Acrylonitrile Butadiene Styrene Research Articles

Development of 3D-printed braces protocol for juvenile idiopathic scoliosis: From the torso measurement and mechanical properties to preliminary experience on fitting

Background: There has been no standard for a rapid prototyping process in manufacturing of the 3D-printed brace with respect to its design, biomechanical properties, procedures, and brace adjustment and fitting. Objective: Objective of this study was to develop the 3D-printed brace protocol for juvenile idiopathic scoliosis. Methods: With the help of the Torso Measurement Frame, the child stands still and is positioned with 1 of 2 manipulation techniques by the physician. Although the patient is in the corrected position, a hand-held scanner registers the three-dimentional (3D) torso, and then the brace is designed using computer aided design (CAD) model. Finite element analysis is used to determine the minimum required thickness of the brace. Acrylonitrile Butadiene Styrene (ABS) material (thermoplastic polymers) and DuraForm PA plastic (Nylon) material were printed by 2 different systems, respectively, and were tested using standard tensile test procedures. Results: The minimum thickness of the brace should be 2 mm to maintain a standard structural factor of safety twice that of the material failure strength. The strain in elongation was less for the ABS compared to the 3D-printed Nylon (6% vs. 14%), and the tensile strength was reduced more for ABS as compared to Nylon (42% vs. 14%). The ABS brace could not withstand changes in tension and cracked when drilled into, heat flared, or donned tightly. However, the Nylon brace improved strength and eliminated the vulnerable aspects. Conclusions: The Nylon material for the 3D-printed brace improved ease of adjustments in trimming, drilling, and heat modifications for better fit and function.

Preliminary Research to Assess the Possibility of Grinding Selected Plastics Using Crushers

This study aims to investigate the effect of the shredding machine used on the recyclability of plastic fractions after primary crushing. This work presents a method for producing aggregates that has yet to be used in the plastics industry. This study included crushing of polymethylmethacrylate (PMMA), polyamide (PA-6), acrylonitrile butadiene-styrene (ABS), polycarbonate (PC), polystyrene (PS), and polypropylene (PP) waste in a jaw, a hammer, and a cone crusher. An analysis of the grain composition was carried out to characterize the obtained crushing products. The influence of feed size on the grain composition of the product and, only on the jaw crusher, the influence of the material used on the parameters of the crushing process was studied. This paper proposes a method to evaluate the grain composition and a way to assess plastic shredding capabilities based on machine kinematics and mechanical properties of a given material.

Three-Dimensional Printed Nanocomposites with Tunable Piezoresistive Response.

This study explores a novel approach to obtaining 3D printed strain sensors, focusing on how changing the printing conditions can produce a different piezoresistive response. Acrylonitrile butadiene styrene (ABS) filled with different weight concentrations of carbon nanotubes (CNTs) was printed in the form of dog bones via fused filament fabrication (FFF) using two different raster angles (0-90°). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) in TUNA mode (TUNA-AFM) were used to study the morphological features and the electrical properties of the 3D printed samples. Tensile tests revealed that sensitivity, measured by the gauge factor (G.F.), decreased with increasing filler content for both raster angles. Notably, the 90° orientation consistently showed higher sensitivity than the 0° orientation for the same filler concentration. Creep and fatigue tests identified permanent damage through residual electrical resistance values. Additionally, a cross-shaped sensor was designed to measure two-dimensional deformations simultaneously, which is applicable in the robotic field. This sensor can monitor small and large deformations in perpendicular directions by tracking electrical resistance variations in its arms, significantly expanding its measuring range.

Enhancement in the Electrical Properties and Electromagnetic Interference Shielding Performance of Acrylonitrile–Butadiene–Styrene/Carbon Nanotubes Foams via the Introduction of Bimodal Cell Structures

The cell structures of conductive polymer‐based composite foams significantly influence their electrical properties and electromagnetic interference (EMI) shielding effectiveness (SE), necessitating a thorough understanding of how these properties improve with evolving cell structures. In this study, supercritical CO2 foaming technique was manipulated to fabricate acrylonitrile–butadiene–styrene (ABS)/carbon nanotubes (CNTs) foams. The constant‐temperature mode was used to prepare unimodal foams (UF), while the bimodal foams (BF) were produced by varying‐temperature mode. The foaming properties, electrical conductivity, complex permittivity, and EMI SE of ABS/CNTs foams with various cell structures are methodically investigated at identical volume expansion ratio and CNTs content. The electrical conductivity of bimodal ABS/CNTs foam with CNTs content of 20% (BF‐C20) is 0.2191 S cm−1, higher than that of unimodal ABS/CNTs foam with CNTs content of 20% (UF‐C20) (0.1765 S cm−1) owing to the introduction of bimodal cell structures. Complex permittivity results manifest that at 8.2 GHz, the ε′ and ε″ of BF‐C20 are 67.7 and 74.5, respectively, which are higher than 57.9 and 52.9 of UF‐C20. Among all ABS/CNTs foams, the total EMI SE of BF‐C20 attains the highest EMI shielding value, which reaches 30.2 dB. Furthermore, the absolute shielding effectiveness of BF‐C20 is 188.5 dB (g cm−2)−1, which is 17.3% higher than that of UF‐C20.

