Carbon Papers from Tall Goldenrod Cellulose Fibers and Carbon Nanotubes for Application as Electromagnetic Interference Shielding Materials - MDPI
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molecules
Article
Carbon Papers from Tall Goldenrod Cellulose Fibers and
Carbon Nanotubes for Application as Electromagnetic
Interference Shielding Materials
Jihyun Park, Lee Ku Kwac, Hong Gun Kim and Hye Kyoung Shin *
Institute of Carbon Technology, Jeonju University, Jeonju-si 55069, Korea; jennai@jj.ac.kr (J.P.);
kwack29@jj.ac.kr (L.K.K.); hgkim@jj.ac.kr (H.G.K.)
* Correspondence: jokwanwoo@jj.ac.kr; Fax: +82-63-220-3161
Abstract: To transform tall goldenrods, which are invasive alien plant that destroy the ecosystem
of South Korea, into useful materials, cellulose fibers isolated from tall goldenrods are applied
as EMI shielding materials in this study. The obtained cellulose fibers were blended with CNTs,
which were used as additives, to improve the electrical conductivity. TGCF/CNT papers prepared
using a facile paper manufacturing process with various weight percent ratios and thickness were
carbonized at high temperatures and investigated as EMI shielding materials. The increase in the
carbonization temperature, thickness, and CNT content enhanced the electrical conductivity and EMI
SE of TGCF/CNT carbon papers. TGCF/CNT-15 papers, with approximately 4.5 mm of thickness,
carbonized at 1300 ◦ C exhibited the highest electrical conductivity of 6.35 S cm−1 , indicating an
EMI SE of approximately 62 dB at 1.6 GHz of the low frequency band. Additionally, the obtained
TGCF/CNT carbon papers were flexible and could be bent and wound without breaking.
Citation: Park, J.; Kwac, L.K.; Kim, Keywords: tall goldenrod; electromagnetic interference shielding materials; carbon nanotube; carbon
H.G.; Shin, H.K. Carbon Papers from papers
Tall Goldenrod Cellulose Fibers and
Carbon Nanotubes for Application as
Electromagnetic Interference
Shielding Materials. Molecules 2022, 1. Introduction
27, 1842. https://doi.org/
Recently, owing to the widespread use of electronic devices and wireless communica-
10.3390/molecules27061842
tion, the amount of exposure to electromagnetic (EM) waves has increased significantly.
Academic Editor: Bhanu P. Long-term exposure to EM waves affects human health. To overcome these issues, electro-
S. Chauhan magnetic interference (EMI) shielding materials are necessary. Generally, EMI shielding
Received: 17 February 2022
materials require a high electrical conductivity, high-efficiency absorption tunability, corro-
Accepted: 9 March 2022
sion resistance, thermal stability, and light weight [1–7].
Published: 11 March 2022
Metals have been widely used as a representative electrically conductive filler for ap-
plication as EMI shielding materials, but they have disadvantages, such as being expensive,
Publisher’s Note: MDPI stays neutral
heavy, corrosive, and difficult to disperse [8]. Therefore, carbon materials have recently
with regard to jurisdictional claims in
received attention as alternative EMI shielding materials. Carbon materials possess several
published maps and institutional affil-
advantages, such as high electrical conductivity, thermal stability, corrosion resistance, light
iations.
weight, cost effectiveness, and low density [9–13].
Carbon materials are obtained from diverse precursors, such as polyacrylonitrile
(PAN), pitch, and cellulose. Among them, PAN- and pitch-based fibers obtained from
Copyright: © 2022 by the authors.
fossil fuels cause various environmental problems including toxic gas emissions during
Licensee MDPI, Basel, Switzerland. severe high-temperature treatment and recycling [14]. However, cellulose is a non-toxic
This article is an open access article and biodegradable material obtained from wood or non-wood and is one of the most
distributed under the terms and abundant materials in nature. Moreover, semi-crystalline cellulose has excellent mechanical
conditions of the Creative Commons properties owing to its high aspect ratio and strong hydrogen bond interactions with
Attribution (CC BY) license (https:// hydroxyl groups in the linear polymer, therefore, they have been applied in the fields
creativecommons.org/licenses/by/ of paper, plastic replacement materials, and composite fillers. However, cellulose does
4.0/). not exhibit electrical conductivity [15–18]. Therefore, the application of cellulose as EMI
Molecules 2022, 27, 1842. https://doi.org/10.3390/molecules27061842 https://www.mdpi.com/journal/molecules
Molecules 2022, 27, 1842 2 of 11
shielding materials requires the induction of electrical conductivity in these materials via
treatments at various carbonization temperatures. Carbon nanotubes (CNTs), which can
be used as additives to improve the EMI shielding effectiveness, demonstrate an excellent
electrical conductivity. Additionally, CNTs with a large aspect ratio show outstanding
thermal and mechanical properties and are cost-effective compared to graphene [19–27].
Therefore, CNTs are considered to be promising EMI shielding additives.
Pang et al. [28] fabricated a composite paper by mixing cellulose as a matrix and
CNTs as conductive fillers via vacuum filtration. As a result, according to the increase
of CNT contents, the electrical conductivity enhanced to 216.3 S m−1 , thereby increasing
the EMI to 45 dB at 175–1600 MHz. Imai et al. [29] studied CNT/cellulose composites
manufactured using a paper-making process, utilizing cellulose fibers with various CNT
contents. Cellulose composites containing a CNT content of 16.7 wt% exhibited an electric
conductivity of 671 S m−1 owing to a large amount of CNT web structures with a high
electrical conductivity; however, in the case of the composites containing CNT over 5 wt%,
the tensile strength decreased. In terms of the EMI SE, CNT/cellulose composite paper
with a CNT content of 4.8 wt% exhibited 50 dB of EMI SE at 5–10 GHz (low-frequencies)
and a CNT content of 10 wt% reached 20 dB at high frequencies. Lee et al. [30] prepared
multi-walled carbon nanotube (MWCNT)-coated cellulose papers through a facile dip-
coating process. As the cycle of the dip-coating increased from 1 to 30, the thickness of
the MWCNT/cellulose paper increased, and therefore, the electrical conductivity changed
from 0.02 S cm−1 to 1.11 S cm−1 in the in-plane direction. Moreover, the EMI SE of
MWCNT/cellulose paper reached ~20.3 dB at 1 GHz, which demonstrated ~1.11 S cm−1
electrical conductivity at a thickness of ~170 µm. In this study, we prepared cellulose-based
carbon papers containing CNTs for application as EMI shielding materials. First, cellulose
was isolated from “tall goldenrods,” which are invasive alien plants in South Korea. Tall
goldenrods cause major issues while preserving the ecosystem of South Korea by interfering
with the growth of native plants [31]. Therefore, it is necessary to convert them into useful
materials with environmental and economic benefits. In this study, we used cellulose
obtained from tall goldenrod as an EMI shielding material, thereby enabling the conversion
of detrimental and noxious plants to useful materials. The obtained tall goldenrod cellulose
fibers (TGCFs) were mixed according to the CNT content and then carbonized at various
carbonization temperatures. The obtained TGCF/CNT carbon papers were characterized
using EMI shielding effectiveness (EMI SE) (0.5–1.6 GHz), electrical conductivity, X-ray
diffraction (XRD), Raman spectral analysis, and scanning electron microscopy (SEM).
