On the 3D Printability of Multi-Walled Carbon Nanotube/High Density Polyethylene Composites

2019 ◽  
Author(s):  
Felicia Stan ◽  
Nicoleta-Violeta Stanciu ◽  
Catalin Fetecau
Keyword(s):  
Carbon Nanotube ◽  
Electrical Properties ◽  
3D Printing ◽  
Shear Viscosity ◽  
High Density Polyethylene ◽  
High Density ◽  
High Shear ◽  
Shear Rates ◽  
Mechanical And Electrical Properties ◽  
Multi Walled Carbon Nanotube

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.

The Influence of Carbon Nanotubes and Reprocessing on the Morphology and Properties of High-Density Polyethylene/Carbon Nanotube Composites

2021 ◽  
pp. 1-31
Author(s):  
Felicia Stan ◽  
Ionut-Laurentiu Sandu ◽  
Adriana-Madalina Constantinescu ◽  
Nicoleta-Violeta Stanciu ◽  
Catalin Fetecau
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Injection Molding ◽  
High Density Polyethylene ◽  
High Density ◽  
Mechanical Degradation ◽  
End User ◽  
Mechanical Recycling ◽  
Mechanical And Electrical Properties

Abstract This study investigates virgin and recycled high-density polyethylene/multi-walled carbon nanotube (HDPE/MWCNT) composites using thermo-physical and mechanical characterization techniques to generate knowledge and understand recyclability of these composites. Firstly, virgin samples with 0.1–5 wt.% of MWCNTs were prepared by injection molding. Then, the HDPE/MWCNT composite waste was mechanically recycled and consecutively reprocessed by injection molding. The experimental results show that the degradation process of the end-user properties (mechanical and electrical properties) depends on the MWCNT wt.%. The higher the carbon nanotube loading, the higher the degradation of the end-user properties. The HDPE/MWCNT composites appear to be resistant to degradation at carbon nanotube loadings below the percolation threshold (which is located around 3 wt.%). In contrast, the recycled HDPE/MWCNT composites with 5 wt.% showed a reduction in viscosity, mechanical and electrical properties with recycling. After four reprocessing cycles, degradation in the Young modulus (−35%), tensile strength (−25%), elongation at break (−60%) and electrical conductivity (−2 orders of magnitude) of the HDPE/MWCNT composite with 5 wt.% was observed as compared with the virgin composite. From an industrial perspective, it is feasible to recycle HDPE/MWCNT composite waste by mechanical recycling and use it to manufacture products with favorable mechanical properties, covering insulating, antistatic and semiconducting ranges depending on the MWCNT loading, owing to the protective effect of carbon nanotubes against thermo-mechanical degradation.

The Influence of Carbon Nanotubes and Reprocessing on the Morphology and Properties of High-Density Polyethylene/Carbon Nanotube Composites

2021 ◽  
Author(s):  
Felicia Stan ◽  
Ionut-Laurentiu Sandu ◽  
Adriana-Madalina Turcanu ◽  
Nicoleta-Violeta Stanciu ◽  
Catalin Fetecau
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Injection Molding ◽  
High Density Polyethylene ◽  
Young Modulus ◽  
High Density ◽  
Mechanical Recycling ◽  
Mechanical And Electrical Properties ◽  
Nanotube Composites

Abstract This study investigates virgin and recycled high-density polyethylene/multi-walled carbon nanotube (HDPE/MWCNT) composites using thermo-physical and mechanical characterization techniques to generate knowledge and understand recyclability of these composites. Firstly, virgin samples with 0.1–5 wt.% of MWCNTs were prepared by injection molding. Then, the HDPE/MWCNT composite waste was mechanically recycled and consecutively reprocessed by injection molding. The experimental results show that, after the first mechanical recycling and reprocessing cycle, the thermal, rheological, mechanical, and electrical properties for the recycled and virgin HDPE/MWCNT composites with 0.1–3 wt.% were rather similar within the experimental error of the measurements. In contrast, the recycled HDPE/MWCNT composites with 5 wt.% showed a reduction in viscosity, mechanical and electrical properties with recycling. After four recycling and reprocessing cycles, degradation in the Young modulus (−35%), tensile strength (−25%), elongation at break (−60%) and electrical conductivity (−2 orders of magnitude) of the HDPE/MWCNT composite with 5 wt.% was observed as compared with the virgin composite. From an industrial perspective, it is feasible to recycle HDPE/MWCNT composite waste by mechanical recycling and use it to manufacture products with favorable mechanical properties, covering insulating, antistatic and semiconducting ranges depending on the MWCNT loading, owing to the protective effect of carbon nanotubes against thermomechanical degradation.

Electrical, Thermal and Positron Lifetime Spectroscopy Studies on Multi-Walled Carbon Nanotube Reinforced High Density Polyethylene/Carbon Black Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 59-62 ◽  
Author(s):  
T. Jeevananda ◽  
O.G. Palanna ◽  
Joong Hee Lee ◽  
Siddaramaiah ◽  
C. Ranganathaiah
Keyword(s):  
Thermal Properties ◽  
Carbon Nanotube ◽  
Carbon Black ◽  
Free Volume ◽  
High Density Polyethylene ◽  
High Density ◽  
Hybrid Nanocomposites ◽  
Positive Temperature ◽  
Multi Walled Carbon Nanotube ◽  
Positron Lifetime Spectroscopy

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.

Characterization of Welding Attributes in Friction Spot Stir Welding of High-Density Polyethylene/Multi-Walled Carbon Nanotube Composites

2018 ◽  
Author(s):  
Felicia Stan ◽  
Nicoleta V. Stanciu ◽  
Catalin Fetecau ◽  
Laurentiu I. Sandu
Keyword(s):  
Carbon Nanotube ◽  
Welded Joints ◽  
Rotational Speed ◽  
High Density Polyethylene ◽  
Dwell Time ◽  
Tensile Load ◽  
High Density ◽  
Tool Rotational Speed ◽  
Lap Shear ◽  
Multi Walled Carbon Nanotube

In this work, friction spot stir welding (FSSW) is applied to join high-density polyethylene/multi-walled carbon nanotube (HDPE/MWCNTs) composites. Injection-molded coupons were welded with a single lap-shear configuration under different welding conditions (tool rotational speed, plunge depth, and dwell time). By analyzing the lap-shear tensile load and the fracture surface of the welded joints, it is found that the weld attributes (e.g. weld area and maximum lap-shear tensile load) increase with increasing dwell time, tool rotational speed, and plunging depth. The maximum lap-shear tensile load increases with nanotube loading up to a threshold, followed by a decreasing trend at nanotube loading higher than 1.0 wt.%. It is hypothesized that the bonding mechanism for FSSW of HDPE/MWCNT composites is mainly through the co-crystallization across the interface. When more nanotubes are involved in the welding zone (>1.0 wt.%), saturation of nucleation is reached, the positive effect on the crystallization is vanished, and consequently the overall mechanical properties decrease. Interface failure of the welded joints and bulk fracture originated from the upper coupon within the weld nugget perimeter were identified as the two main failure mechanisms.

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