Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 2 (2015) 4421 – 4428
International Conference on Nano Science & Engineering Applications (ICONSEA-2014)
Preparation, Characterisation and Conductivity studies of Supramolecular polymer/Ferrite Nanocomposites Rajendran T Va and Jaisankar Vb* a,b PG and Research Department of Chemistry Presidency College (Autonomous), Chennai-600 005, India. * Email :
[email protected]
Abstract Polymer-ferrite nanocomposites have attracted an extensive attention for their wide applications as electromagnetic interference shielding, rechargeable battery, electrodes, sensors and microwave absorption. In this investigation, we report on the preparation and characterisation of ferrite nanoparticles and their supramolecular polymer nanocomposites. The prepared nanocomposites were characterised by FTIR spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Thermal analysis (TG-DSC). Also, the effect of temperature and frequency variation on dielectric constant (ε’), dielectric dissipation factor (tan δ) and AC conductivity (σac) were investigated. The results revealed that the ferrite nanoparticles were uniformly distributed throughout the supramolecular polymer matrix. The interaction between ferrite nanoparticles and supramolecular polymer matrix may be due to the formation of the hydrogen bonding between the amine group of supramolecular polymer and oxygen of metal ferrites (MFe2O4). The percentage of magnetization of the nanocomposite decreases as the concentration of the ferrite increases.
12015
Elsevier # -,#(*+- %$+# 0%+ .$ * , © Ltd. All rights reserved. Selection and peer-review under responsibility of the conference committee members of the on Nano * International ' (' *, conference '+$,$ * '+!(*& ,$('+ % ,$(' ' ** .$ /-' ** +)('+$ $%$,0(!,# # $*+(!,# ', *' ,$(' %('! Science & Engineering Applications - 2014*,# %$ '+ #,,) * ,$. (&&('+(*"%$ '+ + 0' '
#$+$+ '() ' ++ *,$ % -'
$# &$++$(' -)* &(% -% *)(%0& * '( (&)(+$, $ % ,*$ ('+, ', , %! **$, + * Corresponding author: Jaisankar Vb
"
1.Introduction
2214-7853 © 2015 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the conference committee members of the International conference on Nano Science & Engineering Applications - 2014 doi:10.1016/j.matpr.2015.10.043
4422
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
Nanocomposite polymer electrolyte (NCPE) materials are having special attention, due their potential applications in advanced ionic devices such as high performance batteries, fuel cell, supercapacitor, sensors and smart window etc[1-4]. Polymers are good choice for this passivation and stabilization[5,6], by incorporation of inorganic particles within the polymer matrices, homogeneous organic-inorganic hybrid materials with fascinating properties can be obtained[7,8]. Ureido-pyrimidinone based supramolecular polymer is one of the most important polymer host which has been extremely investigated. The above polymer contains nitrogen atom which play an essential role in the interaction of substrate of polymer and ferrite nanoparticles. The other polymer host poly (vinyl alcohol) [PVA], poly (vinyl chloride) [PVC], poly (methyl methacrylate) [PMMA] and poly (aniline) [PA] have been also studied for potential material[9-14]. Nanocrystalline barium ferrites are technologically important and have been used in many applications such as electrical, optical and magnetic devices[15]. * Corresponding author. Tel.: 044-28544894; fax: 044-28510732. E-mail address:
[email protected]
When supramolcular polymer is doped with ferrites, it may occupy at various sites[16,17]. The addition of ferrite creates additional hopping sites for the charge carriers and hence increases in its concentration and increase the conductivity, because the chemical structure of magnetic ferrite (MFe2O4) contains high donating character of numerous either oxygen, strong tendency for crystallisation correlated to high organization and rigidity of polymer units[18]. In view of the above, an important approach has been made to use nanosized Barium ferrite nanoparticles as well as supramolecular polymer/ferrite nanocomposites has been synthesized and characterized by XRD measurement, thermal and electrical instruments. The frequency and temperature dependent behavior of dielectric and AC conductivity have been investigated. 2. Experimental methods 2.1 Materials Barium chloride (BaCl2), iron chloride (FeCl3.6H2O) and NaOH were purchased from Merck; Poly (ethylene glycol) (PEG) was purchased from SD Fine chemicals; 2-amino-4-hydroxy-6-methylpyridine, 2,4-toluene diisocyanato toluene and dibutyl tin dilaurate (DBTDL) were purchased from Aldrich. PEG was dried at 60oC for atleast 24 hrs and 2-amino-4-hydroxy-6-methylpyrimidine was dried at 70oC for 6 hrs before synthesis. Chloroform, DMF and Hexane were dried using common drying agents, distilled and stored prior to use. 2.2 Procedure 2.2.1 Synthesis of UPy based supramolecular polymer nanocomposites Synthesis of UPy synthon was reported in our previous investigation[19]. The ferrite nanoparticles were prepared by co-precipitation method[20]. The nanocomposite was prepared by mixing of synthesised supramolecular polymer in a dispersion of BaFe2O4 nanoparticles in 30 ml of water at room temperature with constant stirring. The solvent was evaporated by dried under reduced pressure. The resulting supramolecular polymer –magnetic ferrite nanocomposite was dried at room temperature for 6 h. 2.3 Characterisation The synthesized supramolecular polymer ferrite nanocomposites was characterised by X-ray diffraction pattern, FT-IR spectra, DSC analysis, SEM morphology and Electronic Impedance Spectroscopy analysis. 3. Results and Discussion
4423
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
3.1 FT-IR analysis Fig 1(a)-(c) shows the various absorption peaks of ferrite nanoparticles, supramolecular polymer and supramolecular polymer nanocomposites respectively. The peak at 3332 cm-1 indicates the NH stretching of secondary amine. The peak at 1348 cm-1 is assigned to C-N stretching of the benzene ring. The peaks at 3620 and 2949 cm-1 indicates the stretching and bending vibration of O-H and C-H bonds respectively. Two absorption bands at 599 and 561 cm-1 corresponding to the Fe-O stretching modes of tetrahedral and octahedral sites as expected from normal spinal structure.