2. Results and Discussion
2.1. Electrical Conductivity and Electromagnetic Interference Shielding Effectiveness
The effect of various carbonization temperatures, the thickness of TGCF/CNT, and
the CNT content on the electrical conductivity are shown in Figure 1. First, all samples
carbonized at 700 ◦ C demonstrated an electrical conductivity of approximately 0 S cm−1 ,
which was unrelated to the thickness of the TGCF/CNT carbon papers and the CNT
contents. At a carbonization temperature of 900 ◦ C, the electrical conductivity was detected
in the samples. In general, the electrical conductivity increased with the increase in the
carbonization temperature, CNT content, and paper thickness. For instance, the electrical
conductivity of TGCF/CNT carbon papers with a thickness of approximately 1.5 mm
reached 3.97 S m−1 as the CNT content and carbonization temperature increased. Similarly,
TGCF/CNT carbon papers with a thickness of approximately 3 mm exhibited a value of
~4.78 S m−1 . Finally, the TGCF/CNT-15 carbon paper with a thickness of approximately
4.5 mm carbonized at 1300 ◦ C reached a value of ~6.35 S cm−1 . This is because the
introduction of more CNTs with a high electrical conductivity (~10 S m−1 ) decreased
the distance between CNTs and led to thicker TGCF/CNT carbon papers with a high
CNT loading, thereby increasing the electrical conductivity. Moreover, the increase in the
carbonization temperature decreased the distance between the carbon clusters, facilitating
Molecules 2022, 27, x FOR PEER REVIEW 3 of 11
Molecules 2022, 27, x FOR PEER REVIEW 3 of 11
Molecules 2022, 27, 1842 3 of 11
thereby increasing the electrical conductivity. Moreover, the increase in the carbonization
temperature decreased
thereby increasing the distance
the electrical between the
conductivity. carbon clusters,
Moreover, facilitating
the increase electron hop‐
in the carbonization
ping and
temperaturethe quasi‐percolation
decreased of the conducting area [32]. These electrical conductivity
electron hopping andthe
thedistance between the of
quasi-percolation carbon clusters, facilitating
the conducting area [32].electron
Thesehop‐
electrical
variations were reflected in the EMI SE results.
ping and the quasi‐percolation of the conducting area [32]. These electrical conductivity
conductivity variations were reflected in the EMI SE results.
variations were reflected in the EMI SE results.
Figure Electricalconductivity
Figure 1. Electrical conductivityofof TGCF/CNT
TGCF/CNT carbon
carbon papers
papers withwith various
various carbonization
carbonization tempera-
tempera‐
tures, thicknesses,
tures,
Figure thicknesses,
1. and
andthe
theCNT
CNT
Electrical conductivity content.
of content.
TGCF/CNT carbon papers with various carbonization tempera‐
tures, thicknesses, and the CNT content.
Generally,
Generally,when
whenincident
incidentEMIEMI waves
waves encounter
encountershielding materials,
shielding the intensity
materials, of of
the intensity
EM waves are
EM Generally, reduced
waves arewhen
reduced owing
owing
incident to
EMI reflection,
towaves
reflection,absorption, and
absorption,
encounter multiple
and
shielding reflections
multiplethe
materials, [33–36].
reflections [33–36].
intensity of
Therefore,
Therefore,
EM EMIreduced
waves are SE
SE isis defined
owingby
defined to measuring
by the
thereduced
measuringabsorption,
reflection, reducedeffect ofof
effect
and EMEM
multiple waves
waves onon
reflectionsthe shield‐
the shielding
[33–36].
ing materials.
materials.
Therefore, TheThe
EMI SE istotal
total EMI‐SE
EMI-SE
defined by is given
ismeasuring
given bybythe
thefollowing
the following
reduced equation:
equation:
effect of EM waves on the shield‐
ing materials. The total EMI‐SE is given by the following
SE = SER + SEA + SEM equation:
SE = SER + SEA + SEM
SE = SEabsorption,
where SER, SEA, and SEM are the reflection, R + SEA + SEM
and multiple reflection values (in
where SE
decibels , SE
(dB)), , and SE are
respectively.
where SER,RSEA,Aand SEM are the reflection, absorption, and multiple
M the reflection, absorption, andmechanism
Figure 2 shows the EMI SE multiple for reflection
valuesvalues
the TGCF/CNT
reflection (in (in
carbon papers
decibels (dB)), [37,38].
respectively. Figure 2 shows the EMI SE mechanism for
decibels (dB)), respectively. Figure 2 shows the EMI SE mechanism for the TGCF/CNT the TGCF/CNT
carbonpapers
carbon papers[37,38].
[37,38].
Figure 2. Electromagnetic interference shielding mechanism of the TGCF/CNT carbon paper.
Electromagnetic
Figure2.2.Electromagnetic
Figure interference
interference shielding
shielding mechanism
mechanism ofTGCF/CNT
of the the TGCF/CNT
carboncarbon
paper. paper.
Figure 3 shows the EMI SE of the TGCF/CNT carbon papers according to the respec‐
tive Figure
conditions.
Figure3 3showsFrom
shows theFigure
the
EMIEMI
SE 3,SE thethe
of ofEMI
the SE of TGCF/CNT
TGCF/CNT
TGCF/CNT carbon
carbon carbon
papers papers
papers
according was
according affected
to the to theby
respec‐ respec-
the
tive electrical
conditions. conductivity,
From which
Figure 3, thevaries
EMI according
SE of to
TGCF/CNT the carbonization
carbon
tive conditions. From Figure 3, the EMI SE of TGCF/CNT carbon papers was affected by papers temperatures,
was affected by
thickness, and
the electrical
the CNT content
electrical conductivity,
conductivity, whichof the
which variesTGCF/CNT papers.
varies according In
according to the the case of
the carbonization the TGCF/CNT
carbonization temperatures, car‐
temperatures, thick-
bon papers
ness, andand
thickness, carbonized
CNT CNTcontent atof
content700
the
of °C,
the the EMI SE was
TGCF/CNT
TGCF/CNT 0 dB because
papers.
papers. theirof
the case
In the case electrical
of conductivity
theTGCF/CNT
the TGCF/CNT car‐carbon
was
bon 0 S m
papers
papers
−1. At a carbonization
carbonized
carbonized atat700 ◦
700 °C, temperature
C, the EMI EMISE of
SEwas 900
was °C,
0 dB EMI
because
0 dB SE
because began
theirtheirto be
electricalobserved owing
conductivity
electrical conductivity
was
was0 0S S m. −
m−1 At1 .a At
carbonization temperature
a carbonization of 900 °C,
temperature ofEMI
900 SE◦ C,began
EMI to SEbebegan
observed owing
to be observed
owing to the presence of the electrical conductivity in the carbon papers. In the case of
TGCF/CNT carbon papers with a thickness of 1.5 mm that were carbonized at 900 ◦ C,
with the increase in the CNT content, the EMI SE increased from 5 dB to 13 dB at 1.6 GHz.
