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Highlights For traditional materials, a polymer composite with high performance and large‐scale production is still the goal pursued by researchers. In our work, polyamide 6/calcium sulfate whiskers (PA6/SCW) composites were fabricated via melt‐compouding method. The calcium sulfate whisker based on gypsum mineral was used as reinforcement. After grafting silane coupling agent on the whisker surface, the whiskers showed a significant reinforcing effect in polyamide. The mechanics and tribology performance of the samples had been significantly inhanced. Based on the nucleation mechanism of lattice matching, calcium sulfate whiskers have obvious heterogeneous nucleation effect in PA6 matrix, while the crystallization period was slightly prolonged. This was caused by the network structure formed by the whiskers in the matrix, which impeded the free movement of polymer chain segments. In combination with the orientation degree of the molecular chains measured by the interdigital electrode, the reinforcing effect of the oriented PA6 specimens was derived from the orientation arrangement of the whiskers and the efficient load transfer. Mechanical and tribological properties of composite were significantly improved. The composite could achieved large‐scale production due to simple preparation. The whiskers had obvious heterogeneous nucleation effect in matrix. The reinforcing effect was derived from efficient load transfer from whiskers. [ABSTRACT FROM AUTHOR]

In this study, the challenges of brittleness and flammability in Polyamide 6/glass fiber (PA6/GF) composites, which are crucial for heat‐resistant and stress‐bearing structural parts, are addressed. Polyphosphazene (PZ) elastomers, known for their exceptional flame‐retardant properties, are introduced to enhance the robustness and safety of these composites. Specifically, poly(diaryloxy)phosphazene (PDAP) and poly(difluoroalkoxy)phosphazene (PDFP) are utilized, both contributing to the improved toughness and flame resistance of the PA6/GF composites. Experimental results show that PDAP mainly played the role of solid‐phase flame retardant, while PDFP mainly acted the role of gas‐phase flame retardant. For PA/PZs composites without adding GF, PDFP plays a more efficient flame retardant effect than PDAP. By introducing 15 Vol% of PDFP, the limiting oxygen index (LOI) of the composite reached 26.1%, while the notched impact strength increased by 297%. For PA/PZs/GF composites, PDAP plays a better flame retardant role than PDFP. Under the action of 30 vol% GF and 15 vol% PDAP, the LOI of PA6/PDAP/GF composite reached 26.8%, and the notch impact strength improved to 18.7 kJ/m2, which is 165% higher than that of PA6/GF, and the UL‐94 test reaches V‐0 level. The findings of the study highlight the potential of PDAP and PDFP to act as dual‐function modifiers. These modifiers can considerably ameliorate both the impact resistance and flame retardancy of PA6 and PA6/GF composites. Such dual enhancement surpasses the typical trade‐offs seen in conventional composites, indicating a constructive direction for future material innovation. Highlights: Polyphosphazenes simultaneously enhance PA6's toughness & flame resistance.Distinct flame retardant mechanisms found in PDAP and PDFP.GF presence alters PDAP and PDFP's flame retardant efficacy.PDAP shows superior flame resistance in GF‐reinforced PA6 composites.Without GF, PDFP outperforms PDAP in enhancing flame retardancy. [ABSTRACT FROM AUTHOR]

Nylon nanocomposites were prepared by in‐situ ring‐opening polymerization to overcome the problem of poor properties due to the uneven dispersion of the nanoparticles by the traditional melt blending. This high‐performance polyamide 6 (PA6) nanocomposites with high dispersion and strong interface was prepared by grafting PA6 onto the surface of cellulose nanocrystals (CNC). The micromorphology, mechanical, crystalline and thermal properties of the composites were also investigated. Firstly, the hydroxyl group on the surface of CNC reacted with the para isocyanate of toluene diisocyanate (TDI), and the remaining ortho isocyanate was blocked by caprolactam to prepare CNC grafted with caprolactam (CNC‐g‐CL). Then CNC‐g‐CL was used as an activator to prepare cellulose nanocrystal grafted with polyamide 6 (CNC‐g‐PA6) composites by the ring‐opening polymerization of caprolactam on the CNC. The effects of different reaction temperatures, solvent amounts and molar ratios on the grafting rate of CNC‐g‐CL were investigated. The results showed that the highest grafting rate of CNC‐g‐CL with 66.7% was achieved at a reaction temperature of 45°C, 0.1 g/mL CNC in toluene, and a molar ratio of 6 for TDI/CNC. Further, different CNC‐g‐PA6 composites prepared from different CNC content and activator content were explored. For CNC‐g‐PA6 composites, CNC was uniformly dispersed in the PA6 matrix and had a good compatibility with the matrix. CNC exhibited significant reinforcement in the composites with a tensile strength of up to 108 MPa. In addition, the glass transition temperature of CNC‐g‐PA6 was increased to 92°C, which significantly improved the heat resistance of the new composites. Highlights: Effects of reaction condition of CNC and TDI on DSTDI and DSCL were studied.Effects of CNC and activator content on CNC‐g‐PA6 properties were studied.CNC is uniformly dispersed in PA6 with average particle size less than 1 micron.The nylon matrix was significantly strengthened by the addition of CNC.The addition of CNC significantly improved the heat resistance of the composites. [ABSTRACT FROM AUTHOR]

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights Interfacial adhesion properties are a key factor affecting the mechanical properties of composites. It is a very effective way to improve the low‐velocity impact resistance of composites by improving the interfacial adhesion properties. To improve the fiber/matrix interfacial adhesion properties of GF/PA6 (glass‐fiber/polyamide 6) composites, polyethyleneimine (PEI) and γ‐aminopropyltriethoxysilane (KH550) were used to co‐modify GF together in this study. The GF/PA6 composites with different modifications of glass‐fiber (GF) were also prepared using a hot pressing process, and then their flexural strength, shear strength, pendulum impact strength, and low‐speed impact resistance were investigated. Next, the relationship between fiber/matrix interfacial adhesion and mechanical properties of GF/PA6 composites was investigated by combining x‐ray photoelectron spectroscopy, scanning electron microscopy, and x‐ray computed tomography test results. The results showed that the GF‐reinforced PA6 matrix composite with co‐modified GF by PEI and KH550 (PEI‐KH550‐GF/PA6) had the best mechanical properties, with flexural, shear, and pendulum impact strengths of 660.7 MPa, 53.1 MPa, and 261.6 kJ/m2, respectively. Furthermore, the low‐velocity impact resistance was measured in terms of stress peak, absorbed energy, residual stress, and damage extension, and the results showed that the low‐speed impact resistance of PEI‐KH550‐GF/PA6 composites was also substantially improved that the Fmax increased from 7402.1 to 10414.0 N. Due to the poor surface activity of GF, in this experiment, GF was co‐modified with PEI and KH550 to achieve better fiber/matrix interfacial adhesion and successfully improve the mechanical properties of the composites; Different modification methods are used to improve the interfacial adhesion of the fiber/matrix interface. The relationship between the interface and impact strength of composites has been studied; The relationship between fiber/matrix interfacial adhesion and internal cracking in composites was investigated using X‐CT and SEM and other test results. [ABSTRACT FROM AUTHOR]

