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As a typical 3D printing process, fused filament fabrication still has disadvantages when operating on manufacturing lines due to the non-uniform textures of the oriented surfaces of the 3D-printed components. This work investigates the effects of structural parameters, i.e., orientations angle, ABS and PLA materials, three different layer thicknesses, three different perimeters, and three different infill rates utilizing a balanced modified Taguchi experimental design and 63 different parametric combinations to characterize the surface roughness parameters: average Ra, mean roughness depth Rz, root mean square Rq, skewness Rsk, and kurtosis Rku. The analysis of the experimental results, i.e., the levels mean values analysis plots and linear residual analysis of variances, showed that the layer thickness strongly influences all surface parameters and interacts considerably with all orientations. In contrast, material type, number of perimeters, and infill rate had insignificant impacts on surface roughness parameters. Finally, the additive linear modelling approach was utilized and validated for proper predictions, making it helpful for surface engineering applications. [ABSTRACT FROM AUTHOR]

Formulating polymer blends is of vital scientific and industrial interest because of their low cost and the possibility of producing new materials with tailored properties. In this research, polypropylene (PP)/acrylonitrile–butadiene–styrene (ABS) polymer blends were prepared using styrene-ethylene-butylene-styrene (SEBS) and styrene-ethylene-propylene (SEP) copolymers. The polymer blends were extruded and injection molded to evaluate the mechanical, rheological, thermal, and thermomechanical properties, infrared spectroscopy, and morphology. Incorporating SEBS and SEP copolymers into the PP/ABS blend increased the torque and reduced the melt flow index, indicating higher viscosity than the PP/ABS base system. As a result, improved compatibility of PP/ABS/SEBS and PP/ABS/SEP blends was achieved, thereby improving the mechanical properties of PP/ABS. However, the SEBS copolymer was more effective. Compared to neat PP, the PP/ABS/SEBS blend with 15% SEBS showed increases in impact strength, elongation at break, and heat deflection temperature (HDT) of 87%, 107%, and 7%, respectively. In addition, the elastic modulus and Shore D hardness were in line with neat PP, and thermal stability measured through thermogravimetry exceeded that of PP by 8 °C. Evidence of fractured ABS particles in the PP matrix was seen in the scanning electron microscopy (SEM) morphology, suggesting that SEBS migrated to the interface. SEBS also remained dispersed in the PP matrix, as confirmed by selective phase extraction, which favored a synergic effect of properties in the PP/ABS/SEBS blend (70/15/15%). This blend offered potential for applications such as toys, furniture accessories, packaging, and housewares. [ABSTRACT FROM AUTHOR]

The paper describes the type of changes in the structure and mechanical properties of 3D printed shapes under the influence of mineral oil. The effects of a room (23 °C) and elevated temperature (70 °C) on 3D prints manufactured by the FDM method and stored in oil for 15, 30, and 60 days on the change of properties and structure were investigated. The samples were produced from ABS (poly(acrylonitrile-co-butadiene-co-styrene)), ASA (poly(acrylonitrile-co-styrene-co-acrylate), PLA (poly(lactic acid)), and HIPS (high-impact polystyrene). Tests related to the strength of the materials, such as the static tensile test and Charpy impact test, were carried out. The structure was evaluated using a scanning electron microscope, and changes in chemical structure were determined by conducting FTIR (Fourier transform infrared spectroscopy) and TGA (thermogravimetric analysis) tests. The analysis of the results provided important information about the impact of mineral oil on specific materials. This is critical for designing and manufacturing components that can withstand mineral oil exposure in real-world environments. The materials underwent varying changes. Strength increased for PLA by about 28%, remained unchanged for ABS and HIPS during exposure for 30 days, and decreased for ASA with extended exposure up to 14%. [ABSTRACT FROM AUTHOR]

Ultrasonic welding (USW) of thermoplastics plays a significant role in the automobile industry. In this study, the effect of the welding time on the joint strength of ultrasonically welded acrylonitrile–butadiene–styrene (ABS) and the weld formation mechanism were investigated. The results showed that the peak load firstly increased to a maximum value of 3.4 kN and then dropped with further extension of the welding time, whereas the weld area increased continuously until reaching a plateau. The optimal welding variables for the USW of ABS were a welding time of 1.3 s with a welding pressure of 0.13 MPa. Interfacial failure and workpiece breakage were the main failure modes of the joints. The application of real-time horn displacement into a finite element model could improve the simulation accuracy of weld formation. The simulated results were close to the experimental results, and the welding process of the USW of ABS made with a 1.7 s welding time can be divided into five phases based on the amplitude and horn displacement change: weld initiation (Phase I), horn retraction (Phase II), melt-and-flow equilibrium (Phase III), horn indentation and squeeze out (Phase IV) and weld solidification (Phase V). Obvious pores emerged during Phase IV, owing to the thermal decomposition of the ABS. This study yielded a fundamental understanding of the USW of ABS and provides a theoretical basis and technological support for further application and promotion of other ultrasonically welded thermoplastic composites. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethane (TPU) has emerged as extremely benign materials for next-generation manufacturing using additive manufacturing processes due to its favorable mechanical properties, durability, and as well as biocompatibility. However, the lack of stiffness of TPU affects its buckling strength and performance efficiency. Therefore, an efficient method of optimization of a 3D-printable composition of TPU-based blends is necessary. In this work, attempts were made to explore material extrusion additive manufacturing technique of acrylonitrile–butadiene–styrene (ABS)/TPU blends with particular reference to mechanical and damping behaviour. Design of experiment (DoE) was used to determine the optimum printing parameters. Rheological studies were exploited to understand the printability, and optimum 3D-printable blend composition. The damping behaviour of each blend composition was calculated and a damping ratio (ξ) between 1 ≤ ξ ≤ 2 was observed for 40 wt% ABS loading, which raised to 1 ≤ ξ ≤ 4 for 80 wt% ABS loaded blend specimen. Furthermore, for ABS incorporated TPU, a significant enhancement of stiffness over neat TPU was achieved, thereby reasonably addressing the filament stiffness issue. This work introduces an efficient method of improving TPU filament printability while parallelly identifying the printable blend composition which can be beneficial for several potential applications. [ABSTRACT FROM AUTHOR]

This study is focused on the application of 3D-printed elements and conventional elements to create a prototype of a custom-made exoskeleton for lower limb rehabilitation. The 3D-printed elements were produced by using Fused Deposition Modeling technology and acrylonitrile butadiene styrene (ABS) material. The scope of this work involved the design and construction of an exoskeleton, experimental testing of the ABS material and numerical research by using the finite element method. On the basis of the obtained results, it was possible to deduce whether the load-bearing 3D-printed elements can be used in the proposed mechanical construction. The work contains full data of the material models used in FEM modeling, taking into account the orthotropic properties of the ABS material. Various types of finite elements were used in the presented FE models. The work is a comprehensive combination of material testing issues with the possibility of implementing the obtained results in numerical strength models of machine parts. [ABSTRACT FROM AUTHOR]