When the thickness of the TGCF/CNT carbon paper carbonized at 900 ◦ C was increased
Molecules 2022, 27, x FOR PEER REVIEW 4 of 11
to the presence of the electrical conductivity in the carbon papers. In the case of
Molecules 2022, 27, 1842 TGCF/CNT carbon papers with a thickness of 1.5 mm that were carbonized at 900 °C, 4 of with
11
the increase in the CNT content, the EMI SE increased from 5 dB to 13 dB at 1.6 GHz.
When the thickness of the TGCF/CNT carbon paper carbonized at 900 °C was increased
to 4.5
to 4.5mm,
mm,thetheEMI
EMISESEreached
reachedapproximately
approximately ~20~20dBdBat at
1.61.6 GHz.
GHz. So,So,
forfor
thethe TGCF/CNT
TGCF/CNT
carbon papers
carbon paperscarbonized
carbonizedatat1100 ◦
1100 C,°C,with
withananincrease
increaseininthetheCNT
CNT content
content and
and thickness,
thickness,
their EMI
their EMISE SEelevated
elevatedtotoapproximately
approximately4242dBdB atat
1.61.6 GHz.
GHz. Finally,
Finally, TGCF/CNT‐15
TGCF/CNT-15 carbon
carbon
papers
papers with
with aa thickness
thickness of 4.5 mm showed the highest EMI EMI SE SE value
value of
of approximately
approximately 62
62
dBdBat at
1.61.6 GHz,
GHz, while
while exhibitingananelectrical
exhibiting electricalconductivity
conductivityof of6.35 cm−1−.1 .
6.35SScm
Figure3.
Figure 3. Electromagnetic
Electromagneticinterference
interferenceshielding
shielding effectiveness
effectiveness of of TGCF/CNT
TGCF/CNT carbon
carbon papers
papers obtained
obtained
accordingto
according tovarious
variouscarbonization
carbonizationtemperatures,
temperatures, thicknesses,
thicknesses, andand carbon
carbon nanotube
nanotube (CNT)
(CNT) content.
content.
2.2.
2.2. XRD
XRD and
andRaman
RamanAnalysis
Analysis
Figure
Figure 4 shows theXRD
4 shows the XRDprofiles
profilesofofthe TGCF/CNT
the TGCF/CNTcarbon carbonpapers
papersobtained
obtainedusing
using
various carbonization temperatures, thicknesses,
various carbonization temperatures, thicknesses, and
andCNT contents. For all the samples,
CNT contents. For all the samples,
broad ◦ ◦ . These two peaks were associated
broadandandweak
weakpeaks
peaksappeared
appearedatat2θ2θ= =24–26
24–26°and
and4343°. These two peaks were associated
with the (002) and (100) crystalline planes owing to the carbonization of cellulose fibers.
with the (002) and (100) crystalline planes owing to the carbonization of cellulose fibers.
Additionally, all TGCF/CNT carbon papers showed a powerful and sharp peak with a
Additionally, all TGCF/CNT carbon papers showed a powerful and sharp peak with a 2θ
2θ value of 26◦ , which is attributed to the (002) plane of CNT. The intensity of the peak at
value of 26°, which is attributed to the (002) plane of CNT. The intensity of the peak at 2θ
2θ = 24–26◦ for the TGCF/CNT carbon papers obtained at 700 ◦ C showed the widest FWHM
= 24–26° for the TGCF/CNT carbon papers obtained at 700 °C showed the widest FWHM
value, owing to the low crystallinity of the carbonized cellulose fibers. As the carbonization
value, owingincreased,
temperature to the lowthecrystallinity
intensity of of
thethe carbonized
peaks cellulose
at 2θ = 24–26 fibers.
◦ of the As the carboniza‐
TGCF/CNT carbon
tion temperature
papers increased, andincreased, the intensity full
their corresponding of the peaks
width at 2θ = 24–26°(FWHM)
at half-maximum of the TGCF/CNT
slightly
carbon papers
decreased (Tableincreased,
1). These and their
results corresponding
were full widthofatthe
due to the conversion half‐maximum (FWHM)
graphite structure as
◦
the carbonization temperature increased. Additionally, a peak at 24–26 as well as peak at
26◦ were observed in all XRD profiles, indicating the successful bonding of cellulose fibers
with the CNTs.
slightly decreased (Table 1). These results were due to the conversion of the graphite struc‐
ture as the carbonization temperature increased. Additionally, a peak at 24–26° as well as
Molecules 2022, 27, 1842 5 of 11
peak at 26° were observed in all XRD profiles, indicating the successful bonding of cellu‐
lose fibers with the CNTs.
Figure 4.
Figure 4. X-ray
X‐ray diffraction profiles of TGCF/CNT
TGCF/CNTcarbon
carbonpapers
papersfor
forvarious
variouscarbonization
carbonizationtempera‐
tempera-
tures and CNT contents.
tures and CNT contents.
Table1.1.X-ray
Table X‐raydiffraction
diffractiondata
dataofofthe
theTGCF/CNT
TGCF/CNTcarbon
carbonpapers
papersobtained
obtained using
using various
various carboniza‐
carbonization
tion temperatures and CNT contents.
temperatures and CNT contents.
Sample
Sample
Temperature (°C)
Temperature (◦ C)
Peak Center (°)
Peak Center (◦ )
FWHM
FWHM
700 24.6732 9.6967
700 24.6732 9.6967
900 23.5305 8.7017
TGCF/CNT‐5 900 23.5305 8.7017
TGCF/CNT-5 1100 24.9558 8.2799
1100
1300 24.9558
23.7124 8.2799
7.8274
1300
700 23.7124
24.1033 7.8274
9.4169
900
700 24.1434
24.1033 8.7306
9.4169
TGCF/CNT‐10
1100
900 23.8214
24.1434 8.3818
8.7306
TGCF/CNT-10
1300
1100
24.5917
23.8214
7.8377
8.3818
700 24.0882 9.4835
1300 24.5917 7.8377
900 24.4107 8.9613
TGCF/CNT‐15 700 24.0882 9.4835
1100 24.6815 8.3149
900 24.4107 8.9613
TGCF/CNT-15 1300 24.9613 7.0362
1100 24.6815 8.3149
1300 24.9613 7.0362
The changes in the ordered and disordered structures of the TGCF/CNT carbon papers
resulting from various carbonization temperatures and CNT contents were observed in the
Raman spectra. As shown in Figure 5, the representative peaks at 1350 cm−1 and 1610 cm−1
corresponding to the graphitic (G) bands and defect (D) were observed in all samples. The
The changes in the ordered and disordered structures of the TGCF/CNT carbon pa‐
pers resulting from various carbonization temperatures and CNT contents were observed
Molecules 2022, 27, 1842 in the Raman spectra. As shown in Figure 5, the representative peaks at 1350 cm 6 of 11and
−1
1610 cm corresponding to the graphitic (G) bands and defect (D) were observed in all
−1
samples. The G band is related to sequential graphite structures with intra‐layer vibra‐
tions
G bandofissprelated
2‐bonded carbon atoms, and D band is associated with disordered and
to sequential graphite structures with intra-layer vibrations of sp2 -bonded defective
graphite [39–41]. The intensity ratios of the G and D peaks (IG/ID), which are listed in Table
carbon atoms, and D band is associated with disordered and defective graphite [39–41].
