Effect of C60 filling on structure and properties of composite films based on polystyrene

Olga V. Alekseeva; Nadezhda A. Bagrovskaya; Andrew V. Noskov

doi:10.1016/j.arabjc.2014.09.008

View/Download PDF

Buy Reprints

PDF

Translate this page into:

Original article

11 (

); 1160-1164

doi:

10.1016/j.arabjc.2014.09.008

Effect of C₆₀ filling on structure and properties of composite films based on polystyrene

Olga V. Alekseeva, Nadezhda A. Bagrovskaya, Andrew V. Noskov^⁎

G.A. Krestov Institute of Solution Chemistry, Russian Academy of Science, Akademicheskaya str., 1, Ivanovo 153045, Russia

⁎Corresponding author. Tel.: +7 4932 351851. avn@isc-ras.ru (Andrew V. Noskov)

Received: 2013-11-14, Accepted: 2014-9-4, Published: 2014-11-01

Disclaimer:
This article was originally published by Elsevier and was migrated to Scientific Scholar after the change of Publisher.

Peer review under responsibility of King Saud University.

Abstract

Both polystyrene films and polystyrene films filled with fullerenes (C₆₀) were fabricated by the solution cast method. Mechanism of fullerene-polystyrene interaction, the structural characteristics of films, and their antimicrobial activity were researched. We found that the polystyrene/fullerene composite films manifest bacteriostatic and fungistatic effect.

Keywords

Polystyrene/fullerene composites

X-ray diffraction

IR spectroscopy

Antimicrobial activity

Show Related Articles from PubMed

1 Introduction

Polymer-matrix composites have attracted much attention of researchers because of the perspective using of these materials in instrument engineering, medicine, biology, etc. (Scholz et al., 2011). Insertion of fillers, such as fullerenes, results in modification of the original polymer matrix, which can lead to creation of materials with improved physical and chemical properties and the main service characteristics (mechanical, electrical). There are numerous publications that deal with the mechanical, optical, tribological, thermochemical properties and structure of polymers containing fullerene (Badamshina and Gafurova, 2008; Alekseeva et al., 2012; Weng et al., 1999; Jiang et al., 2008; Tajima et al., 1997; Ogasawara et al., 2009; Zhao et al., 2013 ).

Modification by carbon nanoparticles results in occurrence of new properties of the polymer, for example, biological activity. Biological activity of fullerenes is due to, firstly, lipophilic properties, so that they can penetrate into the cell membrane, secondly, electron deficit, promoting to react with free radicals, and, thirdly, capacity of excited C₆₀ to generate active oxygen species (Da Ros, 2008). There are researches regarding the effects of fullerenes and fullerene derivatives on bacteria (Mashino et al., 1999; Lyon et al., 2008). Specifically cationic ammonium fullerene derivatives suppressed Escherichia coli growth, whereas an anionic derivative did not (Mashino et al., 1999).

However biological activity of polymer/fullerene composites was not studied enough. It can be assumed that the insertion of fullerenes into a polymer matrix will result in creation of biocomposites, which may be used as agents for drug delivery and antiseptic preparations (Levi-Polyachenko et al., 2008).

Polystyrene (PS) is one of the synthetic polymers capable to content nano-carbonic particles. Some features of the interaction of C₆₀ with polystyrene are known (Weng et al., 1999), while the behavior of such composites containing small concentrations of fullerenes (up to 1 wt.%) was studied insufficiently.

The aims of the present study were to fabricate polystyrene/fullerene composite films (up to 1 wt.% of C₆₀) and to research structure and antimicrobial activity of them. We made IR spectroscopy and X-ray diffraction (XRD) measurements. Also we describe results of the tests that were performed to compare bacteriostatic effect and fungistatic effect of the polystyrene films and polystyrene/fullerene composite films.

For testing we used different types of microorganisms. Antibacterial activity of both PS films and PS/fullerene composite films was tested against gram-positive bacterium Staphylococcus aureus Rosenbach and gram-negative bacterium E. coli, against mixture of bacteria E. coli + S. aureus Rosenbach, and against test cultures’ associations consisting of Bacillus subtilis, Bacillus pumilus, Bacillus stearothermophilus, E. coli, Pseudomonas aeruginosa, Pseudomonas oleovorans, and S. aureus Rosenbach. Fungistatic activity was investigated against fungal association consisting of Aspergillus niger van Thieghem, Cladosporium gossipicola Pidopl, Cladosporium resinae Albida. The choice of these test cultures is due to that these species cause diseases in animals and humans, and dominate during the biological corrosion of technical materials.