Bonsai is a kind of classical art in China and Japan. The traditional method of bonsai shaping of miniature trees is technical and usually requires experienced horticulturists to successfully carry out the process. In order to let ordinary people feel the fun of bonsai shaping, this paper proposes a fast bonsai shaping method, i.e., by use of a plastic guiding mold with customized shape, which is processed by fused deposition 3D printing technology. The tree seedling is bundled onto the mold, and the shape of the mold guides the growth of the tree seedling, thus achieving the purpose of bonsai shaping. In order to further improve the bending properties of the bonsai guiding mold, this paper investigated the main 3D printing parameters of ABS filament. The results showed that with the decrease of printing speed, the increase of extrusion temperature, and the increase of hot bed temperature, the bending strength and elastic modulus of ABS specimens increased, and the bending properties was enhanced; the optimal printing speed was 50 mm/s, the extrusion temperature was 230 °C, and the hot bed temperature was 80 °C. The mechanical properties of the bonsai guiding mold manufactured based on the optimal process parameters were better, the print quality was higher, and it had high practical value. [ABSTRACT FROM AUTHOR]

In this work, the incorporation of halloysite nanotubes (HNTs) and polyphenylene ether-grafted maleic anhydride copolymer (FB) into acrylonitrile butadiene styrene (ABS)/polyphenylene oxide (PPO) blend has been investigated to enhance the compatibility and performance of the blends. ABS/PPO blend (AP) with the weight ratio of ABS/PPO = 70/30 with 5 wt% loading of FB and different weight contents of HNTs were elaborated by melt blending process, and their properties were studied. The SEM observation revealed that AP blend exhibited dispersed phases of PPO droplets with apparent gaps between PPO and ABS phases, indicating poor adhesion between the polymers in the blend. As the compatibilizer, FB effectively enhanced the inter-phase interaction, minimizing the formation of interfacial gaps, evidenced by the SEM images, leading to the adhesion between ABS, PPO, and HNTs phases. As a result, the mechanical performance of the AP blend was significantly improved with the addition of FB and HNTs. At 5 wt% of HNT, the AP/FB/HNT blend exhibited the tensile strength of 37.47 MPa and flexural strength of 59.09 MPa compared to 26.60 MPa and 39.45 MPa of neat AP, respectively. The glass transition temperature of the modified blends showed shifts compared to the neat AP, which indicates the improvement in miscibility of the modified-AP blends. The thermal stability and flame resistance of the blends were also enhanced with the introduction of HNTs and FB, evidenced by the V-1 rating in the UL-94 test and the increase in limiting oxygen index (LOI). These results demonstrated that the incorporation of HNTs and FB is a promising and straightforward method to improve the properties of ABS/PPO blends. [ABSTRACT FROM AUTHOR]

This study investigated the influence of two key printing parameters--namely, layer thickness and infill percentage and also the annealing effect, on the hardness of PLA and ABS components. Employing the design of experiment (DOE) methodology, the most significant factor influencing the Shore D hardness values for each material was established, in addition to determining the optimal printing parameters that yield maximum hardness in the printed parts. Our findings reveal that layer thickness significantly impacts the hardness of 3D printed PLA and ABS specimens, with printing infill percentage exerting a comparatively smaller influence, while in case of PLA annealed samples, the most significant factor is infill percentage. [ABSTRACT FROM AUTHOR]

In this work, a self-lubricating composite was manufactured using a novel hybrid 3D printing/in situ spraying process that involved the printing of an acrylonitrile butadiene styrene (ABS) matrix using fused deposition modeling (FDM), along with the in situ spraying of alumina (Al2O3) and hexagonal boron nitride (hBN) reinforcements during 3D printing. The results revealed that the addition of the reinforcement induced an extensive formation of micropores throughout the ABS structure. Under tensile-loading conditions, the mechanical strength and cohesive interlayer bonding of the composites were diminished due to the presence of these micropores. However, under tribological conditions, the presence of the Al2O3 and hBN reinforcement improved the frictional resistance of ABS in extreme loading conditions. This improvement in frictional resistance was attributed to the ability of the Al2O3 reinforcement to support the external tribo-load and the shearing-like ability of hBN reinforcement during sliding. Collectively, this work provides novel insights into the possibility of designing tribologically robust ABS components through the addition of in situ-sprayed ceramic and solid-lubricant reinforcements. [ABSTRACT FROM AUTHOR]

This paper presents the results of research on the influence of the moisture content in a filament made of ABS polymer on the properties of products manufactured using FDM (fused deposition modeling). Tests were carried out on a standard printer, using the parameters recommended by the manufacturer and the literature on the subject. A special climatic chamber was used to condition the material. A negative impact of ABS filament moisture on the strength and dimensional accuracy of printed products and on the structure of their surface is demonstrated. When the range of the filament moisture is between 0.17% and 0.75%, the strength decreases by 25% and the sample thickness increases by 10%. It is also shown that this effect does not depend on the history of the polymer reaching a given moisture level, i.e., by absorbing moisture in the absorption process or releasing moisture in the desorption process. [ABSTRACT FROM AUTHOR]

This paper presents the results of experimental investigation of the mechanical characteristics of 3D-printed acrylonitrile butadiene styrene (ABS) and its modifications reinforced with different types of short-fiber fillers: carbon, glass, and basalt. Elastic modulus, tensile and bending strength, as well as fracture toughness were determined in series of mechanical tests for samples produced with different manufacturing parameters, such as nozzle diameter and infill angle. It was found that the use of ABS filament reinforced with the short fibers can significantly improve the mechanical properties of 3D-printed devices when the infill angle is oriented along the vector of the applied load. In such a case, the elastic modulus and tensile strength can be increased by more than 1.7 and 1.5 times, respectively. The use of a larger nozzle diameter led to the growth of tensile strength by an average of 12.5%. When the macroscopic load is applied along the normal to the printed layers, the addition of short fibers does not give much gain in mechanical properties compared to pure ABS, which was confirmed by both standard tensile and fracture toughness tests. The surface of the fractured samples was examined using scanning electronic microscopy, which allowed us to make conclusions on the type of defects as well as on the level of adhesion between the polymeric matrix and different types of short fibers. [ABSTRACT FROM AUTHOR]

The advancement of polymers continues to expand relentlessly, becoming increasingly crucial to our daily existence. From high-performance sectors to mass-market industries, polymers permeate every facet of our lives. Consequently, it is imperative that we fully comprehend their properties, characteristics, and behavior. In this context, tensile testing are conducted, out on smooth and notched specimens machined from ABS plates to highlight the presence of residual stresses in the material. This study's objective is to describe how single and double-notched acrylonitrile butadiene styrene polymer specimens behave mechanically when in use. Additionally, to forecast the development of their harm and their immediate dependability. To do this static tensile tests on samples that have been, intentionally damaged by changing the defect length are used to compare the service lives of the damaged specimens. Additionally, the stages of damage were defined using a damage model known as the "unified theory," from which we can determine the critical life fraction βc and determine whether a single or double notch defect is more harmful. In order to identify the element with the lowest service life, we additionally calculated the specimens' dependability. Based on this research, we discovered that the life fraction for specimens with a single notch is lower than that for specimens with a double notch (for single notched and for double notched). As a result, single notched specimens have a shorter lifespan than double-notched specimens. To the conclusion, we also came that a single notch is less reliable than a double notch. [ABSTRACT FROM AUTHOR]