2, can
The be used
intensity to of
ratios determine
the G and the number
D peaks (IG /Iof graphitic structures. The IG/ID ratio of the
D ), which are listed in Table 2, can be used to
TGCF/CNT
determine thecarbon
number papers increased
of graphitic with the
structures. Thecarbonization
IG /ID ratio oftemperature
the TGCF/CNT and carbon
CNT con‐
tent. These
papers increasedresults
withare
thebecause the increase
carbonization in carbonization
temperature temperatures
and CNT content. and the
These results are in‐
creased the
because addition of CNT
increase having the graphite
in carbonization structures
temperatures resulted
and the in the
increased increaseofofCNT
addition graph‐
itization.
having the graphite structures resulted in the increase of graphitization.
Figure5.5.Raman
Figure Ramanspectra
spectraofofTGCF/CNT
TGCF/CNTcarbon
carbonpapers
papersobtained according
obtained to various
according carbonization
to various carbonization
temperaturesand
temperatures andCNT
CNTcontents.
contents.
Table2.2.Ratio
Table Ratioofofgraphitic
graphiticto to defect
defect structures
structures in TGCF/CNT
in TGCF/CNT carbon
carbon papers
papers (i.e., (i.e.,
ratio ratio of heights
of heights of G of
G and D peaks in Figure
and D peaks in Figure 5). 5).
Temperature (°C)
Temperature (◦ C) 700700 900
900 1100
1100 1300
1300
Sample
Sample
TGCF/CNT-5
TGCF/CNT‐5 0.88
0.88 0.96
0.96 1.09
1.09 1.40
1.40
TGCF/CNT‐10
TGCF/CNT-10 0.90
0.90 1.02
1.02 1.11
1.11 1.42
1.42
TGCF/CNT‐15
TGCF/CNT-15 0.94
0.94 1.06
1.06 1.22
1.22 1.45
1.45
2.3. Tensile Strength and Morphology of TGCF/CNT Carbon Paper
2.3. Tensile Strength and Morphology of TGCF/CNT Carbon Paper
Figure6a–d
Figure 6a–dshows
showsphotographs
photographs ofof TGCF/CNT
TGCF/CNT papers
papers with
with different
different CNT CNT ratios.
ratios. As As
shown in Figure 6a, the TGCF/CNT paper became darker gray with
shown in Figure 6a, the TGCF/CNT paper became darker gray with an increase in the an increase in the
CNT content. After carbonization, the TGCF/CNT carbon paper displayed
CNT content. After carbonization, the TGCF/CNT carbon paper displayed an apparent an apparent
sizereduction,
size reduction,but
butmaintained
maintained itsits shape.
shape. InIn addition,
addition, thethe TGCF/CNT
TGCF/CNT carbon
carbon papers
papers could
could
be flexibly
be flexiblybent
bentand
andwound
wound without
without breaking.
breaking. Figure
Figure 6e shows
6e shows that that the tensile
the tensile strengths
strengths of
of samples decreased slightly with the increase of carbonization temperature
samples decreased slightly with the increase of carbonization temperature for every CNT for every
CNT content;
content; even
even at the at the lowest
lowest temperature
temperature and CNTandcontent,
CNT content, thebar
the error error
didbarnotdid not ex‐
extend
tend appreciably
appreciably above above
7 MPa.7 MPa.
Molecules 2022, 27, x FOR PEER REVIEW 7 of 11
Molecules 2022, 27, 1842 7 of 11
Molecules 2022, 27, x FOR PEER REVIEW 7 of 11
Figure6.6.Photographs
Figure Photographs of TGCF/CNT
of TGCF/CNT papers:
papers: (a) with
(a) with different
different carbon‐nanotube
carbon-nanotube (CNT) contents
(CNT) contents
Figure 6. Photographs of TGCF/CNT papers: (a) with different carbon‐nanotube (CNT) contents
before
before carbonization; (b) after and before carbonization, showing shrinkage TGCF/CNT carbon pa‐
before carbonization; (b)after
carbonization; (b) afterand
andbefore
beforecarbonization,
carbonization, showing
showing shrinkage
shrinkage TGCF/CNT
TGCF/CNT carbon
carbon pa‐
per before
paper
per before
beforeand
and
and after
after
after carbonization;
carbonization;
carbonization; (c)bending
(c) (c) bending
bending ofof
of thethethe TGCF/CNT
TGCF/CNT
TGCF/CNT carbon
carbon
carbon paper;
paper;
paper; (d) (d) (d) winding
winding
winding of of the
of the
TGCF/CNT
the TGCF/CNT
TGCF/CNT carbon
carbon
carbon paper.
paper. (e)(e)
paper. Tensile
(e) Tensile
Tensile strength
strength
strength ofof
of the the
theTGCF/CNT
TGCF/CNT carboncarbon
TGCF/CNT carbonpapers
papers papersaccording
accordingaccording
to carbon‐to
to carbon‐
izationtemperature
ization temperature
carbonization and
and
temperature CNTCNT
and content.
content.
CNT content.
The
Thesurface
The surfaceSEM
surface SEM
SEM images
imagesof the TGCF/CNT
of the TGCF/CNT
TGCF/CNT carbon
carbon papers
carbon
papers areshown
papers
are shown ininFigure
are shown Figure
in 7.7.
Figure 7.
CNTs
CNTs are
are more
more attached
attached and
and aggregated on the surface
surface of
of the
the cellulose
cellulose fibers.
fibers.
CNTs are more attached and aggregated on the surface of the cellulose fibers. Therefore, Therefore,
Therefore,
the
theSEM
the SEMresults
SEM resultsindicated
results indicated a higher
indicated amount
a higher of CNT
amount attachment
attachment
of CNT on the
on
attachment theonfiber
fiber improved
theimproved the
the
fiber improved the
electrical
electrical conductivity
conductivity and
and EMI SE.
electrical conductivity and EMI SE.
Figure 7.
Figure 7. SEM
SEM images
images of
of TGCF/CNT
TGCF/CNT paper
paperobtained
obtainedusing
usingvarious
variouscellulose
celluloseand
andCNT
CNTratios.
ratios.
Figure
3.
3. 7. SEM
Materials
Materials images
and of TGCF/CNT paper obtained using various cellulose and CNT ratios.
Methods
3.1.
3.1. Materials
Materials
3. Materials
Tall and Methods
Tall goldenrod
goldenrod plants
plants were
were gathered
gathered in
in the
the southern region of
southern region of South
South Korea.