2 Experimental

2.1

2.1 Materials

Polystyrene (“Aldrich”, US; М_n = 1.4·10⁵, M_w/M_n = 1.64) and fullerenes C₆₀ (”NeoTechProduct”, Russia) were used. A solvent casting of perspective components from solutions was employed for preparing the mixtures of C₆₀ with polymer. Preliminary purification of organic solvent (o-xylene) was made by standard techniques (Coetzee, 1982). Polystyrene/fullerene composite films have been produced as follows. Fullerene batches were dissolved in o-xylene. Concentrations of fullerenes in solutions were equal to 3.6·10⁻², 5.4·10⁻², 1.8·10⁻¹, 0.9, and 1.8 kg·m⁻³. Then polystyrene batches were dissolved in all obtained solutions (17 wt.% of PS) and the mixed solutions were stirred for about 1 day before being cast into thin films. After casting the solvent was slowly evaporated over several days to produce the composite films. By this technique, we prepared five samples of polystyrene/fullerene composites with different fullerene percentages, x (0.02, 0.03, 0.1, 0.5, and 1 wt.% of C₆₀), in the form of film. Unmodified polystyrene film was made by the solution cast method as well.

2.2

2.2 Methods

The structures of both PS films and PS/C₆₀ composite films were evaluated with X-ray diffraction measurements on the basis of Debay–Sherrer scheme within 2–15° (2θ) angle range. XRD patterns of film samples were obtained by X-ray diffractometer DRON-UM1 (Russia) equipped with MoK_α radiation that monochromates by the Zr-filter, λ = 0.071 nm. X-ray diffractometer was modernized for substances in condensed and polycrystalline states. The voltage and the current of the X-ray tubes were 40 kV and 40 mA, respectively. A scan rate of 0.04 degree/s was used.

IR spectra were produced by the spectrophotometer Avatar 360FT-IR ESP (“Nicolet”, USA) in the range of 1800–400 cm⁻¹.

For evaluation of the biological potency of both PS films and PS/C₆₀ composite films the tests have been performed. The essence of the tests is to store the test samples under conditions optimal for growth and development of bacterial and fungal cultures.

Antimicrobial assessments of film were performed with bacterial and fungal cultures listed above. Bacterial and fungal cultures were purchased from All-russian collection of microorganisms – VKM (Moscow, Russia). Nutrient broth used for the preparation of microbial culture medium was made with distilled water.

Tests for the biological potency were carried out as follows. We inoculated an aqueous suspension of mushrooms or bacterial spores into the melted nutrient medium, and cooled down to 45–50 °C. Concentrations of mushrooms or bacterial spores were equal to 2·10⁶ CFU/ml. Plain agar was used as a nutrient medium for bacteria and Czapek-Dox’s medium with agar was used as a nutrient medium for fungi. We prepared a bacterial mixture and a mushroom mixture using a turbidity standard and by the colorimetric method, respectively. The mixture was then thoroughly blended and poured into Petri dishes that were placed on a strictly horizontal surface. After whole congelation we inoculated the test specimens on the surface of congealed mixture and placed Petri dishes into a desiccator, to the bottom of which was poured distilled water. Then we placed the desiccator into the thermostat at a temperature of 30 ± 2 °C for 24 h for bacteria and 28 days for fungi. For every 7 days we opened the cover of the desiccator for the air intake and carried out a preliminary examination of the samples.

By the end of test we took the samples and assessed stability against bacteria and fungi. Visual field illuminance was equal to 200–300 lux. If there is a lysis zone (zone in which there is no microbial growth) around the sample, it means the sample possesses antimicrobial activity. The width of the lysis zone, H, defines the toxicity level of the material against microorganisms. If H < 5 mm, then the sample’s antimicrobial activity is weak. If H = 5 ÷ 10 mm, then the sample’s antimicrobial activity is acceptable. If H > 10 mm, then the sample possesses strong antimicrobial activity.