Highlights Achieving high thermal conductivity in composites with low filler content is a major challenge in current research. In this paper, polypropylene (PP) and polyamide 6 (PA6) were used as polymer matrix, and the hybrid thermal conductive filler, formed by hexagonal boron nitride (h‐BN) and aminated carbon nanotubes (NH2‐CNTs), was integrated into matrix for the fabrication of thermal conductive composites (PP/PA6/h‐BN and PP/PA6/h‐BN@CNTs) via two‐step melt blending technology. The thermal conductive fillers were selectively distributed in a phase of the polymer matrix with a co‐continuous structure, forming a thermal conductive path with a three‐dimensional network structure. The results show that when the content of h‐BN reaches 25 wt%, the thermal conductivity of the PP/PA6/h‐BN and PP/PA6/h‐BN@CNTs composites was 199% and 300% higher than that of PP/PA6, respectively. Through testing the volume resistivity of the composites, it was confirmed that PP/PA6/h‐BN@CNTs composites maintain good electrical insulation. Both composites demonstrated remarkable thermal conductivity and outstanding electrical insulation. This research provides a facile way to prepare highly thermal conductivity polymer composites with excellent processing performances and electrical insulation. h‐BN@CNTs hybrid fillers with sandwich structure were prepared. A two‐step blending method was used to control the selective distribution of hybrid fillers in a phase of the polymer matrix with a co‐continuous structure. The hybrid filler formed a thermal conductive path with a three‐dimensional network structure in the collective. PP/PA6/h‐BN@CNTs composites demonstrated remarkable thermal conductivity, outstanding electrical insulation and favorable processing performances. [ABSTRACT FROM AUTHOR]

Highlights Through resistance welding experiments, the effects of process parameters and heating elements (HE) on the welding strength of carbon fiber reinforced polyamide 6 (CF/PA6) composites were studied. Stainless steel mesh was used as the heating element for welding CF/PA6 composites. The mechanical properties of the weld were tested using a universal testing machine, and the internal structure and fracture of the joint were analyzed by scanning electron microscopy (SEM). The optimal parameters for welding CF/PA6 composites were determined. In addition, the growth of carbon nanotubes (CNTs) on the surface of the metal mesh significantly improved the welding strength, from 14.016 to 16.31 MPa. The experimental results showed that the optimal parameters included 22A current, 0.3 MPa pressure and 35 s welding time, and the optimal specification of the metal mesh heating element was 200 mesh. The burning time of the metal mesh was 10 s, and the optimum pickling time was 30 s. The matrix of the composite material is nylon 6. Improved the experimental process for growing carbon nanotubes. Explore the influence of burning time on welding effect through detection. [ABSTRACT FROM AUTHOR]

The main motivation of this work is to use ceramic microspheres (CMs) as a potential filler in polyamide 6 (PA6) to enhance its mechanical and tribological performances. Polyamide 6 composites bearing CMs in different weight ratios (10%–40%) are processed by melt blending and characterized primarily by tensile and bending test, dynamical mechanical analysis, and ball-on-disc wear test. This work clearly shows that the addition of CMs gives rise to superior mechanical and wear resistance contribution to PA6. The tensile strength, tensile modulus, flexural strength, and flexural modulus of the composites are enhanced up to 11%, 25%, 37%, and 80%, respectively, over those of the pristine polymer. The wear resistance of 40 wt% CMs containing composite is 60% higher than that of pure PA6. Consequently, it has been found that CMs can be a suitable alternative especially in applications where mechanical strength is desired due to its advantages of high rigidity and sliding wear resistance. [ABSTRACT FROM AUTHOR]

The polymer liner of the hydrogen storage cylinder was studied to investigate better hydrogen storage capacity in Type-IV cylinders. Molecular dynamics methods were used to simulate the adsorption and diffusion processes of hydrogen in a graphene-filled polyamide 6 (PA6) system. The solubility and diffusion characteristics of hydrogen in PA6 systems filled with different filler ratios (3 wt%, 4 wt%, 5 wt%, 6 wt%, and 7 wt%) were studied under working pressures (0.1 MPa, 35 MPa, 52 MPa, and 70 MPa). The effects of filler ratio, temperature, and pressure on hydrogen diffusion were analyzed. The results show that at atmospheric pressure when the graphene content reaches 5 wt%, its permeability coefficient is as low as 2.44 × 10−13 cm3·cm/(cm2·s·Pa), which is a 54.6% reduction compared to PA6. At 358 K and 70 MPa, the diffusion coefficient of the 5 wt% graphene/PA6 composite system is 138% higher than that at 298 K and 70 MPa. With increasing pressure, the diffusion coefficients of all materials generally decrease linearly. Among them, pure PA6 has the largest diffusion coefficient, while the 4 wt% graphene/PA6 composite system has the smallest diffusion coefficient. Additionally, the impact of FFV (free volume fraction) on the barrier properties of the material was studied, and the movement trajectory of H2 in the composite system was analyzed. [ABSTRACT FROM AUTHOR]

This study investigates the impact of incorporating graphene (G) and graphene oxide (GO) on the mechanical and thermal properties of polyamide 6 (PA6) composites. We employ a melt-extrusion process to achieve homogeneous dispersion of varying G and GO loadings (1.0–5.0 wt%) within the PA6 matrix. Notably, 2.0 wt% of both G and GO achieve excellent dispersion, leading to significant enhancements in the degradation temperature and a reduction in the thermal decomposition rate of the PA6 blends. Compared to the neat PA6, these composites exhibit improved (mention specific mechanical properties observed, e.g. tensile strength, modulus). This research establishes a novel and cost-effective approach to improve the processability, mechanical properties, and thermal stability of PA6, making it a valuable contribution for applications demanding high performance. [ABSTRACT FROM AUTHOR]

Polyamides can absorb or desorb water from or to their surrounding environment. The impact of this process is significant as water molecules lead locally to a swelling and a coupling of diffusion and deformation behavior. To model these phenomena, a strongly coupled chemo-mechanical (or diffuso-mechanical) model is required, considering both local water concentration and the viscoelastic material behavior of polyamide. In the present work, we derive and apply such a model to polyamide 6. A diffusion equation describing changes in water concentration is coupled to the balance of linear momentum in polyamide 6. The interaction between deformation and concentration is derived from thermodynamic considerations by introducing a free energy consisting of a mechanical and a chemical part. The mechanical part describes a linear viscoelastic model and includes chemical strains due to the presence of water molecules. The chemical part builds upon the theory of Flory and Huggins, that takes into account changes in enthalpy and entropy of mixing due to the interaction of polymer and water molecules. The coupling of deformation to water concentration arises due to a dependency of the water flux on the hydrostatic stress inside the polyamide. We successfully apply the derived model in Finite-Element simulations to predict the drying of polyamide 6 specimens without any coupling to mechanical loads. In addition, we reproduce experimentally obtained data from relaxation measurements, where the drying of polyamide specimens leads to an increase in relaxation modulus. [ABSTRACT FROM AUTHOR]

