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Cheap, gram-scale fabrication of BN nanosheets via substitution reaction of graphite powders and their use for mechanical reinforcement of polymers.

Liu F, Mo X, Gan H, Guo T, Wang X, Chen B, Chen J, Deng S, Xu N, Sekiguchi T, Golberg D, Bando Y - Sci Rep (2014)

Bottom Line: Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials.Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film.In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.

View Article: PubMed Central - PubMed

Affiliation: 1] State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (PR China) [2] Inorganic Nanostructured Materials Group, World Premier International (WPI) Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki, Japan 305-0044.

ABSTRACT
As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5 nm to 40 nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300 nm to 500 nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.

No MeSH data available.


Related in: MedlinePlus

(A) Photographs of the BN/PMMA composite film at (a) 0 wt.% BN; (b) 1 wt.% BN; (c) 2 wt. % BN; (d) 5 wt.% BN; (e) 10 wt.% BN. (B) Stress-strain curves of the BN/PMMA composite films with different BN filling fractions. (C, D) Elastic modulus versus BN filling fraction curve and tensile strength versus BN filling fraction curve of the composite film, respectively. (E) The curves of the modulus reinforcing ratio of the composite film to the BN filling fraction for the BN sheets prepared by different methods.
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f6: (A) Photographs of the BN/PMMA composite film at (a) 0 wt.% BN; (b) 1 wt.% BN; (c) 2 wt. % BN; (d) 5 wt.% BN; (e) 10 wt.% BN. (B) Stress-strain curves of the BN/PMMA composite films with different BN filling fractions. (C, D) Elastic modulus versus BN filling fraction curve and tensile strength versus BN filling fraction curve of the composite film, respectively. (E) The curves of the modulus reinforcing ratio of the composite film to the BN filling fraction for the BN sheets prepared by different methods.

Mentions: At last, we prepared BN-nanosheet/polymethyl methacrylate (PMMA) composites to study the possible reinforcement for a polymer matrix. The as-grown BN sheets and PMMA were uniformly dispersed into the dimethylformamide (DMF) solutions and mixed together, then cast to form a thin film. The films were dried at 80°C; more detailed fabrication process can be found in the Experimental Section. The photographs of BN/PMMA composite films at different BN fractions (0 wt.%, 1 wt.%, 2 wt.%, 5 wt.%, 10 wt.%) are shown in Fig. 6A. Although the transparency of films gradually declines with an increase in BN sheet's fraction, they still exhibit decent transparency even at 10 wt.% loading fraction. The detailed optical transparency data can be found in Fig. S2 (Supporting Information). When BN fraction in the composite is smaller than 5 wt.%, the transparency is still more than 66%. A typical stress-strain curve of the composite film is given in Fig. 6B. Because the linear relation between the tensile stress and the strain can be clearly seen in the curve, the tensile behaviors of the BN-nanosheet/PMMA composite film can be determined to obey the classical Hook's law. The elastic modulus of the PMMA is found to increase from 1.30 GPa to 2.16 GPa when the filling fraction of the BN sheets becomes 10 wt.%. The tensile strength-BN filling fraction and elastic modulus-BN filling fraction curves are respectively given in Figs. 6C and 6D. The elastic modulus of PMMA has enhanced to 1.56 GPa when the BN's fraction is only 2 wt.%, this corresponds to a 20% increase compared to a blank PMMA. Particularly, one can see in Figure 6C that the film's modulus can still continue to increase with an increase of the BN's fraction and doesn't arrive at the climax within our measurement range. The composite film at 1 wt.% BN filling fraction possesses the highest tensile strength (40 MPa), i.e., an increase by 21.2% with respect to the blank PMMA (33 MPa). When the BN filling fraction is 2 wt.%, the tensile strength of the film is 34 MPa, which is slightly higher than that of the blank PMMA. If BN sheet fraction further increases, the tensile strength of the composite film will deteriorate, as seen in Fig. 6D. Therefore, 2 wt.% of the BN sheet loading fraction is thought to be the optimal value based on the considerations of the optical transparency, elastic and tensile properties. Further comparison on the reinforcement effect was made between the present BN sheets and those produced previously, as shown in Fig. 6E. In the curves, σmatrix and σcomposite are respectively the elastic modulus of the blank PMMA film and the composite film. As found in Fig. 6E, the Young's modulus of the composite film produced via the present route increases by 20% when the BN's fraction is 2 wt.%, which is higher than that measured before (14%). Also the reinforcement effect (43.8%) at 5 wt.% BN fraction is also better than that (35%) for a composite with a 6 wt.% BN fraction produced by us previously27. Such good performance may result from the high crystallinity and good dispersion of the sheets within the PMMA matrix. These results are also comparable with the good reinforcement effects of BN or C nanotubes in polymers16545556, which implies that the present BN nanosheets is a decent reinforcement materials for the polymer matrix composites.


