Q-02: Multifunctional Nano-Composites for EMI Shielding
4:00pm - 6:15pm
Session Chair: Raju V. Ramanujan, Nanyang Technological University Session Chair: Takanori Tsutaoka, Graduate School of Education, Hiroshima University
4:00pm - 4:30pm Invited
Electromagnetic Interference Shielding of Thermoplastic Elastomers Carbon Nanotube and Graphene Nanocomposites
Scheyla KUESTER1,2, Guilherme M.O. BARRA2, Bluma G. SOARES3, José Carlos FERREIRA2, Nicole R DEMARQUETTE1
1cole de Technologie Supérieure / Université du Quebec, Montreal, Canada; 2Universidade Federal de Santa Catarina, Brazil; 3Universidade Federal do Rio de Janeiro, Brazil
In this work, poly(styrene-b-ethylene-ran-butylene-b-styrene) (SEBS) nanocomposites containing different types of carbon nanoadditives were prepared by melt compounding and tested for their efficiency as electromagnetic shielding materials.The influence of chemical structure of the polymer, content and type of carbon nanoadditives and processing protocoles on the morphology of the nanocomposites obtained was evalued by Raman spectroscopy, field emission gun scanning electron microscopy and rheological analysis. The influence of the nanocomposite morphology on their electrical (DC electrical conductivity, dielectri properties)and electromagnetic shielding efficiency in the X-band microwave frequency range (8.2-12.4 GHz) were evaluated.
The results indicated that upon addition of 15% carbon nanonotube (CNT) an electromagnetic interference shielding efficiency (EMI-SE) of 30 dB, corresponding to reduction of 99% incident radiation, is obtained. However, more promissing results were obtained when a combination of CNT and graphene was added to the copolymre resulting in an EMI of 36.5 dB, which corresponds to a reduction of 99.98% of the incident radiation. The experimental results also indicated that the processing method influence the morphology of the nanocomposites obtained and consequently their electrical conductivity and electromagnetic shielding efficiency.
4:30pm - 5:00pm Invited
Smart and Economic Conductive Textile for Electromagnetic Interference Shielding
1Rubber Technology Centre, Indian Institute of Technology, India; 2Department of Jute and Fibre Technology, Calcutta University, India
Effective macro-structured carbon clusters are applied on the various types of woven fabric by the knife-over-roll coating technique. The structural parameters of the woven fabrics are optimized for the highest electromagnetic interference shielding effectiveness. Furnace black (normal) particles are stabilized into the clustered composite form by using natural rubber latex, polyvinyl alcohol and others additives. The natural rubber latex, polyvinyl alcohol and carbon black loadings are optimized for lowest surface resistivity and highest electromagnetic interference shielding effectiveness. Fabrics’ parameters are systematically varied to achieve optimal electromagnetic interference shielding effectiveness. The surface morphology of the coated fabrics is characterized by FESEM, AFM & HRTEM. The electrical properties of the composites and their effectiveness as the electromagnetic interference shielding are reported.
5:00pm - 5:15pm Oral
Piezo-resistive Conductive Polymer Nanocomposites (CPC) made of Graphene and Carbon Nanotubes Architectures to Develop Tactile Materials and Implantable Strain Sensors for SHM
Jean-Francois FELLER, Mickaël CASTRO
Smart Plastics group, Bretagne Loire University (UBL), France
During the last decade, several nanocarbon species such as nanoparticles (CNP), nanotubes (CNT) or nanofoils (GR) have been synthesized allowing to design new functional conductive polymer nanocomposite (CPC) films able to react to their environment. In particular nanocarbon based hierarchical conducting architectures can lead to quantum resistive sensors (QRS) able to detect tiny variations of strain  or volatile organic compounds VOC concentrations , thanks to respectively their original piezo- and chemo-resistive properties. When properly structured from the nano- to the macro-scale, these nanohybrids can meet promising applications due to their piezo-resistive properties, such as structural health monitoring in composite materials (SHM) or tactile materials able to detect fingers’ pressure. The best strategies used to control the different types of conductive architectures during their fabrication, and in particular the tailoring of the nano-junctions responsible for QRS sensitivity will be presented and discussed.
 T.T. Tung, C. Robert, M. Castro, J.F. Feller, T.Y. Kim, K.S. Suh, Enhancing the sensitivity of graphene/polyurethane nanocomposite flexible piezo-resistive pressure sensors with magnetite nano-spacers, Carbon N. Y. 108 (2016) 450–460.
 S. Nag, M. Castro, V. Choudhary, J.F. Feller, Sulfonated poly(ether ether ketone) [SPEEK] nanocomposites based on hybrid nanocarbons for the detection and discrimination of some lung cancer VOC biomarkers, J. Mater. Chem. B Biol. Med. 5 (2017) 348–359.
5:15pm - 5:30pm Oral
Poly(vinylidene fluoride) – Carbon Nanotube Composite Films for Electromagnetic Interference Shielding and Strain-sensing Applications
Sudheer Kumar GUNDATI, Umasankar PATRO
Defence Institute of Advanced Technology, India
Composites of poly(vinylidene fluoride) (PVDF) with unfunctionalized (ufCNT) and acid-treated CNTs (fCNT) were prepared by various methods in order to evaluate the potential of these composites as electromagnetic interference (EMI) shielding and strain-sensing applications. The fCNT showed an electrical percolation threshold (PT) of 0.15 wt% in the PVDF matrix as against 0.75 wt% for ufCNT. A gentle acid-treatment of CNT significantly improved the EMI shielding and strain-sensing properties of PVDF composites. Using composite films of 0.1 mm thickness, the maximum shielding effectiveness (SET) values for 4 wt% ufCNT composites are found to be about 32 dB and 31 dB for X and Ku band frequencies; while the corresponding values for only 0.5 wt% acid-functionalized CNT composites are about 26.5 dB and 23 dB, respectively, indicating the advantages of this acid-treatment method. The electrical conductivity for both the cases is ~10-2 S/cm and the weight contents of CNTs are higher than the PT for the respective composites. The shielding mechanism was found to be dominated by absorption loss. The electrical resistance (R) of the composite films under tensile loading was measured by a two-probe method using a custom-made equipment connected to Tektronix DMM 4020 5-1/2 Digital Multimeter. The R vs. strain (ε) curves showed two regimes: (i) linear increase in R in the elastic deformation region, (ii) exponential increases in R in the plastic region as a function of ε. Further, the change in resistance divided by resistance (ΔR/R) also showed increases with ε. It was found that the composites with CNT contents near and/or just above percolation threshold showed better strain-sensitivity (in the elastic regime) than the composites with higher CNT contents. This paves the way for designing polymer composites with optimum CNT contents for efficient strain-sensors for structural health-monitoring. The composites also promise as potential candidates for EMI shielding.