scholarly journals Influence of shear-induced crystallization on the electrical conductivity of high density polyethylene carbon nanotube nanocomposites

Polymer ◽  
2012 ◽  
Vol 53 (25) ◽  
pp. 5909-5916 ◽  
Author(s):  
Fangfang Tao ◽  
Leïla Bonnaud ◽  
Dietmar Auhl ◽  
Bernd Struth ◽  
Philippe Dubois ◽  
...  
2019 ◽  
Vol 53 (15) ◽  
pp. 2091-2104 ◽  
Author(s):  
Gaurav Arora ◽  
Himanshu Pathak ◽  
Sunny Zafar

Carbon nanotubes have been used as reinforcements in polymers due to their high elasticity, flexibility, and thermal conductivity. In this study, pellets of high-density polyethylene +20 wt% carbon nanotube and polypropylene +20 wt% carbon nanotube were cured using microwave energy. X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, uniaxial tensile test, and scanning electron microscopy was used to study morphology, thermal stability, and mechanical performance of the microwave-cured composites. X-ray diffraction analysis confirmed the bonding between the polymer and carbon nanotube as the peaks shifted and intensified. From the thermal study, it was observed that melting point of the composites is affected by microwave curing and the crystallinity of high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube changed by 57.67% and 47.28%, respectively. Results of the uniaxial tensile test indicated that Young’s modulus of microwave cured high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube composites were improved by 295% and 787.8%, respectively. Scanning electron microscopic fractography shows the stretching of polymer over-lapped on carbon nanotubes in the direction of the applied load.


Author(s):  
Felicia Stan ◽  
Nicoleta-Violeta Stanciu ◽  
Catalin Fetecau

Abstract This study focuses on 3D printing of multi-walled carbon nanotube/high density polyethylene (MWCNT/HDPE) composites. First, rheological properties of 0.1, 1, and 5 wt.% MWCNT/HDPE composites were investigated to estimate the 3D printability window. Second, filaments with 1.75 mm diameter were fabricated and subsequently extruded by a commercial 3D printer. Finally, the filaments and 3D printed parts were tested to correlate the rheological, mechanical, and electrical properties with processing parameters. Experimental results show that flow behavior of MWCNT/HDPE composites is a critical factor affecting the 3D printability. The shear viscosity exhibits good shear thinning behavior at high shear rates and significantly increases with increasing nanotube loading from 0.1 to 5 wt.%, at low shear rates. Reliable MWCNT/HDPE filaments were obtained with smooth surface finish and good mechanical and electrical properties. The 0.1 and 1 wt.% MWCNT/HDPE filaments exhibit very good printing characteristics. However, under the flow conditions of a standard 0.4-mm nozzle, 3D printing of 5 wt.% MWCNT/HDPE filament can be rather difficult primarily due to high shear viscosity and nozzle clogging. Thus, further investigation is needed to fully optimize the 3D printing of MWCNT/HDPE composites.


2010 ◽  
Vol 123-125 ◽  
pp. 59-62 ◽  
Author(s):  
T. Jeevananda ◽  
O.G. Palanna ◽  
Joong Hee Lee ◽  
Siddaramaiah ◽  
C. Ranganathaiah

The present study investigates the effect of the carboxylated multi-walled carbon nanotube (0~3 wt %) content on the electrical and thermal properties of high density polyethylene/carbon black/carboxylated multi-walled carbon nanotube (HDPE/CB/c-MWNT) hybrid nanocomposites. The room temperature electrical resistivity and positive temperature coefficient (PTC) intensity of the nanocomposites significantly improved with the addition of c-MWNT. However, the heat of fusion decreases as the amount of c-MWNT increases. Further, the microstructural parameters such as the fractional free volume (Fv) and free volume hole size (Vf) of the nanocomposites shows appreciable changes around the percolation threshold. Secondly, the PALS results seem to correlate well with the electrical and thermal properties of the composites.


Sign in / Sign up

Export Citation Format

Share Document