Korea. CNTs
CNTs
3.1.
were Materials
purchased from Nano Solution (Jeonju-si, Jeollabuk-do, Korea). All chemicals were
were purchased from Nano Solution (Jeonju‐si, Jeollabuk‐do, Korea). All chemicals were of
analytical
Tall grade
of analytical andand
goldenrod
grade were used
plants
were as received.
were
used asgathered
received. in the southern region of South Korea. CNTs
were
3.2. purchased
Preparation from Nano
of TGCF/CNT Solution
Carbon (Jeonju‐si, Jeollabuk‐do, Korea). All chemicals were
Papers
3.2. Preparation of TGCF/CNT Carbon Papers
of analytical grade and were used as received.
As shown in Figure 8, to obtain cellulose fibers from tall goldenrod plants, first, the
As shown in Figure 8, to obtain cellulose fibers from tall goldenrod plants, first, the
flowers and leaves of dried tall goldenrods were disposed and parts of their trunk were
flowers
3.2. and leaves
Preparation of dried tall Carbon
of TGCF/CNT goldenrods were disposed and parts of their◦ trunk were
Papers
chipped by approximately 1 mm. The chips were autoclaved for 5 h at 121 C in 15 wt%
chipped by approximately 1 mm. The chips were autoclaved for 5 h at 121 °C in 15 wt%
NaOHAs shown in Figure 8, to obtain cellulose
solution and then bleached twice using fibers
10 wt% H from tall goldenrod
O solution and a 5 wt% plants,
H Ofirst, the
NaOH solution and then bleached twice using 10 wt% H22O22 solution and a 5 wt% H22O22
stabilizer.
flowers and The bleached tall goldenrod pulps were used as TGCFs.parts The TGCFs were
stabilizer. Theleaves
bleached of tall
dried tall goldenrods
goldenrod pulps werewere
useddisposed
as TGCFs.andThe TGCFsof their
were trunk were
mixed
mixed
chipped with
byCNTs in water at weight
approximately 1 mm. percentage
The chips ratios
were (95:5, 90:10, and
autoclaved for 585:15),
h at and °C
121 1 wt%
in 15 wt%
with CNTs in water at weight percentage ratios (95:5, 90:10, and 85:15), and 1 wt% poly‐
polyacrylamide
NaOH solution (PAM) solution as a binder was added. Finally, through the filtration
acrylamide (PAM)and then as
solution bleached
a bindertwice
was added. 10 wt%through
usingFinally, H2O2 solution andprocess
the filtration a 5 wt% H2O2
process of the TGCF/CNT solution, the respective papers in accordance with the weight
stabilizer. The bleached tall goldenrod pulps were used as TGCFs. The
of the TGCF/CNT solution, the respective papers in accordance with the weight percent‐ TGCFs were mixed
percentage ratios were prepared. The TGCF/CNT papers were carbonized at 700, 900, 1100,
withratios
age CNTs in water
were at weight
prepared. percentage
The TGCF/CNT ratios
papers were(95:5, 90:10, and
carbonized 85:15),
at 700, 900, and
1100,1andwt% poly‐
and 1300 ◦ C. The TGCF/CNT paper samples were labeled as TGCF/CNT-5, TGCF/CNT-10,
1300 °C. The TGCF/CNT
acrylamide (PAM) paper as
solution samples
a were
binder labeled
was as TGCF/CNT‐5,
added. Finally, TGCF/CNT‐10,
through the and process
filtration
and TGCF/CNT-15 according to the CNT content.
TGCF/CNT‐15
of the TGCF/CNT according to thethe
solution, CNT content. papers in accordance with the weight percent‐
respective
age ratios were prepared. The TGCF/CNT papers were carbonized at 700, 900, 1100, and
1300 °C. The TGCF/CNT paper samples were labeled as TGCF/CNT‐5, TGCF/CNT‐10, and
TGCF/CNT‐15 according to the CNT content.
Molecules
Molecules2022,
2022, 27,
27, x1842
FOR PEER REVIEW 8 of8 11
of 11
Molecules 2022, 27, x FOR PEER REVIEW 8 of 11
Figure
Figure 8.8. Process
Processfor
forthe
theextraction ofofcellulose
extractionof fibers
cellulose from
fibers tall goldenrods
from and thethe
preparation of
Figure 8. Process for the extraction cellulose fibers from talltall goldenrods
goldenrods andand preparation
the preparation of of
TGCF/CNT
TGCF/CNT carbon
carbon papers.
TGCF/CNT carbon papers.papers.
The
The chemical
chemicalcompositions
compositionsof ofoftall goldenrods
tallgoldenrods
goldenrods and
andTGCF
TGCF are shown in Table 3. The
The chemical compositions tall and TGCF areare shown
shown in Table
in Table 3. The
3. The
cellulose,
cellulose, hemicellulose, and
hemicellulose,and lignin
andlignin contents
lignincontents
contents were
were obtained
obtained by the Technical Association
cellulose, hemicellulose, were obtained by by
thethe Technical
Technical Association
Association
of the Pulp and Paper Industry (TAPPI) process and the silica ash was settled by the
of the Pulp
Pulp and
andPaper
PaperIndustry
Industry(TAPPI)
(TAPPI) process
process andand
thethe silica
silica ashash
waswas settled
settled by ther‐
by the the ther‐
thermogravimetric analysis (TGA, SDT 650, TA, New Castle, DE, USA). The SEM image in
mogravimetric analysis(TGA,
mogravimetric analysis (TGA,SDT SDT650, 650,TA,
TA,
NewNew Castle,
Castle, DE,DE, USA).
USA). TheTheSEM SEMimageimage
in in
Figure 9a shows that TGCFs have fiber diameters in the range of approximately 8~13 µm.
Figure 9a
9a shows
showsthat
thatTGCFs
TGCFshave
havefiber
fiber diameters
diametersin in
thethe
range
rangeof approximately
of◦approximately 8 ~ 13
8 ~μm.
13 μm.
The XRD profile in Figure 9b shows the diffraction peaks at 2θ = 16 and 22.6◦ , assigned to
The XRD
XRD profile
profileininFigure
Figure9b9bshows
showsthe thediffraction
diffractionpeaks
peaksat 2θ = 16°
at 2θ andand
= 16° 22.6°, assigned
22.6°, assigned
the (110) and (200) planes, respectively; they are associated with cellulose I [42,43].
to the (110)
(110) and
and(200)
(200)planes,
planes,respectively;
respectively; they areare
they associated
associatedwith cellulose
with I [42,43].
cellulose I [42,43].
Table 3. Chemical composition of tall goldenrod and tall goldenrod cellulose fiber (TGCF).
Table 3.
Table 3. Chemical
Chemicalcomposition
compositionofoftall
tallgoldenrod
goldenrodand talltall
and goldenrod cellulose
goldenrod fiberfiber
cellulose (TGCF).
(TGCF).
