scholarly journals Mechanical and Electrical Properties of Injection-Molded MWCNT-Reinforced Polyamide 66 Hybrid Composites

2020 ◽  
Vol 4 (4) ◽  
pp. 177
Author(s):  
Ross Zameroski ◽  
Chadwick J. Kypta ◽  
Brian A. Young ◽  
Seyed Hamid Reza Sanei ◽  
Adam S. Hollinger
Keyword(s):  
Electrical Properties ◽  
Carbon Fiber ◽  
Hybrid Composites ◽  
Skin Layer ◽  
Scanning Electron Micrographs ◽  
Polyamide 66 ◽  
Multiwalled Carbon ◽  
Mechanical And Electrical Properties ◽  
Nylon 6,6 ◽  
Injection Molded

The addition of fillers or reinforcements has a direct influence on the mechanical and electrical properties of polymers. Such properties are a function of the morphology and the distribution of fillers in the polymer base. Each feature may have contrasting effects on mechanical and electrical properties. In this study, chopped carbon fiber of different lengths and multiwalled carbon nanotubes (MWCNTs) were added to nylon 6,6. Specimens were manufactured by injection molding of a polyamide/MWCNT masterbatch with the addition of loose chopped carbon fiber. Tensile testing of dogbone specimens was conducted to obtain Young’s modulus, ultimate tensile strength, and elongation. Electrical conductivity testing was conducted on the same specimens prior to mechanical testing. To evaluate the morphology of fillers, scanning electron micrographs were evaluated. Micrographs show the presence of a skin layer close to the surface of the specimens. For this reason, core and surface conductivities were compared. The results show that while promising electrical properties can be achieved by the addition of fillers, the improvement in mechanical properties is minimal.

Investigation of Structure-Property Relationships in Thermoplastic Polyurethane/Multiwalled Carbon Nanotube Composites

2017 ◽  
Author(s):  
Felicia Stan ◽  
Catalin Fetecau ◽  
Nicoleta V. Stanciu ◽  
Razvan T. Rosculet ◽  
Laurentiu I. Sandu
Keyword(s):  
Electrical Properties ◽  
Shear Viscosity ◽  
Thermoplastic Polyurethane ◽  
Structure Property ◽  
Multiwalled Carbon ◽  
Structure Property Relationships ◽  
Mechanical And Electrical Properties ◽  
High Shear Rates ◽  
Nanotube Composites ◽  
Multi Walled Carbon Nanotubes

In this study, the structure-property relationships in thermoplastic polyurethane (TPU) filled with multi-walled carbon nanotubes (MWCNTs) were investigated. Firstly, the contribution of MWCNTs to the melt shear viscosity and the pressure-volume-temperature (pVT) behavior was investigated. Secondly, injection-molded samples and 2 mm diameter filaments of TPU/MWCNT composites were fabricated and their mechanical and electrical properties analyzed. It was found that the melt processability of TPU/MWCNT composites is not affected by the addition of a small amount (1–5 wt.%) of MWCNTs, all composites displaying shear-thinning at high shear rates. The mechanical and electrical properties of the TPU/MWCNT composites were substantially enhanced with the addition of MWCNTs. However, the conductivity values of composites processed by injection molding were two and three orders of magnitude lower than those of composites processed by extrusion, highlighting the role of melt shear viscosity on the dispersion and agglomeration of nanotubes.

scholarly journals Process Induced Skin-Core Morphology in Injection Molded Polyamide 66

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 894
Author(s):  
Yvonne Spoerer ◽  
René Androsch ◽  
Dieter Jehnichen ◽  
Ines Kuehnert
Keyword(s):  
Polarized Light ◽  
Skin Layer ◽  
Crystalline Morphology ◽  
Polyamide 66 ◽  
Thin Sections ◽  
X Ray ◽  
X Ray Scattering ◽  
Order Of Magnitude ◽  
Injection Molded ◽  
Ray Scattering

Polyamide 66 (PA 66) was injection-molded to obtain samples with a structure gradient between skin and core, as it was revealed by analysis of the semi-crystalline morphology using polarized-light optical microscopy (POM). Wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) were employed to characterize thin sections with a thickness in the order of magnitude of 50 µm, allowing detection of crystals of different perfection, as a function of the distance from the surface. It was found that the transparent and non-spherulitic skin layer contains rather imperfect α-crystals while the perfection of α-crystals continuously increases with extending distance from the surface. Since variation of the molding conditions allows tailoring the skin-core morphology, the present study was performed to suggest a reliable route to map the presence of specific semi-crystalline morphologies in such samples.

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