IRJET- Nanotitania Reinforced Imine Skeletal Maleimido Terminal Phenylene Core Polybenzoxazine (nTiO2/PBZ) Nanocomposites

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 01 | Jan 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 866
Nanotitania Reinforced Imine Skeletal Maleimido Terminal Phenylene
Core Polybenzoxazine (nTiO2/PBZ) Nanocomposites
M. Soundarrajan1, L. Devaraj Stephen2, V. Arivalagan3, S. G. Gunasekaran4
1,2,3Department of Chemistry, SRM Valliammai Engineering College, SRM Nagar, Kattankulathur,
Kancheepuram-603203, India.
---------------------------------------------------------------------***----------------------------------------------------------------------
Abstract- Novel polybenzoxazine-nanotitania(nTiO2/PBZ)
hybrid nanocomposites were synthesized using maleimido
terminal benzoxazine monomer(BZ)andnanotitaniathrough
in-situ sol-gel method. The FT-IR spectra confirmed the
formation of nanotitania in the hybrid nanocomposites. In
comparison with neat polybenzoxazine, the polybenzoxazine/
nanotitania hybrid was accounted for their excellent thermal
stability and high char yield due to thepresenceofnanotitania
networks in nTiO2/PBZ hybrids. The introduction of the
nanotitania particles into the polybenzoxazine matrix
increased the glass transition temperature of the hybrid
composites. The successful incorporation of nanotitania
particles in the way thermal ring opening polymerization of
benzoxazine leads to the shift in both the absorption and
emission wavelengths. Transmission electron microscope and
scanning electron microscope studies were used to image the
morphological features of the molecular level dispersion and
distribution of nTiO2particlesinthepolybenzoxazine matrices.
Key Words: Terminal benzoxazine, organic/inorganic
hybrid nanocomposites, sol-gel method, imine, thermal
stability, absorbance.
1. INTRODUCTION
Among the polymers used for high-performance industrial
applications, polybenzoxazine (PBZ) play a vital role since
they possess high mechanical strength, inherent flame
retardancy and water retention with zero shrinkage during
curing(1,2,3). PBZs obtained from different precursors tend to
show different properties and makes them a very useful
material for microelectronics and aerospace applications.
The design and synthesis of nanomaterials with controlled
properties is a challenging problem. An intensive research
on the development of hybrid organic polymers and
inorganic materials at a nanoscale level is representing
attention for the past few years (4-7).
Various raw materials have been used for the synthesis
of BZ monomer permit considerable molecular-design
flexibility. In general, benzoxazine was synthesized through
Mannich condensation using bisphenol/phenol, primary
amine and formaldehyde solution (8). They were obtained by
thermal curing from the ring-opening polymerization of
cyclic benzoxazine monomers, without using a catalyst and
forming no byproducts. Polybenzoxazines show better
combinations of attractive properties such as cost
effectiveness, heat resistance, fire retardancy and electronic
properties (9-12) compared to the conventional composites in
many aspects. Moreover, they give additional unique
characteristics such as low water absorption, high
dimensional stability and near-zero volume shrinkage or
expansion on curing (13-15).
Polybenzoxazine hybrids were synthesized by sol-gel
process, providing hybrid materials of excellent thermal
stability. It is well known that the sol-gel process make it
attractive for the application in the synthesis of organic-
inorganic hybrid nanocomposites. A number of valuable
hybrid polymers have been prepared through the sol-gel
process (16-19). The sol-gel process is one of the most
comfortable methods toformsilica throughTi-O-linkagesby
the hydrolysis of alkoxysilanes. The properties of the
organic-inorganic hybrid materials are greatly based on the
interaction between the organic polymers and the siloxane
matrix (20), and their homogeneous distribution within the
hybrid nanocomposites. The factors which impact the
efficient interaction between the components involved are
covalent bonding (21), hydrogen bonding (22), stereo regular
complex (23), and π-π and ionic interactions. A new type of
polybenzoxazine-titania based hybrid, with improved
thermal properties was reported(25). Recently, a novel imine
polybenzoxazine hybrid nanocomposite using a new
benzoxazine monomer with improved in thermal stability
and high char yield was synthesized(26).
The main objective of the present work is to synthesize
new type of PBZ with increased solubility in common
solvents with improved thermal and dielectric behaviors
than those of conventional PBZstomakeuseofthemforhigh
performance applications with boosted longevity. In the
present work, different PBZs, soluble in common organic
solvents using kink-structured diiminewithanhydridewere
synthesized and characterized with analytical techniques
and the data received are discussed and reported.
