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ORIGINAL ARTICLE
Year : 2019  |  Volume : 42  |  Issue : 4  |  Page : 150-158  

Comparison of radiation shielding properties of some coordination polymers


1 Department of Physics, Government First Grade College, Kolar, Karnataka; Research and Development Centre, Bharathiar University, Coimbatore, Tamil Nadu, India
2 Department of Physics, Government College for Women, Kolar, Karnataka, India
3 Department of Physics, Government Arts College, Udumalpet, Tamil Nadu, India

Date of Submission30-Jul-2019
Date of Decision02-Sep-2019
Date of Acceptance25-Oct-2019
Date of Web Publication27-Jan-2020

Correspondence Address:
Dr. H C Manjunatha
Department of Physics, Government College for Women, Kolar - 563 101, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/rpe.RPE_27_19

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  Abstract 


We have studied the X-ray and gamma radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, mean free path, half-value layer, tenth-value layer, effective atomic numbers, electron density, exposure buildup factors, specific gamma-ray constant, and mechanical properties in some coordination polymers such as lead monoclinic-(I), lead monoclinic-(II), lead tetragonal, azelato barium (II) polymer, 1-D coordination barium polymer (I), helical lead (II) coordination polymer, calcium bromide polymer (I), calcium bromide polymer (II), 1D-cadmium coordination polymer, and 2D-cadmium coordination polymer. We have also studied the neutron shielding properties in the same coordination polymers. From the detailed study, it is clear that helical lead (II) coordination polymer is a good absorber for X-ray and gamma radiation. The attenuation parameters for neutron are higher for 1D coordination barium polymer (I) compared to that of other studied polymers. This work is useful in the field of radiation shielding.

Keywords: Gamma, polymer, X-ray


How to cite this article:
Nagaraja N, Manjunatha H C, Seenappa L, Sridhar K N, Ramalingam H B. Comparison of radiation shielding properties of some coordination polymers. Radiat Prot Environ 2019;42:150-8

How to cite this URL:
Nagaraja N, Manjunatha H C, Seenappa L, Sridhar K N, Ramalingam H B. Comparison of radiation shielding properties of some coordination polymers. Radiat Prot Environ [serial online] 2019 [cited 2020 Feb 20];42:150-8. Available from: http://www.rpe.org.in/text.asp?2019/42/4/150/276919




  Introduction Top


Radiation shielding to the X-ray, gamma, and neutrons are important topics in radiation physics. The mass attenuation coefficient (MAC) and its deliverables are basic parameters in the selection of shielding materials for X-ray and gamma radiation. Kaçal et al.[1] determined the gamma-ray attenuation characteristics of eight different polymers using transmission geometry utilizing the high-resolution High Purity Germanium (HPGe) detector and different radioactive sources in the energy range 81–1333 keV. Li and Gu,[2] studied the radiation shielding property of structural polymer composite containing radiation protective basalt fiber reinforced epoxy matrix composite containing erbium oxide particles. Mahmoud[3] studied the γ-ray shielding characteristics of composite materials based on recycled high-density polyethylene. Badawy and Latif[4] studied the synthesis and characterizations of magnetite nanocomposite films for radiation shielding. Sayyed[5] studied the gamma and neutron shielding properties (NSP) of eight different types of smart polymers. Mann et al.[6] studied the shielding behaviors of some polymer and plastic materials for gamma rays in the experimental energy range 10–1400 keV.

Seenappa et al.[7] studied the gamma, X-ray, and NSP of polymer concretes. Gurler and Tarim[8] determined the radiation shielding properties of some polymer and plastic materials against gamma rays. Srinivasan and Samuel[9] studied the evaluation of radiation shielding properties of the polyvinyl alcohol/iron oxide polymer composite. Manjunatha and Seenappa[10] studied the X-ray and gamma radiation shielding properties of aluminum polymer concrete, silicon polymer concrete, potassium polymer concrete, sodium polymer concrete, boron polymer concrete, and lead polymer concrete. Pavlenko et al.[11] studied the radiation shielding properties of polymide composites based on surface and physicalmechanical properties of polyimide/Bi2O3 composites.

