivity (ɛ’), the imaginary part of the per-
mittivity (ɛ”) and the dielectric tangent lost tang (δ) at room tem-
–
and asymmetric stretch of C H alkyl. The peak at 1725 cm
is
C = O stretching vibration of caprolactam ring. The sharp peak at

D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
5
Fig. 5. 13 C NMR spectra of PA (a) and poly(PAF) (b).
perature. The measurements were made in a frequency range be-
tween 20 Hz and 10 MHz. First of all, in Fig 8a, the ac electri-
cal conductivity increased continuously with increasing frequency
applied. This can be since, as the frequency increased, additional
electrons are conducted across the interface due to the frequency-
assisted electron hopping [34]. The study of the variation of dielec-
tric permittivity constant as a function of the frequency, makes it
possible to fundamentally define the polarization capacity of the
poly(PAF) during the application of the field. Its both real and
imaginary parts decrease with increasing frequency; this is due
to the dominance of the relaxation process. The values of ɛ’ and
ɛ” became 8.48 and 0.12, respectively, at the maximum frequency.
Tang (δ) is the ratio of ɛ’ to ɛ”, it decreased with increasing fre-
quency due to the dominance of the capacitive element against the
ohmic component [35,36]. The relaxation time has been calculated
around 1340 μs. The ac electrical conductivity also measured as a
function of temperature at different frequencies (Fig. 8b). It is re-
markable that the ac electrical conductivity of poly(PAF) increased
Fig. 8. (a) Variation of σac, ɛ’, ɛ” and tang (δ) of poly(PAF) with frequency. (b) Variation of σac of poly(PAF) with temperature at different frequencies.

6
D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
Fig. 6. IR spectrum of poly(PAF).
Fig. 7. TGA and DSC thermograms of poly(PAF).

D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
7
Fig. 9. Determination of the indirect band-gap of poly(PAF) from a plot of (αhν)1/2
versus hν.
with increasing temperature. This is attributed to the increased
likelihood of electrons in the valence band getting enough energy
to join the conduction band. This result confirms that poly(PAF)
exhibits semiconducting material behavior. The increase in ac elec-
trical conductivity also with frequency is due to the existence of
polymer defect sites, permitting the movement of charges.
Fig. 10. Solubility test results.
of poly(PAF); absence of any kind of inter-chain bonds, that has
been confirmed by the structural characterization. Similar results
have been obtained for the copolymerization of thiophene with
cyclic structures [12].
3.5. Optical analysis
To determine the indirect band-gap of poly(PAF) film, the ex-
trapolation of the plot of (αhv)1/2 versus hv was carried out, the
results are presented in Fig. 9. The region of strong absorption
was exploited to determine the indirect optical band-gap (Eg), us-
ing Tauc formula. The value of the indirect band-gap was obtained
1.63 eV, from the extrapolation of the line to the baseline, where
the value of the (αhv)1/2 is equal to zero. The result obtained al-
lows us to conclude that poly(PAF) is a π-conjugated semiconduc-
tor at room temperature (<2 eV).
3.7. Effect of the amount of Maghnite-h+, reaction time and
temperature on the synthesis of poly(PAF)
In the first part, we have tracked the effect of time on the re-
action synthesis of poly(PAF) for different amounts of Maghnite-
H+. The Fig. 11.a shows the effect of time on the polymeriza-
tion yield, investigated by using various weight ratios Maghnite-
H+/monomers. The polymerization was carried out in solution
(CH2Cl2) and at a temperature of 25 °C. The polymerization yield
increased over time, reaching 90% at 4 h by using 5% Maghnite-H+.
The reaction yield remained constant beyond 4 h. This can be ex-
plained by the total consumption of reagents. The remaining 10%
is oligomers soluble in CH2Cl2. The continuous increase in reaction
yield, depending on the amount of Maghnite-H+ used, is probably
the result of the number of initiating active sites responsible for
the induction of the polymerization, this number is proportional
to the amount of catalyst used in the reaction.
3.6. Solubility test
The solubility of poly(PAF) in common organic solvents is one
of the main objectives, expected from the copolymerization of fu-
ran with PA. Therefore the solubility parameter was evaluated in
dimethylsulfoxide, tetrahydrofuran, N,N-dimethylformamide, sul-
folane and water. 1 g of poly(PAF) was introduced into 30 ml of
solvent; the mixture was allowed to stir for 30 min. The quantity
of poly(PAF) which remained insoluble was recovered by filtration,
dried and then weighed. The following expression made it possi-
ble to calculate the solubility index. The examination results are
shown in Fig. 10.
In the second part, the temperature effect on the polymeriza-
tion reaction of furan with PA was tracked. The polymerization
was carried out for 4 h in the presence of 5 wt% of Maghnite-H+.
The results gained at different temperatures are shown in Fig. 11.b.
From the later, we conclude that the optimal temperature for the
reaction is 25 °C (the yields reach a maximum). After this tem-
perature, the reaction yield was reduced, indicating that the tem-
perature 25 °C is the ceiling temperature, at which the rates of
polymerization and depolymerization phenomena are equal. These
results show the double role in the opposite direction played by
Maghnite-H+ as a cationic catalyst. Same results have been ob-
tained during the synthesis of polyurethane using Maghnite-H+ as
a catalyst [21].
Initial product mass − Insoluble product mass
Solubility index
%
( )
=
Initial product mass
According to the values of the calculated solubility index, most
of the poly(PAF) was found to be soluble in the solvents tested
except water. Poly(PAF) has conjugated chains due to the degree
of dehydrogenation, giving yellow solutions of high concentrations.
The very good solubility of poly(PAF) despite their high degree of
π-conjugation is due essentially to the large unitary groups (capro-
lactam/benzene), which are meta linked to the carbon atom of the
furan ring, and also is largely due to the linear molecular structure