Cellulose (%) Hemicellulose (%) Lignin (%) Silica Ash (%)
Cellulose
Cellulose (%) Hemicellulose (%) Lignin (%) Silica AshAsh
(%)
Tall golden rod 42.66 ± 2.10 (%) Hemicellulose
29.17 ± 1.97 (%) 19.62
Lignin
± 1.05(%) Silica
25.95 ± 0.17 (%)
Tall golden
Tall golden rod
rod 42.66
42.66± 2.10
± 2.10 29.17 ±
29.17 1.97 19.62 ± 1.05 25.95 ± 0.17
TGCF 95.05 ± 2.45 0 ± 1.97 19.62
0 ± 1.05 25.95
0 ± 0.17
TGCF 95.05 ± 2.45 0 0 0
TGCF 95.05 ± 2.45 0 0 0
Figure
Figure 9.9. Tall
Tall goldenrod
goldenrod cellulose
cellulose fibers: (a) Scanning
fibers: (a) Scanning electron
electron micrograph;
micrograph; (b)
(b) X‐ray
X-ray diffraction
diffraction
profile.
profile.
Figure 9. Tall goldenrod cellulose fibers: (a) Scanning electron micrograph; (b) X‐ray diffraction
profile.
3.3.
3.3. Analysis
Analysis
The
The EMI
EMISE
3.3. Analysis SEanalyzer
analyzer(KEYSIGHT,
(KEYSIGHT,E5080AE5080A Vector
VectorNetwork
NetworkAnalyzer,
Analyzer,Santa Rosa,
Santa CA,
Rosa,
USA) was
CA, USA) scanned
was scannedin the frequency
in the(KEYSIGHT, range
frequency range of 0.5 to 1.6
of 0.5VectorGHz.
to 1.6 GHz. Figure 10 shows
FigureAnalyzer, the
10 shows Santa EMI
the EMI
The analyzer
shielding EMI SE apparatus.
analyzer This network E5080A
analyzer can Network
determine the effectiveness Rosa,
of the
shielding analyzer
CA, USA) was apparatus.
scanned inand This network
thereflection
frequency analyzer can determine the effectiveness of
absorption, transmission,
the absorption, transmission, and ofrange
reflection
of 0.5 to
TGCF/CNT
of TGCF/CNT
1.6 GHz.
carbon Figure 10 shows the EMI
papers.
carbon papers.the effectiveness of
shielding analyzer apparatus. This network analyzer can determine
the absorption, transmission, and reflection of TGCF/CNT carbon papers.
carbon fibers obtained with various CNT contents and carbonization temperatures was
observed using XRD (RIGAKU, D/MAX‐2500 instrument, Tokyo, Japan) with Cu Kα ra‐
diation operating at 40 kV and 30 mA. Raman spectra were obtained using an ARAMIS
instrument (Horiba Jobin Yvon, Tokyo, Japan) with a 514 nm laser. The morphology of
Molecules 2022, 27, 1842
the TGCF/CNT carbon papers was observed using SEM (SU8220, HITACHI, Tokyo, Ja‐ 9 of 11
pan).
Figure10.
Figure Apparatus
10.Apparatus ofof
EMIEMI shielding
shielding analyzer.
analyzer.
The electrical conductivity was measured using an electrical conductivity surface and
4. Conclusions
volume low resistivity
We isolated cellulosefor conductive
fiber from tall materials
goldenrods,(MCP-T700,
which is anLOTESTA-GX, NITTOSEIKO
invasive plant in Korea,
ANALYTECH, Kanagawa, Japan). The conversion of crystalline structures
for application as an EMI shielding material. CNTs were used as additives to develop of TGCF/CNT
the
carbon fibers
electrical obtained
conductivity andwith
EMIvarious CNT contents
SE. Through and carbonization
a facile paper temperatures
process, TGCF/CNT papers was
observed
with using
different XRDpercent
weight (RIGAKU,ratios D/MAX-2500
were prepared andinstrument,
carbonizedTokyo, Japan)
at various with
high tem‐Cu Kα
radiationand
peratures operating
used asat 40 kV
EMI and 30materials.
shielding mA. Raman spectra were
The increase in theobtained usingtemper‐
carbonization an ARAMIS
instrument
ature, (Horiba
thickness, Jobincontent
and CNT Yvon, Tokyo,
enhancedJapan) with a 514
the electrical nm laser. The
conductivity morphology
and EMI SE of the of the
TGCF/CNTcarbon
TGCF/CNT carbon papersAmong
papers. was observed using SEM (SU8220,
them, TGCF/CNT‐15 HITACHI,
papers with Tokyo, 4.5
approximately Japan).
mm in thickness that are carbonized at 1300 °C exhibited the highest electrical conductiv‐
4. Conclusions
ity of 6.35 S cm−1, demonstrating EMI SE of approximately 62 dB at 1.6 GHz of the low
frequency band. Incellulose
We isolated addition, fiber
we observed that
from tall all sampleswhich
goldenrods, were flexible enough to
is an invasive be bent
plant in Korea,
and wound.
for application as an EMI shielding material. CNTs were used as additives to develop
the electrical conductivity and EMI SE. Through a facile paper process, TGCF/CNT pa-
Author
pers withContributions: Conceptualization,
different weight H.K.S.;were
percent ratios Data prepared
curation, J.P.
andandcarbonized
H.K.S.; Formal
at analysis,
various high
J.P. and H.K.S.; Funding acquisition, H.K.S.; Investigation, H.K.S.; Methodology, J.P. and H.K.S.;
temperatures and used as EMI shielding materials. The increase in the carbonization
Project administration, L.K.K., H.G.K. and H.K.S.; Resources, L.K.K. and H.K.S.; Software J.P.,
temperature,
L.K.K. thickness,
and H.K.S.; andH.G.K.
Supervision, CNTand content
H.K.S.;enhanced
Validation,the
J.P.electrical
and H.K.S.;conductivity and EMI
Writing—original
SE of the TGCF/CNT carbon papers. Among them, TGCF/CNT-15 papers with
draft, J.P. and H.K.S.; Writing—review & editing, J.P. and H.K.S. All authors have read and agreed approxi-
mately
to 4.5 mmversion
the published in thickness that are carbonized at 1300 ◦ C exhibited the highest electrical
of the manuscript.
conductivity of 6.35 −1
Funding: This study wasSsupported
cm , demonstrating
by the NationalEMI SE ofFoundation
Research approximately
of Korea62(NRF)
dB atfunded
1.6 GHz of
thethe
by low frequency
Ministry band. In
of Education addition, we observed that
(NRF‐2020R1I1A1A01072906). Thisallresearch
sampleswaswere
also flexible
supportedenough
by to
be Basic
the bent and wound.
Science Research Program through the National Research Foundation of Korea (NRF)
funded by the Ministry of Education (No. 2016R1A6A1A03012069).
Author Contributions:
Institutional Conceptualization,
Review Board H.K.S.; Data curation, J.P. and H.K.S.; Formal analysis, J.P.
Statement: Not applicable.
and H.K.S.; Funding acquisition, H.K.S.; Investigation, H.K.S.; Methodology, J.P. and H.K.S.; Project
Data AvailabilityL.K.K.,
administration, Statement: Not and
H.G.K. applicable.
H.K.S.; Resources, L.K.K. and H.K.S.; Software J.P., L.K.K. and
H.K.S.; Supervision,
Conflicts H.G.K.
of Interest: The anddeclare
authors H.K.S.;no
Validation,
conflict of J.P. and H.K.S.; Writing—original draft, J.P. and
interest.