Prokhorenko et al.[12] studied the radiation-protective properties of composition material polystyrene, which was reinforced by aluminum. AL-Dhuhaibat[13] studied the shielding properties against gamma rays emitted from the radioactive source of (Cs-137) for the shields of epoxy polymer supported by cement, aluminum, and lead using a Geiger–Muller counter tube detector. Shin et al.[14] studied the polyethylene/boron-containing high-density polyethylene composites with modified boron nitride fillers for radiation shielding. A coordination polymer is an organic or inorganic structure containing metal cation centers linked by organic ligands. Coordination polymers are constructed from metal nodes and organic linkers as organic-inorganic hybrid solids; it finds many applications due to their intriguing topologies and structural properties. Lead monoclinic-(I), lead monoclinic-(II), helical lead (II), and lead tetragonal polymers are a combination of lead and organic materials. Azelato barium (II) and 1D coordination barium polymer (I) are a combination of barium and organic materials. Similarly, calcium bromide polymer (I), calcium bromide polymer (II), cadmium coordination polymer (I), and cadmium coordination (II) polymer are a combination of heavy metals and organic materials. Lead, barium, and cadmium are observed to be good absorbers of X-ray and gamma. The coordination polymers with heavy cation metal centers are having high density and expected to be good absorbers of X-ray, gamma, and neutron radiations. Hence, in the present work, we have studied the shielding properties in these coordination polymers. We have studied the X-ray and gamma radiation shielding parameters such as MAC, linear attenuation coefficient, mean free path, half-value layer (HVL), tenth-value layer (TVL), effective atomic numbers, electron density, exposure buildup factors (EBFs), specific gamma-ray constant and mechanical properties in some coordination polymers such as lead monoclinic-(I) (C22H14 Cl2N4O9 Pb), lead monoclinic-(II) (C22H10 Cl2N4O9 Pb), lead tetragonal (C22H14 Cl2N4O8 Pb), Azelato Barium (II) polymer (C9H16O5 Ba), 1D coordination barium polymer (I) (C22H30N4O15 Cl2 BaCo), helical lead (II) coordination polymer (C9H4O6 Pb), calcium bromide polymer (I) (C10H22N2O6 Br2 Ca), calcium bromide polymer II (Br2C10H18N2O4 Ca), 1D cadmium coordination polymer (C30H34O6P2N2 Cd), and 2D cadmium coordination polymer (C37H15O5P2N4 Cd). We have also studied the NSP in the same coordination polymers.


  Theory Top


Gamma /X-ray interaction parameters

In the present work, the MACs and photon interaction cross sections in the energy range from 1 keV to 100 GeV are generated using WinXCom.[15] The total linear attenuation coefficient (μ) can be evaluated by multiplying the density of compounds to MACs. The total linear attenuation coefficient (μ) is used in the calculation of HVL. HVL is the thickness of interacting medium that reduces the radiation level by a factor of 2 that is to half the initial level and is calculated by the ratio of 0.693 to the linear attenuation coefficient. The total linear attenuation coefficient (μ) is also used in the calculation of TVL. It is the thickness of interacting medium for attenuating a radiation beam to 10% of its radiation level and is computed by the ratio of 2.303 to the linear attenuation coefficient. The average distance between two successive interactions is called the relaxation length (λ). It is also called the photon mean free path which is determined by the reciprocal of the linear attenuation coefficient. The gamma interaction parameters such as linear attenuation coefficients μ/cm, HVL (in cm), TVL (in cm), and mean free path λ are evaluated.