8
D.E. Kherroub, L. Bouhadjar and M. Medjahdi / Journal of Molecular Structure 1225 (2020) 129174
Fig. 11. Effect of the amount of Maghnite-H+, reaction time and temperature on the reaction yield of poly(PAF) synthesis.
4. Conclusions
CRediT authorship contribution statement
A new conductive polymer poly(PAF) was successfully syn-
thesized using a heterogeneous green catalyst. It was obtained
by the copolymerization of furan and a synthesized monomer
phenylazepane-2-one at room temperature. The alternation be-
tween single and double bonds in the structure is responsible for
the conductivity of poly(PAF). The reaction yield was 90% after
5 h. The chemical structure of poly(PAF) has been identified using
UV–Vis, IR, 1H NMR and 13C NMR. 1H NMR analysis showed that
the furan ring is attached to the meta-position of the phenyl ring.
ATG analysis showed that the poly(PAF) is thermally stable below
200 °C. The results of solubility tests have shown that dimethyl-
sulfoxide, tetrahydrofuran, N, N-dimethylformamide and sulfolane
present good solvents to the poly(PAF). Its solubility property was
acquired through the introduction of aromatic groups (caprolac-
tam/benzene) into the furan polymer chain, and also it is due to its
linear chemical structure that has been proven by 1H NMR analy-
sis. The obtained poly(PAF) is a useful precursor to small band-gap
soluble polymers, the value of its indirect band-gap is 1.63. The
values of ɛ’ and ɛ” are 8.48 and 0.12, respectively. The relaxation
time was measured at around 1340 μs. Both optical and electrical
properties have shown that poly(PAF) can be a promising material
used in photovoltaic and solar cell applications.
Djamal Eddine Kherroub: Conceptualization, Writing - original
draft, Visualization. Larbi Bouhadjar: Methodology, Investigation,
Validation. Malika Medjahdi: Resources, Writing - review & edit-
ing, Validation.
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Declaration of Competing Interest
[7] M. Badaoui, L. Bouhadjar, D.E. Kherroub, K. Chikh, A. Seghier, E.H. Belarbi,
Green Copolymerization of Thiophene with para-Cholorobenzaldehyde
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cial interests or personal relationships that could have appeared to
influence the work reported in this paper.
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