Copyright of BHM Berg- und Hüttenmännische Monatshefte is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, investigations of the non-isothermal crystallization kinetics of polyamide 6 (PA6) and PA6/m-lignin composites were conducted by differential scanning calorimetry (DSC). The crystallization kinetics of the PA6, including crystallization temperature and rate, were characterized by monitoring the heat flow during cooling. The study found that the crystallization temperature shifted to lower temperatures and the crystallization kinetics slowed down with increasing lignin. Besides, the Avrami equation modified by Jeziorny and Mo's method were used to study the non-isothermal crystallization kinetics of the neat PA6 and PA6 composites. The curve fit resulting from the modified Avrami equation was not convincing. However, Mo's method did successfully characterize the overall non-isothermal crystallization kinetics for neat PA6 and the PA6 composites. In addition, the activation energies of the non-isothermal crystallization were calculated by the Kissinger method. It was found that the PA6 composite crystallization rate increased when adding less than 10% lignin. However, the more the content of m-lignin, the slower the crystallization rate. The same conclusion was reached based on the fitting results of the non-isothermal crystallization activation energies. [ABSTRACT FROM AUTHOR]

Polyamide 6-short glass fiber composite is one of the advanced materials used for lightweight-high strength applications. To some extent, the mechanical properties of the composite depend on its manufacturing process. The most common method to produce thermoplastic polymer products is injection molding. Production of injection-molded components may use process parameters that can vary significantly since it is a variable that depends on the type of polymer materials. This study intends to find the relationship between tensile strength and impact strength of short glass fiber reinforced polyamide-6 composite with the injection molding process parameters, namely barrel temperature, holding pressure, and injection pressure. The Taguchi method was used for the analysis. The result shows that barrel temperature is the most influencing parameter for tensile strength and impact strength.

The field of production engineering is constantly attempting to be distinguished for promoting sustainability, energy efficiency, cost-effectiveness, and prudent material consumption. In this study, three control parameters (3D printing settings), namely nozzle temperature, travel speed, and layer height (LH) are being investigated on polyamide 6/carbon fiber (15 wt%) tensile specimens. The aim is the optimum combination of energy efficiency and mechanical performance of the specimens. For the analysis of the results, the Box-Behnken design-of-experiment was applied along with the analysis of variance. The statistical analysis conducted based on the experimental results, indicated the importance of the LH control setting, as to affecting the mechanical strength. In particular, the best tensile strength value (σB = 83.52 MPa) came from the 0.1 mm LH. The same LH, whereas caused the highest energy consumption in 3D printing (EPC = 0.252 MJ) and printing time (PT = 2272 s). The lowest energy consumption (EPC = 0.036 MJ) and printing time (PT = 330 s) were found at 0.3 mm LH. Scanning electron microscopy was employed as a part of the manufactured specimens' 3D printing quality evaluation, while Thermogravimetric analysis was also conducted. The modeling approach led to the formation of equations for the prediction of critical metrics related to energy consumption and the mechanical performance of composite parts built with the MEX 3D printing method. These equations proved their reliability through a confirmation run, which showed that they can safely be applied, within specific boundaries, in real-life applications. [ABSTRACT FROM AUTHOR]

In this study, the influence of four different process parameters on hot gas welding of CF/epoxy fiber composites functionalized with a PA6 thermoplastic film is investigated. Additional experiments are carried out on specimens adorned with triangular beads of coupling material that are printed onto the plates, ensuring extra material within the joining zone. This approach offers a great advantage for compensating geometric tolerances. The parameters considered are common process parameters for regular two-step processes: Heating element temperature (THE), heating time (HT), welding force (F) and welding time (HTF). The design of experiments (DoE) is planned according to the Taguchi method. An orthogonal array is used to set up the experimental plan. Three factor levels of each welding parameter are considered. The test series are carried out with two sample variants. In the second sample variant, additional thermoplastic material is placed in the joining zone. The strength of the welded joints is investigated by tensile shear tests according to DIN EN 1465. The results show that the welding force has the greatest influence on the welding strength. Heating times of 20 s were found to be optimal. Within the first sample variant, a saturation behavior of the welding force can be observed at 500 N. Higher heating element temperatures (500 °C) and welding forces (1165 N) are advantageous using additional material. High welding temperatures result in a negative effect on the interdiffusivity of the polymer chains. [ABSTRACT FROM AUTHOR]

Polyamide 6 (PA6) is a widely used thermoplastic engineering polymer, and the toughening modification for PA6 is always a main research topic. Meanwhile, the rigidity and heat resistance of PA6 usually deteriorate. To address this conflict, an epoxy compound (EGDE‐GA) was designed and synthesized and used to modify PA6 by dynamic vulcanization in twin‐screw extruder. EGDE‐GA is a linear molecule with a flexible molecular structure, which is favorable to toughening of PA6, and epoxy groups of EGDE‐GA can form local cross‐linked structure to improve the rigidity and retain the heat resistance of PA6. At the loading of 20 wt% of EGDE‐GA, the modified PA6 (PA6/EGDE‐GA 20) exhibited very high elongation at break and notched impact strength, which were increased by 413% and 520%, respectively, compared to those of PA6. The tensile strength was 61.4 MPa, which was higher than that of PA6. The heat deflection temperature remained almost unchanged. The results showed that the modified polymers may possess the high toughness without sacrificing the original rigidity by building the local crosslinked structure using dynamic vulcanization. The findings provide a feasible method for reusing and upcycling PA6 and other polymers with higher value and wider use in the industry. Highlights: The polyamide 6 (PA6) is toughened via dynamic vulcanization.The toughness of modified PA6 is increased by 520% compared with pure PA6.The toughened PA6 exhibits higher tensile strength than that of pure PA6.The toughened PA6 maintains its rigidity and heat resistance. [ABSTRACT FROM AUTHOR]

Polymeric liners, one of the main components of hydrogen tanks, have attracted significant research interest because of their lightweight and high-impact strength. Despite their advantages, high gas permeability limits their applications. Thus, numerous studies have been conducted to improve the gas barrier properties of polymer-based composites. In this study, we used a polyamide 6 (PA6)/ethylene vinyl alcohol (EVOH) blend as a matrix for high hydrogen gas barrier properties and ethylene propylene diene monomer (EPDM) rubber as reinforcement for injection moldability. The ternary polymer blends were successfully injection molded, and their morphology, mechanical properties, and gas permeability were measured. In addition, we performed a rheological investigation to analyze the processability of the ternary polymer blends. As a result, the developed material system showed a 28% reduction in hydrogen permeability and a 11% improvement in tensile strength compared to a commercial material. This study will be a valuable resource for the research of polymeric liners with efficient and reliable performance. [ABSTRACT FROM AUTHOR]