300
% T ransm ittance
250 200
150 100
50 0 4000
3500
3000
2500
2000
1500
1000
500
W aven u m b er(cm -1) Fig. 1(a). FT-IR spectra of barium ferrite nanoparticle; (b) supramolecular polymer and (c) supramolecular polymer /ferrite nanocomposites
3.2 XRD-analysis
1100
1700
a
900
Intensity /a.u
1600
Intensity (a.u.)
b
1000
1500 1400 1300
800 700 600 500 400 300
1200
200
1100 30
40
50
60
2 Theta
70
80
90
20
30
40
50
60
2 Theta
Fig. 2. (a) and (b) XRD pattern of ferrite nanoparticles and polymer ferrite nanocomposites
70
80
4424
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
The above peaks indicates the spinal structure of ferrite nanoparticles and the crystalline nature of polymer ferrite nanocomposites. XRD line broadening was used to estimate the average grain size of the nanocomposites according to Scherrer’s formula: D=0.9λ/β cosθ The results showed an average crystalline size of supramolecular polymer nanocomposites was calculated as 59.8 nm. The X-ray diffractogram of the composite containing barium ferrite nanoparticles showed a remarkable reduction in the intensity of XRD peaks.
3.3 SEM analysis The scanning electron microscopy (SEM) image of the ferrite nanoparticles, supramolecular polymer and supramolecular polymer nanocomposites shown in fig 3(a)-(c) respectively. It is observed that the grain size is small and not fully growth in Fig 3(a). There is observable difference between Figs 3(b) and 3(c) in grain morphology. It is clearly observed from the image that they are agglomerated and porous in nature. Thus, the above discussion confirms the formation of supramolecular polymer ferrite nanocomposites.
Fig. 3.(a)-(c) SEM images of ferrite, supramolecular polymer and supramolecular polymer/ferrite nanocomposites respectively.
3.4 DSC analysis Thermal analysis was performed for the synthesis of the supramolecular polymer nanocomposites. The weight loss from room temperature to 100°C is attributed to desorption of water molecules present in the sample, which appear on the DSC curve as an endothermic peak at 140°C. Thereafter, a continuous two step weight loss is noticed in the temperature ranging from 220OC to 400°C, showing a maximum weight loss, which also appeared an endothermic peak, at 340°C on the DSC trace corresponds to the evaporation of water and absorbed –OH of surface in the samples. At the onset temperature of 574oC, a prominent exothermic peak is observed without any mass loss. This peak may be attributed to the grain growth of polymer ferrite nanocomposites.
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
4425
Fig. 4. TG/DSC curve of supramolecular polymer/ferrite nanocomposites
3.5 Electrical analysis The ac conductivity (σac), dielectric constant (ε ) and dielectric loss (tanδ) parameters have been calculated from the electronic impedance values. 3.5.1 Conductivity studies The resistance ρac of the sample was calculated using the equation ρac =Rp ×A/t where Rp is the resistance of the nanocomposite was determined from the intercept of the impedance spectrum on the Z’ real axis, t is the thickness of the polymer nanocomposite and A is the surface area of it. The σac conductivity was determined using the formula σac=1/ρac The calculated ionic conductivity of nanocomposites values are 3.56×10-4 S/cm and 9.05×10-4 S/cm at 30oC and 100oC respectively.