H.K.S.; Writing—review & editing, J.P. and H.K.S. All authors have read and agreed to the published
version of the manuscript.
Funding: This study was supported by the National Research Foundation of Korea (NRF) funded by
the Ministry of Education (NRF-2020R1I1A1A01072906). This research was also supported by the
Basic Science Research Program through the National Research Foundation of Korea (NRF) funded
by the Ministry of Education (No. 2016R1A6A1A03012069).
Institutional Review Board Statement: Not applicable.
Data Availability Statement: Not applicable.
Conflicts of Interest: The authors declare no conflict of interest.
Sample Availability: The samples are available from the corresponding author.
Molecules 2022, 27, 1842 10 of 11
References
1. Geetha, S.; Satheesh Kumar, K.K.; Rao, C.R.K.; Vijayan, M.; Trivedi, D.C. EMI Shielding: Methods and Materials-A Review. J.
Appl. Polym. Sci. 2009, 112, 2073–2086. [CrossRef]
2. Al-Saleh, M.H.; Sundararaj, U. Electromagnetic Interference Shielding Mechanisms of CNT/Polymer Composites. Carbon 2009,
47, 1738–1746. [CrossRef]
3. Maruthi, N.; Faisal, M.; Raghavendra, N. Conducting Polymer Based Composites as Efficient EMI Shielding Materials: A
Comprehensive Review and Future Prospects. Synth. Met. 2021, 272, 116664. [CrossRef]
4. Bhaskaran, K.; Bheema, R.K.; Etika, K.C. The Influence of Fe3 O4 @GNP Hybrids on Enhancing the EMI Shielding Effectiveness of
Epoxy Composites in the X-Band. Synth. Met. 2020, 265, 116374. [CrossRef]
5. Liu, P.; Ng, V.M.H.; Yao, Z.; Zhou, J.; Lei, Y.; Yang, Z.; Lv, H.; Kong, L.B. Facile Synthesis and Hierarchical Assembly of Flowerlike
NiO Structures with Enhanced Dielectric and Microwave Absorption Properties. ACS Appl. Mater. Interfaces 2017, 9, 16404–16416.
[CrossRef]
6. Shui, X.; Chung, D.D.L. Magnetic Properties of Nickel Filament Polymer-Matrix Composites. J. Electron. Mater. 1996, 25, 930–934.
[CrossRef]
7. Chang, H.; Yeh, Y.-M.; Huang, K.-D. Electromagnetic Shielding by Composite Films Prepared with Carbon Fiber, Ni Nanoparticles,
and Multi-Walled Carbon Nanotubes in Polyurethane. Mater. Trans. 2010, 51, 1145–1149. [CrossRef]
8. Das, P.; Deoghare, A.B.; Maity, S.R. Exploring the Potential of Graphene as an EMI Shielding Material—An Overview. Mater.
Today Proc. 2020, 22, 1737–1744. [CrossRef]
9. Madhusudhan, C.K.; Mahendra, K.; Madhukar, B.S.; Somesh, T.E.; Faisal, M. Incorporation of Graphite into Iron Decorated
Polypyrrole for Dielectric and EMI Shielding Applications. Synth. Met. 2020, 267, 116450. [CrossRef]
10. Lee, S.H.; Yu, S.; Shahzad, F.; Hong, J.; Noh, S.J.; Kim, W.N.; Hong, S.M.; Koo, C.M. Low Percolation 3D Cu and Ag Shell Network
Composites for EMI Shielding and Thermal Conduction. Compos. Sci. Technol. 2019, 182, 107778. [CrossRef]
11. Mei, H.; Zhao, X.; Gui, X.; Lu, D.; Han, D.; Xiao, S.; Cheng, L. SiC Encapsulated Fe@CNT Ultra-High Absorptive Shielding
Material for High Temperature Resistant EMI Shielding. Ceram. Int. 2019, 45, 17144–17151. [CrossRef]
12. Park, J.; Kwac, L.K.; Kim, H.G.; Shin, H.K. Fabrication and Characterization of Waste Wood Cellulose Fiber/Graphene
Nanoplatelet Carbon Papers for Application as Electromagnetic Interference Shielding Materials. Nanomaterials 2021, 11, 2878.
[CrossRef] [PubMed]
13. Kim, H.G.; Kim, Y.S.; Kwac, L.K.; Shin, H.K. Characterization of Activated Carbon Paper Electrodes Prepared by Rice Husk-
Isolated Cellulose Fibers for Supercapacitor Applications. Molecules 2020, 25, 3951. [CrossRef] [PubMed]
14. Akonda, M.H.; Lawrence, C.A.; Weager, B.M. Recycled Carbon Fibre-Reinforced Polypropylene Thermoplastic Composites.
Compos. Part A Appl. Sci. Manuf. 2012, 43, 79–86. [CrossRef]
15. Reddy, N.; Yang, Y. Properties of High-Quality Long Natural Cellulose Fibers from Rice Straw. J. Agric. Food Chem. 2006, 54,
8077–8081. [CrossRef]
16. Cheek, M.D.; Semple, J.C. First Official Record of Naturalised Populations of Solidago altissima L. var pluricephala M.C. Johnst.
(Asteraceae: Astereae) in Africa. S. Afr. J. Bot. 2016, 105, 333–336. [CrossRef]
17. Weber, E. Biological Flora of Central Europe: Solidago altissima L. Flora 2000, 195, 123–134. [CrossRef]
18. Wang, Y.Y.; Zhou, Z.H.; Zhu, J.L.; Sun, W.J.; Yan, D.X.; Dai, K.; Li, Z.M. Low-Temperature Carbonized Carbon Nanotube/Cellulose
Aerogel for Efficient Microwave Absorption. Compos. B Eng. 2021, 220, 108985. [CrossRef]
19. Jung, M.; Lee, Y.S.; Hong, S.G.; Moon, J.H. Carbon Nanotubes (CNTs) in Ultra-High Performance Concrete (UHPC): Dispersion,
Mechanical Properties, and Electromagnetic Interference (EMI) Shielding Effectiveness (SE). Cem. Concr. Res. 2020, 131, 106017.
[CrossRef]
20. Madinehei, M.; Kuester, S.; Kaydanova, T.; Moghimian, N.; David, É. Influence of Graphene Nanoplatelet Lateral Size on the
Electrical Conductivity and Electromagnetic Interference Shielding Performance of Polyester Nanocomposites. Polymers 2021, 13,
2567. [CrossRef]
21. Tian, S.; Zhou, L.; Liang, Z.; Yang, Y.; Wang, Y.; Qiang, X.; Huang, S.; Li, H.; Feng, S.; Qian, Z.; et al. 2.5 D Carbon/Carbon
Composites Modified by In Situ Grown Hafnium Carbide Nanowires for Enhanced Electromagnetic Shielding Properties and
Oxidation Resistance. Carbon 2020, 161, 331–340. [CrossRef]
22. Feng, L.; Zuo, Y.; He, X.; Hou, X.; Fu, Q.; Li, H.; Song, Q. Development of Light Cellular Carbon nanotube@graphene/Carbon
Nanocomposites with Effective Mechanical and EMI Shielding Performance. Carbon 2020, 168, 719–731. [CrossRef]
23. Li, Y.; Xue, B.; Yang, S.; Cheng, Z.; Xie, L.; Zheng, Q. Flexible Multilayered Films Consisting of Alternating Nanofibrillated
Cellulose/Fe3 O4 and Carbon Nanotube/Polyethylene Oxide Layers for Electromagnetic Interference Shielding. Chem. Eng. J.