3 Results and discussion

By the above described technique, we prepared one sample of polystyrene film and four samples of polystyrene/fullerene composite films with different C₆₀ percentages. The film thickness was 60 ÷ 80 μm. We found both polystyrene films and PS/C₆₀ composite films to be transparent. Unmodified polystyrene samples were colorless, whereas the polystyrene/fullerene composite films were light purple. The intensity of color depended on the content of C₆₀ in the composite.

3.1

3.1 X-ray diffraction analysis

XRD patterns of both PS films and PS/C₆₀ composite films with 0.03, 0.1, 0.5, and 1 wt.% of C₆₀ are given in Fig. 1. XRD of solid C₆₀ is reported in Ref. Krätschmer et al. (1990). Comparing these data it can be seen that the reflexes associated with fullerene are absent in XRD patterns of composite films (Fig. 1). Apparently, this is due to that the concentration of C₆₀ in the studied films is inadequate for the occurrence of reflex. This finding correlates with the data of Ref. Ginzburg et al. (2004), in which there is a comparison of wide-angle diffraction patterns of both polymethylmethacrylate (PMMA) and composites PMMA/C₆₀ (1 wt.% of C₆₀) and PMMA/C₆₀ (10 wt.% of C₆₀). It is found in Ref. Ginzburg et al. (2004) that diffraction pattern does not change under insertion of fullerene (up to 1 wt.%) into the polymer matrix. From the opinion of the authors, the absence of these changes is due to the weak aggregation of C₆₀. But in the diffraction pattern of composite PMMA/C₆₀ (10 wt.% of C₆₀) there are additional peaks associated with fullerene aggregates (Ginzburg et al., 2004).

X-ray diffraction patterns for the films with different concentrations of C60 (wt.%): 0 (1); 0.03 (2); 0.1 (3); 0.5 (4); 1 (5).

It is shown in Fig. 1, that both PS films and PS/C₆₀ composite films exhibit a broad diffraction peak (halo). Its location does not depend on the film composition. Abscissa of maximum, 2θ_m, is equal to 5.2 degree. In the reciprocal space, the position of peak appears at 8.029 nm⁻¹. We calculated the repetitive characteristic distance in structural arrangement, d, using the relation (Guinier, 2001):

(1)

2 d \sin θ_{m} = K λ,

where K = 1.2 ÷ 1.3. We obtained the value of d which is equal to 0.94 ÷ 1.02 nm for all the studied composites.

The presence of the broad peak in the X-ray diffraction patterns of films is an indication of the existence of the intermediate-range order (N’Dri et al., 2012) in these materials. The full width at half maximum, ΔS, makes it possible to specify a correlation length (a scale of the intermediate-range ordering) in the disordered phase, L, using the relation:

(2)

L = 2 π / Δ S,

where

S = 4 π \sin θ / λ

is the modulus of dispersion vector.

The values of L calculated by Eq. (2) are given in Table 1. The obtained data demonstrate the following. When the concentration of fullerenes in the film does not exceed 0.03 wt.%, the value of L is 0.39 ÷ 0.42 nm. Greater correlation length (L = 0.68 ÷ 0.71 nm) occurs if concentrations of C₆₀ are 0.1 ÷ 1 wt.%.

Table 1 X-ray diffraction results of the PS and PS/C₆₀ films.

x (wt.%)	ΔS (nm⁻¹)	L (nm)
0	15.53 ± 0.55	0.40 ± 0.01
0.03	16.12 ± 0.60	0.39 ± 0.01
0.1	8.80 ± 0.45	0.71 ± 0.04
0.5	9.29 ± 0.40	0.68 ± 0.03
1.0	8.98 ± 0.40	0.69 ± 0.03

Thus, insertion of fullerenes into polystyrene promotes “local ordering in the disordered phase”. Note such conclusion is consistent with the findings of Ref. Gladchenko et al. (2002). It is found in Gladchenko et al., 2002 that if the content of fullerenes is more than 0.1 wt.%, the effects of the intermolecular interaction of fullerene with polystyrene dominate, which may result in cross-linking of the polymer chains.