Injection welding is an excellent adhesive‐free bonding method for thermoplastic resins, demonstrating outstanding connection effectiveness. The incorporation of carbon fibers (CFs) significantly enhances the weld shear strength at the injection interface. This study aims to investigate the reinforcement effect of CF‐reinforced thermoplastic composites (CFRTP) during the injection welding process. And explore the influence of the amount of added CFs on the weld shear strength. Polyamide 6 (PA6)/CF composites with CF contents of 10 wt% and 30 wt% were subjected to injection welding for the first and second molding cycles, respectively. It was observed that the reinforcement effects varied considerably depending on the combinations studied. Under the optimal combination and process parameters, the weld shear strength of PA6/CF composites reached 63 MPa, equivalent to 90% of the shear strength (70 MPa) of the original PA6/CF material. Polarized light microscopy and scanning electron microscopy were utilized to analyze the distribution of CFs at the interface and the reinforcing mechanism during tensile fracture. The significance of maintaining uniform CF content during the welding process of PA6/CF composites was emphasized. Highlights: Preparation of PA6 composite materials with different carbon fiber contents.Achieving high welding shear strength of composite materials through injection welding.Identified the optimal injection welding conditions to achieve the highest strength.The positive effect of specific fiber distribution on welding strength was analyzed. [ABSTRACT FROM AUTHOR]

Microplastic pollution has become one of the most concerned focuses in the world. Among many treatment methods, photocatalysis is considered to be one of the most environmentally friendly methods. In this work, the photodegradation behavior of polyamide microplastics is studied by using polyamide 6 PA6) as model microplastics and FeCl 3 as catalyst. It is hoped that the PA6 fiber can be effectively degraded by utilizing the strong oxidizing active species that can be produced after FeCl 3 is irradiated in water. The results shows that PA6 fiber can be almost completely degraded after 10 days of irradiation in FeCl 3 aqueous solution, indicating that it is promising to use this new method to solve the problem of PA6 type microplastics. In addition, the chain scission mechanism and degradation process of PA6 are analyzed in detail by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS), which provides a new insight for the study of polymer degradation mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM) is one of the additive manufacturing (AM) techniques in which intricate shapes are produced effectively with time and cost. Thermoplastics and filler-incorporated thermoplastics composite materials were used in the form of filament. The mechanical properties of the printed sample varies with the parameters involved in FDM printing. In the present investigation, polyamide 6 (PA) with 20 wt.% of short carbon fiber (CF) was used as filament. The filaments were printed with different raster orientations namely 0°, 45°, 90°, and ±45° by keeping other printing parameters constant such as 100% infill density, 0.2 mm layer thickness, 30 mm/min printing speed, 240°C printing temperature, 80°C bed temperature, and XY or 0° body orientation with a clear justification studied. The printed samples were investigated for structure, morphology and mechanical properties using tensile test and impact test respectively. The results shows that bidirectional ±45° raster orientation specimens show the highest tensile strength of 35.2 MPa in comparison with 0°,45°, and 90° raster orientation, and PACF composite material showed improved mechanical properties as compared to pure PA. The highest impact energy was observed for a PACF composite with a raster orientation of 90°. Morphological analysis of composites showed a uniform dispersion of CF in PA matrix and improved interfacial adhesion between matrix and reinforcement. [ABSTRACT FROM AUTHOR]

• The fragility of leathers is caused by different improper environmental conditions. • Molecular modeling showed good prediction for the application efficiency of PA6 in the consolidation of leathers. • The advantages of polyamide 6 make it suitable for the consolidation of fragile leather. • Some physical characteristics of leather were used for the evaluation of polyamide 6. • 2% and 3% polyamide 6 can be safely applied to historical leathers. This study aims to determine the efficiency of Polyamide 6 in consolidating fragile vegetable-tanned leather artifacts. Through two proposed interaction strategies, molecular modeling calculations demonstrated how the proposed polyamide 6 structure can protect vegetable-tanned leather from deteriorating environmental conditions. The total dipole moment was calculated as a potential descriptor of structure reactivity, and all of PA6 and the two proposed interaction models reveal poor reactive behavior when compared to pristine structures, confirming its capabilities as a protective layer. Furthermore, electrostatic potential maps were created to enhance PA6′s ability to safeguard leather artifacts and transform them into neutral, non-reactive substances. It was also created new vegetable-tanned leather prototypes. Polyamide 6 was produced in various concentrations and impregnated into the aged untreated samples. The evaluation process used some physical qualities (digital and scanning electron microscopes, color change, water absorption, and water vapor permeability). All examinations and investigations revealed that 2% and 3% concentrations produced the best results, while the concentration of 5% produced the worst. As a result, this study suggests employing 2% and 3% concentrations to treat historical and archaeologically fragile vegetable-tanned leather objects. [Display omitted] [ABSTRACT FROM AUTHOR]

In the field of material modeling, thermoplastic polymers are often studied because of their complex material behavior and their prevalence in industry applications due to their low cost and wide range of applications. Nowadays, where reusability becomes more and more important, materials which can undergo reversible thermomechanical deformations are appealing for, e.g., the construction of car body components. To predict such complex forming processes with multiple influencing factors, such as temperature, strain rate or underlying material morphology, model formulations are needed that account for these influences simultaneously and are validated against experimental data. Unfortunately, up to now only a few contributions are available which consider all these phenomena. In addition, the range of process parameters considered is often narrow due to the experimental effort required for testing. This usually results in limited predictive capabilities of the model. To overcome these limitations, in this work, a thermo-mechanically coupled material model is developed that accounts for the underlying morphology in terms of the degree of crystallinity (DOC). The model formulation is derived in a thermodynamically consistent manner, incorporating coupled nonlinear visco-elastic and elasto-plastic material behavior at finite strains. To characterize and further validate the model, mechanical as well as thermal experiments are conducted for polyamide 6 (PA6). Here, a blending strategy of PA6 together with an amorphous co-polymer is introduced during specimen production to achieve a wider range of stable DOCs(approximately 15%). The model formulation is successfully applied to experimental results and its predictions are in good agreement with experimental observations. [ABSTRACT FROM AUTHOR]

