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 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.

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

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.

scholarly journals Improved Weathering Performance of Poly(Lactic Acid) through Carbon Nanotubes Addition: Thermal, Microstructural, and Nanomechanical Analyses

Biomimetics ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 61
Author(s):  
Thevu Vu ◽  
Peyman Nikaeen ◽  
William Chirdon ◽  
Ahmed Khattab ◽  
Dilip Depan
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Uv Light ◽  
Degradation Mechanism ◽  
Decomposition Temperature ◽  
Poly Lactic Acid ◽  
Accelerated Weathering ◽  
Degradation Behavior ◽  
Scanning Calorimetry ◽  
Norrish Type

To understand the interrelationship between the microstructure and degradation behavior of poly(lactic acid) (PLA), single-walled carbon nanotubes (CNTs) were introduced into PLA as nucleating agents. The degradation behavior of PLA-CNT nanocomposites was examined under accelerated weathering conditions with exposure to UV light, heat, and moisture. The degradation mechanism proceeded via the Norrish type II mechanism of carbonyl polyester. Differential scanning calorimetry (DSC) studies showed an increase in glass transition temperature, melting temperature, and crystallinity as a result of the degradation. However, pure PLA showed higher degradation as evidenced by increased crystallinity, lower onset decomposition temperature, embrittlement, and a higher number of micro-voids which became broader and deeper during degradation. In the PLA-CNT nanocomposites, CNTs created a tortuous pathway which inhibits the penetration of water molecules deeper into the polymer matrix, making PLA thermally stable by increasing the initial temperature of mass loss. CNTs appear to retard PLA degradation by impeding mass transfer. Our study will facilitate designing environmentally friendly packaging materials that display greater resistance to degradation in the presence of moisture and UV light.

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