3.2

3.2 IR spectroscopy

In the infrared spectrum of polystyrene there are bands corresponding to valence vibrations of C⚌C bond in the benzene ring at 1600–1585 and 1500–1400 cm⁻¹ in the form of doublets (Fig. 2). Bands corresponding to planar and out-of-plane deformation vibrations of C–H bonds in the benzene ring are in the area 1300–1000 cm⁻¹ and 900–675 cm⁻¹, respectively (Silverstein et al., 1991). In the IR spectrum of the fullerene molecule, four vibrations are active with the absorption bands at 527, 577, 1183 and 1429 cm⁻¹ (Konarev and Lyubovskaya, 1999).

IR-spectra for the films with different concentrations of C60 (wt.%): 0 (1); 0.02 (2); 0.03 (3).

Analysis of IR spectroscopy shows that the novel bands do not appear in the spectra of composites (Fig. 2). However there is a change in the contours of the absorption band in range of 700–400 cm⁻¹ and line broadening at 621 cm⁻¹.

Quantitative interpretation of IR spectra of composites is difficult because of overlapping of bands corresponding to the phenyl ring and fullerene (1451 and 1429 cm⁻¹). In this study we defined the ratio of optical densities of characteristic absorption bands to the optical density of the band of the C–H bond at 908 cm⁻¹ selected as an internal standard.

The analysis shows that there is a significant difference between the relative intensities of the modes in the IR spectra of the composite and the corresponding parameters in the spectrum of polystyrene film (Table 2). The most significant decrease in the intensities of the modes at 1601 и 1373 cm⁻¹ was observed in the spectrum of the composite containing 0.03 wt.% of fullerene. A combination of these changes indicates that the electronic structure of the phenyl rings of the polystyrene macromolecule is distorted. One can assume that there is a non-covalent interaction of the polystyrene donor macromolecules with fullerene acceptor molecule. Probably, decrease in the intensity of the band at 1373 cm⁻¹ is due to changes in the helical conformation of polystyrene macromolecules by the influence of fullerene (Dechant et al., 1972).

Table 2 Relative intensities of characteristic absorption bands for the PS and PS/C₆₀ films.

x (wt.%)	D₁₆₀₁/D₉₀₈	D₁₃₇₃/D₉₀₈	D₁₃₁₁/D₉₀₈
0	2.85	0.93	0.60
0.02	2.87	0.96	0.64
0.03	2.18	0.69	0.58

3.3

3.3 Antimicrobial properties

Studies on bacteriostatic activity and fungistatic activity for polystyrene films and polystyrene/fullerene composite films were performed. The results are shown in Fig. 3 and Table 3. It can be seen in Fig. 3 that there is a distinct zone of lysis around the sample of polystyrene/fullerene composite film.

Effect of the PS/C60 composite film on Staphylococcus aureus Rosenbach.

Table 3 Antibacterial and fungistatic activities of the film materials.

x (wt.%)	H (mm)
x (wt.%)	E. coli	S. aureus	E. coli + S. aureus	Bacterial association	Fungal association
0	0	0	0	0	0
0.03	2	3	1–2	^⁎	^⁎
0.1	3	2	2	^⁎	^⁎
1	^⁎	^⁎	^⁎	8	7

⁎ Tests were not performed.

The inhibition zone of bacterial growth was formed in the nutrient medium. Its width, H, that defines the inactivation degree of bacteria and fungi has been represented in Table 3. From the data we can conclude that polystyrene becomes bacteriostatic because of filling with fullerenes. If x ⩽ 0.1 wt.%, the antimicrobial activity against both E. coli and S. aureus for PS/C₆₀ samples researched is weak (H < 5 mm). The level of toxicity increases with concentrations of C₆₀ in film. If x = 1 wt.%, the antimicrobial activity against bacterial association is acceptable (H = 8 mm). Thus it can be asserted that the test samples with a small concentration (0.03 wt.%) of antimicrobial agent possess a bactericidal action both on surface and near (several mm) the contact zone.

In addition polystyrene/fullerene composite films have been attributed by fungistatic action. Since H = 7 mm (Table 3), the fungistatic activity of PS/C₆₀ composite films is acceptable.

