In the present study we have synthesized interpenetrating polymer network (IPN) of fullerene and N-vinyl carbazole (NVK). The IPN was characterized using infrared (IR) spectroscopy, scanning electron microscope (SEM) and conductivity techniques which reveals desirable and interesting results. IR spectroscopy reveals presence of fullerene at 527 cm− 1 and 1600 cm− 1 and poly (N-vinyl carbazole) at 1101 cm− 1. A thin polymeric interconnected film is seen via SEM technique, revealing transparent and dual phase morphology. IPN was also analyzed for permeability and permittivity, which reveals maximum value of εr՛, εr՛՛ and tanδε at 2.77, 0.48 and 0.11 respectively and maximum values of µ՛r of µ՛՛r and tanµr ranging from 0.99 to 1.50, 0.01–0.103 and 0.01–0.08 respectively. Moderate values of permeability and permittivity reveals electromagnetic property of the IPN. Conductivity IPN was calculated and found to be was found to be 4.98 S/m which describes the semi conducting nature of the polymeric network.
Research Article
Morphological and conductivity studies of fullerene and N-vinyl carbazole based interpenetrating Polymer network
https://doi.org/10.21203/rs.3.rs-3433879/v1
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Interpenetrating polymer network
flexibility
fullerene
crystalline
conductivity
Interpenetrating polymer network (IPN); an overcome of researcher’s hard work have proved to be a new domain of the polymer chemistry [1, 2]. An IPN is a network of two or more polymer entangled such that they cannot be pulled apart from each other. It usually reveals physical and mechanical characteristics of the reacting network species such as stiffer hydrogel to greater swellability [3, 4] to tune enhanced modulus properties. IPN is an equivalence combination of pliancy, modulus and robustness. Millar in [1] put forward idea of polymeric interpenetration which provided a new branch of chemistry; the IPN chemistry. This is an applicable idea of researchers to form novel IPN system. Many scientists and co-workers provided their best for upgradation of IPN structure. Idea of IPN was initially put forwarded by Sperling et al. Zahao and coworkers reported the synthesis of elastomer from IPN [5], Buist and his team [6] fabricated IPN based on of polyurethane. Patel et al. reported hydrogel formation [7]. Vlad and team members synthesized an IPN with an immiscible component. Lastly, Meet et al. contributed towards the innovation of electromagnetic properties of fullerene based semi-IPN of PAN and polyaniline [11]. Another important nanomaterial towards the polymer research has been discovered. This is Fullerene molecule, which exists as a hollow sphere. Nowadays buckyballs (C60) [8, 9, 10] have been a subject of intense study. Che and co-workers studied Microwave absorption enhancement of iron encapsulated within carbon nanotubes [12] in the year 2004. Next year in 2005 Wang and his group studied intrinsic properties of conducting polymers such as electromagnetic Interference shielding effect [13]. C60 is a truncated icosahedron, resembling football of twenty hexagons and twelve pentagons. Nanotechnology research study reveals, a controlled reactivity of fullerene may be achieved by the addition of desired groups to their surfaces. This is good to see that Fullerenes are stable, but not totally unreactive.
In the literature enormous work has been carried on fullerene and vinyl monomers independently but fullerene based novel vinyl polymers and IPNs are still rare. Thus, the present study put light over the formation of these fullerene-based IPNs of NVK. The discussed polymeric network possesses good conductivity properties. The vinyl polymer provides good interpenetration, conductivity and flexibility and fullerene surface is an important factor for toughness, crystalline behavior and conductivity too for the IPN.
2.1 Synthesis of IPN
IPN was synthesized via in situ polymerization by systematic variations of concentration N-vinyl carbazole (NVK), benzoyl peroxide (BPO), fullerene and divinyl benzene (DVB) as a cross linker as shown in table-1. The systems were kept over water bath for 2.5 hours at 70oC under inert atmosphere of nitrogen. These polymer networks were precipitated and dried.
3.1 Infrared (IR) spectroscopic studies
The IR spectrum of formed IPN was recorded in IIT (Indian institute of technology), Kanpur, on Vertex 70 (Bruker) instrument using KBr pellet. The data acquisition is based on two channel delta sigma ADCs with 24-bit dynamic range, which are running in parallel and integrated into the detector pre-amplifier electronics. The structural IR analysis of polymer network was studied by IR spectroscopic technique.
3.2 Scanning electron microscopy (SEM); Morphological analysis
The polymer network was analyzed using SEM in IIT (Indian institute of technology), Kanpur. The fabricated sample was adhered on doubled sided carbon tape along with carbon coating was done for analysis under different magnification.
3.3 Permeability and permittivity analysis
Network Analyzer (VNA) E 8364 B is employed to measure the reflection/transmission coefficients of the composite specimen in the X band (8.2–12.4 GHz) frequency region. Based on the measured scattering coefficients the complex permittivity and permeability is calculated using Nicholson-Ross-Weir (NRW) algorithm.
