•Our experimental attempts revealed that the ideal nanofiber morphology was obtained from the solution that included 11wt.% of PA6.•SEM analysis exhibited that uniform and defect free nanofibers were ...produced and the sputter coating was carried out effectively.•Uncoated PA6 nanofibers were the finest fibers among all. The diameter of 50 nm coated fibers rose almost by 25% compared with the uncoated one, on the other hand, approximately 75% increase in diameter of 100 nm coated fibers was calculated.•According to the tensile strength graph (Fig. 3), the highest value was obtained for 100nm coated fibers.•100nm coated nanofibrous membranes showed higher EMSE performance than the 50nm coated one.
PA6 nanofibers were electrospun successfully and sputter coated with gold and palladium to create functional nanofibrous membranes that possess electromagnetic shielding ability. Properties of the electrospinning solutions were analyzed in terms of viscosity, conductivity and pH values. Coating thicknesses of the nanofibrous membranes were determined as 50nm and 100nm. Morphology of the nanofibrous membranes were observed by SEM analysis. Elemental composition of the specimens was explored by using Energy Dispersive Spectroscopy. Results revealed that defect free and uniform nanofibers were obtained, and the diameters of the fibers were changed after coating. Tensile strength and elongation measurements confirmed that the mechanical characteristics of the nanofibrous membranes were merely altered after coating. Electromagnetic Shielding Effectiveness (EMSE) of the nanofibers was determined according to the ASTM D4935-10 protocol by using coaxial transmission line measurement technique in the frequency range of 15–3000MHz. It was observed that 100nm coated membrane performed better EMSE than uncoated and 50nm coated nanofibrous membranes.
Carbon black (CB)-filled polypropylene (PP) with surface resistivity between 106 and 109 Ω sq−1 is the ideal antistatic plastic material in the electronics and electric industry. However, a large ...amount of CB may have an adverse effect on the mechanical properties and processing performance of the material, thus an improved ternary system is developed. Blends of CB-filled PP and polyamide 6 (PA6) have been prepared by melt blending in order to obtain electrically conductive polymer composites with a low electrical percolation threshold based on the concept of double percolation. The morphological developments of these composites were studied by scanning electron microscopy. The results showed that CB particles were selectively dispersed in PA6 phases due to the good interaction and interfacial adhesion between CB and PA6. At the same CB loadings, the surface resistivity of PP/PA6/CB composite was smaller than that of PP/CB composite system, which indicated the better conductivity in the former composite. The increasing amount of PA6 in the composites changed the morphology from a typical sea–island morphology to a co-continuous morphology. What is more, with 8 wt% of CB and PP/PA6 phase ratio of 70/30 in which the PP and PA6 phases formed a co-continuous structure, the electrical conductivity of the composite peaked at 2.01 × 105 Ω sq−1.
This Special Issue covers manufacturing of a smart polymer composites via choice of ingredients, such as polymer, filler, and additives, as well as their unique composition. It also covers the smart ...processing of polymer composites, which is influenced by the choice of mixers, processing condition, processing technique, etc.
Lithium–sulfur batteries have attracted considerable attention due to its high theoretical specific capacity, low cost, environmental friendliness, etc. However, the dissolution of polysulfide ...intermediate in the electrolyte leads to rapid capacity decay in the charge–discharge process. A sulfur‐based cathode with the specific discharge capacity of 630 mAh g−1 and ultrahigh capacity retention ratio of 0.11% per cycle after 400 cycles at 0.5 C that simply blend the sublimed sulfur and acetylene black in the mortar with the polyamide‐6 (PA6) as binder is reported. The intense complexation between the lithium polysulfide and amide groups (CONH) in PA6 can effectively inhibit the “shuttling effect” and reduce the loss of active materials during the charge–discharge process. The discovery provides a handy and practicable strategy for developing the excellent cycling stability lithium–sulfur batteries.