Thus from the biological activity tests of some materials based on polystyrene, we found that the polystyrene/fullerene composite films manifest bacteriostatic and fungistatic activities. This effect cannot be explained by the decrease of oxygen permeability of the films due to the addition of fullerenes, because the inhibition zone size shown is larger than the film (Fig. 3). It is likely that one of the reasons of microorganism’s inactivation is interaction of the fullerenes with functional groups of the amino acids composing bacterial proteins. This results in the cell membrane damage and destruction of the cell wall leading to their death. It should be noted that dynamics of the bacterial inactivation persists during a month.

4 Conclusions

Structure and properties of both polystyrene films and polystyrene films filled with fullerenes (C₆₀) fabricated by the solution cast method have been researched. It was revealed by XRD that there is the intermediate-range order in these materials. Incorporation of fullerenes into polymer matrix does not change the value of the repetitive characteristic distance in structural arrangement, but increases a correlation length (a scale of the intermediate-range ordering) in the disordered phase. Mechanism of fullerene-polystyrene interaction was researched by IR spectroscopy. It was shown that change in spectra of composite films in comparison with pure polystyrene is due to changes in helical conformation of polystyrene macromolecules by the influence of fullerene. Antimicrobial activity of both pure polystyrene and composite films was researched. We found that the polystyrene/fullerene composite films manifest bacteriostatic and fungistatic effects whereas the polystyrene films did not show any bacteriostatic and fungistatic activities.

Acknowledgement

This research was supported by the Russia Foundation for Basic Research (Grant No 12-03-97528-a).

References

Alekseeva O.V., Barannikov V.P., Bagrovskaya N.A., Noskov A.V., . DSC investigation of the polystyrene films filled with fullerene. J. Therm. Anal. Calor.. 2012;109:1033-1038.
[Google Scholar]
Badamshina E.R., Gafurova M.P., . Characteristics of fullerene C₆₀-doped polymers. Polym. Sci. B.. 2008;50:215-225.
[Google Scholar]
Coetzee J.F., ed. Recommended Methods for Purification of Solvents and Tests for Impurities. Oxford: Pergamon Press; 1982.
Da Ros T., . Twenty years of promises: fullerene in medicinal chemistry. In: Cataldo F., Da Ros T., eds. Carbon Materials: Chemistry and Physics. V.1. Medicinal Chemistry and Pharmacological Potential of Fullerenes and Carbon Nanotubes. Springer; 2008. p. :1-21.
[Google Scholar]
Dechant J., Danz R., Kimmer W., Schmolke R., . Ultrarotspektroskopische Untersuchungen an Polymeren. Berlin: Akademie-Verlag; 1972.
Ginzburg B.M., Pozdnyakov A.O., Shepelevskij A.A., Melenevskaya E.Y., Novoselova A.V., Shibaev L.A., Pozdnyakov O.F., Redkov B.P., Smirnov A.S., Shiryaeva O.A., . Structure of fullerene C₆₀ in a poly(methyl methacrylate) matrix. Polym. Sci. Ser. A. 2004;46:169-175.
[Google Scholar]
Gladchenko S.V., Polotskaya G.A., Gribanov A.V., Zgonnik V.N., . The study of polystyrene-fullerene solid-phase composites. Tech. Phys. Russ. J. Appl. Phys.. 2002;47:102-106.
[Google Scholar]
Guinier A., . X-ray diffraction. In: Crystals, Imperfect Crystals, and Amorphous Bodies. New York: Dover Publications; 2001.
[Google Scholar]
Jiang Z., Zhang H., Zhang Z., Murayama H., Okamoto K., . Improved bonding between pan-based carbon fibers and fullerene-modified epoxy matrix. Compos. Part A – Appl. Sci.. 2008;39:1762-1767.
[Google Scholar]
Konarev D.V., Lyubovskaya R.N., . Donor–acceptor complexes and radical ionic salts based on fullerenes. Russ. Chem. Rev.. 1999;68:19-38.
[Google Scholar]
Krätschmer W., Lamb L.D., Fostiropoulos K., Huffman D.R., . Solid C₆₀: a new form of carbon. Nature. 1990;347:354-358.
[Google Scholar]
Levi-Polyachenko N.H., Carroll D.L., Stewart J.H., . Applications of carbon-based nanomaterials for drug delivery in oncology. In: Cataldo F., Da Ros T., eds. Carbon Materials: Chemistry and Physics. V.1. Medicinal Chemistry and Pharmacological Potential of Fullerenes and Carbon Nanotubes. Springer; 2008. p. :223-266.
[Google Scholar]
Lyon D.Y., Brown D., Sundstrom E.R., Alvarez P.J.J., . Assessing the antibiofouling potential of a fullerene-coated surface. Int. Biodeter. Biodegr.. 2008;62:475-478.
[Google Scholar]
Mashino T., Okuda K., Hirota T., Hirobe M., Nagano T., Mochizuki M., . Inhibition of E. coli growth by fullerene derivatives and inhibition mechanism. Bioorg. Med. Chem. Lett.. 1999;9:2959-2962.
[Google Scholar]
N’Dri K., Houphouet-Boigny D., Jumas J.-C., . Study of first sharp diffraction peak in As₂S₃ glasses by X-ray powder diffraction method. J. Non-oxide Glasses. 2012;3:29-37.
[Google Scholar]
Ogasawara T., Ishida Y., Kasai T., . Mechanical properties of carbon fiber/fullerene-dispersed epoxy composites. Compos. Sci. Technol.. 2009;69:2002-2007.
[Google Scholar]
Scholz M.-S., Blanchfield J.P., Bloom L.D., Coburn B.H., Elkington M., Fuller J.D., Gilbert M.E., Muflahi S.A., Pernice M.F., Rae S.I., Trevarthen J.A., White S.C., Weaver P.M., Bond I.P., . The use of composite materials in modern orthopaedic medicine and prosthetic devices: a review. Compos. Sci. Technol.. 2011;71:1791-1803.
[Google Scholar]
Silverstein R.M., Bassler G.C., Morrill T.C., . Spectrometric Identification of Organic Compounds. Chichester: Wiley; 1991.
Tajima Y., Tezuka Y., Yajima H., Ishii T., Takeuchi K., . Photo-crosslinking polymers by fullerene. Polymer. 1997;38:5255-5257.
[Google Scholar]
Weng D., Lee H.K., Levon K., Mao J., Scrivens W.A., Stephens E.B., Tour J.M., . The influence of Buckminsterfullerenes and their derivatives on polymer properties. Eur. Polym. J.. 1999;35:867-878.
[Google Scholar]
Zhao L., Guo Z., Cao Z., Zhang T., Fang Z., Peng M., . Thermal and thermo-oxidative degradation of high density polyethylene/fullerene composites. Polym. Degrad. Stab.. 2013;98:1953-1962.
[Google Scholar]