2. EXPERIMENTAL METHODS
2.1. Synthesis of Maleimido Terminal Phenylene Core
Imine Linked Aromatic Benzoxazine
The Maleimido terminal p-phenylene core imine linked
aromatic benzoxazine monomer (p-PCBZ) (Scheme 1) from
hydroxyl terminal p-phenylene core aromatic diimine
derivative was synthesized by the following procedure as
shown in Scheme 1. In a 250 ml round bottomed flask, 50 ml

of dioxane, hydroxyl terminal p-phenylene core aromatic
diimine (0.0074mol, 4.0g), N-(4-aminophenyl) maleimide
(0.015mol, 4.82g) and formaldehyde solution (0.029 mol,
1.52 g) were added and refluxed at 120oC for 6 hrs. The
reaction mixture was filtered and the precipitate was
washed once with 1M NaHCO3 aqueous solution (200 ml),
and dried with anhydrous sodium sulphate for 24 hrs.
Removal of solvent by rotation evaporator anddryingunder
vacuum resulted benzoxazine as a yellow colored powder.
The yield was 68 %. Here, BZs are denoted as o-PCBZ =
HPPDA-MIA (N1E,N4E)-N1,N4-bis((3-(4-(9H-carbazol-9-
yl)phenyl)-3,4-dihydro-2H-benzo[e] [1,3]oxazine-6-
yl)methylene)benzene-1,4-diamine; o-PCBZ = HOPDA-MIA
(N1E,N2E)-N1,N2-bis((3-(4-(9H-carbazol-9-yl)phenyl)-3,4-
dihydro-2H-benzo[e] [1,3]oxazin-6-yl)methylene)benzene-
1,2-diamine.
Scheme - 1: Synthesis of maleimido terminal phenylene
core imine linked aromatic benzoxazine monomers
2.2 Preparation of Maleimido Terminal Phenylene
Core Imine Linked Nanotitania Reinforced
Polybenzoxazine (nTiO2/PBZ) Hybrid Nanocomposites
A series of experimental procedures have been adapted
to synthesis nanotitania incorporated polybenzoxazine
hybrid nanocomposites (Scheme2).Benzoxazinemonomers
were dissolved in 1, 4-dioxaneandthecuring wasperformed
at 120oC for 2 hours and then post cured at 180oC for 2
hours. The curing cycle time is given in Table 1. The solution
of nanotitania in 1,4-dioxane were added to the exact
equivalents of the dilute acid, with nonstop stirring for 20
min followed by the addition of 1 equivalent of benzoxazine
monomer dissolved in 1,4-dioxane and blended well to geta
clear solution, and again stirred for 1 hour at 35oC. Then, the
mixture was transferred in a silane coated glass plate and
cured at 120oC and 180oC for 2 hours to get polybenzoxazine
(PBZ) nanocomposites.
Scheme - 2: Schematic representation of the preparation
of maleimido terminal phenylene core imine linked
nanotitania reinforced polybenzoxazine (nTiO2/PBZ)
hybrid nanocomposites
2.3 CHARACTERIZATION
About 100 mg of optical-grade KBr was grounded with
sufficient quantity of the solid sample to make 1.0 wt %
mixture for making KBr pellets. Afterthesamplewasloaded,
a minimum of 10 scans was collected for each sample at a
resolution of ±4 cm-1, FT-IR spectra were recorded on a
Perkin Elmer 6X FT-IR spectrometer. Then, the neat
polybenzoxazine and nanotitania incorporated
polybenzoxazine (nTiO2/PBZ) nanocomposites were
characterized by UV-Vis- spectrophotometer (UV-Vis) (U-
4100, Hitachi, Japan). The absorbance of the solution was
measured with a wavelength ranging from 200 to 1300 nm.
All 1H-NMR and 13C-NMR analyses were done in CDCl3 and
DMSO-d6 recorded on a Bruker 300 NMR spectrometer. The
emission properties of the PBZ and PBZ-nTiO2
nanocomposites were also studied using Fluorescence
spectrophotometer (Cary Eclipse, FL1201M002, Japan)with
an excitation wavelength. Scanning electron microscope
(SEM) (Desktop Mini-SEM with EDS, ALFATECH), 5Kv to
30kV variable accelerating voltage was used to observe the
surface morphology of the PBZ and PBZ-nTiO2
nanocomposites. The transmission electron microscope
(TEM) observations were carried on a JEOL JEM-2100 plus,
SRM IST, Chennai, India, with an accelerating voltage of 200
KV, Emission gun-Thermionic emission (LaB6). And Raman
spectra were recorded by Micro-Raman spectrometer (785
nm laser source, HORIBA France, LABRAM HR Evolution).
Thermo gravimetric analysis (TGA) was performed in a
DSC-2920 from TA Instruments coupled with a TA-2000
control system. The samples were heated at a scanning rate
of 10°C/min under nitrogen atmosphere.ANetzschDSC-200
differential scanning calorimeter was used for the

calorimetric analysis. The instrument was calibrated with
Indium supplied by Netzsch.Measurementswereperformed
under a continuous flow of nitrogen (60 ml/min). All the
samples (about 10 mg in weight) were heated from ambient
to 400°C and the thermograms were recorded at a heating
rate of 10°C/min.