The present work proposes to investigate the effect of an ultrahigh molecular weight silicone rubber (UHMW-SR) and two ethylene methyl acrylate copolymers (EMA) with different methyl acrylate (MA) content on the mechanical and fire performance of a fireproof acrylonitrile butadiene styrene copolymer (ABS) composite, with an optimum amount of ammonium polyphosphate (APP) and aluminum diethyl phosphinate (AlPi). ABS formulations with a global flame retardant weight content of 20 wt.% (ABS P) were melt-compounded, with and without EMA and UHMW-SR, in a Brabender mixer. During this batch process, ABS P formulations with UHMW-SR and/or EMA registered lower torque values than those of ABS P. By means of scanning electron microscopy (SEM), it was possible to observe that all ABS composites exhibited a homogenous structure without phase separation or particle agglomeration. Slightly improved interfacial interaction between the well-dispersed flame-retardant particles in the presence of EMA and/or UHMW-SR was also noticed. Furthermore, synergies in mechanical properties by adding both EMA and UHMW-SR into ABS P were ascertained. An enhancement of molecular mobility that contributed to the softening of ABS P was observed under dynamic mechanical thermal analysis (DMTA). An improvement of its flexibility, ductility and toughness were also registered under three-point-bending trials, and even more remarkable synergies were noticed in Charpy notched impact strength. Particularly, a 212% increase was achieved when 5 wt.% of EMA with 29 wt.% of MA and 2 wt.% of UHMW-SR in ABS P (ABS E29 S P) were added. Thermogravimetric analysis (TGA) showed that the presence of EMA copolymers in ABS P formulations did not interfere with its thermal decomposition, whereas UHMW-SR presence decreased its thermal stability at the beginning of the decomposition. Although the addition of EMA or UHMW-SR, as well as the combination of both in ABS P increased the pHRR in cone calorimetry, UL 94 V-0 classification was maintained for all flame-retarded ABS composites. In addition, through SEM analysis of cone calorimetry sample residue, a more cohesive surface char layer, with Si-O-C network formation confirmed by Fourier transform infrared (FTIR), was shown in ABS P formulations with UHMW-SR. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to develop a correlation between the properties of acrylonitrile butadiene styrene parts 3D printed by material extrusion (MEX) process. Design/methodology/approach: The two MEX parameters and their values have been selected by design of experiment method. Three properties of MEX parts, i.e. strength (tensile and three-point bending), surface roughness and the dimensional accuracy, are studied at different build speeds (35 mm/s, 45 mm/s and 55 mm/s) and the layer heights (0.06 mm, 0.10 mm and 0.15 mm). Findings: The results show that tensile strength and three-point bending strength both increase with the decrease in build speed and the layer height. The artifact selected for dimensional accuracy test shows higher accuracy of the features when 3D printed with 0.06 mm layer height at 35 mm/s build speed as compared to those of higher layer heights and build speeds. The optical images of the 3D-printed specimen reveal that lower build speed and the layer height promote higher inter-layer diffusion that has the effect of strong bonding between the layers and, as a result, higher strength of the specimen. The surface roughness values also have direct relation with the build speed and the layer height. Originality/value: The whole experiments demonstrate that the part quality, surface roughness and the mechanical strength are correlated and depend on the build speed and the layer height. [ABSTRACT FROM AUTHOR]

Acrylonitrile‐butadiene‐styrene (ABS) based composites with a high content of tungsten and bismuth oxide were developed using an innovative process to obtain lead‐free x‐ray shielding materials. ABS was chosen for its good mechanical properties and its widespread availability as a recycled material. The composites underwent flexural tests, Shore D hardness tests, thermogravimetric and morphological analysis, and their x‐ray attenuation properties were determined through numerical simulations and experimental measurements. Despite their high filler content (up to 75 wt%), the composites showed good filler dispersion within the polymeric matrix and maintained their mechanical properties. Across the investigated energy range (50–150 kV), the lead equivalence for x‐ray shielding was achieved with composite plates containing 75 wt% of tungsten and bismuth oxide, at thickness values corresponding to a weight increase of only 29% and 36%, respectively, in comparison to lead. These findings pave the way for a new generation of lead‐free x‐ray shielding materials. Moreover, their mechanical properties, including flexibility for potential application in wearable personal protective equipment, can be tailored by adjusting the filler content. Highlights: High filler content lead‐free ABS composites with WO3 and Bi2O3 were developed.They show good polymer/filler interfacial adhesion and flexural properties.Numerical simulations of their x‐ray shielding properties were performed.Experimental tests with polychromatic sources confirmed good x‐ray attenuation.Results pave the way for the development of new lead‐free x‐ray shielding systems. [ABSTRACT FROM AUTHOR]

In this study, organosilicon compounds were used as modifiers of filaments constituting building materials for 3D printing technology. Polymethylhydrosiloxane underwent a hydrosilylation reaction with styrene, octadecene, and vinyltrimethoxysilane to produce new di- or tri-functional derivatives with varying ratios of olefins. These compounds were then mixed with silica and incorporated into the ABS matrix using standard processing methods. The resulting systems exhibited changes in their physicochemical and mechanical characteristics. Several of the obtained composites (e.g., modified with VT:6STYR) had an increase in the contact angle of over 20° resulting in a hydrophobic surface. The addition of modifiers also prevented a decrease in rheological parameters regardless of the amount of filler added. In addition, comprehensive tests of the thermal decomposition of the obtained composites were performed and an attempt was made to precisely characterize the decomposition of ABS using FT-IR and optical microscopy, which allowed us to determine the impact of individual groups on the thermal stability of the system. [ABSTRACT FROM AUTHOR]

This study surveys the impacts of injection parameters on the deformation rate of the injected flexure hinge made from ABS, PP, and HDPE. The flexure hinges are generated with different filling time, filling pressure, filling speed, packing time, packing pressure, cooling time, and melt temperature. The amplification ratio of the samples between different injection parameters and different plastic types is measured and compared to figure out the optimal one with a high amplification ratio. The results show that the relationship between the input and output data of the ABS, PP, and HDPE flexure hinges at different injection molding parameters is a linear relation. Changing the material or many injection molding parameters of the hinge could lead to a great impact on the hinge's performance. However, changing each parameter does not lead to a sudden change in the input and output values. Each plastic material has different optimal injection parameters and displacement behaviors. With the ABS flexure hinge, the filling pressure case has the greatest amplification ratio of 8.81, while the filling speed case has the lowest value of 4.81. With the optimal injection parameter and the input value of 105 µm, the ABS flexure hinge could create a maximum average output value of 736.6 µm. With the PP flexure hinge, the melt temperature case achieves the greatest amplification ratio of 6.73, while the filling speed case has the lowest value of 4.1. With the optimal injection parameter and the input value of 128 µm, the PP flexure hinge could create a maximum average output value of 964.8 µm. The average amplification ratio values of all injection molding parameters are 6.85, 5.41, and 4.01, corresponding to ABS, PP, and HDPE flexure hinges. Generally, the ABS flexure hinge has the highest amplification ratios, followed by the PP flexure hinge. The HDPE flexure hinge has the lowest amplification ratios among these plastic types. With the optimal injection parameter and the input value of 218 µm, the HDPE flexure hinge could create a maximum average output value of 699.8 µm. The results provide more insight into plastic flexure hinges and broaden their applications by finding the optimal injection parameters and plastic types. [ABSTRACT FROM AUTHOR]

