Electromagnetic interference shielding, mechanical properties and water
absorption of copper/bamboo fabric (Cu/BF) composites
, Longlong Xue
Department of Materials Science, Fudan University, Shanghai 200433, China
Received 28 July 2011
Received in revised form 1 February 2012
Accepted 11 February 2012
Available online 19 February 2012
A. Textile composites
B. Electrical properties
B. Mechanical properties
Electromagnetic shielding interference
Copper/bamboo fabric (Cu/BF) composites were prepared by electroless deposition via a tin-free process.
The process involved 3-aminopropyltrimethoxysilane modiﬁcation, noble metal (Au or Pd) activation and
electroless copper planting of BF. The copper deposition rate via Pd catalytic process was 1.01 mg/cm
higher than that by Au catalytic process (0.85 mg/cm
h). The microstructure of Cu/BF composites was
analyzed by scanning electron microscopy (SEM), and the copper coatings were composed of ball-shaped
copper particles. The composition and chemical state of copper layers were measured by X-ray diffraction
(XRD) and X-ray photoelectron spectroscopy (XPS) spectra, Cu
was detected but copper dioxide was not
found in both spectra. The electromagnetic interference, water absorption, mechanical tension, conduc-
tivity and adhesion properties of Cu/BF samples (weight ratio of Cu/BF: 0.36 ± 0.01) were measured to
obtain the qualities of the composites.
Ó 2012 Elsevier Ltd. All rights reserved.
Bamboo fabric (BF) is made from the raw material of bamboo. It
is produced by an eco-friendly process without chemical additives.
BF is also a unique biodegradable textile material. As a natural cel-
lulose fabric, BF can be 100% biodegraded in soil by microorgan-
isms and sunshine [1,2]. Scientists have found that BF owns an
unusual anti-bacteria and bacteriostatic bio-agent. BF is praised
as ‘‘the natural, green and eco-friendly textile material of 21st cen-
tury’’ [3,4]. However, BF is an insulator, a serious problem with
electromagnetic interference (EMI), which can cause noise signals
and even malfunction of the electronic appliances, is encountered
. One effective technique to overcome the EMI problem is to im-
prove the electrical conductivity of BF by incorporation of conduc-
tive ﬁllers in the insulate matrix. Generally, insulator can be made
electrically conductive composites by either coating or compound-
ing with conductive materials. Among these investigations, copper
coated fabrics provide the composites with good EMI shielding,
high strength and elasticity modulus, light weight, and high aspect
ratio of fabrics [6–9].
Since electroless copper deposition takes place only on conduc-
tors, it is necessary to use a catalyst to seed the insulator’s (BF’s)
surface with catalytic metal particles. Traditionally, a two-step
treatment is used in which a SnCl
solution acts as a sensitizer
and a PdCl
solution as an activator to provide catalytic metallic
Pd sites. The method uses tin which is known to be toxic and there-
fore it is not suitable for medical implants and human-bodies
[10,11]. From the economic and environmental points of view, as
well as the simplicity in process operation, it is of importance to de-
velop a tin-free, one-step activation process for the industry [12,13].
In the present work, electroless copper planting on natural
bamboo fabrics by a tin-free process was reported. Firstly, the
bamboo textile was modiﬁed by 3-aminopropyltrimethoxysilane
(hereafter abbreviated as silane), and NH
groups was grafted to
the surface of the substrate . Secondly, the grafted bamboo fab-
rics (BFs) were activated by Au or Pd particles in solution via Au–N
or Pd–N chemical bonds . Finally, the activated BFs were cov-
ered by copper layer by electroless deposition. Various character-
ization techniques were utilized to obtain information on the
sample morphology, and the quantity of Cu/BF composite. More-
over, the mechanical properties and wetting behavior of the copper
coated BF samples were investigated, and compared them with the
original natural bamboo textiles.
2.1. Copper coating on BF
Plain weave 100% natural bamboo fabrics (BFs) (108 Â
, 220 g/m
) with a thickness of 100
m in white col-
or were used as the substrate. The surface area of each specimen is
0266-3538/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
Abbreviations: BF(s), bamboo fabric(s); Cu/BF, copper/bamboo fabric; SE,
shielding effectiveness; EMI, electromagnetic interference; Silane, 3-aminopropyl-
trimethoxysilane; PVP, polyvinylpyrrolidone; Au-process, Au catalytic process; Pd-
process, Pd catalytic process; Au-process sample, samples from Au catalytic
process; Pd-process sample, samples from Pd catalytic process.
Corresponding author. Tel./fax: +86 21 65642871.
E-mail address: firstname.lastname@example.org (Y. Lu).
Composites Science and Technology 72 (2012) 828–834
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