Papers by Keyword: Polyamide 6

Abstract: An experimental study was performed to evaluate the effect of iron, ferronickel, and stainless steel 304L (85-92wt%) powder injection molding (PIM) on the compressive strength and rheological behavior of polyamide (PA6/M) composite. The feedstock, prepared at 260°C, was extruded into a composite film. The effect of particle shapes and size distribution was investigated using Scanning Electron Microscopy (SEM) to evaluate the relative viscosity value of the PA6/M feedstock. The results showed that the compressive strength and rheological behavior were determined by the blend composition. The increase in compressive strength was due to the higher strength of the metal powders compared to PA6, along with heightened surface energy leading to mechanical interlocking. Furthermore, the metal powders generated frictional resistance resulting in an increase in viscosity, making the feedstock unstable and decreasing the rheological properties. According to the compression and rheology test, all variations with an 85wt% metal powder exceeded the minimum specifications for frangible projectile materials. The highest compressive strength of PA6/85Fe was 144.503 MPa and the lowest viscosity of PA6/85FeNi was 352.85 Pa.s.

Abstract: Fused deposition modeling (FDM) has several advantages, including design freedom, part customization, and ease of realizing complex geometries. However, there exist some challenges with the process; these include but are not limited to porosity, anisotropy, roughness, and material compatibility. This study is focussed on the additive manufacturing of polymer composites (short carbon fiber reinforced polyamide 6) through the process of FDM. Such 3D-printed parts are very lightweight and possess superior mechanical properties, which makes them a potential candidate for applications where a high strength-to-weight ratio is desired. The combination of FDM parameters, namely nozzle temperature, layer height, and flow rate, are studied in this work. The effect of variation in these parameters on the porosity and flexural strength is recorded following the Taguchi design of experiments. In calculating porosity, the weight difference between the printed part and the CAD part is used. For the flexural test, the standard three-point bending test is performed. The optimal combination of parametric settings is observed to be the same for minimum porosity and maximum flexural strength. Moreover, the flow rate is identified as a significant parameter for FDM printing of the composite material under study. The prints obtained at a raster angle 0˚/90˚ and on-edge orientation are observed to have better flexural strength than the prints at a raster angle ±45˚ and flat orientation.

Abstract: Global plastic production and consumption have increased due to its outstanding properties. Their widespread use is cause for concern, as most plastics deteriorate but never fully decompose, posing a risk to ecosystems. A large source of ocean plastic waste is "ghost gear", a result of intentional or accidental abandonment of fishing gear at sea. To reduce their impact, mechanical recycling is considered a viable option as it is an efficient recycling method in terms of time, cost-effectiveness, and environmental impact. This study aims to investigate the feasibility of producing injection moulded components from recycled fishing nets composed of polyamide 6 (PA6). The degradation in a marine environment allied with the mechanical recycling process was evaluated by comparing the physical and mechanical properties of injection moulded specimens of both recycled fishing nets and commercially available extruded PA6 plates. In addition, both materials were subjected to an additional mechanical recycling step (after the injection) to determine the impact on the properties of additional recycling cycles. Finally, the feasibility of injection moulding of cardholders was also studied. The physical and mechanical characterization concluded that the property values obtained in the tensile test and the density measurements of the recycled fishing nets are within the range of values established for the properties of an extruded, non-recycled PA 6, and that the effect of the second recycling on its properties was negligible. The marine degradation had a more significant impact on the tensile properties and Charpy notched impact strength than on the hardness and density values.

Abstract: Textile products are of great importance in the dissemination of newly developed communication devices and flexible electronics in conjunction with the advantages of covering the entire human body and being used all day long by all individuals in society. Various approaches have been developed to ensure the required electrical conductivity of textiles. Our research deals with melt spinning of carbon nanomaterial-based composites (CNCs) into electrically conductive filaments. By combining the various composite structures and property profiles with a conductive filler at high concentration, specific morphological structures can be achieved that offer a much higher potential for the development of new functional fibers for different smart textile applications.This study aims to produce nanocomposites from polyamide 6 (PA6) and polyethylene (PE) matrices with single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) by using a small-scale mixing device that provides short mixing time, and material savings in the first stage of the research.

Abstract: In this paper, the effect of nanoTiO₂ content on the thermal properties, mechanical properties, photocatalytic properties of PA6/TiO₂-GO composites were investigated. The results indicated that the melting point of the composites decreased gradually with an increase of nanoTiO₂ content, and the degree of crystallinity exhibited an increasing trend at first and then tended to decrease. Meanwhile, the breaking strength decreased gradually, whereas the elongation at break increased gradually. Moreover, the nanoTiO₂ exhibited an increasing photocatalytic activity for degradation of the methylene blue solution. The incorporation of graphene oxide (GO) could effectively improve the photocatalytic effectiveness of nanoTiO₂ by approximately 11%.