3. RESULTS AND DISCUSSION
3.1 Structure of Benzoxazine Monomers
Two different types of maleimido terminal benzoxazine
monomers (BZs) were synthesizedusing o-phenyleneandp-
phenylene core diimine with N-(4-aminophenyl) maleimide
with formaldehyde solution through Mannich condensation
26 as shown in Scheme 1. Here, BZs are denoted as o-PCBZ
and p-PCBZ.
3.1.1 FT-IR absorption properties of monomers
FT-IR (KBr, cm-1): 944 cm-1 (oxazine, N-C-O stretching
frequency), 1227 cm-1 (C-O-C), 1563 cm-1 (trisubstituted
benzene ring), 3488 cm-1 (phenyl hydroxyl).
3.1.2 NMR absorption properties of monomers
NMR Data of o-PCBZ
1H NMR: (400MHz, DMSO-d6) δ (ppm): 8.66 (s, 2H), 8.54 (s,
2H), 8.18 (t, 3H), 7.90 (d, 4H), 6.81 (d, 2H) 6.42 (d, 4H), 4.70
(s, 4H) 4.68 (s, 4H).
13C NMR: δ (ppm): 160, 158, 149, 143, 137, 131, 129, 128,
127, 126, 121, 114, 110, 93, 68, 59 (aromatic carbon).
NMR Data of p-PCBZ
1H NMR: (400MHz, DMSO-d6) δ (ppm): 8.66 (s, 2H), 8.54 (s,
2H), 8.18 (t, 3H), 7.90 (d, 4H), 6.81 (d, 2H) 6.42 (d, 4H), 4.70
(s, 4H) 4.68 (s, 4H).
13C NMR: δ (ppm): 160, 158, 149, 143, 137, 131, 129, 128,
127, 126, 121, 114, 110, 93, 68, 59 (aromatic carbon).
3.1.3 UV-Vis absorption properties of monomers
Absorption (nm): 384 (o-PMBZ), 390 (p-PMBZ)
3.1.4 PL properties of monomers
Emission (nm): 503 (o-PMBZ), 591 (p-PMBZ)
3.2 Curing behavior of Benzoxazine monomers
The curing behavior of maleimidoterminal benzoxazine
monomers were studied by the DSC analysis as shown in
Figure 1 and Table 1. The DSC thermogram shows a single
exothermic peak, which is assigned to the polymerization.
The onset and peak top temperatures of the major peaksare
187oC for o-PMBZ and 196oC for p-PMBZ respectively,which
is lower than the conventional benzoxazine monomer. The
peak curing temperatures of the resulting monomers were
230oC and 239oC (o-PMBZ and p-PMBZ) and the two
benzoxazinemonomerscouldpolymerizeatthetemperature
range of 260oC and 270oC (o-PMBZ and p-PMBZ) as it can be
shown from Figure 1.
Temperature (oC)
Heatflow(mg/mw)
100 200 300
14PMBZ
12PMBZ
Figure – 1: Curing behaviors of maleimido terminal
benzoxazine monomers
Table – 1: Curing behaviour of Benzoxazine monomers
Sample Ti (oC) Tp (oC) Tf (oC) Sample
o-PMBZ 121 202 270 o-PMBZ
p-PMBZ 124 205 278 p-PMBZ
Ti =initial polymerization temperature; Tp =peak curing
temperature; Tf = final polymerization temperature.
3.3 Characterization of nTiO2/PBZ Nanocomposites
Scheme 1 illustrates the sequence of reactions involved
in the preparation of the nanotitania reinforced
polybenzoxazine hybrid nanocomposites, using nTiO2
through the sol-gel process. The composition of reactants
used for the preparation of nanotitania reinforced
polybenzoxazine hybrids was summarized in Table 2.
Wave number (cm-1)
Transmittance(a.u)
4000 3500 3000 2500 2000 1500 1000 500
d nTiO2
/p-PMBZ
c Neat p-PMBZ
b nTiO2
/o-PMBZ
a Neat o-PMBZ
3486
1710
1590
715
910
1480
(a)
(d)
(c)
(b)
1208
1495
Figure – 2: FT-IR Spectra of neat PBZ and nTiO2/PBZ
Figure 2 shows the FT-IR spectra of neat
polybenzoxazine (Neat PBZ) and nanotitania reinforced

polybenzoxazine hybrids (PBZs). The intensity of the
absorption band at 3486cm-1 confirmsthehydrogenbonded
phenolic OH in the polybenzoxazine matrix. These also
indicate that the Mannich bridge linkage and phenolic
hydroxyl groups are produced by the ring-opening
polymerization of BZ at 180oC. 26In the case of nanotitania
reinforced polybenzoxazine (nTiO2/PBZ) hybrids, the
disappearance of the peak at 941 cm-1 (oxazine) and 1235
cm-1 (C-O-C) confirm the ring opening polymerization of
benzoxazines. The intensity of the peaks at638and715cm-1
confirms the formation of the -Ti-O- linkages in the
nanotitania-benzoxazine (nTiO2/PBZ) hybrids.
