5. Application of graphene-like nanocomposite

Depending on the type of GLNs and its inherent properties, the designed properties of nanocomposite can be received. Extraordinary properties of GLNs, such as BNNSs, including high thermal properties, structural stability, good mechanical properties, and antioxidant ability, have attracted the attention of researchers to use as a filler [53, 54]. A summary of the application of GLNs nanocomposites is shown in Figure 4.

Fillers with a high aspect ratio and crystallinity can improve thermal conductivity and reduce Kapitza resistance [55, 56]. For example, most thermoplastic polymers, such as polyethylene, polypropylene, polyamide and thermosets such as epoxy, are insulating and have very low thermal conductivity, but these properties can be improved by adding fillers such as boron nitride. The use of BN in insulating polymer matrix is the solution if both of electrical properties and thermal conductivity are needed in an electronic device [57]. So far, few studies have been carried out on the thermal conductivity of thermoplastics filled with 2D boron nitride [58–65]. Therefore, researchers focus the investigation on the effect of filler (chemical composition, morphology, surface characteristics, shape and size) on electrical conductivity.

polyvinyl alcohol, poly(hydroxy amino ether), PS, polyethylene (PE), polyethylene oxide (PEO) and epoxy can be used. Low viscosity of polymer in the solution (contrary to the molten method) with mechanical stirring or ultrasonic waves can help the

(c) in-situ polymerization, (d) electrospinning and (e) layer by layer (LBL) assembly.

Schematic image of basic set-up of processing methods of composites (a) melt processing, (b) solvent processing,

Figure 3.

Nanorods and Nanocomposites

146

properties of the nanocomposite. 2D graphene-like nanomaterials as inorganic fillers, if they are well spread on the polymer matrix, can create a physical barrier inside the polymer and prevent the penetration of heat and degradation of polymeric materials. Totally, the addition of 2D nanosheets results in the thermal stability of polymers. This effect can be due to the thermal stability of filler and the

barrier effect of these nanomaterials, which leads to the resistance of the

(due to high chemical resistance) are used [71–73].

polymers [61, 70].

Graphene-Like Nanocomposites

DOI: http://dx.doi.org/10.5772/intechopen.85513

polyethylene matrix [74, 75].

6. Future outlook

149

nanocomposite to thermal degradation and prevents the penetration of degradation products from the polymer matrix to the gas phase. Several studies have been carried out on the effects of these nanomaterials on the thermal stability of various

GL nanomaterials are capable of separating, organic pollution absorption, water and wastewater treatment, contaminant elimination from oil, due to the nanosheet structure, the polarity of bonds and the high surface area. In practical application and in different situations, these nanosheets due to their powdery state and the ease of collection after separation require for the embedding in a substrate. Therefore, polymer-based nanocomposites of GLNs such as polyvinylidene fluoride (PVDF)

One of the special applications of BNNSs is the neutron shielding property, due

Since graphene and graphene oxide have been successfully used in biomedical applications, much attention has been paid to GLNs due to their 2D structure, which is similar to graphene. Polymers, on the other hand, were used in bio-detecting research because of low weight, ease of fabrication, and relatively low cost of processing. The simultaneous use of 2D materials and polymers offers a lot of potential to the researchers. BN has a high biocompatibility due to its excellent chemical stability, good process—ability and good biology activity [76]. For example, chitosan/ BN nanocomposites have been used as protective coating for stainless steel. Also, BN is used to strengthen polypropylene as a bio-composite for bone prosthesis [77]. The water-soluble polymers have a widespread in biomedical science. The polyethylene glycol (PEG) nanocomposite containing MoS2 nanosheets has been used as a multi-functional drug carrier for combined cancer therapy [78]. Also, PEG nanocomposites containing WS2 have been used as a multifunctional agent for dual-modal CT/photoacoustic imaging in photo-thermal therapy [79]. Also, MoS2 based nanocomposites are used in DNA sensors to detect DNA molecules [80]. Another application of GLNs nanocomposites are the increasing the impermeability of nanocomposites against oxygen that used in the food packaging industry. Most polymers used in this industry suffer from the problem of oxygen penetration. 2D nanosheets form a strong barrier against oxygen penetration due to their layered structure. For example, the nanocomposites based on cellulose nanofibers containing BNNSs prevent the penetration of oxygen. In addition, GLNs improve the mechanical

properties of the nanocomposite and does not alter the brittleness [81].

ered before fully understanding their effects in polymer composites.

The fillers based on GL nanomaterials are at the beginning of their path to expand. However, there are several fundamental challenges that must be consid-

to intrinsic property of boron in absorbing neutrons. The placement of boron nitride in a polymeric matrix can produce a multifunctional nanocomposite that exhibits structural, radiation protection, and even resistance to flame. These polymer nanocomposites can be used in spacecraft and nuclear reactors. NASA has focused on the protective properties of nanocomposites containing BNNSs in a

Figure 4. A summary of the application of GLNs nanocomposites.