The development of additive manufacturing (AM) technologies has significantly advanced fabrication capabilities, yet achieving optimal surface quality and mechanical properties in end-use products is challenging. The primary objective of this study is to improve specific characteristics of 3D-printed components by employing a chemical post-processing technique including acetone. This technique is specifically applied to acrylonitrile butadiene styrene (ABS) material, utilizing a customized mechanical cold-vapor system. A complete investigation was undertaken to assess the effects of treatment on many factors, such as temperature, solvent volume, and exposure duration, on the tensile strength, physical dimensions, and mass of the ABS samples. Acetone post-processing has notably improved tensile strength, influenced by treatment duration and temperature and has led to dimensional changes such as a slight length reduction and increases in width and thickness. Furthermore, the mass of the samples exhibited variability upon acetone treatment, which was shown to be dependent on both the ambient temperature and the duration of solvent exposure. The tensile strength was assessed under various conditions, showing a significant enhancement at higher temperatures and longer exposure times. These results, demonstrating smoother surfaces and a tensile strength increase of up to 20% at 65 °C, underscore the efficacy of our techniques in modifying the mechanical and physical properties of 3D-printed ABS components. This innovative approach provides valuable insights into the relationship between post-processing conditions and ABS properties, enriching the body of knowledge in AM technology. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine the effect of manufacturing conditions on the mechanical properties and structure of ABS parts. Two sets of samples with the same geometric characteristics were produced by Fused Deposition Modelling (FDM) and injection molding (IM). The molding pressure and cooling rate were found to have a significant effect on shaping the mechanical properties and structure of ABS products. The manufacturing method and adopted process parameters have a significant impact on the degree of packing of macromolecules in the volume of the product, and thus determine its density. Selected mechanical properties were determined and compared with their specific gravity. The research was carried out using tools and machines, i.e. injection molds of unique design and standard measuring stations. Tensile and bending strengths and Young's modulus were related to the density of products obtained under different process conditions and having gradient and solid structures. The results provide useful information for engineers designing products using FDM technology. Relating tensile and flexural strength and Young's modulus to the specific gravity of the product. It was found that the value of product properties is closely related to various process conditions, which further provides a true description of the products. [ABSTRACT FROM AUTHOR]

Unconventional injection methods include i.e. blowing injection that allows for production of moldings with a lower weight while maintaining mechanical properties of detail. Due to the fact that most polymers are dyed at the processing stage, it is important to examine the simultaneous effect of blowing and colorbatch, as well as variable processing conditions, on the functional properties of moldings made of the most popular construction material, i.e. ABS. Samples were made of ABS polymer without and with the addition of a colorbatch containing brown pigment on ABS matrix, and blowing agent. Variable processing conditions were: mold and injection temperature, holding pressure and time. Other parameters were constant. Samples were tested for basic functional properties such as color, gloss, mass, density and thickness. Moldings produced with a higher blowing agent content and a higher injection temperature were characterized by lower mass. No significant influence of processing parameters and content of colorbatch on mass of samples was found. Blowing agent has no significant impact on thickness of moldings, regardless of processing conditions. Addition of a colorbatch influenced samples' gloss. Increase in colorbatch and blowing agent content and mold temperature allow to obtain moldings with a higher surface gloss. Colorbatch also changed color of samples - a decrease in luminance L even by about 40% and great changes in parameters "a" and slight changes in parameter "b". It was found that blowing agent content had the greatest influence on density of moldings. Injection temperature and colorbatch, do not significantly affect density of moldings. [ABSTRACT FROM AUTHOR]

Polylactic Acid (PLA) and Acrylonitrile–Butadiene–Styrene (ABS) are commonly used polymers in 3D printing for biomedical applications. Dental Pulp Stem Cells (DPSCs) are an accessible and proliferative source of stem cells with significant differentiation potential. Limited knowledge exists regarding the biocompatibility and genetic safety of ABS and PLA when in contact with DPSCs. This study aimed to investigate the impact of PLA and ABS on the adhesion, proliferation, osteogenic differentiation, genetic stability, proteomics, and immunophenotypic profile of DPSCs. A total of three groups, 1- DPSC-control, 2- DPSC+ABS, and 3- DPSC+PLA, were used in in vitro experiments to evaluate cell morphology, proliferation, differentiation capabilities, genetic stability, proteomics (secretome), and immunophenotypic profiles regarding the interaction between DPSCs and polymers. Both ABS and PLA supported the adhesion and proliferation of DPSCs without exhibiting significant cytotoxic effects and maintaining the capacity for osteogenic differentiation. Genetic stability, proteomics, and immunophenotypic profiles were unaltered in DPSCs post-contact with these polymers, highlighting their biosafety. Our findings suggest that ABS and PLA are biocompatible with DPSCs and demonstrate potential in dental or orthopedic applications; the choice of the polymer will depend on the properties required in treatment. These promising results stimulate further studies to explore the potential therapeutic applications in vivo using prototyped polymers in personalized medicine. [ABSTRACT FROM AUTHOR]

This study investigates the performance of asphalt concrete containing recycled plastics as synthetic aggregates in the dry mixing process. Two types of recycled plastics were used, namely, acrylonitrile butadiene styrene (RABS) and Polyethylene Terephthalate (RPET), based on the high-temperature properties of the plastics that make them suitable to be treated as synthetic aggregates (i.e. do not melt during the asphalt mixing phase). The proportions of recycled plastics were chosen at 0.5%, 1%, 2% and 4% of the mix mass. The laboratory testing programme includes the evaluation of compactability properties, moisture resistance, cracking resistance via IDEAL-CT test, fatigue resistance via four-point bending beam test and rutting resistance via Hamburg wheel tracking (wet) test. It was found that the inclusion of recycled plastics did affect the compactability of the mixes depending on their relative size and shape. On the other hand, the inclusion of recycled plastics did not significantly vary the moisture resistance of asphalt mixes. The cracking and rutting behaviour of asphalt mixes that incorporated recycled plastics were also modified and some benefits were observed depending on the plastic content and size. [ABSTRACT FROM AUTHOR]