The absorption peak at 1590 cm-1 corresponded to the
stretching vibration of the C=N and the new absorption
peaks appear at 1495 and 910 cm-1 due to the substituted
benzene ring, which further confirms the ring opening
polymerization of the nanotitania-PBZ hybrids.29
3.4 Thermal Properties
3.4.1 Differential Scanning Calorimetry
DSC measurements were performed for studying the
influence of nanotitania on benzoxazines networks. The
measurements of glass transition temperature give direct
insight into the mobility of polymer chains. The values of
glass transition temperature for this study were taken as
midpoint in the specific heat transition. The DSC curves for
the unfilledPBZ,nanotitania reinforced benzoxazinesystems
are presented in Figure 3.
All the DSC thermograms showed single Tg in the
experimental temperature range from 30°C to 350°C. It is
noticed that the unfilled PBZ and 2 wt% nTiO2 reinforced
PBZ systems showed the Tg at 183°C and 185°C,respectively
for nTiO2/o-PMBZ and 208°C and 211°C, respectively for
nTiO2/p-PMBZ (Table 1). Similarly,5wt%and10wt% nTiO2
reinforced PBZ systems displayedthe Tgvaluesat198°Cand
205°C respectively for nTiO2/o-PMBZ and 208°C and 211°C,
respectively for nTiO2/p-PMBZ 30 (Table 2).
Temperature (oC)
Heatflow(mg/mw)
100 200 300
10wt% nTiO2
-14PMBZ
5wt% nTiO2
-14PMBZ
2wt% nTiO2
-14PMBZ
Neat 14PMBZ
(b)
Temperature (oC)
Heatflow(mg/mw)
100 200 300
10wt% nTiO2
-12PMBZ
5wt% nTiO2
-12PMBZ
2wt% nTiO2
-12PMBZ
Neat 12PMBZ
(a)
Figure - 3: DSC thermograms of neat PBZ and nTiO2/PBZ
The incorporation of 2, 5 and 10 wt% of nTiO2/PBZ
systems has increased the Tg values of according to the rise
in percentage concentration (Tables 1). The enhancement in
the values of Tg for these benzoxazine systems is mainly due
to the well-dispersed nTiO2 in the matrix and strong
interfacial adhesion between the nTiO2 and PBZ resin which
limits the mobility of the polymer chain.
3.4.2 Thermo Gravimetric Analysis
Thermogravimetric analysis was studied to find out the
thermal stability of the unfilled and nanotitania filled
benzoxazine systems. The TGA curves for the above PBZ
systems are shown in Figure 4. The initial decomposition
temperature for unfilled PBZ and 2 wt% nTiO2 reinforced
PBZ systems are 183°C and 185 °C respectively, with
respective char yield of 34% and 35% at 700°C (Table 2).
The 5 wt% and 10 wt% nTiO2 reinforced PBZ systems start
to degrade at 208°C and 211°C respectively, with respective
char yield of 33% and 34% (Tables 1).
The incorporation of nTiO2 wt% in benzoxazines
systems has been enhanced the degradation temperature
and improved the thermal stability according to the rise in
percentage concentration (Table 2). The delay in
degradation temperature may be due to the formation of
thermally stable cross-linked structure between nTiO2 and
benzoxazine resins. The delay in degradationtemperatureis
due to the nanoscaled dispersion of nTiO2 in PBZ matrix and
strong interaction between the PBZ resin matrix and nTiO2
which retards the decomposition temperature and acts as
barrier for diffusion of small molecules during
decomposition.30
Temperature (ºC)
Weight(%)
100 200 300 400 500 600 700
0
10
20
30
40
50
60
70
80
90
100
110
10wt% nTiO2
-12PMBZ
5wt% nTiO2
-12PMBZ
2wt% nTiO2
-12PMBZ
Neat 12PMBZ
Temperature (ºC)
Weight(%)
100 200 300 400 500 600 700
0
10
20
30
40
50
60
70
80
90
100
110
10wt% nTiO2
-14PMBZ
5wt% nTiO2
-14PMBZ
2wt% nTiO2
-14PMBZ
Neat 14PMBZ
(b)(a)
Figure - 4: TGA thermograms of neat PBZ and nTiO2/PBZ
Table – 3: Thermal and dielectric data of neat PBZ and
nTiO2/PBZ hybrid nanocomposites
Exp.
code
Systems
Tg
(oC)
Char
Yield
at
700oC
(%)
Dielectric
Constant
(έ)
LOI
At
700oC
0.4
(σ)+1
7.5
Water
Absorpt
ion
(%)
o-PMBZ
Neat
o-PMBZ
183 34 3.45 30.3 0.63

o-PMBZ1
2%nTiO2/
o-PMBZ
185 35 3.15 31.1 0.57
o-PMBZ2
5%nTiO2/
o-PMBZ
198 37 2.85 31.5 0.49
o-PMBZ3
10%nTiO/
o-PMBZ
205 38 2.73 32.3 0.43
p-PMBZ
Neat
p-PMBZ
208 33 3.52 31.1 0.64
p-PMBZ1
2%nTiO2/
p-PMBZ
211 34 3.37 31.5 0.54
p-PMBZ2
5%nTiO2/
p-PMBZ
214 35 3.0 32.3 0.45
p-PMBZ3
10%nTiO/
p-PMBZ
219 37 2.75 32.7 0.42
3.4.3 Limiting Oxygen Index
The present study describes the flame retardant
behaviour of the PBZ and nTiO2/PBZ nanocomposites for
their char yield at 700oC using Van Krevelen’s equation. The
LOI values are presented in Table 2 and Figure 5. The flame
retardancy increased after the incorporation of nanotitania
particles into the benzoxazine matrices.
