Supercritical CO2 assisted preparation of open-cell foams of linear low-density polyethylene and linear low-density polyethylene/carbon nanotube composites

Abstract In this paper, the impact of recycling and remanufacturing on the behavior of low-density polyethylene/multi-walled carbon nanotube (LDPE/MWCNT) composites is investigated. LDPE/MWCNT composites with 0.1–5 wt.%, previously manufactured by injection molding, were mechanically recycled and remanufactured by injection molding and 3D filament extrusion, and the rheological, electrical, and mechanical properties were analyzed and compared with those of virgin composites under the same conditions. Experimental results demonstrate that the recycled LDPE/MWCNT composites have similar rheological, electrical, and mechanical properties to virgin composites, if not better. Therefore, the recycled LDPE/MWCNT composites have a great potential for being used in engineering applications, while reducing the environmental impact.

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Experimental Investigation of the Melt Shear Viscosity, Specific Volume and Thermal Conductivity of Low-Density Polyethylene/Multi-Walled Carbon Nanotube Composites Using Capillary Flow

Polymers ◽

10.3390/polym12061230 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1230 ◽

Cited By ~ 1

Author(s):

Nicoleta-Violeta Stanciu ◽

Felicia Stan ◽

Catalin Fetecau

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotube ◽

Shear Viscosity ◽

Specific Volume ◽

Melt Processing ◽

Low Density Polyethylene ◽

Low Density ◽

Processing Conditions ◽

Nanotube Composites ◽

Carbon Nanotube Composites

Understanding the flow behavior of polymer/carbon nanotube composites prior to melt processing is important for optimizing the processing conditions and final product properties. In this study, the melt shear viscosity, specific volume and thermal conductivity of low-density polyethylene (LDPE) filled with multi-walled carbon nanotubes (MWCNTs) were investigated for representative processing conditions using capillary rheometry. The experimental results show a significant increase in the melt shear viscosity of the LDPE/MWCNT composite with nanotube loadings higher than 1 wt.%. Upon increasing shear rates, the composites flow like a power-law fluid, with a shear-thinning index less than 0.4. The specific volume decreases with increasing pressure and nanotube loading, while the pVT transition temperature increases linearly with increasing pressure. The thermal conductivity of the LDPE/MWCNT composite is nearly independent of nanotube loading up to the thermal percolation threshold of 1 wt.% and increases linearly with further increases in nanotube loading, reaching 0.35 W/m·K at 5 wt.%. The Carreau–Winter and Cross viscosity models and Tait equation, respectively, are able to predict the shear viscosity and specific volume with a high level of accuracy. These results can be used not only to optimize processing conditions through simulation but also to establish structure–property relationships for the LDPE/MWCNT composites.

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Mechanical Recycling of Low-Density Polyethylene/Carbon Nanotube Composites and Its Effect on Material Properties

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4044101 ◽

2019 ◽

Vol 141 (9) ◽

Author(s):

Felicia Stan ◽

Nicoleta-Violeta Stanciu ◽

Catalin Fetecau ◽

Ionut-Laurentiu Sandu

Keyword(s):

Mechanical Properties ◽

Carbon Nanotube ◽

Injection Molding ◽

Low Density Polyethylene ◽

Low Density ◽

Mechanical Recycling ◽

Multi Walled Carbon Nanotube ◽

Nanotube Composites ◽

Carbon Nanotube Composites ◽

The Impact

In this paper, the impact of recycling and remanufacturing on the behavior of low-density polyethylene/multi-walled carbon nanotube (LDPE/MWCNT) composites is investigated. LDPE/MWCNT composites with 0.1–5 wt%, previously manufactured by injection molding, were mechanically recycled and remanufactured by injection molding and 3D filament extrusion, and the rheological, electrical, and mechanical properties were analyzed and compared with those of virgin composites under the same conditions. Experimental results demonstrate that the recycled LDPE/MWCNT composites have similar rheological, electrical, and mechanical properties as that of virgin composites, if not better. Therefore, the recycled LDPE/MWCNT composites have a great potential for being used in engineering applications, while reducing the environmental impact.

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The preparation of carbon nanotube/linear low density polyethylene composites by a water-crosslinking reaction

Materials Letters ◽

10.1016/j.matlet.2006.01.112 ◽

2007 ◽

Vol 61 (13) ◽

pp. 2744-2748 ◽

Cited By ~ 21

Author(s):

Chen-Feng Kuan ◽

Hsu-Chiang Kuan ◽

Chen-Chi M. Ma ◽

Chia-Hsun Chen ◽

Han-Lang Wu

Keyword(s):

Carbon Nanotube ◽

Low Density Polyethylene ◽

Crosslinking Reaction ◽

Low Density ◽

Linear Low Density Polyethylene ◽

Polyethylene Composites

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Enhanced mechanical properties of a multiwall carbon nanotube attached pre-stitched graphene oxide filled linear low density polyethylene composite

Journal of Materials Chemistry A ◽

10.1039/c3ta14393g ◽

2014 ◽

Vol 2 (8) ◽

pp. 2681-2689 ◽

Cited By ~ 30

Author(s):

Nam Hoon Kim ◽

Tapas Kuila ◽

Joong Hee Lee

Keyword(s):

Graphene Oxide ◽

Carbon Nanotube ◽

Low Density Polyethylene ◽

Multiwall Carbon Nanotube ◽

Low Density ◽

Linear Low Density Polyethylene ◽

Polyethylene Composite ◽

Multi Walled Carbon Nanotube ◽

Multiwall Carbon ◽

Reinforcing Filler

Multi-walled carbon nanotube attached pre-stitched graphene oxide used as a reinforcing filler in linear low density polyethylene (LLDPE) composite. The tensile strength of the composite with 1 wt. % filler was enhanced dramatically by 148.7% compared to that of the neat LLDPE.

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Effect of Step-Heating on Microstructure and Mechanical Properties of Linear Low Density Polyethylene/Multi-Walled Carbon Nanotube Composites Prepared via Melt Mixing Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.979.107 ◽

2014 ◽

Vol 979 ◽

pp. 107-110

Author(s):

Samor Boonphan ◽

Pisith Singjai

Keyword(s):

Mechanical Properties ◽

Carbon Nanotube ◽

Testing Machine ◽

Single Step ◽

Low Density Polyethylene ◽

Low Density ◽

Linear Low Density Polyethylene ◽

Melt Mixing ◽

Multi Walled Carbon Nanotube ◽

Step Heating

Step-heating (single-and four-step heating) was used in the melt-mixing preparation of linear low density polyethylene (LLDPE)/multi-walled carbon nanotube (MWNT) composites. The MWNT in the composites were used at volume fractions of 0, 1, 3, 5, and 10 vol% (four-step heating), and 0, 1, 3, and 5 vol% (single-step heating). The effects of the heating steps on the microstructure of the LLDPE/MWNT composites were studied. An ultimate tensile testing machine and an impact testing machine were used to characterize the mechanical properties of the composites. The sample prepared using four-step heating had a lower porosity than the sample prepared using single-step heating. The sample with 3 vol% MWNT that was prepared using four-step heating had tensile strength, elastic modulus, and impact strength values that were higher than those of the other samples.

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