Introduction

Experimental

Materials
Methods

Results and discussion

X-ray diffraction analysis
IR spectroscopy
Antimicrobial properties

Conclusions

Fulltext Views
161

PDF downloads
92

View/Download PDF
Download Citations

BibTeX
RIS

Show Sections

[1] Alekseeva O.V., Barannikov V.P., Bagrovskaya N.A., Noskov A.V., . DSC investigation of the polystyrene films filled with fullerene. J. Therm. Anal. Calor.. 2012;109:1033-1038.
[Google Scholar]

[2] Badamshina E.R., Gafurova M.P., . Characteristics of fullerene C₆₀-doped polymers. Polym. Sci. B.. 2008;50:215-225.
[Google Scholar]

[3] Coetzee J.F., ed. Recommended Methods for Purification of Solvents and Tests for Impurities. Oxford: Pergamon Press; 1982.

[4] Da Ros T., . Twenty years of promises: fullerene in medicinal chemistry. In: Cataldo F., Da Ros T., eds. Carbon Materials: Chemistry and Physics. V.1. Medicinal Chemistry and Pharmacological Potential of Fullerenes and Carbon Nanotubes. Springer; 2008. p. :1-21.
[Google Scholar]

[5] Dechant J., Danz R., Kimmer W., Schmolke R., . Ultrarotspektroskopische Untersuchungen an Polymeren. Berlin: Akademie-Verlag; 1972.