Coupling agent (ratio)
LOI(%)
a b c d
30
32
34
14PMBZ
12PMBZ
Figure - 5: LOI values of neat PBZ and nTiO2/PBZ hybrid
nanocomposites
The burning behaviour was correlated to the crosslink
density of the organic matrix, i.e., with increasing crosslink
density; the flammability resistance increases due to the
formation of higher char yield. Thus, the formation of inter-
cross linked network attained from the polymerization of
benzoxazines with inorganic segments developed in the
present work can be considered as better flame retardant
material than neat PBZ.
3.5 Dielectric constant
The dielectric constant values of the neat PBZ and
nanotitania reinforced benzoxazines systems were
measured by using impedance analyzer as function of
frequency (Table 2). The incorporation of nTiO2 into
benzoxazine system decreases the values of dielectric
constant with increase in percentage concentration.
The decrease in the valuesofdielectricconstantisdueto
the higher insulating capabilities of incorporated
polybenzoxazine systems. The decreased the values of
dielectric constant are due to reduces the dipole-dipole
interactions by Ti-O linkages.
Dielectricconstant(ε’)
a b c d
2.0
2.5
3.0
3.5
4.0
14PMBZ
12PMBZ
Figure – 6: Dielectric behaviour of neat PBZ and
nTiO2/PBZ hybrid nanocomposites
3.6 Optical properties
3.6.1 UV-Vis absorption spectra
The UV-Vis absorption studies of the neat PBZ and
nTiO2/PBZ nanocomposites were illustrated in Figure 7. It
was found that symmetrical shape of absorption peaks was
observed at around wavelength 400 nmforthe neat PBZ and
nTiO2/PBZ nanocomposites.
Wavelength (nm)
Absorbance(a.u)
Wavelength (nm)
Absorbance(a.u)
(b)(a)
200 300 400 500 600 700
12PMBZ-10%nTiO2
12PMBZ- 5%nTiO2
12PMBZ- 2%nTiO2
Neat 12PMBZ
300 600
14PMBZ-10%nTiO2
14PMBZ- 5%nTiO2
14PMBZ- 2%nTiO2
Neat 14PMBZ
Figure - 7: UV-Vis absorption spectra of (a) neat o-PMBZ
and nTiO2/o-PMBZ (b) p-PMBZ and nTiO2/p-PMBZ hybrid
nanocomposites
The incorporation of nanotitania particles into the
organic components shifts the position of peaks
corresponding to the respective benzoxazine monomers. In
addition, the slight shift in the absorption wavelength
revealed the successful incorporation of nanotitania
particles through thermal ring opening polymerization of
benzoxazine and nTiO2.

3.6.2 Photoluminescence spectra
Figure 8 shows PL spectra of the neat PBZ and
nTiO2/PBZ nanocomposites. The polymer emits blue
fluorescence in THF solution with a major fluorescence
emission at 637nm for nTiO2/o-PMBZ and 510nm for
nTiO2/p-PMBZ respectively.
Wavelength(nm)
PLintensity(a.u)
Wavelength(nm)
PLintensity(a.u)
(b)(a)
200 300 400 500 600 700
Neat 12PMBZ
12PMBZ-10% nTiO2
12PMBZ- 5% nTiO2
12PMBZ- 2% nTiO2
200 300 400 500 600 700
14PMBZ-10% nTiO2
14PMBZ- 5% nTiO2
14PMBZ- 2% nTiO2
Neat 14PMBZ
Figure - 8: Photoluminescence spectra of (a) neat o-PMBZ
and nTiO2/o-PMBZ (b) p-PMBZ and nTiO2/p-PMBZ hybrid
nanocomposites
The blue fluorescent emissions were observed for the
absorption of nTiO2/PBZ nanocomposites. This is due to the
presence of intercross linked nanotitania particles in the
hybrid materials. This study further confirms the
homogeneous dispersion of nTiO2 in the PBZ matrix. Hence,
such aromatic heterocyclic polymers can be used for light-
emitting diode materials for high performance opto-
electronic applications.
3.7 Water absorption behaviour
The presence of moisture in the matrix material may
affect the electrical insulation characteristics and the
mechanical properties. Water absorption characteristics of
the neat PBZ and nanotitania reinforced polybenzoxazine
systems are presented in Table 2. The water absorption test
was carried out by immersing the specimen of appropriate
dimension in deionized water at 25 ºC for 48 hours. The
percentage water uptake of neatPBZsystemsis0.63 %for o-
PMBZ, 0.64 % for p-PMBZ respectively.