The application of epoxy as a thermoset polymer is highly sought-after due to high chemical resistance, corrosion and significant mechanical properties. However, due to very low thermal conductivity (0.15–0.35 W/mK), its use in electronic tools and carbon fiber reinforced plastic (CFRP) tooling is limited. Hence, researchers have used BNNSs to improve the thermal conductivity of this polymer [66, 67].

PVA/BNNSs can be used to make memory devices, due to the huge potential of trapping charge carriers and to perceive the non-volatile memory effect. In these devices, a thin film of hybrid nanocomposite is used as a sandwiched active layer between two conductive electrodes to form the memristor structure [68].

Flexible insulation nanocomposites such as PU/BN nanocomposites show high thermal conductivity that are a desirable option for miniaturization of high-power electronics and portable devices [69].

Polymer materials are widely used in most important industries. However, these materials are high-risk materials to burn, and most of them are decomposed with the emission of toxic gases. Therefore, nanocomposite modification is necessary to reduce their flammability. There are three common strategies to achieve this: the use of inherently flame resistant polymers, flame retardant materials and surface/ coating modifications. Usually, a small amount of filler can improve the thermal

#### Graphene-Like Nanocomposites DOI: http://dx.doi.org/10.5772/intechopen.85513

properties of the nanocomposite. 2D graphene-like nanomaterials as inorganic fillers, if they are well spread on the polymer matrix, can create a physical barrier inside the polymer and prevent the penetration of heat and degradation of polymeric materials. Totally, the addition of 2D nanosheets results in the thermal stability of polymers. This effect can be due to the thermal stability of filler and the barrier effect of these nanomaterials, which leads to the resistance of the nanocomposite to thermal degradation and prevents the penetration of degradation products from the polymer matrix to the gas phase. Several studies have been carried out on the effects of these nanomaterials on the thermal stability of various polymers [61, 70].

GL nanomaterials are capable of separating, organic pollution absorption, water and wastewater treatment, contaminant elimination from oil, due to the nanosheet structure, the polarity of bonds and the high surface area. In practical application and in different situations, these nanosheets due to their powdery state and the ease of collection after separation require for the embedding in a substrate. Therefore, polymer-based nanocomposites of GLNs such as polyvinylidene fluoride (PVDF) (due to high chemical resistance) are used [71–73].

One of the special applications of BNNSs is the neutron shielding property, due to intrinsic property of boron in absorbing neutrons. The placement of boron nitride in a polymeric matrix can produce a multifunctional nanocomposite that exhibits structural, radiation protection, and even resistance to flame. These polymer nanocomposites can be used in spacecraft and nuclear reactors. NASA has focused on the protective properties of nanocomposites containing BNNSs in a polyethylene matrix [74, 75].

Since graphene and graphene oxide have been successfully used in biomedical applications, much attention has been paid to GLNs due to their 2D structure, which is similar to graphene. Polymers, on the other hand, were used in bio-detecting research because of low weight, ease of fabrication, and relatively low cost of processing. The simultaneous use of 2D materials and polymers offers a lot of potential to the researchers. BN has a high biocompatibility due to its excellent chemical stability, good process—ability and good biology activity [76]. For example, chitosan/ BN nanocomposites have been used as protective coating for stainless steel. Also, BN is used to strengthen polypropylene as a bio-composite for bone prosthesis [77].

The water-soluble polymers have a widespread in biomedical science. The polyethylene glycol (PEG) nanocomposite containing MoS2 nanosheets has been used as a multi-functional drug carrier for combined cancer therapy [78]. Also, PEG nanocomposites containing WS2 have been used as a multifunctional agent for dual-modal CT/photoacoustic imaging in photo-thermal therapy [79]. Also, MoS2 based nanocomposites are used in DNA sensors to detect DNA molecules [80].

Another application of GLNs nanocomposites are the increasing the impermeability of nanocomposites against oxygen that used in the food packaging industry. Most polymers used in this industry suffer from the problem of oxygen penetration. 2D nanosheets form a strong barrier against oxygen penetration due to their layered structure. For example, the nanocomposites based on cellulose nanofibers containing BNNSs prevent the penetration of oxygen. In addition, GLNs improve the mechanical properties of the nanocomposite and does not alter the brittleness [81].

#### 6. Future outlook

The fillers based on GL nanomaterials are at the beginning of their path to expand. However, there are several fundamental challenges that must be considered before fully understanding their effects in polymer composites.

The application of epoxy as a thermoset polymer is highly sought-after due to high chemical resistance, corrosion and significant mechanical properties. However, due to very low thermal conductivity (0.15–0.35 W/mK), its use in electronic tools and carbon fiber reinforced plastic (CFRP) tooling is limited. Hence, researchers have used BNNSs to improve the thermal conductivity of this polymer [66, 67].

PVA/BNNSs can be used to make memory devices, due to the huge potential of trapping charge carriers and to perceive the non-volatile memory effect. In these devices, a thin film of hybrid nanocomposite is used as a sandwiched active layer

Flexible insulation nanocomposites such as PU/BN nanocomposites show high thermal conductivity that are a desirable option for miniaturization of high-power

Polymer materials are widely used in most important industries. However, these materials are high-risk materials to burn, and most of them are decomposed with the emission of toxic gases. Therefore, nanocomposite modification is necessary to reduce their flammability. There are three common strategies to achieve this: the use of inherently flame resistant polymers, flame retardant materials and surface/ coating modifications. Usually, a small amount of filler can improve the thermal

between two conductive electrodes to form the memristor structure [68].

electronics and portable devices [69].