Polystyrene (PS)/acrylonitrile-butadiene-styrene (ABS) blends were processed in a corrotational twin-screw extruder and molded by injection. Styrene-(ethylene-propylene) (SEP), styrene-(ethylene-butylene)-styrene (SEBS), and styrene-butadiene-styrene (SBS) copolymers were tested as compatibilizing agents. The rheological, mechanical, thermal, thermomechanical, spectroscopic, and morphological behavior were reported. The type of compatibilizer greatly influences the final performance of the PS/ABS, considering that the incorporation of SEP formed a brittle and incompatible blend. In contrast, SEBS containing styrene terminal groups on both sides of the molecular structure, formed a PS/ABS blend with greater ductility. However, it has lower performance compared to SBS. The torque rheometry increased, and the melt flow index (MFI) reduced significantly for the PS/ABS/SBS blend, indicating more significant interaction between the components. As a result, gains of 113.7% and 379.3% in impact strength and elongation at break compared to PS. In addition, elastic modulus, tensile strength, Shore D hardness, and heat deflection temperature (HDT) maintained high results, confirming a synergistic effect of the PS/ABS/SBS blend. By thermogravimetry (TG), a gain of around 22 °C was observed in the PS/ABS/SBS blend for a mass loss of 50%, possibly due to acrylonitrile. Scanning electron microscopy (SEM) and atomic force (AFM) analyses reinforced these excellent results, revealing better compatibility and a more homogeneous distribution of ABS in the PS matrix in the presence of SBS. The PS/ABS/SBS blend results indicate potential applications such as electronics, air conditioning grilles, and toys. [ABSTRACT FROM AUTHOR]

In recent years, additive manufacturing technology, particularly in plastic component fabrication, has gained prominence. However, fundamental modelling of the influence of materials like ABS, PC, and PLA on tribological properties in fused deposition modeling (FDM) remains scarce, particularly in non-lubricated, oil-lubricated, and grease-lubricated modes. This experimental study systematically investigates the effects of material type, lubrication method, layer thickness, and infill density on FDM component tribology. A tribology analysis is conducted using a TRB3 tribometer. The results indicate a coefficient of friction (CoF) range between 0.04 and 0.2, generally increasing and decreasing with layer thickness and filler density. The lubrication impact hinges on the material surface texture. The study models the intricate relationships between these variables via full-factor analysis, showing a strong alignment between the modelled and measured friction coefficients (an average error of 3.83%). Validation tests on different materials affirm the model's reliability and applicability. [ABSTRACT FROM AUTHOR]

Polymers are widely employed in many areas, e.g. transport, packaging, electronic devices, etcetera. Among them, acrylonitrile–butadiene–styrene (ABS) is one of the most employed polymers due to its mechanical properties, its ease to mechanize and recyclability. Nevertheless, according to the fire properties, ABS behaviour is usually worse than other polymers, therefore, they have to be upgraded with flame retardant additives. To characterize the fire behaviour of a certain material is necessary to address several typology of tests, providing relevant properties such as thermal conductivity, flammability and heat released. However, researchers may not always be able to run all tests due to the lack of apparatus or samples. Therefore, it is necessary to seek bibliographic sources. As one might expect, for a given material, the property values should be similar, regardless of who performs the test. However, sometimes slightly different results are obtained, which may be due to different causes, such as differences in test set-up and in material composition/manufacture. These differences in properties may lead researcher to doubt which data to use. This paper presents the results of different types of tests using neat ABS polymer. Additionally, these results are compared with the data from literature, discussing the similarities/differences and offering a more comprehensive characterization of ABS. The laboratory techniques included in this work are: thermogravimetric analysis, differential scanning calorimetry, laser flash analysis, smoke density, cone calorimeter, fire propagation and flammability. [ABSTRACT FROM AUTHOR]

Abstract In the present work, acrylonitrile-butadiene-styrene (ABS)/glass fiber (varying fiber orientation angle) and with different % of carbon black (CB) particles-based hybrid composites are fabricated by hot press compression molding technique. Prepared composites were examined under marine conditions in sea water medium and erosion behavior under erodent particles entrained in gas fluid and found reduced impact. Morphological studies are studied through scanning electron microscope. Material removal mechanism is found to be micro-cracking at the impingement angle of 90°. Additionally, numerical analysis for the composite material with respect to single particle impact for erosion was conducted using LS-DYNA. [ABSTRACT FROM AUTHOR]

The purpose of this work was to investigate the structural, thermal, micromechanical and tribological properties of novel polymer/metal composite materials for bearing applications. Copper (Cu)-filled Acrylonitrile Butadiene Styrene (ABS) composites were mixed in a laboratory scale by an internal mixer with two blade impellers, and then injection-molded. Neat ABS, ABS+5wt% Cu, ABS+10wt% Cu, and ABS+15wt% Cu were the four materials that were tested. The dispersion of Cu particles in the ABS matrix was investigated using Scanning Electron Microscopy (SEM) and a micro-tomography scan. The filler particles have a uniform distribution in the matrix, according to the observations. The incorporation of Cu filler also refined an increase in the glass transition temperature from Differential Scanning Calorimetry (DSC) and less intensity in the amorphous phase by X-ray diffraction (XRD). Nanoindentation tests were carried out to characterize the micro-mechanical behavior of the composites. Friction and wear analysis were also examined using a pin-on-disk tribometer. Compared with neat ABS, all the micro-composites showed much higher indentation hardness, Vickers hardness, and indentation elastic modulus. It was also concluded that the incorporation of Cu filler into ABS simultaneously improved the friction and wear properties of the composites, which contributed to the suitability of the micro-filled composites with hard metallic particles for a wider range of mechanical components for bearing applications. [ABSTRACT FROM AUTHOR]

The multicomponent injection molding of liquid silicone rubbers (LSR) with thermoplastics, such as polybutylene terephthalate (PBT) or polyamide (PA), is a state-of-the-art technique and is used in the manufacturing process for many components in the automotive industry and in the field of sanitary engineering. Standard thermoplastics, such as acrylonitrile butadiene styrene (ABS), cannot be bonded with silicone rubbers in injection molding because of their low heat deflection temperature. In this study, we investigated ABS grades approved for medical applications to show how dynamic mold heating and various pretreatment methods for thermoplastic surfaces can be used to produce ABS-LSR test specimens. In addition, such components' sterilization effect on the adhesive bond will be shown. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate how the amount of material used and printing parameters affect the mechanical and water sorption properties of acrylonitrile butadiene styrene printed parts. Design/methodology/approach: The specimens were printed using different printing parameters such as shell number, infill pattern and printing orientation, while accounting for the amount of material used. The mechanical properties of the printed parts were then evaluated using tensile, compression and flexural tests, along with sorption tests. Findings: The results revealed that the maximum tensile stress of 31.41 MPa was obtained when using 100% infill and a horizontal printing orientation. Similarly, the maximum flexural strength and compression of 40.5 MPa and 100.7 MPa, respectively, were obtained with 100% infill. The printing orientation was found to have a greater impact on mechanical behavior compared to the number of shells or infill patterns. Specifically, the horizontal printing orientation resulted in specimens with at least 25% greater strength compared to the vertical printing orientation. Furthermore, the relationship between the amount of material used and strength was evident in the tensile and flexural tests, which showed a close correlation between the two. Originality/value: This study's originality lies in its focus on optimizing the amount of material used to achieve the best strength-to-mass ratio and negligible water infiltration. The findings showed that specimens with two shells and a 60% infill density exhibited the best strength-to-mass ratio. [ABSTRACT FROM AUTHOR]