Waterabsorption(%)
a b c d
0.4
0.6
0.8
14PMBZ
12PMBZ
Figure - 9: Water absorption of neat PBZ and nTiO2/PBZ
The incorporation of inorganic nanotitania into o-PMBZ
and p-PMBZ systems decreases thepercentagewateruptake
to 0.57, 0.49, 0.43 and 0.54, 0.45, 0.42 % respectively. The
decrease in the percentage water uptake for nanotitania
reinforced benzoxazine systems is due to the hydrophobic
property and high crosslink density of benzoxazines. Also
the decrease in percentage water uptake is due to the
combined developments of nanocomposites structure and
the formation of effective matrices which in-turn increase
the crosslinking density and rigidity.
3.8 Morphological properties
3.8.1 X-Ray Diffraction analysis
The X-ray diffraction patterns for neat PBZ and
nTiO2/PBZ hybrid nanocomposites are shown in Figure 10.
The diffraction pattern of nTiO2/PBZ hybrid system showed
a broad amorphous peak at 2θ = 21.31º, which suggested
that the nTiO2 particles are completely dispersed in the PBZ
matrix systems. 30 The pristine PBZ showed a broad peak
centered at 2θ = 20.01º, indicatingitsamorphousstructures.
Upon incorporation of nTiO2 particles, a general patternwas
not significantly changed but two-theta value at a peak
maximum was slightly shifted. The shift of d-spacing upon
polymerization is presumably due to the fact that the silica
disturbs the amorphous nature of polymeric chains. This is
evidenced by the SEM images, as can be seen from Figure 11.
2θ (angle)
Relativeintensity(a.u)
10 20 30 40 50 60 70
14PMBZ-nTiO2
Neat 14PMBZ
12PMBZ-nTiO2
Neat 12PMBZ
Figure – 10: XRD patterns of neat PBZ and nTiO2/PBZ
3.8.2 SEM Morphology
SEM micrographs for the fractured surfaces of the neat
PBZ andnanotitania reinforcedpolybenzoxazinesystemsare
shown in Figure 11.
The neat PBZ system showed the homogeneous and
glassy microstructure. The 10 wt% nTiO2 and PBZ systems
show homogeneous, smooth andglassysurfacemorphology,
which confirms the chemical interaction between nTiO2 and
polybenzoxazine resin and these nanocomposites exhibit
homogeneous morphology due to good and uniform
dispersion of nTiO2 at the nano scale level into the polymer
matrix.31 The strong interfacial interaction arises due to the

effect of adhesion and catalytic effect of nTiO2 with
polybenzoxazine resin and hence leads to the formation of
nanocomposites. The morphology is furthermore evidenced
by TEM analysis (Figure 12).
Figure – 11: SEM micrographs of (a) o-PMBZ (b) nTiO2/o-
PMBZ (c) p-PMBZ (d)nTiO2/p-PMBZ hybrid
nanocomposites
3.8.3 Transmission Electron Microscopy
The TEM micrographs of neat PBZ and nTiO2 reinforced
polybenzoxazine nanocomposites are shown in Figures 12.
The dark portions of nTiO2 (50 nm) are observed in the
polymer matrix, which represents the self-aggregations of
nTiO2. The area surrounding the dark portions indicates the
homogeneous phase morphology of PBZ matrix.
Consequently, this study further confirms the successful
incorporation of nanotitania particles into the maleimido
terminal polybenzoxazine matrix.
Figure – 12: TEM images of (a) o-PMBZ (b) nTiO2/o-PMBZ
(c) p-PMBZ (d) nTiO2/p PMBZ hybrid nanocomposites
4. CONCLUSION
The synthesis of a new series of nanotitania reinforced
maleimido terminal polybenzoxazine (nTiO2/PBZ)
nanocomposites was developed using maleimido terminal
benzoxazine monomers and nTiO2. The nTiO2/PBZ
nanocomposites were synthesized by in-situ sol-gel method,
using varying weight percentages of nTiO2 (0, 2, 5 and 10 wt
%) with respect to benzoxazine monomers. The
nanocomposites were characterized by FT-IR, UV-Vis
spectroscopy, DSC, TGA, XRD, photo luminescence, SEM and
TEM techniques. The synthesized nTiO2/PBZ hybrids
revealed enhancement in thermal stability and higher char
yield than those of neat PBZs, due to the higher percentage
content of nanotitania present in the hybrids. The
incorporation of Ti-O-Ti network into the polybenzoxazine
matrix increased the glass transition temperature to about
10 % than that of neat PBZs. With the higher percentage of
LOI values, these materials can be regarded as flame
retardant materials. The blue fluorescent emission peaks
were observed for these reinforced polybenzoxazine hybrid
nanocomposites as evidenced by PL studies. The molecular
level dispersion of nanotitania particles in the nTiO2/PBZ
matrix was found out by morphological studies. These
hybrids may find wide a range of application in the field of
optoelectronics.