Polyamide6 is a vital high-performance commercial engineering thermoplastics polymer, but it exhibits low toughness and high hydrophilicity. To improve its disadvantages, the facile melt co-polycondensation method was proposed to synthesis a novel polyamides 6-1012 copolymers (PA6-1012) with different PA1012 salt loading. Experimental results show that the melting temperature (Tm), crystallization temperature(Tc), melting enthalpy(ΔHm), and crystallinity(Xc) decreased with the increase of PA1012 loading in the copolyamides. The size and number of the copolymers' spherical crystals decrease by the additions of 1012 units, but its crystalline structure and thermal stabilities does not be affected. The hydrophilicity decreases with increasing PA1012 content from 0 to 28 wt% and the highest contact angle value at the PA1012 loading of 28 wt% is 96°, which can be considered as a surface hydrophobic material. Low temperature (−5 °C)mechanical test results reveal that loss in tensile strength is exchanged for a considerable increase in the strain at break. The impact strength of the PA6-1012 copolyamides is notably enhanced by increasing the PA1012 loading in different test temperatures due to the increase of molecular chain flexibility, indicating that the copolyamindes exhibit enough toughness to suitably apply in low temperature environment. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the debonding behavior of the interface between continuously and discontinuously fiber reinforced thermoplastics using the climbing drum peel test. The study emphasizes on the importance of considering different climatic boundary conditions on the properties of thermoplastics. Specimens with varying moisture contents, from 0 m. % up to above 6 m. % are prepared and tested. It is observed that an increase in moisture content from 0 m. % to 2 m. % results in an increase of the fracture surface energy from 1.07 · 10 3 J / m 2 to 2.40 · 10 3 J / m 2 required to separate the two materials, but a further increase in moisture to 6.35 m. % conversely results in a subsequent decrease of the required energy to 1.91 · 10 3 J / m 2 . The study presents an explanatory model of increasing plasticization of the polymer due to increased polymer chain mobility, which results in more deformation energy being required to propagate the crack, which is corroborated in SEM investigations of the fracture surface. A further increase in humidity leads to polymer degradation due to hydrolysis, which explains the subsequent reduction of the fracture energy. The experimental set up is modeled numerically for the first time with cohesive surfaces, which could successfully reproduce the effective force-displacement curve in the experiment by varying the interface parameters in the model over an influence length, allowing the conclusion of a process induced variation in the interface properties over a specific consolidation length. [ABSTRACT FROM AUTHOR]

Biaxially oriented polyamide 6 (BOPA6) films were prepared by extrusion casting and biaxial stretching with polyamide 6. The effects of different biaxially oriented on the macroscopic properties of BOPA6 were investigated by characterizing the rheological, crystallization, optical, barrier and mechanical properties. The results show that the increase of stretching temperature leads to the diffusion and regular stacking rate of BOPA6 chain segments towards crystal nuclei increases, the relative crystallinity increases, reaching 27.87% at 180 °C, and the mechanical strength and optical performance decrease. Heat-induced crystallization promotes the transformation of β-crystals to α-crystals in BOPA6, resulting in a more perfect crystalline structure and enhancing oxygen barrier properties. BOPA6 chains are oriented, and strain-induced crystallization (SIC) occurs during the biaxial stretching. Further increasing the stretch ratio, the relative crystallinity increased to 30.34%. The machine direction (MD) and transverse direction (TD) tensile strength of BOPA6 (B-33) are nearly two times higher than the unstretched film, reaching 134.33 MPa and 155.28 MPa, respectively. In addition, the permeation decreases to 57.61 cc·mil/(m2 day), and the oxygen barrier performance has improved by nearly 30% compared to the sample B-22. BOPA6 has a high storage modulus at a high stretching rate (300%/s). Rapid chain relaxation would promote the molecular chain disorientation, destroy the entangled network of the molecular chain, and lead to a decrease in tensile strength, reducing to about 110 MPa. [ABSTRACT FROM AUTHOR]

This study investigated the impact of stabilization time on pretreated polyamide 6 (PA6) fibers using various analytical techniques, including thermal analysis (TGA and DSC), infrared (IR) spectroscopy, X-ray diffraction (XRD), tensile testing, and density measurements. The two-step atmospheric air-based stabilization process for pretreated PA6 multifilament bundles involved initial thermal stabilization at 170 °C in an air atmosphere after ferric chloride impregnation, followed by a second step of thermal stabilization at 245 °C. Ferric chloride impregnation followed by thermal stabilization in an air atmosphere resulted in crucial structural transformations. The density values of the samples increased following thermal stabilization, accompanied by a decrease in tensile values. Ferric chloride pretreated and thermally stabilized PA6 fibers were found to be fully stabilized after 120 min of stabilization before the carbonization stage. The findings obtained from the DSC, XRD, and IR spectroscopy methods indicated the occurrence of disordering phases due to the scission of hydrogen bonds. The TGA findings showed significant increases in carbon yield percentages at 500 °C and 850 °C, reaching 71.4% and 63.5%, respectively, for the sample heat treated at 245 °C for 120 min. The addition of ferric chloride is expected to potentially reduce processing costs for final carbon fiber production by decreasing the time required for the thermal stabilization of PA6. [ABSTRACT FROM AUTHOR]

In recent years, bio-reinforced composite materials have occupied an important class among the materials of mass use in our daily lives thanks to their potential advantages such as lightness, low cost, ease of implementation, and in particular biodegradation. The latter has been the objective of several studies focusing particularly on poorly biodegradable polymers, among these polymers we find polyamide 6 (PA6). It is a semi-crystalline polymer, distinguished by its good mechanical properties, excellent chemical and thermal stability, and low price compared to other polyamides. In this research, we investigated the impact of reinforcing PA6 with peanut shell powder (PSP), olive pomace powder (OPP), and plaster (PL) on its biodegradation process. Our objective was to determine whether the incorporation of these reinforcements accelerates, delays, or has no effect on PA6 biodegradation. To achieve this, we conducted degradation experiments using the bacterium Alcaligenes faecalis (AF), isolated from the public landfill of Meknes, Morocco. Our findings revealed intriguing insights into the biodegradation behavior of the PA6 composites. Specifically, the incorporation of PSP significantly enhanced PA6 biodegradation, resulting in a notable 38 % weight loss. Conversely, the inclusion of OPP led to a delay in biodegradation, with only a 19 % weight loss observed. Interestingly, the addition of plaster exhibited a biodegradation pattern similar to that of raw PA6. Furthermore, we utilized FTIR and SEM coupled with EDS elemental analysis to confirm the biodegradation of the composites. These techniques provided valuable insights into the structural, morphological, and elemental changes undergone by the composites during the biodegradation process. Overall, our study contributes novel insights into the biodegradation dynamics of PA6 composites reinforced with natural materials. By elucidating the effects of reinforcement on biodegradation, our research paves the way for the development of sustainable and eco-friendly composite materials.

Despite the increasing interest in polyamide-based composites, few studies on polyamide-based natural fiber composites have been conducted due to their high melting temperatures of polyamide 6 (PA6). In this study, kenaf fiber-reinforced polyamide 6 composites (KF/PA6) were successfully prepared and their properties were investigated. Thermogravimetric analysis demonstrated that the neat PA6 has higher thermal stability with higher melting temperatures of 426°C, respectively, than KF/PA6 composites. The results of the differential scanning calorimeter showed that the glass transition temperature (T g) of KF/PA6 composites was slightly shifted to a higher temperature at 59°C than that of the neat PA6 at 45°C. The thermal and mechanical characteristics using dynamic mechanical analysis results showed that the storage and loss modulus of the neat PA6 were higher than those of KF/PA6 composites. The neat PA6 showed the maximum tensile strength of 48 MPa; however, the maximum tensile modulus was obtained at 10 wt% KF with 2,100 MPa. The flexural strength and modulus of the neat PA6 were 91 and 2,506 MPa, respectively, which were higher than those of KF/PA6 composites. The impact strength also deteriorated with the addition of KF, from 3.72 to 1.91 kJ·m−2. Voids, fiber pulled-out, and agglomeration were observed in scanning electron microscope analysis on the tensile fractured surfaces.