Abstract: Significant improvement of compatibility in PET/PA6 blends is essential to obtain fibers having enough mechanical strength as well as the comprehensive performance. In this article, copoly (ester-amide 6) was used as compatibilizer to improve the compatibility of PET and PA6. Three copoly (ester-amide 6) s with 5, 10% content of PA6 were prepared by co-polymerization from PTA , EG, as well as PA6 or caprolactam (A6), i.e. polyamide was incorporated both in the form of polymer and monomer, respectively. The sequence length of PET in the copoly (ester-amide 6) s is 33.4, 16.5 and 38.4 for PET-PA6-5%, PET-PA6-10% and PET-A6-5%, respectively, calculated by ¹³C NMR. Then PET/PA6 blend fibers were fabricated by melting spinning of PET and PA6 with 20 %wt addition of PET-PA6-5%, PET-PA6-10% and PET-A6-5%, respectively, to explore the effect of copoly (ester-amide 6) s on compatibility of PET/PA6 blend fibers, where the mass ratio of PET and PA6 is 85/15. DSC results show that the crystallization peaks of PET and PA6 during cooling from the blend melt become adjacent each other with increasing addition of copoly (ester-amide 6) s, even forming fused crystallization of them. It was found from SEM that the size of PA6 phase decreased and the phase boundary became indistinct due to the presence of copoly (ester-amide 6) s. Further more, the glass transition temperatures (T_g) of PET and PA6 closed to each other based on DMA result. Among these three copoly (ester-amide 6) s, PET-A6-5% display the best effect on the compatibility of PET and PA6 blend fiber, suggesting copoly (ester-amide 6) s could play important role in raise the compatibility of PET and PA6 blend.

Abstract: Polymer composites of polyaniline (PANI)/polyamide 6 (PA6) blends and reduced graphene oxide (rGO) were prepared via the in situ synthesis method in order to improve formability and electrical properties. Polymer blends and composites were characterized by the Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal gravimetric analysis. It was found that the composites prepared by the in situ synthesis method have better compatibility between polymer blends and matrix than that prepared by the conventional dry-mix method as investigated by scanning electron microscope (SEM). The Fourier-transform infrared (FT-IR) spectrograms indicate the presence of covalent bonds between functional groups between polyaniline and reduced graphene oxide. The PA6/PANI-rGO films show the electrical conductivity of 2.970×10^-6 S/cm while PA6/PANI-GtO show electrical conductivity of 4.082×10^-7 S/cm. Thermal stability of polymer blend was characterized by the thermogravimetric analysis. The thermal stability of polyamide 6 after blending is not changed significantly.

Abstract: Carbon nanotube (CNT) is excellent in mechanical and thermal characteristics, and are expected to be used in various fields such as nanoelectronic devices and reinforcing nanofillers for composites. It is expected that mechanical properties can be improved by adding CNT into the polymer. However, since CNT exists in a state of aggregation due to van der Waals forces, it is necessary to uniformly disperse CNT in order to fully extract the properties of CNT. In this study, CNT/polyamide 6 (PA6) composite nanofibres were fabricated by the electrospinning method. In order to disperse CNT in the CNT/PA6 nanofibres, CNT were subjected to air oxidation treatment. As a result of evaluating the dispersibility of CNT by sedimentation test, the dispersibility in pure water and HFIP is improved by oxidizing the surface of CNT. By conducting tensile tests and SEM observation of the nanofibre non-woven fabric, the influence of the surface treatment on the tensile strength of CNT/PA6 nanofibres and the dispersion of CNT was clarified. Although the addition of untreated CNT to PA6 nanofibres reduces the displacement at break, air oxidized CNT/PA6 suppressed the formation of CNT aggregates, and showed higher tensile strength and larger displacement at break than untreated CNT/PA6.

Abstract: An effective integration of natural fibers into engineering thermoplastics requires sufficient thermal stability of natural fibers during processing, since melting temperature of engineering thermoplastics lies above 200 °C. The aim of the work was to protect natural fibers from the heat of the molten thermoplastic via coating with a modified epoxy resin, thus enabling manufacture of natural fiber-reinforced engineering thermoplastic composites with minimized thermal degradation of the fibers. Processing temperature comprised the range of engineering thermoplastic polyamide 6 (PA6), which was 225 °C. Flax fabrics were spray coated with partially bio-based epoxy resin and incorporated via hot press technique into a PA6 matrix. The composite samples including spray coated flax fibers as well as the reference flax fibers without coating were characterized with regard to their mechanical properties, namely bending and tensile tests, thermal properties with differential scanning calorimetry (DSC) as well as thermogravimetric analysis (TGA) and optical via scanning electron microscopy (SEM) and computer tomography (CT). The results show that this approach enables manufacture of composites with reproducible mechanical properties, i.e. bending and tensile properties as well as enhanced thermal stabilities.

Abstract: Studies of microwave radiation on polymeric materials have shown the possibility of modifying the characteristics of materials. At the same time, the efficiency of the microwave effect can be increased by introducing into the polymer matrix electrically conductive particles (carbon, metal particles, etc.). In this case, the absorption coefficient of the microwave waves is greatly increased. The paper evaluated the physical and mechanical properties of polyamide 6 subjected to microwave exposure. To intensify the microwave, well-proven carbon nanotubes were used, which were added to the polymer in small amounts. The most effective was the addition of carbon nanotubes in an amount of 1 wt%. The data obtained are changes in strength under tensile, Shore D hardness conditions, as well as thermophysical characteristics (heat resistance and change in the specific energy absorption rate in the melting zone of the samples). Microwave can be used as a modifying radiation, and as a method of heating polymers for subsequent molding in products. This method significantly reduces the technological process of obtaining materials and products with improved performance characteristics.