The equivalent atomic number of a composite material that will produce the same effect as that of a single element when it interacts with photons is referred as equivalent atomic number. The effective atomic number is evaluated by taking the ratio between atomic cross-section and electronic cross-section. The procedure of evaluation of atomic and electronic cross-section is explained in the previous work.[16],[17],[18],[19]

The number of electrons per unit mass is referred as electron density. The effective electron density is derived from the evaluated effective atomic number. The procedure of the evaluation of effective electron density is explained in the previous work.[16],[17],[18],[19]

Secondary radiation during the interaction of gamma/X-ray

During the interaction of gamma/X-ray with the medium, it degrades their energy and produces secondary radiations through different interaction processes. The quantity of secondary radiations produced in the medium and energy deposited/absorbed in the medium is studied by calculating buildup factors. In the present work, we have estimated energy exposure build up factors (Ben) using GP fitting method.[20],[21],[22] We have evaluated the G-P fitting parameters (b,c,a,Xk, and d) for different coordination polymers using following expression which is based on Lagrange's interpolation technique.[20],[21],[22] GP fitting parameters (b,c,a,Xk, and d) for element adjacent to Zeff are provided by the standard data available in literature.[23] The computed G-P fitting parameters (b,c,a,Xk, and d) were then used to compute the EABF in the energy range 0.015MeV-15MeV up to a penetration depth of 40 mean free path with the help of G-P fitting formula, as given by the equations.[20],[21],[22]







Where X is the source-detector distance for the medium in mean free paths (mfp) and b is the value of build-up factor at 1 mfp. K (E, X) is the dose multiplication factor and b,c,a,Xk and d are computed G-P fitting parameters that depend on attenuating medium and source energy.

Neutron shielding parameters

The NSPs such as coherent neutron scattering length, incoherent neutron scattering lengths, coherent neutron scattering cross-section, incoherent neutron scattering cross-sections, total neutron scattering cross-section, and neutron absorption cross-sections in coordination polymers are calculated using the following mixture rule



Here, (NSP)i is the neutron shielding parameter of ith element[24] in the coordination polymer and fi is the fractional abundance (a mass fraction of the ith element in the molecule).

Mechanical properties

The rule of mixture is used to calculate the properties of mixtures by taking into account the fraction and a parameter of each component. It is given by



Where V and E are the volume fraction and elastic modulus of each component; however, sometimes, this rule is not valid since some parameters such as the particle shape and interaction are not taken into account. Alternatively, one could use the inverse additive model which is written as follows:



Universal accepted model[25],[26] to calculate elastic modulus is given by



Elastic moduli such as Young's modulus, bulk modulus, and rigidity modulus are calculated using the above equations. Other mechanical properties, such as yield strength and tensile strength are also very important. The yield strength is the maximum stress that can be applied along its axis before it begins to change shape. Yield strength is empirically determined using the following equation.[20]



Tensile strength is the ability of a material to withstand a pulling (tensile) force. Tensile strength is determined using the following equation.



Pitting resistance equivalent number (PREN) is a predictive resistance corrosion based on its chemical composition. The higher PREN-value, the more resistant to corrosion and it is calculated using the relation.

PREN = % Cr + 3.3%Mo + 30% N (10)


  Results and Discussion Top


The calculated MAC values for different coordination polymers in the energy range 1 keV–100 GeV are shown in [Figure 1]. MAC values for coordination polymers are large in the low energy region and decreases progressively. In the low energy region, MAC is observed to be high due to the dominant photoelectric interaction. In the high energy region, Compton scattering becomes dominant, which depends linearly with atomic number. Hence, MAC value becomes minimum value.
Figure 1: The variation of mass attenuation coefficient (μ/ρ) in cm2/g versus energy in MeV