Correlating Microstructural and Rheological Variations in Acrylonitrile-Butadiene-Styrene (ABS) with Interlayer Bond Formation in Material Extrusion Additive Manufacturing

Correlating Microstructural and Rheological Variations in Acrylonitrile-Butadiene-Styrene (ABS) with Interlayer Bond Formation in Material Extrusion Additive Manufacturing

Antimicrobial Efficacy of GS-2 on Reusable Food Packaging Materials for Specialty Crops.

The European Union (EU) regulations mandate 10% of all food packaging to be reusable by 2030. United States (U.S.) exporters of specialty crops face new challenges in ensuring microbiological food safety using reusable packaging. A novel antimicrobial formulation consisting of ammonium carboxylate salt of capric acid and L-arginine (GS-2) was recently developed as a spray coating chemical for food packaging materials. In this study, we evaluated the antimicrobial efficacy of GS-2 against microbial strains representing three foodborne bacterial pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica), one fungal spoilage organism (Aspergillus niger), and one surrogate viral pathogen (murine norovirus) on three reusable plastic materials (acrylonitrile butadiene styrene, high-density polyethylene, and polypropylene) and one cardboard packaging material, respectively. Different chemical concentrations, exposure times, and storage conditions were individually evaluated for the relative antimicrobial efficacies of GS-2 against these microorganisms. Our results showed that GS-2 was highly effective for inactivating bacterial pathogens on both plastic and cardboard surfaces. For instance, 3% GS-2 achieved a >5 log CFU/in2 reduction in E. coli O157:H7, L. monocytogenes, and S. enterica on tested plastic surfaces at an exposure time of 60 min. However, its efficacy against A. niger and murine norovirus was less optimal, resulting in a ≤1 log CFU/in2 reduction on all tested surfaces. Based on our study, GS-2 demonstrated a strong potential as an antibacterial coating reagent for reusable food packaging materials to minimize pathogen contamination and ensure the safety of the specialty crops.

Assessing the Tribological Impact of 3D Printed Carbon-Reinforced ABS Composite Cylindrical Gears

The tribological performance of carbon-reinforced acrylonitrile butadiene styrene (ABS) composites is very important in determining their suitability for advanced engineering applications. This study employs response surface methodology (RSM) to evaluate the effects of printing temperature and post-processing annealing on the wear resistance and frictional properties of these composites. A central composite design is used to systematically explore the interaction between these two factors, enabling the development of predictive models for key tribological parameters. The results reveal that both the coefficient of friction (COF) and wear are affected by printing and annealing temperatures, although in a non-linear manner. Moderate printing temperatures and lower annealing temperatures were found to reduce friction and wear, with annealing temperature having a more pronounced effect on wear. To further optimize these responses, the desirability approach was applied for predicting the optimal conditions. The optimal combination of input parameters for minimizing both COF and wear was found to be a printing temperature of 256 °C and an annealing temperature of 126 °C. This research provides valuable insights for optimizing additive manufacturing processes of carbon-reinforced ABS composites, contributing to enhanced material durability in practical applications.

Application of Poly(lactic Acid) Composites in the Automotive Sector: A Critical Review.

The introduction of bio-based matrices in automotive applications would, in principle, increase their sustainability and, in case the use of secondary raw materials is also involved, even result in reduced resource depletion. The bio-based polymer composite matrix that has been mainly brought forward towards industrial application is poly(lactic acid) (PLA), which has often been proposed as the replacement for matrices based on polyolefins in fields such as packaging and short-term commodities since, in general, it matches the needs for conventional thermoplastic production processes. The passage to the automotive sector is not obvious, though: problems affecting durability, the relation with water and the environment, together with the requirement for outstanding mechanical and impact performance appear very stringent. On the other hand, PLA has obtained durable success in additive manufacturing as a competitor for acrylonitrile butadiene styrene (ABS). Also, the perspective for 3D and 4D printing does not appear to be confined to bare prototyping. These contrasting pieces of evidence indicate the necessity to provide more insight into the possible development of PLA use in the automotive industry, also considering the pressure for the combined use of more sustainable reinforcement types in automotive composites, such as natural fibers.

Development and Testing of a Fast-Acting, 8-Bit, Digital Throttle for Hybrid Rocket Motors

The potential for throttle control of hybrid rocket systems has long been known as a potential advantage for a variety of applications. Because only a single flow path is controlled, theoretically, hybrids should be significantly easier to throttle than bipropellant systems. Unfortunately, the slow response times and nonlinearity of traditional position-control valves have limited practical applications of hybrid throttling. This paper presents an alternative throttling system where the oxidizer flow path is broken into multiple streams, with each flow path controlled by a solenoid-operated on/off valve. The parallel paths allow significantly faster and more precise control than can be achieved using a single position-control valve. The achievable thrust levels are limited only by the size and number of components in the valve cascade. The 8-bit digital throttle system, developed by Utah State University’s Propulsion Research Lab, uses commercial, off-the-shelf components. The throttle system was tested using a 200-N hybrid rocket motor, burning gaseous oxygen, and ABS plastic as propellants. The testing campaign of more than 50 hot fires has demonstrated multiple profiles, including deep throttle ramps, multistep boxcars, and sine waves at frequencies varying from 0.25 to 1-Hz. Comparisons to analytical models are also presented, showing good agreement. Fourier-transform spectra demonstrating the total-system, frequency response are also presented.