A summary of the application of GLNs nanocomposites.

Nanorods and Nanocomposites

Figure 4.

148


#### 7. Conclusions

Graphene-like nanomaterials and polymer-based nanocomposites demonstrate the increasing growth in technology and applications. In this study, recent advances in the production of polymer-filled nanocomposites with GLNs were investigated, properties and applications of these materials. Although these materials are in the early stages of development, their value added and their ability to address them is quite evident. Of course, one should take into account the unfulfilled expectations of graphene nanocomposites and consider the challenges and problems involved in the development of these materials that need to be solved and used them to develop polymer-filled with GLNs.

The first challenge is the production of GLNs. On the other hand, high-quality and large-scale of GLNs preparation at affordable cost is still not possible. Although recent steps have been taken for this purpose seriously, but new synthesis methods should be created to reduce the use of acid and solvent.

Author details

Tehran, Iran

151

Zahra Rafiei-Sarmazdeh<sup>1</sup>

Graphene-Like Nanocomposites

DOI: http://dx.doi.org/10.5772/intechopen.85513

Research Institute, Tehran, Iran

\*Address all correspondence to: zrafiei@alumni.ut.ac.ir

provided the original work is properly cited.

\* and Seyed Javad Ahmadi2

1 Plasma and Nuclear Fusion Research School, Nuclear Science and Technology

2 Nuclear Fuel Cycle School, Nuclear Science and Technology Research Institute,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

The second major challenge is the nanocomposite production process. The full utilization of GLNs-filled nanocomposites with the good dispersion of GLNs increases the cost-effectiveness of final nanocomposite production. Many efforts have been made to improve and enhance the properties of nanocomposites by modifying the interfacial interaction of filler and polymer matrix through functionalization or use the compatibilizers. Several studies use the functionalization of filler in order to create strong interaction between GLNs with a polymer matrix. This improves bonding between GLNs and polymer, which improves stress transfer, increases thermal stability and other properties. Efforts in this field can lead to the production of nanocomposites that have widespread use in the field of bio-detecting, drug delivery, food packaging, thermal shields, contamination absorption, electronics device etc.

#### Conflict of interest

The authors declare that they have no conflict of interest.

Graphene-Like Nanocomposites DOI: http://dx.doi.org/10.5772/intechopen.85513

1. Distribution of fillers in the polymeric matrix is important to achieve the properties of nanocomposites. However, most of the composite processing methods are not economically optimal. Solvent processing, LBL assembly and electrospinning have a better result in dispersion of the filler but are not economically affordable. The melt processing method is economical, but the filler has no proper dispersion and the final properties are less than optimal.

2. GL nanomaterials can act as nucleating sites and affect the polymer's

the mechanical properties of the composites should be investigated.

purity of the filler, the amount of dispersion in the polymer, and the interaction between the filler and the polymer matrix. However, so far, no systematic study has been done to compare the effect of aspect ratio, filler purity, functionalization degree, and the types of functional groups on the

properties of nanocomposites.

develop polymer-filled with GLNs.

absorption, electronics device etc.

Conflict of interest

150

should be created to reduce the use of acid and solvent.

The authors declare that they have no conflict of interest.

7. Conclusions

Nanorods and Nanocomposites

crystallinity. Therefore, the degree of dependence of the crystallinity value on

3. The development and quality of nanocomposites containing GL nanomaterials depend on several factors, including the type of filler, the number of layers, the

Graphene-like nanomaterials and polymer-based nanocomposites demonstrate the increasing growth in technology and applications. In this study, recent advances in the production of polymer-filled nanocomposites with GLNs were investigated, properties and applications of these materials. Although these materials are in the early stages of development, their value added and their ability to address them is quite evident. Of course, one should take into account the unfulfilled expectations of graphene nanocomposites and consider the challenges and problems involved in the development of these materials that need to be solved and used them to

The first challenge is the production of GLNs. On the other hand, high-quality and large-scale of GLNs preparation at affordable cost is still not possible. Although recent steps have been taken for this purpose seriously, but new synthesis methods

The second major challenge is the nanocomposite production process. The full

utilization of GLNs-filled nanocomposites with the good dispersion of GLNs increases the cost-effectiveness of final nanocomposite production. Many efforts have been made to improve and enhance the properties of nanocomposites by modifying the interfacial interaction of filler and polymer matrix through functionalization or use the compatibilizers. Several studies use the functionalization of filler in order to create strong interaction between GLNs with a polymer matrix. This improves bonding between GLNs and polymer, which improves stress transfer, increases thermal stability and other properties. Efforts in this field can lead to the production of nanocomposites that have widespread use in the field of bio-detecting, drug delivery, food packaging, thermal shields, contamination
