The Effect of the Preparation Method and the Dispersion and Aspect Ratio of CNTs on the Mechanical and Electrical Properties of Bio-Based Polyamide-4,10/CNT Nanocomposites

Abstract

Bio-based polymeric nanocomposites (NCs) with enhanced electrical conductivity and rigidity were obtained by adding multi-walled carbon nanotubes (CNTs) to a commercial bio-based polyamide 4,10 (PA410). Two different types of commercial CNTs (Cheap Tubes and Nanocyl NC7000 TM ) and two different preparation methods (using CNTs in powder form and a PA6-based masterbatch, respectively) were used to obtain melt-mixed PA410/CNT NCs. The effect of the preparation method as well as the degree of dispersion and aspect ratio of the CNTs on the electrical and mechanical properties of the processed NCs was studied. Superior electrical and mechanical behavior was observed in the Nanocyl CNTs-based NCs due to the enhanced dispersion and higher aspect ratio of the nanotubes. A much more significant reduction in aspect ratio was observed in the Cheap Tubes CNTs than in the Nanocyl CNTs. This was attributed to the fact that the shear stress applied during melt processing reduced the length of the CNTs to similar lengths in all cases, which pointed to the diameter of the CNTs as the key factor determing the properties of the NCs. The PA6 in the ternary PA410/PA6/CNT system led to improved Young's modulus values because the reinforcing effect of CNTs was greater in PA6 than in PA410.

Calculation of the Electrical Conductivity of Polymer Nanocomposites Assuming the Interphase Layer Surrounding Carbon Nanotubes

“…(4)) as a function of (a) "R" and "l" and (b) "t" and "u" factors. Figure 3 exhibits the effects of different parameters on "fiu" term as the fraction of percolated filler above percolation threshold using Equation (6). Figure 3a indicates that the least "fiu" as about 0.05 is obtained at R = 50 nm and l = 3 μm, while the smallest level of "R" and l > 10 μm significantly improve the level of "fiu" to 0.28.…”

“…Polymers 2020, 12, 404 7 of 13 Figure 3. The variations of "fiu" term at different levels of (a) "R" and "l" and (b) "t" and "u" parameters according to Equation (6). Figure 4 illustrates the influences of "R" and "l" parameters on the electrical conductivity of PCNT predicted by the conventional and developed models in Equations (9) and (12).…”

“…The variations of "f iu " term at different levels of (a) "R" and "l" and (b) "t" and "u" parameters according to Equation(6).…”

Analysis of the Connecting Effectiveness of the Interphase Zone on the Tensile Properties of Carbon Nanotubes (CNT) Reinforced Nanocomposite

“…The carbon nanotubes (CNT) as ideal nanoparticles can add high stiffness and good electrical conductivity to polymer matrices. Additionally, the nanoscale diameter and large aspect ratio of CNT significantly improve the general properties of polymer CNT nanocomposites (PCNT) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The van der Waals attraction between nanotubes leads the aggregation/agglomeration in the nanocomposites, which reduces the filler surface expanse and interrupts the networking level [18][19][20].…”

Development of Expanded Takayanagi Model for Tensile Modulus of Carbon Nanotubes Reinforced Nanocomposites Assuming Interphase Regions Surrounding the Dispersed and Networked Nanoparticles

“…Carbon nanotubes (CNT) have involved significant interest in nanocomposites due to amazing mechanical behavior and good electrical conductivity, as well as nanometer size and high aspect ratio [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. It was reported that only a low content of CNT is enough to prepare a nanocomposite with significant mechanical and conductivity properties.…”