Effect of Nanoscale Species on the Behavior of Polymer Nanocomposites Subjected to Laser Pulse Heating

2012 ◽  
Vol 1519 ◽  
Author(s):  
Stephen F. Bartolucci ◽  
Jeffrey Warrender ◽  
Karen Supan ◽  
Jeffery Wiggins ◽  
Lawrence LaBeaud
Keyword(s):  
Carbon Nanotube ◽  
Mass Loss ◽  
Polymer Nanocomposites ◽  
Surface Characterization ◽  
Single Pulse ◽  
Heating Rates ◽  
Time Resolved ◽  
Nanotube Composites ◽  
Laser Pulse Heating ◽  
Multiple Pulses

ABSTRACTPolymers and polymer nanocomposites have been studied under conditions of extremely high heating rates. Traditionally, these materials have been examined by the flammability research community using methods which have heating rates on the order of 10 degrees C/min. In this study, we have examined how polypropylene-nanoclay (montmorillonite) and polypropylene-carbon nanotube nanocomposites behave subjected to heating rates on the order of one million degrees C/min when irradiated with a 1064 nm Nd-YAG variable pulse millisecond laser. Time-resolved temperature data and mass loss data was collected for each sample as well as post-mortem surface characterization using spectroscopy and electron microscopy. The analysis shows that the nanospecies are effective in providing a protective barrier that decreases the amount of degradation and mass loss to the underlying polymer material. The effect is clearly seen after irradiating with a single pulse and multiple pulses. A comparison between the performance of the nanoclay and carbon nanotube composites is given.

scholarly journals Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Edna X. Figueroa-Rosales ◽  
Javier Martínez-Juárez ◽  
Esmeralda García-Díaz ◽  
Daniel Hernández-Cruz ◽  
Sergio A. Sabinas-Hernández ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hexagonal Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Co Precipitation ◽  
Functionalized Mwcnts

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.

Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Electromagnetic Interference ◽  
Effective Medium Theory ◽  
Scale Model ◽  
Shielding Effectiveness ◽  
Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

Interaction Stresses in Carbon Nanotube–Polymer Nanocomposites

2011 ◽  
Vol 3 (9) ◽  
pp. 3425-3431 ◽  
Author(s):  
Meysam Rahmat ◽  
Kaushik Das ◽  
Pascal Hubert
Keyword(s):  
Carbon Nanotube ◽  
Polymer Nanocomposites
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