Polyamide 6-short glass fiber composite is one of the advanced materials used for lightweight-high strength applications. To some extent, the mechanical properties of the composite depend on its manufacturing process. The most common method to produce thermoplastic polymer products is injection molding. Production of injection-molded components may use process parameters that can vary significantly since it is a variable that depends on the type of polymer materials. This study intends to find the relationship between tensile strength and impact strength of short glass fiber reinforced polyamide-6 composite with the injection molding process parameters, namely barrel temperature, holding pressure, and injection pressure. The Taguchi method was used for the analysis. The result shows that barrel temperature is the most influencing parameter for tensile strength and impact strength. [ABSTRACT FROM AUTHOR]

Nanocomposites based on an immiscible blend of polyamide 6 (PA6) and polyamide 12 (PA12) 50/50 wt.% with different contents of multi‐walled carbon nanotubes (MWCNTs) were prepared by extrusion followed by compression molding. These materials have been proved to be electrically conductive in previous investigations for the range of filler content assayed. The morphology of the nanocomposites was analyzed using scanning electron microscopy, both on cryo‐fractured and postmortem uniaxial tensile samples. Rheological measurements were performed along with differential scanning calorimetry, to assess the materials microstructure and thermal transitions. Furthermore, uniaxial tensile tests were carried out to determine mechanical properties such as stiffness, strength, and strain at break and to investigate the effect of MWCNTs on these properties. Finally, fracture tests were also conducted to evaluate how incorporating MWCNTs affected nanocomposites toughening capabilities. The obtained results suggest a notable improvement in the mechanical properties in the nanocomposites with low amounts of nanofiller. This expands their potential applications as conductive polymer composites (CPCs) and positions them as promising multifunctional materials. Highlights: CPCs based on a PA blend and MWCNTs were successfully obtained.CNTs strongly affected the blend morphology and rheological properties.CNTs significantly modified the crystallization behavior of PA6.Ductility greatly improved at low CNT contents but decreased at high loadings.Stiffness increased steadily with increasing CNT content. [ABSTRACT FROM AUTHOR]

This study addresses the significant issue of noise pollution, which has detrimental effects on both human health and the environment. We synthesized pristine polyamide 6 (PA6) and hybrid PA6-SiO2 and PA6-Ag membranes using the electrospinning method. These membranes were then coated on polyurethane (PU) foams in single-layer and multi-layer (both gradually and non-gradually) configurations to evaluate their potential in sound absorption (α). We investigated the effects of SiO2 and Ag nanoparticles (NPs) on the microstructure, crystallinity, molecular groups, porosity, and mechanical properties of PA6 membranes. The average fiber diameter size of PA6 was 177.1 ± 5 nm and PA6-SiO2, and PA6-Ag nanofibers were observed to be, 181.9 ± 5, and 103 ± 1 nm, respectively. Interestingly, SiO2 NPs increased the roughness of fibers and created uneven paths at the nanoscale for sound waves to pass through. The PA6 membrane achieved the highest surface area (20.868 m2.g−1), while the hybrid PA6-SiO2 membrane obtained the highest crystallinity (60.1%). Non-gradually membrane coatings could increase α in the range of 0.25 to 2 kHz, while single-layer coating didn't have a practical effect. The performance of coatings to enhance the noise reduction coefficient (NRC) was drastically increased when functionally graded membranes were applied. This improvement is attributed to the particular arrangement of pores and deposition of fibers with different crystallinity, size, thickness, and roughness. The maximum performance improvement (+47.9%) was measured for a coating consisting of two layers of PA6-SiO2 membrane at the bottom and three layers of PA6 membranes at the top. Our findings suggest that functionally graded electrospun membranes can be effectively used in the field of acoustic energy absorption research. Highlights: PA6, PA6-SiO2, and PA6-Ag membranes were synthesized via the electrospinning method Membranes were arranged gradually on a PU Foam The composition, morphology and crystallinity of PA6 was changed gradually The surface area and pore size of membranes were changed gradually Functionally graded membranes are suggested for acoustic energy absorption [ABSTRACT FROM AUTHOR]

This study explored the crucial relationship between base fluids and polyamide, a prevalent polymer in electric vehicle (EV) components, with the aim of enhancing the longevity and performance of EVs in the context of thermal management by immersion cooling. Focusing on polyalphaolefin and polyol ester as base fluids, an immersion test was conducted to assess their interaction with polyamide 6 using adapted ASTM standards. The results revealed the significant influences of both fluids on the physical properties and chemical structure of polyamide. Polyol ester demonstrated a lesser impact on the chemical and mechanical properties of polyamide 6. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To meet the lightweight production requirements of automobiles and achieve high strength, reinforced thermoplastic composite materials are gradually replacing metal materials. Injection molding is the preferred manufacturing method to enable the production of complex‐shaped parts, facilitate production, and reduce costs. In this study, carbon fiber (CF) was added to the commonly used resin‐reinforcing material, polyamide (nylon) PA6, to create a CF‐reinforced thermoplastic composite (polyamide 6 [PA6]/CF) that was welded using injection molding. This study not only investigates the impact of different welding conditions on shear strength but also discusses the sequence of welding. Achieving 85% of the shear strength of the PA6 base material under ideal circumstances. The CF distribution and reinforcement mechanism were analyzed by observing the connection interface and cross section using a polarizing microscope and a scanning electron microscope. When PA6/CF was used as the secondary molded body, the welding results were better. The addition of CF had a significant strengthening effect on the strength of the PA6 injection welding. Highlights: Carbon fiber‐reinforced thermoplastic composite materials were prepared, and welding with PA6 was achieved using the injection molding method.The optimal welding parameters were determined by varying the mold, injection speed, injection temperature, and order of injection. The maximum welding shear strength reached 85% of the base material shear strength.The positive effect of specific fiber distribution on welding strength was analyzed by observing the interface using a scanning electron microscope and a polarizing microscope.This study provides valuable insights into the optimization of welding processes for carbon fiber thermoplastic composite materials, offering possibilities for connecting dissimilar materials with poor compatibility. [ABSTRACT FROM AUTHOR]

To attain a lightweight structure with high pressure and a high hydrogen storage mass ratio, the type IV hydrogen storage tank is the most popular choice for many fuel cell vehicle enterprises. Using polymer as the liner material prevents hydrogen embrittlement and hydrogen-induced damage of the tanks, but hydrogen permeation is inevitable. Within the service conditions (233–358 K, 0–87.5 MPa) of the Type-IV tanks, the dissolution and diffusion behaviors of H 2 in polyamide 6 are comprehensively explored for the first time through the molecular dynamics and Grand Canonical Monte Carlo simulations in this study. The diffusion mechanism of H 2 in polyamide 6 is further revealed. The results show that both the diffusion and permeability coefficients have positive correlations with temperature, whereas the opposite is true for the solubility coefficient. These relationships are all consistent with Arrhenius's law in the temperature range, although multiple Arrhenius regions are needed to describe them. A slight decrease in the diffusion and permeability coefficients is observed with increasing pressure. However, this effect is not as significant as that of temperature and can be ignored when the pressure range is narrow enough. The "hopping" mechanism can be used to describe the diffusion of H 2 in polyamide 6, where the continuous vibrations and "hopping" allow the diffusion of H 2 molecules. These findings will contribute to a more comprehensive understanding of the permeation behavior of H 2 in polyamide 6 and evaluate the gas barrier property of the material in practical applications. • The dissolution and diffusion behaviors of H 2 in PA6 are explored by MD and GCMC simulations. • The "hopping" mechanism can describe the diffusion of H 2 in PA6. • Multiple Arrhenius regions are observed under service conditions. • The effect of pressure on permeability is not as significant as that of temperature. [ABSTRACT FROM AUTHOR]