2021, 410, 128356. [CrossRef]
24. Tian, D.; Xu, Y.; Wang, Y.; Lei, Z.; Lin, Z.; Zhao, T.; Hu, Y.; Sun, R.; Wong, C.P. In-Situ Metallized Carbon Nanotubes/Poly(Styrene-
Butadiene-Styrene) (CNTs/SBS) Foam for Electromagnetic Interference Shielding. Chem. Eng. J. 2021, 420, 130482. [CrossRef]
25. Yu, Y.; Wu, L.; Gao, S.; Jia, K.; Zeng, W.; Liao, B.; Pang, H. Fabrication of Multi-Nanocavity and Multi-Reflection Interface in rGO
for Enhanced EMI Absorption and Reduced EMI Reflection. Appl. Surf. Sci. 2021, 562, 150034. [CrossRef]
26. Xiang, C.; Pan, Y.; Guo, J. Electromagnetic Interference Shielding Effectiveness of Multiwalled Carbon Nanotube Reinforced
Fused Silica Composites. Ceram. Int. 2007, 33, 1293–1297. [CrossRef]Molecules 2022, 27, 1842 11 of 11
27. Chen, X.; Liu, H.; Hu, D.; Liu, H.; Ma, W. Recent Advances in Carbon Nanotubes-Based Microwave Absorbing Composites.
Ceram. Int. 2021, 47, 23749–23761. [CrossRef]
28. Pang, Z.; Sun, X.; Wu, X.; Nie, Y.; Liu, Z.; Yue, L. Fabrication and Application of Carbon Nanotubes/Cellulose Composite Paper.
Vacuum 2015, 122, 135–142. [CrossRef]
29. Imai, M.; Akiyama, K.; Tanaka, T.; Sano, E. Highly Strong and Conductive Carbon Nanotube/Cellulose Composite Paper. Compos.
Sci. Technol. 2010, 70, 1564–1570. [CrossRef]
30. Lee, T.W.; Lee, S.E.; Jeong, Y.G. Carbon Nanotube/Cellulose Papers with High Performance in Electric Heating and Electromag-
netic Interference Shielding. Compos. Sci. Technol. 2016, 131, 77–87. [CrossRef]
31. Kim, H.G.; Lee, U.S.; Kwac, L.K.; Lee, S.O.; Kim, Y.S.; Shin, H.K. Electron Beam Irradiation Isolates Cellulose Nanofiber from
Korea “Tall Goldenrod” Invasive Alien Plant Pulp. Nanomaterials 2019, 9, 1358. [CrossRef] [PubMed]
32. Rhim, Y.; Zhang, D.; Fairbrother, D.H.; Wepasnick, K.A.; Livi, K.J.; Bodnar, R.J.; Nagle, D.C. Changes in Electrical and Mi-
crostructural Properties of Microcrystalline Cellulose as Function of Carbonization Temperature. Carbon 2010, 48, 1012–1024.
[CrossRef]
33. Yim, Y.J.; Rhee, K.Y.; Park, S.J. Electromagnetic Interference Shielding Effectiveness of Nickel-Plated MWCNTs/High-Density
Polyethylene Composites. Compos. B Eng. 2016, 98, 120–125. [CrossRef]
34. Yim, Y.J.; Lee, J.J.; Tugirumubano, A.; Go, S.H.; Kim, H.G.; Kwac, L.K. Electromagnetic Interference Shielding Behavior of
Magnetic Carbon Fibers Prepared by Electroless FeCoNi-Plating. Materials 2021, 14, 3774. [CrossRef] [PubMed]
35. Al-Saleh, M.H.; Saadeh, W.H.; Sundararaj, U. EMI Shielding Effectiveness of Carbon Based Nanostructured Polymeric Materials:
A Comparative Study. Carbon 2013, 60, 146–156. [CrossRef]
36. Zeng, Q.; Du, Z.; Qin, C.; Wang, Y.; Liu, C.; Shen, C. Enhanced Thermal, Mechanical and Electromagnetic Interference Shielding
Properties of Graphene Nanoplatelets-Reinforced Poly(Lactic Acid)/Poly(Ethylene Oxide). Nanocomposites 2020, 25, 101632.
[CrossRef]
37. Thi, Q.V.; Nguyen, N.Q.; Oh, I.W.; Hong, J.P.; Koo, C.M.; Tung, N.T.; Sohn, D.S. Thorny Trunk-Like Structure of Reduced Graphene
Oxide/HKUST-1 MOF for Enhanced EMI Shielding Capability. Ceram. Int. 2021, 47, 10027–10034. [CrossRef]
38. Wan, Y.J.; Zhu, P.L.; Yu, S.H.; Sun, R.; Wong, C.P.; Liao, W.H. Anticorrosive, Ultralight, and Flexible Carbon-Wrapped Metallic
Nanowire Hybrid Sponges for Highly Efficient Electromagnetic Interference Shielding. Small 2018, 14, e1800534. [CrossRef]
39. Ma, X.; Yuan, C.; Liu, X. Mechanical, Microstructure and Surface Characterizations of Carbon Fibers Prepared from Cellulose
after Liquefying and Curing. Materials 2013, 7, 75–84. [CrossRef]
40. Rajabpour, S.; Mao, Q.; Gao, Z.; Khajeh Talkhoncheh, M.; Zhu, J.; Schwab, Y.; Kowalik, M.; Li, X.; van Duin, A.C.T. Low-
Temperature Carbonization of Polyacrylonitrile/Graphene Carbon Fibers: A Combined ReaxFF Molecular Dynamics and
Experimental Study. Carbon 2021, 174, 345–356. [CrossRef]
41. Zong, Z.; Ren, F.; Guo, Z.; Lu, Z.; Jin, Y.; Zhao, Y.; Ren, P. Dual-Functional Carbonized loofah@GNSs-CNTs Reinforced by Cyanate
Ester Composite with Highly Efficient Electromagnetic Interference Shielding and Thermal Management. Compos. B Eng. 2021,
223, 109132. [CrossRef]
42. Shin, H.K.; Jeun, J.P.; Kim, H.B.; Kang, P.H. Isolation of Cellulose Fibers from Kenaf using Electron beam. Radiat. Phys. Chem.
2012, 81, 936–940. [CrossRef]
43. Gong, J.; Li, J.; Xu, J.; Xiang, Z.; Mo, L. Research on Cellulose Nanocrystals produced from Cellulose Sources with Various
Polymorphs. RSC Adv. 2017, 7, 33486–33493. [CrossRef]You can also read