This article introduces a multi-objective optimization approach for determining the best 3D printing parameters (layer thickness and infill percentage) to efficiently produce PLA and ABS parts, extensively analyzing mechanical behavior under tests for different traits such as tensile strength, compression, flexural, impact, and hardness. The value analysis method is used to optimize settings that balance use value (Vi- represented by mechanical characteristics) and production cost (Cp). Findings reveal that the infill percentage significantly influences the Vi/Cp ratio for tensile, compression, and hardness tests, while flexural tests are influenced by layer thickness. Impact strength is influenced nearly equally by both factors, with material-specific variations. The desirability function proved useful for optimizing processes with multiple responses, identifying the optimal parameters for the FDM process: a layer thickness of 0.15 mm with 100% infill percentage for PLA, a layer thickness of 0.20 mm with 100% infill percentage for annealed PLA, and a layer thickness of 0.15 mm with 100% infill percentage for ABS. Overall, this study guides efficient 3D printing parameter selection through a technical-economic optimization based on value analysis. [ABSTRACT FROM AUTHOR]

New types of hybrid aluminum joints: Al-acrylonitrile butadiene styrene (ABS) carbon fiber reinforced thermoplastic polymer (CFRTP) designated Al/Ni-CFP/ABS, and Al-18-8 Stainless steel, Al/Ni-CFP/18-8, by Ni-plated carbon fiber plug (Ni-CFP) insert not before seen in the literature have been fabricated. The goal is to take advantage of extremely high ~6 mm CF surface area for high adhesion, to enhance the safety level of aircraft and other parts. This is without fasteners, chemical treatment, or glue. First, the CFP is plated with Ni. Second, the higher melting point half-length is spot welded to the CFP; and third, the remaining half-length is fabricated. The ultimate tensile strength (UTS) of Al/Ni-CFP/ABS was raised 15 times over that of Al/ABS. Normalized cUTS according to CFP cross-section by Rule of Mixtures for cAl/Ni-CFP/18-8 was raised over that of cAl/Ni-CFP/18-8 from 140 to 360 MPa. Resistance energy to tensile deformation, UT, was raised 12 times from Al/ABS to Al/Ni-CFP/ABS, and 6 times from Al/CFP/18-8 to Al/Ni-CFP/18-8. Spot welding allows rapid melting followed by rapid solidification for amorphous metal structures minimizing grain boundaries. The Ni-coating lowers or counters the effects of brittle Al4C3 and FexC formation at the interface and prevents damage by impingement to CFs, allowing joints to take on more of the load. [ABSTRACT FROM AUTHOR]

Acrylonitrile butadiene styrene (ABS) is one of the most widely used polymers in the manufacture of different parts in engineering applications. This polymer is sometimes subjected to metallizing processes that seek to modify the surface properties of the accessories. These processes often require the use of chromium and palladium. Some of the accessories in which ABS is used are subjected during their day-to-day use to environments in which they are prone to colonization of bacteria, generating multiple problems that affect both human health and the useful life of different equipment and devices. Recently, there have been great developments of nanoparticles with antibacterial properties, such as zinc oxides. However, these nanoparticles have not yet been incorporated and evaluated in metal coatings on ABS substrates with a view to conferring such properties on the polymer. This work implements the use of an electroless antibacterial Ni-P coating, modified with zinc oxide nanoparticles through processes free of chromium and palladium, on ABS substrates. The results showed that the addition of zinc oxide nanoparticles in quantities of 0.5 g/L and above in the electroless bath confer antibacterial characteristics on the surface for S. aureus under JIS Z 2801 standard. Through the methodology developed, the future development of 3D printed parts with metallized coating is possible, implementing processes chrome and palladium free, expanding the applications and uses of these. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in the field of 3D printing technology. Among the various technologies available, fused deposition modeling (FDM) has emerged as the most popular and widely used method. However, achieving optimal results with FDM presents a significant challenge due to the selection of appropriate process parameters. Therefore, the objective of this research was to investigate the impact of process parameters on the tribological and frictional behavior of acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) 3D-printed parts. The design of experiments (DOE) technique was used considering the input design parameters (infill percentage and layer thickness) as variables. The friction coefficient values and the wear were determined by experimental testing of the polymers on a universal tribometer employing plane friction coupling. Multi-response optimization methodology and analysis of variance (ANOVA) were used to highlight the dependency between the coefficient of friction, surface roughness parameters, and wear on the process parameters. The optimization analysis revealed that the optimal 3D printing input parameters for achieving the minimum coefficient of friction and linear wear were found to be an infill percentage of 50% and layer thickness of 0.1 mm (for ABS material), and an infill percentage of 50%, layer thickness of 0.15 mm (for PLA material). The suggested optimization methodology (which involves minimizing the coefficient of friction and cumulative linear wear) through the optimized parameter obtained provides the opportunity to select the most favorable design conditions contributing to a more sustainable approach to manufacturing by reducing overall material consumption. [ABSTRACT FROM AUTHOR]

Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed plastics in contemporary artworks and design objects. In this study, the chemical and thermal properties of an ABS-based polymer and its photo-degradation process were investigated through a multi-analytical approach based on thermal, mass spectrometric and spectroscopic techniques. LEGO® building blocks were selected for studying the ABS properties. First, the composition of unaged LEGO® bricks was determined in terms of polymer composition and thermal stability; then, the bricks were subjected to UV–Vis photo-oxidative-accelerated ageing for evaluation of possible degradation processes. The modifications of the chemical and thermal properties were monitored in time by a multi-technique approach aimed at improving the current knowledge of ABS photodegradation, employing pyrolysis online with gas chromatography and evolved gas analysis, coupled with mass spectrometric detection (Py-GC-MS and EGA-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and corroborated by external reflection FT-IR spectroscopy. The multimodal approach provided new evidence on the two-step degradation pathway proposed for ABS, defining molecular markers for polybutadiene oxidation and styrene-acrylonitrile depolymerization. Moreover, the results highlighted the feasibility of correlating accurate compositional and thermal data acquired by bulk techniques with external reflection FT-IR spectroscopy as a non-invasive portable tool to monitor the state of conservation of plastic museum objects in-situ. [ABSTRACT FROM AUTHOR]

Functionally graded materials (FGM) have attracted considerable attention in the field of composite materials and rekindled interest in research on composite materials due to their unique mechanical response achieved through material design and optimization. Compared to conventional composites, FGMs offer several advantages and exceptional properties, including improved deformation resistance, improved toughness, lightness properties, and excellent recoverability. This study focused on the production of functionally graded (FG) polymer materials by the additive manufacturing (AM) method. FG structures were produced by the fused deposition modeling (FDM) method using acrylonitrile benzidine styrene (ABS) and polylactic acid (PLA) materials, and tensile tests were performed according to ASTM D638. The effects of different layer thicknesses, volume ratios, and total thicknesses on mechanical behavior were investigated. The tensile standard of materials produced by additive manufacturing introduces geometric differences. Another motivation in this study is to reveal the differences between the results according to the ASTM standard. In addition, tensile tests were carried out by producing single-layer samples at certain volume ratios to create a numerical model with the finite element method to verify the experimental data. As a result of this study, it is presented that the FG structure produced with FDM improves mechanical behavior. [ABSTRACT FROM AUTHOR]