ACKNOWLEDGEMENTS:
The authors acknowledge SRM institute of Science and
Technology for providing HRTEM facility.Theauthorsthank
SRMIST, Kattankulathur, Chennai, for providing SEM and
XRD facility. The authors thank Dr. S. Venkataprasad Bhat,
Professor, Research Department, SRMIST, Kattankulathur,
Chennai, India for providing photoluminescence analysis
facility.
REFERENCES
[1] M. El Fray, A. R. Boccaccini, “Novel Hybrid PET/DFA–
TiO2 Nanocomposites by In situ Polycondensation”,
Materials Letters, vol. 59, no. 18, pp. 2300–2304, 2005.
[2] J. J. Maya, R. D. Anandjiwala, “Recent developments in
chemical modification and characterization of natural
fiber-reinforced composites”, Polymer Composites,
vol.29, no. 2, pp. 187–207, 2007.
[3] S. Kohjiya, Y. Ikeda, “Reinforcement of General-Purpose
Grade Rubbers by Silica Generated In Situ”, Rubber
Chemistry and Technology, vol. 73, No. 3, pp. 534-550,
2000
[4] G. S. Sur, J. E. Mark, “Elastomeric Networks Cross-linked
by Silica or Titania Filler”, European Polymer Journal,
vol. 21, no. 12, pp. 1051-1052, 1985.
[5] C. C. Sun, J. E. Mark, “Comparisons among the
Reinforcing Effects provided by Various Silica-based
Fillers in a Siloxane Elastomer”, Polymer, vol. 30, no. 1,
pp. 104-106, 1989.

[6] B. C. Dave, B. Dunn, J. S. Valentine, J. I. Zink, “Sol-gel
encapsulation methods for biosensors”, Analytical
Chemistry, vol. 66, no. 22, pp. 1120-1127, 1994.
[7] S. G. Gunasekaran, V.Arivalagan,M.Dharmendirakumar,
“Pyrenyl pendent siloxane core dendritic skeletal chain
extended multiwalled carbon nanotube reinforced
hyperbranched polyimide (MWCNT/PI)
nanocomposites”, International Research Journal of
Engineering and Technology,vol.5,no.1,pp.1-11,2018.
[8] L. Jin, T. Agag, Y. Yagci, H. Ishida, “Methacryloyl-
functional Benzoxazine: Photopolymerization and
Thermally Activated Polymerization”, Macromolecules,
vol. 44, no. 4, pp. 767-772, 2011.
[9] S. Jothibasu, S. Premkumar, M. Alagar, I. Hamerton,
“Synthesis and Characterization of a POSS-maleimide
Precursor for Hybrid Nanocomposites”, High
Performance Polymers, vol. 20, no. 1, pp. 67-85, 2008.
[10] T. Takeichi, T. Agag, R. Zeidam, “Preparation and
Properties of polybenzoxazine-poly (imide-siloxane)
Alloys: In situ Ring-opening Polymerization of
Benzoxazine in the Presence of Soluble poly
(imidesiloxane)s,” Journal of Polymer Science Part A:
Polymer Chemistry, vol. 39, no. 15, pp. 2633–2641,
2001.
[11] C. Karikal Chozhan, M. Alagar, P. Gnanasundaram,
“Synthesis and Characterization of 1,1-bis (3-methyl-4-
hydroxyphenyl) cyclohexane polybenzoxazine-
organoclay Hybrid Nanocomposites”, Acta Materialia,
vol. 57, no. 3, pp.782-794, 2009.
[12] A. Kierys, R. Zaleski, W. Buda, S. Pikus, M. Dziadosz, J.
Goworek, “Nanostructured Polymer–Titanium
Composites and Titanium Oxide through Polymer
Swelling in Titania Precursor”, Colloid and Polymer
Science vol. 291, pp.1463–1470, 2013.
[13] H. Ishida, D. P. Sanders, “Improved Thermal and
Mechanical Properties of Polybenzoxazines based on
Alkyl‐substituted Aromatic Amines”, Journal ofPolymer
Science Part B: Polymer Physics, vol. 38, pp. 3289-3301,
2000.
[14] S. B. Shen, H. Ishida, “Dynamic Mechanical and Thermal
Characterization of High-performance
Polybenzoxazines”, Journal of Polymer Science Part B:
Polymer Physics, vol. 37, no. 23, pp. 3257-3268, 1999.
[15] C. F. Wang, Y. T. Wang, P. H. Tung, S. W. Kuo, C. H. Lin, Y.
C. Sheen, F. C. Chang, “Stable Super Hydrophobic
Polybenzoxazine Surfaces over a Wide pH range”,
Langmiur, vol. 22, no. 20, pp. 8289-8292, 2006.
[16] K. Adachi, A. Achimuthu, Y. Chujo, “SynthesisofOrganic-
inorganic Polymer Hybrids Controlled by Diels-Alder
Reaction”, Macromolecules, vol. 37, no. 26, pp. 9793-
9797, 2004.