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We have calculated the HVL, TVL, and mean free path for different coordination polymers. The comparison of HVL, TVL, and mean free path for different coordination polymers are as shown in [Figure 2], [Figure 3], [Figure 4]. From this comparison, it is clear that the HVL, TVL, and mean free path are small for helical lead (II) coordination polymer than the other coordination polymers. It means gamma/X-ray penetrates less in helical lead (II) coordination polymer than the other coordination polymers. The variation of effective atomic number and effective electron density with energy for different coordination polymers are shown in [Figure 5] and [Figure 6]. These parameters for coordination polymers are large in the low energy region (due to the photoelectric effect) and decrease progressively, thereafter increases and become constant for high energy (due to pair production).
Figure 2: Comparison of half-value layer with different polymers at different energies lead monoclinic-(i) (A), lead monoclinic-(II) (B), lead tetragonal (C), azelato barium (II) polymer (D), 1D coordination barium polymer (i) (E), helical lead (II) coordination polymer (F), calcium bromide polymer (i) (G), calcium bromide polymer (II) (H), 1D cadmium coordination polymer (I) and 2D cadmium coordination polymer (J)

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Figure 3: Comparison of mean free path (λ) with different polymers at various energies lead monoclinic-(i) (A), lead monoclinic-(II) (B), lead tetragonal (C), azelato barium (II) polymer (D), 1-D coordination barium Polymer (i) (E), helical lead (II) coordination polymer (F), calcium bromide polymer (i) (G), calcium bromide polymer (II) (H), 1D cadmium coordination polymer (I) and 2D cadmium coordination polymer (J)

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Figure 4: Comparison of tenth-value layer with polymers at different energies Lead Monoclinic-(i) (a), lead monoclinic-(II) (b), lead tetragonal (c), azelato barium (II) polymer (d), 1D coordination barium polymer-(i) (e), helical lead (II) coordination polymer (f), calcium bromide Polymer (i) (g), calcium bromide polymer (II) (h), 1D cadmium coordination polymer (i) and 2D cadmium coordination polymer (j)

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Figure 5: The variation of effective atomic number (Zeff) with energy in MeV

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Figure 6: The variation of effective electron density (Ne) with energy in MeV

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The variation of energy with EBF for coordination polymers are as shown in [Figure 7]. It is observed that EBF increases up to the Epe and then decreases. Here, Epe is the energy value at which the photoelectric interaction coefficients match with Compton interaction coefficients for a given value of effective atomic number (Zeff). The variation of EBFs with mean free path at various energies (0.1, 0.5, 1.5, 5, and 15MeV) for different coordination polymers is as shown in [Figure 8]. From [Figure 8], it is clear that EBF values increases with increase in the target distance. This is due to the reason that with increase in the target distance, scattering events in the medium increases.
Figure 7: The variation of energy absorption buildup factor (Ben) at different mean free path with energy in MeV for different polymers

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Figure 8: The variation of energy absorption buildup factor (Ben) with mean free path at different energies

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The comparison of evaluated coherent neutron scattering length, incoherent neutron scattering lengths, coherent neutron scattering cross-section, incoherent neutron scattering cross-sections, total neutron scattering cross-section and neutron absorption cross-sections for different coordination polymers are as shown in [Figure 9]. From [Figure 9], it is clear that coherent neutron scattering length and incoherent neutron scattering lengths are minimum for 1-D coordination barium polymer (I). Coherent and total neutron scattering cross-sections are minimum for 1D coordination barium polymer (I). The neutron absorption cross-section is high for 1D coordination barium polymer (I).
Figure 9: Comparison of neutron shielding parameters (coherent scattering length [bcoh], incoherent scattering length [binc], coherent scattering cross section [σcoh], incoherent scattering cross section [σinc], total scattering cross section [σtot] and absorption scattering cross section [σabs]) with different polymers lead monoclinic-(i) (a), lead monoclinic-(II) (b), lead tetragonal (c), azelato barium (II) polymer (d), 1-D co-ordination barium polymer (i) (e), helical lead (II) co-ordination polymer (f), calcium bromide polymer (i) (g), calcium bromide polymer (II) (h), 1D cadmium coordination polymer (i) and 2D cadmium co-ordination polymer (j)

