scholarly journals Essential Nanostructure Parameters to Govern Reinforcement and Functionality of Poly(lactic) Acid Nanocomposites with Graphene and Carbon Nanotubes for 3D Printing Application

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1208 ◽  
Author(s):  
Rumiana Kotsilkova ◽  
Evgeni Ivanov ◽  
Vladimir Georgiev ◽  
Radost Ivanova ◽  
Dzhihan Menseidov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
3D Printing ◽  
Percolation Threshold ◽  
Structural Parameters ◽  
Electromagnetic Properties ◽  
Rheological Parameters ◽  
Poly Lactic Acid ◽  
Structure Property ◽  
Degree Of Dispersion

Poly(lactic) acid nanocomposites filled with graphene nanoplatelets (GNPs) and multiwall carbon nanotubes (MWCNTs) are studied, varying the filler size, shape, and content within 1.5–12 wt.%. The effects of the intrinsic characteristics of nanofillers and structural organization of nanocomposites on mechanical, electrical, thermal, and electromagnetic properties enhancement are investigated. Three essential rheological parameters are identified, which determine rheology–structure–property relations in nanocomposites: the degree of dispersion, percolation threshold, and interfacial interactions. Above the percolation threshold, depending on the degree of dispersion, three structural organizations are observed in nanocomposites: homogeneous network (MWCNTs), segregated network (MWCNTs), and aggregated structure (GNPs). The rheological and structural parameters depend strongly on the type, size, shape, specific surface area, and functionalization of the fillers. Consequently, the homogeneous and segregated network structures resulted in a significant enhancement of tensile mechanical properties and a very low electrical percolation threshold, in contrast to the aggregated structure. The high filler density in the polymer and the low number of graphite walls in MWCNTs are found to be determinant for the remarkable shielding efficiency (close to 100%) of nanocomposites. Moreover, the 2D shaped GNPs predominantly enhance the thermal conductivity compared to the 1D shaped MWCNTs. The proposed essential structural parameters may be successfully used for the design of polymer nanocomposites with enhanced multifunctional properties for 3D printing applications.

Properties of poly(lactic acid)/montmorillonite/carbon nanotubes nanocomposites: determination of percolation threshold

2021 ◽  
Author(s):  
Olawale Monsur Sanusi ◽  
Abdelkibir Benelfellah ◽  
Lazaros Papadopoulos ◽  
Zoe Terzopoulou ◽  
Dimitrios N. Bikiaris ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Percolation Threshold ◽  
Poly Lactic Acid

scholarly journals Effects of Filament Extrusion, 3D Printing and Hot-Pressing on Electrical and Tensile Properties of Poly(Lactic) Acid Composites Filled with Carbon Nanotubes and Graphene

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 35 ◽  
Author(s):  
Giovanni Spinelli ◽  
Rumiana Kotsilkova ◽  
Evgeni Ivanov ◽  
Ivanka Petrova-Doycheva ◽  
Dzhihan Menseidov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Lactic Acid ◽  
3D Printing ◽  
Tensile Properties ◽  
Hot Pressing ◽  
Multiwall Carbon Nanotubes ◽  
Poly Lactic Acid ◽  
The Matrix ◽  
3D Printed

In this study, the effects of three processing stages: filament extrusion, 3D printing (FDM), and hot-pressing are investigated on electrical conductivity and tensile mechanical properties of poly(lactic) acid (PLA) composites filled with 6 wt.% of multiwall carbon nanotubes(MWCNTs), graphene nanoplatelets (GNPs), and combined fillers. The filaments show several decades’ higher electrical conductivity and 50–150% higher values of tensile characteristics, compared to the 3D printed and the hot-pressed samples due to the preferential orientation of nanoparticles during filament extrusion. Similar tensile properties and slightly higher electrical conductivity are found for the hot-pressed compared to the 3D printed samples, due to the reduction of interparticle distances, and consequently, the reduced tunneling resistances in the percolated network by hot pressing. Three structural types are observed in nanocomposite filaments depending on the distribution and interactions of fillers, such as segregated network, homogeneous network, and aggregated structure. The type of structural organization of MWCNTs, GNPs, and combined fillers in the matrix polymer is found determinant for the electrical and tensile properties. The crystallinity of the 3D printed samples is higher compared to the filament and hot-pressed samples, but this structural feature has a slight effect on the electrical and tensile properties. The results help in understanding the influence of processing on the properties of the final products based on PLA composites.

scholarly journals Morphological, Rheological and Electromagnetic Properties of Nanocarbon/Poly(lactic) Acid for 3D Printing: Solution Blending vs. Melt Mixing