[17] C. Schramm, B. Rinderer, R. Tessadri, H. Duelli,
“Synthesis and Characterization of an Aliphatic
Monoimide-bridged Polysilsesquioxanes by the Sol-gel
Route”, Journal of Sol-Gel Science and Technology, vol.
53, no. 3, pp. 579-586, 2010.
[18] S. Jothibasu, A. Ashok Kumar, M. Alagar, “A Facile
Synthesis of Cyanate Ester Silica Hybrid
Nanocomposites by Insitu Sol-gel Method”, High
Performance Polymers, vol. 23, no. 1, pp. 11-21, 2011.
[19] S. G. Gunasekaran, S. Devaraju, M. Alagar, M.
Dharmendirakumar, "Studies on Synthesis and
Characterization of Multi-walled Carbon nanotube-
reinforced Polyimide Nanocomposites based on a
Siloxane-modified Anhydride”, High Performance
Polymers, vol. 26, no. 1, pp. 43-51.
[20] Q. W. Yuan, J. E. Mark, “Reinforcement of
poly(dimethylsiloxane) Networks by Blended and In-
situ Generated Silica Fillers having Various sizes, Size
Distributions, and Modified Surfaces’, Macromolecular
Chemistry and Physics, vol. 200, no. 1, pp. 206-220,
1999.
[21] K. Kamahori, S. Tada, K. Ito, S. Itsuno, “Optically active
polymer synthesis by Diels−Alder polymerization with
chirally modified lewis acid catalyst’, Macromolecules,
vol. 32, no. 3, pp. 541-547, 1999.
[22] R. Tamaki, Y. Chujo, “Synthesis of IPN Polymer Hybrids
of Polystyrene Gel and Silica gel by an In-situ Radical
Polymerization Method”,Journal ofMaterialsChemistry,
vol. 8, no. 5, pp. 1113-1115, 1998.
[23] A. Ashok Kumar, K. Adachi, Y. Chujo, “Synthesis and
Characterization of Stereoregular poly (methyl
methacrylate)-silica Hybrid Utilizing Stereo Complex
Formation”, Journal of Polymer Science Part A: Polymer
Chemistry, vol. 42, no. 3, pp. 785-794, 2004.
[24] K. H. Wu, T. C. Chang, Y. T. Wang, Y. S. Chiu, “Organic-
inorganic Hybrid Materials. I. Characterization and
Degradation of poly (imide-silica) Hybrids”, Journal of
Polymer Science Part A: Polymer Chemistry, vol. 37, no.
13, pp. 2275-2284, 1999.
[25] T. Agag, H. Tsuchiya, T. Takeichi, “Novel Organic-
inorganic Hybrids Prepared from Polybenzoxazine and
Titania using Sol-gel Processes”, Polymer,vol.45,no.23,
pp. 7903-7910, 2004.
[26] S. Devaraju, M. R. Vengatesan, A. Ashok Kumar, M.
Alagar, “Polybenzoxazine-silica (PBZ-SiO2) Hybrid
Nanocomposites through InsituSol-gel Method”,Journal
of Sol-Gel Science and Technology, vol. 60, no. 1, pp. 33-
40, 2011.
[27] A. Różycka, A. Iwan, K. A. Bogdanowicz, M. Filapek, N.
Górska, D. Pociecha, M. Marzec, “Synthesis and
Characterization of Two New TiO2-containing
Benzothiazole-based Imine Composites for Organic
Device Applications”, Beilstein Journal of
Nanotechnology, vol. 9, PP. 721–739, 2018.
[28] I. Kitsou, A. Tsetsekou, “A Water-Based Synthesis of
Hybrid Silica/Hyperbranched Poly (ethylene imine)
Nanopowder for Heavy Metal Sorption from Aqueous
Solutions”, Journal ofNanomaterials,vol.2019,pp.1–10,
2019.

[29] Q. Zhu, X. Li, Z. Fan, Y. Xu, H. Niu, C. Li, Y. Dang, Z.
Huang, Y. Wang, J. Guan “Biomimetic Polyurethane/
TiO2 Nanocomposite Scaffolds Capable of Promoting
Biomineralization and Mesenchymal Stem Cell
Proliferation”, Materials Science and Engineering C:
Materials for Biological Applications, vol. 85, pp. 79–87,
2018.
[30] A. Koltsakidou,Z. Terzopoulou, G. Z. Kyzas, D.N.Bikiaris,
D. A. Lambropoulou,“BiobasedPoly(ethylenefuranoate)
Polyester/TiO2 Supported Nanocomposites as Effective
Photocatalysts for Anti-inflammatory/AnalgesicDrugs”,
Molecules, vol. 24, pp. 564-585, 2019.
[31] S. M. M. A. Mutoki , B. A. H. A. Ghzawi, E. A. J. A. Mulla , S.
A. Amohsin “Enhancement of Mechanical Properties of
Polyamide Hexaglycol by Dispersion of TiO2 Nanofiller”,
Nano Biomedical Engineering, vol. 8, pp. 55-59, 2016.

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