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We have calculated the mechanical properties such as young's modulus, bulk modulus, yield strength, tensile strength, and PREN for the studied coordination polymers. The comparison of mechanical properties among the studied coordination polymers is, as shown in [Figure 10]. From this comparison, it is found that all the studied mechanical properties are higher for helical lead (II) coordination polymer than that of the other coordination polymers. This means helical lead (II) coordination polymer is mechanically more stable than the other studied coordination polymers. To validate the present work, we have calculated the MACs for some polymers using the present work and compared with that of the experimental values available in literature.[27],[28] This comparison is shown in [Table 1].
Figure 10: Variation of mechanical properties (young's modulus [q], bulk modulus [k], yield strength, tensile strength, and pitting resistance equivalent number) with different polymers lead monoclinic (I) (A), lead monoclinic (II) (B), lead tetragonal (C), azelato barium (II) polymer (D), 1-D coordination barium polymer (I) (E), helical lead (II) coordination polymer (F), calcium bromide polymer (I) (G), calcium bromide polymer (II) (H), 1D cadmium coordination polymer (I) and 2D cadmium coordination polymer (J)

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Table 1: Comparison of experimental values for known polymers with that of the present work

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  Conclusions Top


Based on the present computed values of material strengths and shielding parameters for X-rays, gamma rays, and neutrons in some coordination polymers, it can be concluded that helical lead (II) is a good shield material for X-rays and gamma rays, while 1D coordination barium polymer is good for neutrons.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Kaçal MR, Akman F, Sayyed MI, Akman F. Evaluation of gamma-ray and neutron attenuation properties of some polymers. Nucl Eng Technol 2019;51:818-24.  Back to cited text no. 1
    
2.
Li R, Gu Y. Radiation shielding property of structural polymer composite: Continuous basalt fiber reinforced epoxy matrix composite containing erbium oxide. Compos Sci Technol 2017;143:67-74.  Back to cited text no. 2
    
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Mahmoud, Mohamed E, El-Khatib, Ahmed M, Badawi, Mohamed S. Recycled high-density polyethylene plastics added with lead oxide nanoparticles as sustainable radiation shielding materials. J Clean Prod 2018;176:276-87.  Back to cited text no. 3
    
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Badawy SM, Abd El-Latif AA. Synthesis and characterizations of magnetite nanocomposite films for radiation shielding. Polym Compos 2017;38:974-80. [doi: 10.1002/pc. 23660].  Back to cited text no. 4
    
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Sayyed MI. Investigation of shielding parameters for smart polymers. Chin J Phys 2016;54:408-15.  Back to cited text no. 5
    
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Mann KS, Rani A, Heer MS. Shielding behaviors of some polymer and plastic materials for gamma-rays. Radiat Phys Chem 2015;106:247-54.  Back to cited text no. 6
    
7.
Seenappa L, Manjunatha HC, Sridhar KN, Hanumantharayappa C. Gamma, X-ray and neutron shielding properties of polymer concretes. Indian J Pure Appl Phys 2018;56:383-91.  Back to cited text no. 7
    
8.
Gurler O, Tarim A. Determination of radiation shielding properties of some polymer and plastic materials against Gamma-rays. Acta Phys Polonica A 2016;130:236-8.  Back to cited text no. 8
    
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Srinivasan K, Samuel EJ. Evaluation of radiation shielding properties of the polyvinyl alcohol/Iron oxide polymer composite. J Med Phys 2017;42:273-8.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Manjunatha HC, Seenappa L. Gamma, X-ray and neutron radiation shielding properties of Al, Si, K, Na, B and Pb polymer concretes. Int J Nucl Energy Sci Technol 2018;12:294-311.  Back to cited text no. 10
    