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2256 ◽  
Author(s):  
Giovanni Spinelli ◽  
Patrizia Lamberti ◽  
Vincenzo Tucci ◽  
Rumiana Kotsilkova ◽  
Sonia Tabakova ◽  
...  
Keyword(s):  
Lactic Acid ◽  
3D Printing ◽  
Aspect Ratio ◽  
Electromagnetic Compatibility ◽  
Mechanical Stability ◽  
Electromagnetic Properties ◽  
Poly Lactic Acid ◽  
Filler Concentration ◽  
Melt Mixing ◽  
Solution Blending

The limitation of poor mechanical stability and difficulties in printing electrically conductive components can be overcome owing to the recent introduction of nanotechnology into the field of additive manufacturing (AM) and the consequent development of nonconventional polymer nanocomposites suitable for 3D printing. In the present work, different weight percentages (up to 6 wt % in total) of carbon-based nanostructures—multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and a combination of both fillers (MWCNTs/GNPs)—were incorporated into poly(lactic) acid (PLA, Ingeo™) in an attempt to overcome several limitations of conventional 3D manufacturing based on insulating materials. Solution blending and melt mixing were the two fabrication methods adopted for preparation of the samples under test. A comparison of the morphological, rheological, and electrical properties of the resulting nanocomposites was carried out. Moreover, for the same weight concentrations, the influence of physical and geometrical features (i.e., functionalization and aspect ratio) of the embedded fillers was also investigated. Rheological methods were applied to control the quality of fillers dispersion in PLA matrix. The rheological percolation threshold was considered as reference in order to evaluate the internal structure of nanodispersions. TEM visualization, combined with rheological characterizations, was used for efficient control of the nanofiller dispersion. DC characterization revealed that lower electrical percolation thresholds and higher values of electrical conductivity were achieved using fillers with a larger aspect ratio and melt mixing, respectively. Moreover, given the possibility of obtaining complex and appropriate shapes for electromagnetic compatibility (EC) applications, electromagnetic (EM) response of the nanocomposites at the highest filler concentration was investigated in GHz and THz regions. It was found that the electromagnetic shielding efficiency (EMI) of nanocomposites strongly depended on the aspect ratio of the nanofillers, whereas the type of processing technique did not have a significant effect. Therefore, a careful choice of methods and materials must be made to address the final application for which these materials and further 3D printed architectures are designed.

Shear Flow and Carbon Nanotubes Synergistically Induced Nonisothermal Crystallization of Poly(lactic acid) and Its Application in Injection Molding

2012 ◽  
Vol 13 (11) ◽  
pp. 3858-3867 ◽  
Author(s):  
Hu Tang ◽  
Jing-Bin Chen ◽  
Yan Wang ◽  
Jia-Zhuang Xu ◽  
Benjamin S. Hsiao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Shear Flow ◽  
Injection Molding ◽  
Poly Lactic Acid ◽  
Nonisothermal Crystallization

Preparation and properties enhancement of poly(lactic acid)/calcined‐seashell biocomposites for 3D printing applications

2021 ◽  
pp. 51591
Author(s):  
Mohammed Seddik Razali ◽  
Kamel Khimeche ◽  
Redouane Melouki ◽  
Ammar Boudjellal ◽  
Isabelle Vroman ◽  
...  
Keyword(s):  
Lactic Acid ◽  
3D Printing ◽  
Poly Lactic Acid

scholarly journals Release of Graphene and Carbon Nanotubes from Biodegradable Poly(Lactic Acid) Films during Degradation and Combustion: Risk Associated with the End-of-Life of Nanocomposite Food Packaging Materials

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2346 ◽  
Author(s):  
Stanislav Kotsilkov ◽  
Evgeni Ivanov ◽  
Nikolay Vitanov
Keyword(s):  
Risk Assessment ◽  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Food Packaging ◽  
Safety Concern ◽  
Barrier Properties ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Qualitative Risk Assessment ◽  
The Matrix

Nanoparticles of graphene and carbon nanotubes are attractive materials for the improvement of mechanical and barrier properties and for the functionality of biodegradable polymers for packaging applications. However, the increase of the manufacture and consumption increases the probability of exposure of humans and the environment to such nanomaterials; this brings up questions about the risks of nanomaterials, since they can be toxic. For a risk assessment, it is crucial to know whether airborne nanoparticles of graphene and carbon nanotubes can be released from nanocomposites into the environment at their end-life, or whether they remain embedded in the matrix. In this work, the release of graphene and carbon nanotubes from the poly(lactic) acid nanocomposite films were studied for the scenarios of: (i) biodegradation of the matrix polymer at the disposal of wastes; and (ii) combustion and fire of nanocomposite wastes. Thermogravimetric analysis in air atmosphere, transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscope (SEM) were used to verify the release of nanoparticles from nanocomposite films. The three factors model was applied for the quantitative and qualitative risk assessment of the release of graphene and carbon nanotubes from nanocomposite wastes for these scenarios. Safety concern is discussed in respect to the existing regulations for nanowaste stream.

Sign in / Sign up

Export Citation Format

Share Document