Antistatic packaging has gained great importance for protecting sensitive electronic devices against static charges. In this work, polyamide 6 (PA6)/carbon nanotubes (MWCNT) nanocomposites were developed in the molten state, aiming to evaluate the potential for dissipation of static charges. The properties of torque rheometry, melt flow index (MFI), mechanical (impact, tensile, and Shore D hardness), Raman spectroscopy, electrical conductivity, differential scanning calorimetry (DSC), thermogravimetry (TG), and scanning electron microscopy (SEM) were investigated. In the Raman spectra of the nanocomposites, the main MWCNT bands were observed at 1347 cm−1 and 1580 cm−1, confirming the distribution in the PA6 matrix. Incorporating 5 phr (parts per hundred resin) of MWCNT into the PA6 matrix promoted better distribution, as verified in the storage module and scanning electron microscopy (SEM). In addition, there were gains in elastic modulus, Shore D hardness, and heat deflection temperature (HDT) by 11%, 4.5%, and 12.3%, respectively, in relation to PA6. Differential scanning calorimetry (DSC) indicated an increase in the crystallization process for all PA6/MWCNT nanocomposites, while an increase of 9.4 °C was verified in thermal stability by thermogravimetry for PA6/MWCNT (5 phr). From the point of view of the potential for antistatic application, the PA6/MWCNT (5 phr) nanocomposite presented electrical conductivity in the order of 1.1 × 10–06 S/cm, an adequate value for dissipating static charges. In view of this, the tailor-made PA6/MWCNT (5 phr) nanocomposite has the potential for antistatic protection. [ABSTRACT FROM AUTHOR]

The utilization of 2-level factorial design has been extensive in the literature to observe the relationship between parameters and responses. Among the subjects open for exploration, the process of nanofiber creation stands out as an intriguing avenue to explore the correlations that emerge between variables and outcomes. The primary objective of the shidy is to establish the relationship between the parameters of electro spuming of polyamide 6 (PA6) solutions to obtain desired nanofiber diameters by two level full factorial design. The investigation hones in on four critical parameters related to the electro spinning process of PA6 solutions. These parameters are solution concentration, applied voltage, distance between the spinneret and the collector, and the flow rate of the solution. Employing a two-level factorial design, these parameters are methodically manipulated at two distinct levels each to systematically unravel their individual and collective impacts on nanofiber diameter outcomes. After the model is obtained, the full model was fitted to first response. In the step of identifying important variables, background elimination and forward selection was chosen. Clearly polymer concentration have strong effect on the response and the effects of other main factors and interactions are explained in detail. [ABSTRACT FROM AUTHOR]

The chain extension of polyamide 6 (PA6) via a chemical reaction between a chain extender and the amino and carboxyl groups of the polymer increases the molecular weight and improves the mechanical properties, while typically deteriorates PA6 processability owing to cross‐linking. To resolve this issue, a dynamic covalent chain extender containing two anhydride groups is synthesized, which reacts only with amino groups, and employed to connect the PA6 molecular chains via the reaction between anhydride groups and terminal amino groups of PA6. On adding 3 wt% of the chain extender, the content of amino end groups is decreased from 30.6 to 5.8 μmol g−1 and the yield strength and elastic modulus of chain‐extended PA6 exceed those of original PA6 by 15.8% and 23.4%, respectively; meanwhile, the melt torque of chain‐extended PA6 is lower by 35.0% approximately, and the complex viscosity is also decreased. As far as we know, the dynamic covalent chain extender is used for the first time in the chain extension of PA6. This study provides a prospective approach to recycle PA6 for simultaneously improving mechanical properties and processability. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) can be added to a polymer matrix to achieve electrical conductivity, leading to a potential sensor application. In this study, we evaluated the tensile strength of AC when mixed with a polybutylene terephthalate (PBT)/polyamide 6 (PA6) blend. The PBT/PA6/AC composite was prepared by injection molding with 0, 2, 4, 6, 8, and 10% AC. The samples were subjected to a tensile test following the International Organization for Standardization 527 standard. The tensile strengths of the PBT/PA6/2% AC, PBT/PA6/4% AC, PBT/PA6/6% AC, and PBT/PA6/8% AC samples were found to be 45.13, 44.60, 42.48, and 41.82 MPa, respectively. These values are higher than that (40.93 MPa) of the PBT/PA6 blend, which has no AC. Incorporating AC into the PBT/PA6 blend increases the tensile strength. The PBT/PA6/2% AC sample has the highest tensile strength, whereas the PBT/PA6/10% AC sample has a lower tensile strength of 39.79 MPa than the PBT/PA6 blend. All the PBT/PA6/AC samples have tensile moduli higher than that of the PBT/PA6 blend. When adding AC to the PBT/PA6 blend, the microstructure becomes smaller and finer, enhancing cohesion and improving the mechanical properties. A conceivable application area of the approaches analyzed in this work is that the PBT/PA6 blend can be recycled into conductive polymer composites with a small amount of AC. [ABSTRACT FROM AUTHOR]

Nanofibers serve as widely employed tissue engineering scaffolds in diverse biomedical applications. When implanted in vivo, it is crucial for tissue engineering scaffolds to be visualizable, enabling the monitoring of their shape, position, and performance. This capability facilitates the effective assessment of implant deformations, displacements, degradations, and functionalities. However, in many biomedical imaging techniques such as magnetic resonance imaging (MRI), the contrast of tissue engineering scaffolds is often inadequate. MRI is particularly notable for its effectiveness in imaging soft tissues. Previous endeavors to enhance the contrast of tissue engineering scaffolds in MRI have involved the use of negative contrast agents (CAs). Nonetheless, negative CAs can result in artifacts, thus favoring the preference for positive CAs due to their ability to generate clearer boundaries. In this study, we successfully prepared composite polyamide 6 nanofibrous scaffolds with ultrafine dispersion Fe(OH)3 nanoparticles using electrospinning and in-situ growth techniques. The relaxation properties of the magnetic nanofibrous scaffolds confirmed the successful production of scaffolds suitable for positive imaging. In vitro cell seeding experiments demonstrated the efficient proliferation and adhesion of endothelial cells and fibroblasts. In vivo studies further revealed the biocompatibility and functionality of the scaffolds. These findings indicate that the prepared PA6/Fe(OH)3 composite nanofibrous scaffolds can enable straightforward, safe, and efficient in vivo positive contrast MRI monitoring, thereby playing a pivotal role in the integration of diagnosis and treatment within tissue engineering scaffolds.