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Pavlenko VI, Cherkashina NI, Yastrebinsky RN. Synthesis and radiation shielding properties of polyimide/Bi2O3 composites. Condens Matter Phys 2019;5:e01703.  Back to cited text no. 11
    
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Prokhorenko EM, Klepikov VF, Lytvynenko VV, Zakharchenko AA, Khazhmuradov MA, Morozov AI, et al. Radiation-shielding properties of polymer composite materials. East Eur J Phys 2015;2:41-5.  Back to cited text no. 12
    
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AL-Dhuhaibat RJ. Study of the shielding properties for some composite materials manufactured from polymer epoxy supported by cement, aluminum, iron and lead against gamma rays of the cobalt radioactive source (Co-60). Int. Jour. Appl. Inno. Eng. & Man 2015;4: 90-8.  Back to cited text no. 13
    
14.
Ji Wook Shin, Jang Woo Lee, Seunggun Yu, Bum Ki Baek, Jun Pyo Hong, Yongsok Seo, et al. Polyethylene/boroncontaining composites for radiation shielding, Thermochimica Acta 2014;585:5-9.  Back to cited text no. 14
    
15.
Gerward L, Guilbert XN, Jensen KB, Levring H. WinXCom—A Program for Calculating X-Ray Attenuation Coefficients. Radiat Phys Chem 2004;71:653-4.  Back to cited text no. 15
    
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Manjunatha HC, Rudraswamy B. Study of effective atomic number and electron density for tissues from human organs in the energy range of 1 keV-100 GeV. Health Phys 2013;104:158-62.  Back to cited text no. 16
    
17.
Suresh KC, Manjunatha HC, Rudraswamy B. Study of Zeff for DNA, RNA and Retina by numerical methods. Radiat Prot Dosimetry 2008;128:294-8.  Back to cited text no. 17
    
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Manjunatha HC, Rudraswamy B. Computation of CT-number and Zeff in teeth. Health Phys 2011;100:S92-9.  Back to cited text no. 18
    
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Manjunatha HC. A study of photon interaction parameters in lung tissue substitutes. J Med Phys 2014;l39:112.  Back to cited text no. 19
    
20.
Manjunatha HC, Rudraswamy B. Energy absorption and exposure build-up factors in hydroxyapatite. Radiat Meas 2012;47:364-70.  Back to cited text no. 20
    
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Manjunatha HC, Rudraswamy B. Computation of exposure build-up factors in teeth. Rad Phys Chem 2011;80:14-21.  Back to cited text no. 21
    
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Manjunatha HC, Rudraswamy B. Energy absorption build-up factors in teeth. J Radioanal Nucl Chem 2012;294:251-60.  Back to cited text no. 22
    
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American National Standard. Gamma-Ray Attenuation Coefficients and Buildup Factor for Engineering Materials ANSI/ANS 6.4.3. American National Standard; 1991.  Back to cited text no. 23
    
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Sears VF. Neutron scattering lengths and cross sections. Neutron News 2006;3:26.  Back to cited text no. 24
    
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Shenoy AV, Saini DR, Nadkarni VM. Melt rheology of polymer blends from melt flow index. Int J Polym Mater Polym Biomater 1984;10:213.  Back to cited text no. 25
    
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Saini DR, Shenoy AV, Nadkarni VM. Dynamic mechanical properties of highly loaded ferrite-filled thermoplastic elastomers. J Appl Polym Sci 1984;29:4123.  Back to cited text no. 26
    
27.
Singh VP, Shirmardi SP, Medhat ME, Badiger NM. Determination of mass attenuation coefficient for some polymers using Monte Carlo simulation. Vacuum 2015;119:284-8.  Back to cited text no. 27
    
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Manjunata HC. A study of gamma attenuation parameters in poly methylmethacrylate and Kapton. Radiat Phys Chem 2017;137:254-9.  Back to cited text no. 28
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]
 
 
    Tables

  [Table 1]



 

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