[6] Ginzburg B.M., Pozdnyakov A.O., Shepelevskij A.A., Melenevskaya E.Y., Novoselova A.V., Shibaev L.A., Pozdnyakov O.F., Redkov B.P., Smirnov A.S., Shiryaeva O.A., . Structure of fullerene C₆₀ in a poly(methyl methacrylate) matrix. Polym. Sci. Ser. A. 2004;46:169-175.
[Google Scholar]

[7] Gladchenko S.V., Polotskaya G.A., Gribanov A.V., Zgonnik V.N., . The study of polystyrene-fullerene solid-phase composites. Tech. Phys. Russ. J. Appl. Phys.. 2002;47:102-106.
[Google Scholar]

[8] Guinier A., . X-ray diffraction. In: Crystals, Imperfect Crystals, and Amorphous Bodies. New York: Dover Publications; 2001.
[Google Scholar]

[9] Jiang Z., Zhang H., Zhang Z., Murayama H., Okamoto K., . Improved bonding between pan-based carbon fibers and fullerene-modified epoxy matrix. Compos. Part A – Appl. Sci.. 2008;39:1762-1767.
[Google Scholar]

[10] Konarev D.V., Lyubovskaya R.N., . Donor–acceptor complexes and radical ionic salts based on fullerenes. Russ. Chem. Rev.. 1999;68:19-38.
[Google Scholar]

[11] Krätschmer W., Lamb L.D., Fostiropoulos K., Huffman D.R., . Solid C₆₀: a new form of carbon. Nature. 1990;347:354-358.
[Google Scholar]

[12] Levi-Polyachenko N.H., Carroll D.L., Stewart J.H., . Applications of carbon-based nanomaterials for drug delivery in oncology. In: Cataldo F., Da Ros T., eds. Carbon Materials: Chemistry and Physics. V.1. Medicinal Chemistry and Pharmacological Potential of Fullerenes and Carbon Nanotubes. Springer; 2008. p. :223-266.
[Google Scholar]

[13] Lyon D.Y., Brown D., Sundstrom E.R., Alvarez P.J.J., . Assessing the antibiofouling potential of a fullerene-coated surface. Int. Biodeter. Biodegr.. 2008;62:475-478.
[Google Scholar]

[14] Mashino T., Okuda K., Hirota T., Hirobe M., Nagano T., Mochizuki M., . Inhibition of E. coli growth by fullerene derivatives and inhibition mechanism. Bioorg. Med. Chem. Lett.. 1999;9:2959-2962.
[Google Scholar]

[15] N’Dri K., Houphouet-Boigny D., Jumas J.-C., . Study of first sharp diffraction peak in As₂S₃ glasses by X-ray powder diffraction method. J. Non-oxide Glasses. 2012;3:29-37.
[Google Scholar]

[16] Ogasawara T., Ishida Y., Kasai T., . Mechanical properties of carbon fiber/fullerene-dispersed epoxy composites. Compos. Sci. Technol.. 2009;69:2002-2007.
[Google Scholar]

[17] Scholz M.-S., Blanchfield J.P., Bloom L.D., Coburn B.H., Elkington M., Fuller J.D., Gilbert M.E., Muflahi S.A., Pernice M.F., Rae S.I., Trevarthen J.A., White S.C., Weaver P.M., Bond I.P., . The use of composite materials in modern orthopaedic medicine and prosthetic devices: a review. Compos. Sci. Technol.. 2011;71:1791-1803.
[Google Scholar]

[18] Silverstein R.M., Bassler G.C., Morrill T.C., . Spectrometric Identification of Organic Compounds. Chichester: Wiley; 1991.

[19] Tajima Y., Tezuka Y., Yajima H., Ishii T., Takeuchi K., . Photo-crosslinking polymers by fullerene. Polymer. 1997;38:5255-5257.
[Google Scholar]

[20] Weng D., Lee H.K., Levon K., Mao J., Scrivens W.A., Stephens E.B., Tour J.M., . The influence of Buckminsterfullerenes and their derivatives on polymer properties. Eur. Polym. J.. 1999;35:867-878.
[Google Scholar]

[21] Zhao L., Guo Z., Cao Z., Zhang T., Fang Z., Peng M., . Thermal and thermo-oxidative degradation of high density polyethylene/fullerene composites. Polym. Degrad. Stab.. 2013;98:1953-1962.
[Google Scholar]