In the search for alternatives to the commonly used methods of the pre-treatment of surfaces, plasma discharge applications are appearing more and more. In the case of the automotive industry, where the attention is focused on finding methods that are more environmentally friendly, more economically advantageous and process-friendly, plasma is a suitable option. In the case of gluing additional parts with polyurethane glue to the car glass, the use of plasma activation or cleaning of the joined materials improves the adhesion properties. Through this process, it is possible to achieve an increase in the force required to break the joint, as well as an increase in the proportion of the desired cohesive failure of the adhesive. A process including a point nozzle plasma used on the glass surface and a rotating plasma nozzle to activate the surface of the holder made of polyamide 6 with a glass fibre content of 30% was found to be particularly suitable. The effect of plasma was also investigated using a surface tension test using test inks, observing the materials using an optical microscope, and the cleaning efficiency was analysed using infrared spectroscopy.

The polymer liner of the hydrogen storage cylinder was studied to investigate better hydrogen storage capacity in Type-IV cylinders. Molecular dynamics methods were used to simulate the adsorption and diffusion processes of hydrogen in a graphene-filled polyamide 6 (PA6) system. The solubility and diffusion characteristics of hydrogen in PA6 systems filled with different filler ratios (3 wt%, 4 wt%, 5 wt%, 6 wt%, and 7 wt%) were studied under working pressures (0.1 MPa, 35 MPa, 52 MPa, and 70 MPa). The effects of filler ratio, temperature, and pressure on hydrogen diffusion were analyzed. The results show that at atmospheric pressure when the graphene content reaches 5 wt%, its permeability coefficient is as low as 2.44 × 10−13 cm3·cm/(cm2·s·Pa), which is a 54.6% reduction compared to PA6. At 358 K and 70 MPa, the diffusion coefficient of the 5 wt% graphene/PA6 composite system is 138% higher than that at 298 K and 70 MPa. With increasing pressure, the diffusion coefficients of all materials generally decrease linearly. Among them, pure PA6 has the largest diffusion coefficient, while the 4 wt% graphene/PA6 composite system has the smallest diffusion coefficient. Additionally, the impact of FFV (free volume fraction) on the barrier properties of the material was studied, and the movement trajectory of H2 in the composite system was analyzed.

Previous studies on the fused deposition modelling (FDM) processed short carbon fiber/Polyamide 6 (PA6) matrix composites and neat PA6 have mostly concentrated on the quasi-static mechanical properties. Present study focused on the strain rate-dependent deformation behavior of a short carbon fiber-reinforced PA6 (Onyx) and neat PA6, produced in different layer heights, infill patterns and built angles. As compared with PA6, Onyx showed a higher compression stress at all strain rates investigated. A layer height of 0.2 mm in PA6 specimens promoted a better bonding between [0/90°] infill layers; hence, a higher flow stress than 0.2 mm layer height specimens, while 0.2 mm layer height induced a higher porosity in Onyx specimens, leading to a lower flow stress. The porosities in Onyx [0/90°] infill specimens were due to the constraining effect of 0/90° fiber layers. Changing infill pattern from a [0/90°] to a concentric one decreased porosity at the same layer height and hence increased the compressive flow stress. The highest compressive strength was found in the specimens with the loading axis 90 and 0° to [0/90°] infill plane. The lowest strength was, however, determined in the specimens with the loading axis 30 and 60o to [0/90°] infill plane in quasi-static loading. However, the specimens with the loading axis of 60, 45, 30 and 0° exhibited a brittle behavior in high strain rate loading (1500 s−1). The specimens with the loading axis of 45° had the lowest fracture stress and strain in the high strain rate loading. This signified the importance of loading angle at high strain rates. Finally, the rate sensitivities of PA6 and Onyx specimens were shown to be similar, showing a matrix dominated deformation. However, the strain rate jump tests indicated a slightly higher rate sensitivity of Onyx specimens at quasi-static strain rates (10−3-10−1 s−1). [ABSTRACT FROM AUTHOR]

In the 21st century, researchers have been exploring different designs, performance characteristics, charging–discharging regions, and regenerative braking aspects of electric vehicles. However, there has been a major gap in the multimodal analysis of the accelerating pedal drive for electric vehicles; therefore, herein, a novel analytical model of a mimicked foot pedaling control of an electric vehicle is developed by cascading five sub-models (i.e., foot pedal, resistive potentiometer, 555 timer, buck converter, and the permanent magnet DC motor) to synthesize the overall third-order transfer function of the system. MATLAB is utilized to comprehensively analyze the transient and steady-state characteristics of the developed model by considering the pedaling force, four different materials (i.e., aluminum, brass, carbon fiber, and polyamide 6), the potentiometer's resistance, and the mechanical and electrical attributes of the motor. The results highlight that the linear pedaling drive is possible by considering the polyamide 6 material's pedaling properties of 0.25 kg mass and 2.679 Ns/m damping coefficient. Furthermore, at a lesser potentiometer track length (around 10 cm) and equivalent inertia of 5 Kgm2, the motor generates the regulated angular velocity, thereby minimizing the transient characteristics of the accelerating pedal. [ABSTRACT FROM AUTHOR]

The weathering and environmental factors to which components are exposed during their useful life can promote damage and, consequently, premature failure in service. Thus, through the morphological analysis of fracture surfaces, it is possible to identify the failure modes and the main fractographic aspects present on the fracture surface. From these data, it is possible to increase the knowledge of the behavior of the material in service or even to have information for preventive corrections in the processing and use of material. Fractographic studies of carbon fiber (CF)/thermoplastic matrix composites are still little explored in the literature and can bring important contributions to understanding the failure mode of this class of materials. The objective of this work is to study the fractographic aspects of CF/polyamide 6 (PA6) composite exposed to two different conditionings, that is, distilled water at 80 ºC and saline solution, tested in tensile. Scanning electron microscopy analyses showed that the CF/PA6 laminate has a good consolidation and an excellent CF/matrix interface. Plastic deformations and fiber bridging are present in the fracture surface of the unconditioned specimens. However, after conditioning in distilled water at 80 ºC, the matrix became more fragile and the interface weaker. The conditioning in saline solution was less aggressive due to the salt effect that decreased the water migration into the specimens. The fractographic study performed shows in detail the influence of environmental deterioration using accelerated weathering on the fracture surface of thermoplastic laminates tested in tensile. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the impact of mechanical recycling on the physical and mechanical properties of recycled polyamide 6 (PA6) and polyamide 66 (PA66) in relation to their microstructures. Both PA6 and PA66 raw materials were reprocessed six times, and the changes in their properties were investigated as a function of recycling number. Until the sixth round of recycling, slight changes in the mechanical properties were detected, except for the percentage of elongation. For the physical properties, the change in both flexural strength and Young's modulus followed a decreasing trend, while the trend in terms of elongation showed an increase. Microscopic analysis was performed on virgin and recycled specimens, showing that imperfections in the crystalline regions of polyamide 6 increased as the number of cycles increased. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)