4426
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
Fig. 5. Z’ and Z’’ plots of polymer nanocomposites at 30oC and 100oC
3.5.2 Dielectric constant and loss studies The variation of dielectric constant and loss values with frequency for supramolecular polymer nanocomposites are shown in figure 6. It is found that in polymer nanocompoaites, as frequency increases dielectric constant decreases and it remains constant for further increasing in frequency.
3500 12000 3000
Dieletric constant
Dielectric constant
10000 8000 6000 4000 2000
2000 1500 1000 500
0 -2000 2.0
2500
2.5
3.0
3.5
4.0
log (f)
4.5
5.0
5.5
6.0
0 2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
log (f)
Fig. 6. Variation of dielectric constant of polymer nanocomposite at different temperatures.
This behavior is may be due to the fact that at low frequencies the ionic charges have sufficient time to align with the field before it changes its direction and consequently, the dielectric constant is high. While the decreases of dielectric constant value with increasing of applied frequency toward higher values is attributed the insufficient time for ionic charges to align the field changes direction.
4427
400
400
350
350
300
300
Dielectric loss
Dielectric loss
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
250 200 150 100
250 200 150 100
50
50
0
0
1
2
3
log (f)
4
5
6
1
2
3
4
5
6
log (f)
Fig. 7. Variation of loss tangent of polymer nano composite at different temperatures.
The dielectric loss decreased with increasing the frequency due to high periodic of the field at the interface; the contribution of ionic charges towards the dielectric decreases with increasing frequency. 4. Conclusion The synthesized ureido-pyrimidinone based supramolecular polymer/ferrite nanocomposites are characterised by various techniques such as, the identification of ferrite particles in polymer matrix and its crystalline size is investigated by using XRD analysis. FT-IR spectral analysis, revealed that the absorption bonds present in polymer nanocomposites. The morphology of ferrite nanoparticles and polymer nanocomposites are analysed by using Scanning electron microscopy (SEM). The crystallinity of the polymer material with ferrite nanoparticles is revealed by Differential scanning calorimetry (TG/DSC) analysis. The effect of temperature and frequency variation on dielectric constant, dielectric loss and ac conductivity are determined by LCR meter and the calculated ionic conductivity values are 3.56×10-4 S/cm and 9.05×10-4 S/cm at 30oC and 100oC respectively. The enhanced electrical conductivity of these supramolecular polymer nanocomposites at room temperature is used in the application of solid state electronic devices. References [1]. J.R.Owen, A.L.Chandra and S.Laskar. ed.Academic press 1989; 111: 13. [2]. R.C.Agarwal, G.P.Pandey. J.Phys. 2008; 41: 223001. [3]. J.H.Koo. McGraw hill professional 2006; 79: 34. [4]. K.Pandey, M.M.Dwivedi, M.Singh and M. Tripathi. Ionics 2008; 14: 515. [5]. L.Li, H.Qiu, Y.Wang, J.Jiang, F.Xu. J.Rare Earth 2008; 26: 558. [6]. Y.A. Badr, K.m.A.El.Kadar and R.M.Khafagy. J.Appl.Polym.Sci 2004; 92: 1984. [7]. M.A.Ahmad, n.Okasha, S.F.Mansour and S.I.El-dek. J.Alloys Comp 2010; 496: 345. [8]. S.Varshney, k.Singh, A.Ohlan, V.K.Jain, V.P.Dutta and S.K.Dhawan. J.Alloys Comp 2012; 538: 107. [9]. A.Awadhia, S.K.Patel, S.L.Agarwal. Progress in crystal growth 2006; 52: 61. [10]. M.Alamgir and K.M. Abraham. J.Electrochem. Soc 1993; 140: 96. [11]. S.Rajendran and T.Uma. Mater. Lett 2000; 44: 208. [12]. H.Tsuchida and T.Toko. Jpn. J. Appl. Phys 1983; 22: 1543. [13]. O.Bohnke and B.Vuillemin, Mater. Sci. Eng. B 1992; 12: 243. [14]. G.B.Appetechi, F.Croce and B. Scrosati. Electrochim. Acta 1995; 40: 991.
4428
T.V. Rajendran and V. Jaisankar / Materials Today: Proceedings 2 (2015) 4421 – 4428
[15]. M. Sugimoto. J.Am. Ceram. Soc 1999; 82: 269. [16]. K.Pandey, M.M.Dwidevi, M.Singh and S.L.Agarwal. Journal of Polymer Research 2010; 17: 217. [17]. R.Iyar, R.Desai and R.V.Upadhyay. Bull.Mater. Sci 2009; 32: 141. [18]. A.Tanwar, K.K.Guota, J.P.Singh and Y.K.Vijai. Bull. Mater. Sci 2006; 29: 397. [19]. T.V Rajendran and V.Jaisankar, J. of Polymer composites 2014; 3: 1. [20]. D. Makovec, A. Kodre, I. Arcon, J. Nanopart Res 2011; 13: 1781.