During the charge–discharge process of lithium–sulfur batteries, S or Li2S2/Li2S cathodes go through a series of intermediate polysulfides and become Li2S2/Li2S or S. The complexation between the lithium polysulfides and the amide groups inhibits the “shuttle” of lithium polysulfides when S or Li2S2/Li2S transform to the soluble lithium polysulfides during the discharge process, preventing the loss of active materials.
Carbon fiber reinforced thermoplastics (CFRTP) using polyamide 6 (PA6) as the matrix resin were examined for the effects of ozone oxidation treatment and water absorption on the mechanical ...properties. Strength tests were conducted on CFRTP samples subjected to vacuum drying, conditioning, and temperature and humidity cycles. The relationship between the water content and the mechanical strength was clarified from the results. The water content of the samples was measured using the Karl Fischer method. In comparison with the untreated sample, the CFRTP sample subjected to ozone oxidation treatment (for both the CF fabrics and the PA6 films) exhibited higher values of flexural and tensile strengths at all the environmental conditions. This is attributed to the improved interfacial adhesion between the CF and the PA6 in the ozone-oxidized CFRTP sample even after water absorption. However, it was found that the rate of increase due to the ozone oxidation treatment tended to reduce under increased water penetration, because the interfacial adhesion between the CF and the PA6 matrix decreased.
Piperazine pyrophosphate (PAPP) was mixed in polyamide 6 (PA6) to investigate its flame retardant properties. The PAPP was characterised by Fourier transform infrared (FT-IR), elemental analysis, ...proton nuclear magnetic resonance (1H-NMR) spectroscopy and thermogravimetric analysis (TGA). The elemental analysis and TGA results of PAPP indicated it had a high P element content and good thermal stability. The flame retardancy of PA6/PAPP was also characterised by TGA, limiting oxygen index (LOI), UL-94 vertical test and microscale combustion calorimetry (MCC). The TGA results showed that the PAPP increased the stability of the PA6/PAPP and resulted in a significant increase of char residue. PA6/PAPP passed the UL94 V-0 rating with a LOI value of 42 vol %. The MCC test indicated that the PAPP can greatly decrease the peak heat release rate (PHRR) and total heat release (THR). The results of scanning electron microscope (SEM) illustrated that PAPP can promote the formation of compact char layer.
The joining of aluminium alloy AA6082-T6 to polyamide 6 (PA6) by friction stir spot welding (FSSW) was investigated in the current work. Although previous studies can be found on the joining of ...polymers and metals by FSSW, welding using aluminium plates as thin as the ones used in this work (1 mm) was not found. The influence of the plunge depth (0.1 to 0.5 mm) and the dwell time (15 and 30 s) parameters on the welding results was studied. In general, the increase of these parameters led to the improvement of the maximum load of the joints under tensile-shear testing. Additionally, the feasibility of multiple spot welding was tested and proven. Finally, although most of the welds were performed with a pinless tool, a tool with a conical pin and a concave shoulder was used for comparison. The use of this more conventional tool resulted in joints easily broken by handling. Still, the potential of the conical pin tool was demonstrated. The different conditions were evaluated based on morphology and tensile-shear testing. The weld with the best mechanical behaviour was produced with multiple spot welding, which failed for a maximum load of about 2350 N.
This study investigates the addition of ground tire rubber (GTR) into virgin polyamide 6 (PA6) to produce thermoplastic elastomer (TPE) blends. In particular, a wide range of GTR concentration ...(0–100% wt.) was possible by using a simple dry blending technique of the materials in a powder form followed by compression molding. The molded samples were characterized in terms of morphological (scanning electron microscopy), physical (density and hardness) and mechanical (tension, flexion and impact) properties. The results showed a decrease in tensile and flexural moduli and strengths with GTR due to its elastomeric nature. However, significant increases were observed on the tensile elongation at break (up to 167%) and impact strength (up to 131%) compared to the neat PA6 matrix. Based on the results obtained, an optimum GTR content around 75% wt. was observed which represents a balance between high recycled rubber content and a sufficient amount of matrix to recover all the particles. These results represent a first step showing that a simple processing method can be used to produce low cost PA6/GTR compounds with a wide range of physical and mechanical properties.
PDF