3.4 Electrical conductivity
The conductivity measurements were taken in vacuum 10− 5torr by mounting the sample in specially designed sample holder. The sample holding has two parts. The upper part consists of two electrodes and an evaporation port. The samples were mounted between the jaws of two electrodes having a spring arrangement. At the end of two electrodes, two UHF connectors were used for electrical connection of the sample. A calibrated copper constant thermocouple was mounted very near to the sample to measure its temperature. An O-ring was provided between the two parts of sample holder for proper evacuation inside the chamber. The resistance was measured using Kietheley electrometer (Model 614).
The low percentage of extractable material shown in table 2, 3, 4 and 5 may be due to proper crosslinking of polymer making them insoluble. Thus, the present study put light over the formation of these fullerene-based IPNs of NVK.
4.1 IR Spectroscopy
The detailed vibrational analysis of the synthesized IPN was performed, which reveals shifting in band positions of the reacting molecular structures. IR study for pure fullerene shows peaks at 1430 cm-1, 527 cm-1 (for C-C vibration mode) and 1600 cm-1 (for –C=C- mode) respectively and for pure poly (n-vinyl carbazole) (PVK) at 900 cm-1. While Figure-1 shows IR spectra for the synthesized polymer network, which reveals the presence of fullerene at 500 cm-1(for caged vibrations), 1632 cm-1 (for C=C mode) and for PVK at 1101 cm-1. Thus, as evident from IR analysis that shifting in band positions has taken place, which is an indication of proper interpenetration among the reacting species. The FTIR investigations revealed multiple non-covalent interactions achieved by polymerization with physical anchoring on the polymeric network surfaces.
4.2 Electrical conductivity
Conductivity was found to be 4.17 S/m, revealing semiconductor behavior of IPN. The discussed polymeric network possess good conductivity properties. The IPN may be used in the photoreceptors. IPN is semi crystalline and in some form it may be a little brittle form. The properties of IPN are determined by molecular chains, orientation, size and degree of crystallization. Fullerene also played a great role in the improvement of strength of IPN. Fullerene is also responsible for the conductive nature and electromagnetic properties of the synthesized IPN
4.3 Permeability and permittivity analysis
Measurement of the complex permittivity and permeability of the IPN The polymer network is analyzed for its complex permittivity (ε* = ε՛-jε՛՛) and permeability (μ* = μ՛r− μ՛՛r) values in X band (8.2–12.4 GHz) frequency region. The complex permittivity and permeability is calculated using Nicholson-Ross-Weir (NRW) algorithm in the band X (8.2–12.4 GHz) frequency region. Fig. 2 depicts the graph of εr՛, εr՛՛ and fig.3 depicts graph of tanδε Vs frequency reaching to the maximum value of IPN at 2.47, 0.15 and 0.08 respectively. Similarly, Fig. 4 depicts the graph of μ՛r of μ՛՛r and fig. 5 depicts graph of tanμr Vs frequency of the IPN ranging from 0.92 to 1.20, 0.01–0.103 respectively.
4.4 SEM analysis
The structure of the fabricated fullerene based interpenetrating polymer network of PVK is detected by means of SEM technique which confides dual phase morphology (Figure-6). The network structure is variegated, which indicates sample heterogeneity of solution, used for the film preparation, which describes the happening of phase separation just after solvent evaporation. This is clearly prominent in the microscopic picture. This indicates that under top layer there is a presence of heterogeneous regions, depicting a clear dual phase morphology. Although such a combination of opposite properties is not easily possible, but we have tried to combine such different molecular domains on one platform, which reveals a proper packing and interpenetration of fullerene spheres with the monomeric species.
4.5 Evaluation of extractable polymeric material
The solute component of IPN was removed with the help of Soxhlet apparatus. The percentage extractable material was calculated (table 1) using the following equation.
Where, Wb = Weight of IPN before extraction and Wa = Weight of IPN after extraction
4.6 Swelling measurement and calculation
Swelling was calculated in DMF, DMSO, benzene and toluene till a constant mass was achieved (nearly 24 hrs.) (Table-1). The percentage swelling (table 1, 2, 3, 4 and 5 was calculated according to the following relationship.
Where, Ws = weight of swollen IPN and Wd = Weight of dry IPN.
4.6 Crosslink density calculation
IPN sample was taken and its crosslink density was determined (table 2, 3, 4 and .5) by using the swelling data of IPN in DMF by using Flory-Rehner equation.
Where, Mc= average molecular weight of network between crosslinks, p = density of the network, V1= molar volume of solvent, and Vp = volume fraction of polymer in swollen gel, X12 = polymer solvent interaction parameter, calculated by the expression.
Where δp and δs = solubility parameters of polymer and swelling solvent, respectively, and B = lattice constant, which is taken as 0.34. Thus the vinyl polymer provides good interpenetration, conductivity and flexibility and fullerene surface is an important factor for toughness, crystalline behavior and conductivity too for the IPN.