This study aimed to identify the optimum printing parameters for the fused filament fabrication (FFF) of acrylonitrile butadiene styrene (ABS) and polyamide (nylon), to improve strength properties. For this purpose, the methodology of the paper involves an experimental study that used Taguchi's method to identify the effects of the infill pattern, infill density, and printing speed on the mechanical properties of the materials. ABS and nylon plastic parts were tested in tension to failure. Based on the results of the tensile tests, it was found that ABS material produced the highest ultimate tensile strength when printed using a tri-hexagonal infill pattern, 100% infill density, and a printing speed of 65 mm/s. On the other hand, nylon material exhibited a better performance when printed using an octet geometric structure, with identical other parameters. [ABSTRACT FROM AUTHOR]

Material extrusion (ME) is an additive manufacturing technique capable of producing functional parts, and its use in multi-material fabrication requires further exploration and expansion. The effectiveness of material bonding is one of the main challenges in multi-material fabrication using ME due to its processing capabilities. Various procedures for improving the adherence of multi-material ME parts have been explored, such as the use of adhesives or the post-processing of parts. In this study, different processing conditions and designs were investigated with the aim of optimizing polylactic acid (PLA) and acrylonitrile–butadiene–styrene (ABS) composite parts without the need for pre- or post-processing procedures. The PLA-ABS composite parts were characterized based on their mechanical properties (bonding modulus, compression modulus, and strength), surface roughness (Ra, Rku, Rsk, and Rz), and normalized shrinkage. All process parameters were statistically significant except for the layer composition parameter in terms of Rsk. The results show that it is possible to create a composite structure with good mechanical properties and acceptable surface roughness values without the need for costly post-processing procedures. Furthermore, the normalized shrinkage and the bonding modulus were correlated, indicating the ability to utilize shrinkage in 3D printing to improve material bonding. [ABSTRACT FROM AUTHOR]

Due to the insufficient flowability of ABS resin, the injection molding products of ABS have suffered from defects, such as flow marks and poor surface gloss. In our study, it was found that diethylene glycol distearate (DGD) could effectively improve the flowability of ABS. When the content of DGD is 2%, the melt flow index of ABS could be improved by 23%. Subsequently, the mechanism of DGD on improving the flowability of ABS was studied by rotational rheometer and dynamic mechanical analysis (DMA). The results showed complex viscosity in the low frequency region of rheology and tensile plateau modulus of DMA both gradually decrease with increasing amount of DGD. This indicated that DGD can effectively improve the flowability of ABS resin. The flowability of ABS mainly depend on the SAN. Therefore, the lubrication effect of DGD on SAN was investigated. The lubrication effect of DGD in SAN is better than that in ABS. This can be explained by the fact that the PB rubbers grafted with SAN as entanglement points weakened the lubrication effect of DGD on the molecular chains. This paper provides a new and efficient lubricant for ABS and explains its lubrication mechanism in ABS. [ABSTRACT FROM AUTHOR]

The changes in tire pressure will cause braking force to significantly vary due to the change in the tire-to-road contact during hard braking. The most important reason of this issue is the changes in road contact because of the changes in the vertical stiffness and slip stiffness of tire, as tire pressure varies. Therefore, in this study, it was aimed to investigate the effects of the tire pressure on anti-lock brake system (ABS) control performance through vertical and slip stiffness of tire. For this, first, the friction coefficient extended to tire pressure was integrated into the braking dynamics equations using the magic tire model. In this way, the effects of tire pressure were analytically revealed on braking performance. Then, taking into account the theoretical results, ABS braking tests were carried out with three different tire pressures: higher (38 psi) and lower (25 psi) tire pressure than the nominal (33 psi) tire pressure. In experimental studies, tests were carried out for braking initial speeds 30 and 60 km/h with the same tire pressures in µ-jump road conditions. In this way, the effects of the tire pressure were experimentally investigated on control performance of ABS under critical road conditions. At 33 psi tire pressure, the highest brake pressure was observed when switching to wet roads. At 25 psi tire pressure, the brake pressure did not build up in time. This showed that low tire pressure causes brake pressure to increase with a delay. On the slippery part, the lock-up limit is closer at 38 psi tire pressure. Therefore, it was seen that the decrease and increase in tire pressure have great effect on control performance of ABS under µ-jump road conditions. [ABSTRACT FROM AUTHOR]

The effect of short carbon fiber (SCF) filler on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) was investigated. The fused filament fabrication (FFF) method was used for the manufacturing of samples. Elastic properties and strength characteristics of samples made of conventional ABS and SCF-reinforced ABS were compared in tensile and bending tests. Fracture toughness and critical strain energy release rate were also determined. In addition, 3D-printed monofilament SCF-reinforced samples were fabricated, the internal structure of which was analyzed using microcomputed tomography (micro-CT). Based on the tomography data, finite-element (FE) models of representative volume elements (RVEs) of the reinforced material were created and used for the numerical calculation of effective characteristics. Numerical and experimental results for the effective elastic properties were compared with the Mori-Tanaka homogenization technique. The ABS samples filled with SCF showed considerably higher mechanical characteristics than those of the conventional ABS. Finally, the dependence between the strength characteristics and elastic properties of the samples on the diameter of the nozzle used for 3D printing was established. 3D-printed ABS reinforced with SCF demonstrated a gain in tensile strength and fracture toughness by 30% and 20%, respectively. Interlayer adhesion strength in flexure tests showed an increase of 28% compared to pure ABS samples. [ABSTRACT FROM AUTHOR]

Thermoplastic composite materials are typically used as feedstock filaments in material extrusion-based 3D printing. Understanding the mechanism of stress transfer at the filler/matrix interface in a composite filament helps in improving its properties. In this work, ABS/reduced graphene oxide (rGO) composite has been prepared by the solution mixing method, and 3D printable filaments are made by single screw extrusion. At filler loading of 0.2 wt. %, tensile strength of the composite filament is increased by ~40 % compared to the neat ABS filament. To understand the mechanism of stress transfer , a multi-scale mathematical model is presented. At the microscale, interface stress transfer is studied by using two-dimensional finite element (FE) analysis. The filler dimensions required for FE analysis are estimated using XRD and Raman analysis of rGO. In the present case, the filament making process yields filler dimensions comparable to the critical length, hence providing better stress transfer. The macroscopic strength of nanocomposite is estimated by using rule of mixtures. The better interface stress transfer and extrusion-induced filler orientation increases the filament strength. T. [ABSTRACT FROM AUTHOR]

This study is dedicated to investigate the rheological, mechanical, and morphological properties of polyamide 6/poly (acrylonitrile butadiene styrene) (PA6/ABS) blends in the presence of graphene oxide nanoplates (GO). In this regard, scanning electron microscopy analysis, rheological assessments, and mechanical tests were performed. PA6/ABS (65 wt%, 35 wt%) blends were prepared by melt mixing method in the presence of 0.25 wt%, 0.5 wt%, and 1 wt% GO nanoparticles. Also, to study the effect of mixing protocol on these properties, the mixing sequences varied for the blends containing 0.5 wt% GO. The rheological, mechanical, and morphological analyses demonstrated the formation of significant interaction between PA6 and GO for polymer blends having 0.25 wt% GO. On the other hand, the decrease in the elasticity for the 0.5 wt% GO incorporated polymer blend was attributed to the lubricating role of GO in PA6 as a consequence of weak interactions between PA6 and GO. ABS/GO pre-mixed blend showed good interfacial adhesion between PA6 and ABS as a result of kinetic influence of GO for interfacial localization in PA6/ABS polymer blends. Furthermore, PA6/GO pre-mixing protocol demonstrated the highest elasticity for PA6/ABS blend due to the PA6/GO adhesion reinforcement. [ABSTRACT FROM AUTHOR]