Cheap, gram-scale fabrication of BN nanosheets via substitution reaction of graphite powders and their use for mechanical reinforcement of polymers.

Liu F, Mo X, Gan H, Guo T, Wang X, Chen B, Chen J, Deng S, Xu N, Sekiguchi T, Golberg D, Bando Y - Sci Rep (2014)

(A) Photographs of the BN/PMMA composite film at (a) 0 wt.% BN; (b) 1 wt.% BN; (c) 2 wt. % BN; (d) 5 wt.% BN; (e) 10 wt.% BN. (B) Stress-strain curves of the BN/PMMA composite films with different BN filling fractions. (C, D) Elastic modulus versus BN filling fraction curve and tensile strength versus BN filling fraction curve of the composite film, respectively. (E) The curves of the modulus reinforcing ratio of the composite film to the BN filling fraction for the BN sheets prepared by different methods.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3936228&req=5

f6: (A) Photographs of the BN/PMMA composite film at (a) 0 wt.% BN; (b) 1 wt.% BN; (c) 2 wt. % BN; (d) 5 wt.% BN; (e) 10 wt.% BN. (B) Stress-strain curves of the BN/PMMA composite films with different BN filling fractions. (C, D) Elastic modulus versus BN filling fraction curve and tensile strength versus BN filling fraction curve of the composite film, respectively. (E) The curves of the modulus reinforcing ratio of the composite film to the BN filling fraction for the BN sheets prepared by different methods.
Mentions: At last, we prepared BN-nanosheet/polymethyl methacrylate (PMMA) composites to study the possible reinforcement for a polymer matrix. The as-grown BN sheets and PMMA were uniformly dispersed into the dimethylformamide (DMF) solutions and mixed together, then cast to form a thin film. The films were dried at 80°C; more detailed fabrication process can be found in the Experimental Section. The photographs of BN/PMMA composite films at different BN fractions (0 wt.%, 1 wt.%, 2 wt.%, 5 wt.%, 10 wt.%) are shown in Fig. 6A. Although the transparency of films gradually declines with an increase in BN sheet's fraction, they still exhibit decent transparency even at 10 wt.% loading fraction. The detailed optical transparency data can be found in Fig. S2 (Supporting Information). When BN fraction in the composite is smaller than 5 wt.%, the transparency is still more than 66%. A typical stress-strain curve of the composite film is given in Fig. 6B. Because the linear relation between the tensile stress and the strain can be clearly seen in the curve, the tensile behaviors of the BN-nanosheet/PMMA composite film can be determined to obey the classical Hook's law. The elastic modulus of the PMMA is found to increase from 1.30 GPa to 2.16 GPa when the filling fraction of the BN sheets becomes 10 wt.%. The tensile strength-BN filling fraction and elastic modulus-BN filling fraction curves are respectively given in Figs. 6C and 6D. The elastic modulus of PMMA has enhanced to 1.56 GPa when the BN's fraction is only 2 wt.%, this corresponds to a 20% increase compared to a blank PMMA. Particularly, one can see in Figure 6C that the film's modulus can still continue to increase with an increase of the BN's fraction and doesn't arrive at the climax within our measurement range. The composite film at 1 wt.% BN filling fraction possesses the highest tensile strength (40 MPa), i.e., an increase by 21.2% with respect to the blank PMMA (33 MPa). When the BN filling fraction is 2 wt.%, the tensile strength of the film is 34 MPa, which is slightly higher than that of the blank PMMA. If BN sheet fraction further increases, the tensile strength of the composite film will deteriorate, as seen in Fig. 6D. Therefore, 2 wt.% of the BN sheet loading fraction is thought to be the optimal value based on the considerations of the optical transparency, elastic and tensile properties. Further comparison on the reinforcement effect was made between the present BN sheets and those produced previously, as shown in Fig. 6E. In the curves, σmatrix and σcomposite are respectively the elastic modulus of the blank PMMA film and the composite film. As found in Fig. 6E, the Young's modulus of the composite film produced via the present route increases by 20% when the BN's fraction is 2 wt.%, which is higher than that measured before (14%). Also the reinforcement effect (43.8%) at 5 wt.% BN fraction is also better than that (35%) for a composite with a 6 wt.% BN fraction produced by us previously27. Such good performance may result from the high crystallinity and good dispersion of the sheets within the PMMA matrix. These results are also comparable with the good reinforcement effects of BN or C nanotubes in polymers16545556, which implies that the present BN nanosheets is a decent reinforcement materials for the polymer matrix composites.

Bottom Line: Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials.Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film.In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.

View Article: PubMed Central - PubMed

Affiliation: 1] State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (PR China) [2] Inorganic Nanostructured Materials Group, World Premier International (WPI) Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki, Japan 305-0044.

ABSTRACT
As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5 nm to 40 nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300 nm to 500 nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.

No MeSH data available.


Related in: MedlinePlus