4.7 Effect of composition
Effect of composition of fullerene and NVK shows a trend, results in increased swelling and Mc. It shows that fullerene becomes cross-linked to NVK. As the concentration of fullerene increases the probability of interpenetration of NVK also increases. The conductivity of polymer network is directly proportional to the concentration increase of fullerene and NVK. The increase in con-centration of N-vinyl carbazole favors the flexibility of the IPN. Effect of cross-linker (DVB) Variation of DVB concentration has direct impact on percent-age of extractable material (Table 5). The variation and effect of BPO concentration over swelling and Mc of IPN is shown in Table 2. It is clear that both swelling and crosslinking increases with increasing molar concentration of DVB. The variation in percentage of extractable material is shown in.
The present work has given rise to the formation of flexible and crystalline interpenetrating polymer network of fullerene-based PVK along with the conductive properties too. We have tried to combine different molecular domains on one platform, which reveals a proper packing and interpenetration of fullerene spheres with the monomeric species. SEM pictures depicts a clear transparent and dual phase morphology of polymer network. Conductivity analysis of IPN was performed which was found to be 4.17 S/m which reveals the semiconductor behavior of IPN.
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- Sperling LH, Hu R (2003) Interpenetrating polymer networks. In: Utracki LA (ed) polymer blends Handbook. Springer, Dordecht, The Netherlands, pp 417–447
- Sperling H, Sperling H (1981) (Plenum, New York, NY, USA,
- Kudela V, Kroschwitz I, Hydrogels (1987) Encyclopedia of Polymer Science and Engineering. J. Ed., pp.783–807,
- Solid YH, F.J. and, Jang HQ (2010) A thermodynamic model of physical gels. J Mech Phy Solids 58:2083–2099. 10.1016/j.jmps.2010.09.002
- Zhao X (2012) A theory for large deformation and damage of interpenetrating polymer networks. J Mech Phys Solids 60:319–332. 10.1016/j.jmps.2011.10.005
- Buist JM, Gudgeon H (1970) Advances in polyurethane technology. Elsevier, London
- Patel B, Patel L, Shah H, Modasiya K (2011) Review on hydrogel nanoparticles in drug delivery. J Pharma 1:19–38
- Arbogast JW, Foote CS, Kao M Electron transfer to triplet fullerene. J Am Chem Soc, 114, 2277–2279. https://doi.org/10.1021/ja00032a063
- Baggett J (1991) Great balls of carbons. J New Scientists, (
- Clarson SJ, Semlyen JA (1993) Siloxane Polymers. Prentice Hall, New Jersey
- Kamal M, Jafri MJ, Singh DK, Shami TC, Himanshu BB (2018) Electromagnetic analysis of semi interpenetrating polymer network of fullerene based of poly acrylonitrile and polyaniline. J Adv Polym Technol Wiley 37:2663–2673. https://doi.org/10.1002/adv.21941
- Che R, Peng L, Duan X, Chen Q, Liang X (2004) Microwave absorption enhancement and complex permittivity and permeability of Fe Encapsulated within carbon nanotubes. J Adv Mater 16:401–405
- Wang Y, Jing X (2005) intrinsically conducting polymers for electromagnetic Interference shielding. J Polym Adv Technol 16:344–351
Table 1: Polymeric network revealing swelling behavior with various solvents
|
Sample used |
DMF (%)
|
Benzene (%) |
DMSO (%)
|
Toluene (%)
|
IPN obtained (Extracted) |
|
IPN 1 |
85 |
45 |
61 |
45 |
12.3 |
|
IPN 2 |
69 |
58 |
52 |
50 |
25 |
|
IPN 3 |
55 |
36 |
67 |
60 |
59 |
|
IPN 4 |
70 |
52 |
77 |
64 |
55.6 |
|
IPN 5 |
49 |
79 |
49 |
51 |
67.1 |
Table 2: BPO with varying concentration and effect on IPN
|
Sample Taken |
BPO Mole in100 ml |
Swelling (%) |
Mc |
|
|
IPN 6 |
1.0 x 10–2 |
84 |
155 |
|
|
IPN 7 |
2.0 x 10–2 |
75 |
192 |
Table 3: Variation of concentration of Fullerene and its effect on IPN
|
Sample Taken |
Fullerene (Mole in 100 ml) |
Yield |
Swelling (%) |
Mc |
|
IPN 8 |
2.1 x 10–3 |
13.9 |
71 |
152 |
|
IPN 9 |
4.2x 10–3 |
9.8 |
66 |
139 |
Table 4: Concentration variation effect of N-vinyl carbazole (NVK) monomer on IPN
|
Sample Taken |
NVK (Mole in 100 ml) |
Yield |
Swelling (%) |
Mc |
|
IPN 10 |
1.1 x 10–3 |
11.9 |
57 |
134 |
|
IPN 11 |
2.0 x 10–2 |
17.8 |
70 |
180 |
Table 5: Concentration variation of DVB and its effect over IPN
|
Sample Used |
DVB (Mole / 100 ml) |
Yield |
Swelling (%) |
Mc |
|
IPN 13 |
2.0 |
13.9 |
45 |
165 |
|
IPN 14 |
4.0 |
11 |
47 |
182 |
No competing interests reported.