Additive manufacturing or 3D printing technologies might advance the fabrication sector of personalised biomaterials with high-tech precision. The selection of optimal precursor materials is considered the first key-step for the development of new printable filaments destined for the fabrication of products with diverse orthopaedic/dental applications. The selection route of precursor materials proposed in this study targeted two categories of materials: prime materials, for the polymeric matrix (acrylonitrile butadiene styrene (ABS), polylactic acid (PLA)); and reinforcement materials (natural hydroxyapatite (HA) and graphene nanoplatelets (GNP) of different dimensions). HA was isolated from bovine bones (HA particles size < 40 μm, <100 μm, and >125 μm) through a reproducible synthesis technology. The structural (FTIR-ATR, Raman spectroscopy), morphological (SEM), and, most importantly, in vitro (indirect and direct contact studies) features of all precursor materials were comparatively evaluated. The polymeric materials were also prepared in the form of thin plates, for an advanced cell viability assessment (direct contact studies). The overall results confirmed once again the reproducibility of the HA synthesis method. Moreover, the biological cytotoxicity assays established the safe selection of PLA as a future polymeric matrix, with GNP of grade M as a reinforcement and HA as a bioceramic. Therefore, the obtained results pinpointed these materials as optimal for future composite filament synthesis and the 3D printing of implantable structures. [ABSTRACT FROM AUTHOR]

Fused Deposition Modeling (FDM) is one of the most efficient and frequently used methods for the development of biomedical implants, bio-sensors, and customized products. In the FDM process, the filament made of polymers or composites is passed through a nozzle in which heaters are provided to melt the feedstock filament. The addition of copper particles to the polymer filament would enhance its thermal and electrical conductivity which finds vast applications in the development of sensors and other electronic components. Thus, it is obligatory to maintain the melt flow index of the filament following the size of the nozzle and the speed of the filament through the nozzle. The virgin polymer materials used as feedstock filament have an appropriate melt flow index (MFI), but the rheological properties of the polymer composites are not defined. This study focuses on the calculation and measurement of the melt flow rate of copper reinforced with acrylonitrile butadiene styrene (ABS) and nylon 6 thermoplastic matrices using fused deposition modeling. The copper particles of different sizes (149 μm, 74 μm, and 37 μm) were added in ABS and nylon 6 thermoplastic matrices to study the mechanical properties. The melt flow rate has been checked for different concentration ratios varying from 1% to 10% of copper reinforcements. The impact of single, double, and triple-sized copper particles on MFI has been investigated. It has been found that with an increase in copper powder concentration in nylon 6, the melt flow index decreases. On the other hand, the MFI initially increases up to 6% and further decreases by adding more particulates of copper powder in ABS. The surface topography of copper reinforced with different percent-compositions of ABS and nylon 6 based polymer composites have been carried out by using scanning electron microscopy. [ABSTRACT FROM AUTHOR]

In this work, a series of 3D printable ABS/PC blends were successfully prepared via filament extrusion and fused deposition fabrication. Influence of styrene–isoprene–styrene (SIS) copolymer on printability and mechanical properties were examined. It was revealed that SIS not only enhances the compatibility of the two blend phases, but also enhances the 3D printability of the resulting materials. The effect of print temperature, bed temperature, print speed, layer thickness, number of shell and infill density on mechanical properties of the printed parts were investigated using the Taguchi experimental design method, and the samples were printed using optimized process parameters according to the Taguchi method. It was revealed that the optimization of extrusion multiplier was an efficient method to overcome voids in the printed parts. Interestingly, incorporation of SIS considerably improved the adhesion and distribution of the blend phases. In addition, with an increase in SIS content, tensile strength, yield strength, elastic modulus, and hardness were found to decrease, whereas Izod impact strength and percentage elongation values of the 3D-printable blend increased. Finally, an efficient post-processing technique was successfully employed to improve the aesthetics of additive manufactured specimens. This work provides a facile strategy to prepare new 3D-printable polymer blends with improved adhesion between phases and minimized voids in the printed parts. [ABSTRACT FROM AUTHOR]

A hydrogen-oxygen torch igniter was developed and utilized to study its effects on a solid acrylonitrile butadiene styrene thermoplastic (ABS)-gaseous oxygen (GOx) hybrid rocket motor. The effects thereof are not presently found in literature. An increase of the hydrogen mass flow rate, at constant GOx mass flow rate, led to an increase in the average linear regression rate and a decrease in characteristic ignition time for fuel-lean and stoichiometric hydrogen-oxygen flames. Additionally, extending the duration of hydrogen flow from 10% to 50% of the total burn time led to an increase in the regression rate. Results suggest that the hydrogen-oxygen torch igniter can be used as a reliable starter with reignition capabilities and also for regression rate and ignition delay enhancement that targets the rate-limiting step, pyrolysis, for hybrid rocket combustion at stoichiometric and fuel-lean operating conditions of the torch igniter. • An increase in hydrogen mass flow rate can increase average linear regression rate. • An increase in hydrogen mass flow rate can decrease characteristic ignition time. • At fuel-rich torch operation, there is a competition between hydrogen and the ABS. • Extending hydrogen duration led to an increase in average linear regression rate. [ABSTRACT FROM AUTHOR]

Most addresses on modern address-based sampling frames derived from the U.S. Postal Service's Computerized Delivery Sequence file have a one-to-one relationship with a household. Some addresses, however, are associated with multiple households. These addresses are referred to as drop points, and the households therein are referred to as drop point units (DPUs). DPUs pose a challenge for self-administered surveys because no apartment number or unit designation is available, making it impossible to send targeted correspondence. The authors evaluate a method for substituting sampled DPUs with similar non-DPUs, which was implemented in the 2021 Healthy Chicago Survey alongside a concurrent survey of the originally sampled DPUs. Comparing aggregate distributions of DPUs and the non-DPU substitutes, the authors observe certain differences with respect to age, employment status, marital status, and housing tenure but no substantive differences in key health outcomes measured by the survey. [ABSTRACT FROM AUTHOR]

The article presents the results of research on the influence of the natural moisture of a filament made of acrylonitrile–butadiene–styrene terpolymer (ABS) on the mechanical properties and quality of products fabricated with fused filament fabrication (FFF). The concept of the natural moisture of the filament was defined, and the range of its variability was identified in reference to the range of the natural ambient humidity. It is shown that a change in the ambient humidity by 10% resulted in a change in filament moisture by about 0.05%. The results of the research on the moisture variability of an ABS filament stored in a package, an airtight container, or a container with a moisture absorber are also discussed. The last part of the article presents the results of the research on the impact of the moisture of the filament in its natural range of variability on select mechanical properties of filaments and products made using FFT. It is shown that this impact was significant and had a value of 1 MPa on 0.1% filament moisture. [ABSTRACT FROM AUTHOR]