Polyalkenamers as Drop-In Additives for Ring-Opening Metathesis Polymerization: A Promising Upcycling Paradigm.

We report a distinct strategy to upcycle waste polyalkenamers such as polybutadiene into new, performance-advantaged materials by using them as drop-in additives for ring-opening metathesis polymerization (ROMP). The polyalkenamers serve as competent chain-transfer agents in ROMPs of common classes of cyclic olefin monomers, facilitating good molecular weight control, allowing low Ru catalyst loadings, and enabling efficient incorporation of the polyalkenamer into the synthesized polymeric material. We successfully demonstrate ROMP using model polyalkenamers and translate these learnings to leverage commercial polybutadiene and acrylonitrile butadiene styrene (ABS) as chain transfer agents for ROMP copolymerizations. Critically, our strategy is shown to be highly efficient and operationally simple, quantitatively incorporating the polyalkenamer and inheriting aspects of its thermomechanical performance. Our results highlight a promising pathway for the upcycling of polyalkenamers and provide an alternative to existing deconstruction and functional upcycling strategies.

Experimental investigation on tailoring compressive properties and energy absorption of 3D printed gradient star re-entrant hybrid auxetic structure

Purpose Fused filament fabrication (FFF) is a widely used 3D printing technique for the fabrication of mechanical metamaterials with intricate geometries. Gradient strategy is applied to geometric parameters of gradient star re-entrant hybrid auxetic (GSRA) structure. Deformation behaviour is studied under compressive loading. The purpose of this study is to investigate the influence of gradient geometric parameters on mechanical properties, namely, specific strength (SS), specific modulus (SM) and specific energy absorption (SEA). Design/methodology/approach Response surface methodology (RSM) is implemented for the design of experiments of gradient geometric parameters to minimize the number of experimental tests. Acrylonitrile butadiene styrene material is used for the fabrication of GSRA structures by FFF technique. The best set of gradient parameters has been optimized maximizing all three responses using RSM and artificial neural network optimization technique. Findings During compressive testing, row-wise deformation is observed with two-stage plateau regions, which results in increase in SEA of the structure. Furthermore, based on analysis of variance and 3D response plots, it is found that height gradient is the most influencing gradient geometric parameter on SS and SM, whereas the wall thickness gradient has maximum influence on SEA. Meanwhile, the interaction effect of wall thickness gradient and height gradient has maximum influence on SS, SM and SEA. Research limitations/implications This study of applying gradient strategy to geometric parameters is limited to GSRA structure under compressive loading. In addition, findings are valid within the selected range of gradient geometric parameters. These findings are useful for the selection of gradient geometric parameters to maximize SS, SM and SEA of GSRA structure simultaneously. These outcomes pave the way for designing light-weight gradient hybrid auxetic structures in the field of construction, aerospace, automobile and biomedical engineering. Originality/value Limited experimental study is available on investigating the influence of gradient geometric parameters on mechanical properties, namely, SS, SM and SEA, and deformation behaviours of hybrid auxetic structures. This study directly addresses the above research gaps.

Mechanical, thermal, and microstructure analysis of 3D printed polyolefin elastomer-acrylonitrile butadiene styrene blends for tunable mechanical properties

Fused Deposition Modeling (FDM) has emerged as a cost-effective and user-friendly technique that has garnered significant attention in recent years. However, challenges persist when printing soft materials using FDM technology. This study proposes a solution by blending a soft polyolefin elastomer (POE) with a stiffer material, acrylonitrile butadiene styrene (ABS). A comprehensive experimental investigation utilizing a direct pellet printing method was conducted to 3D print POE-ABS blends in various ratios (10%, 30%, and 50% ABS content). The study encompassed material preparation, 3D printing, SEM (Scanning Electron Microscopy) analysis, Dynamic Mechanical Thermal Analysis (DMTA), uniaxial tensile testing, and compression testing to assess the mechanical properties and energy absorption capabilities of the 3D printed blends. The results of the DMTA showed that the blends with a higher amount of ABS have a larger area under the Tan δ curve, indicating their ability to absorb more energy. The SEM images revealed that as the proportion of ABS increases, the gaps between layers and beads become smaller. The mechanical properties of the pure printed POE, such as its elongation at break and tensile strength, were 2138% and 2.83 MPa, respectively. However, as the ABS content increased, the samples exhibited more rigid behavior, with a final transition to 50/50 ratio resulting in 9.4 MPa tensile strength and 160% elongation at break. The energy absorption test demonstrated that the sample with 30% ABS content has the highest energy absorption capability among all the tested samples. This research underscores the potential of blending soft and stiff materials to tailor properties for additive manufacturing applications, emphasizing the significance of material composition in achieving desired mechanical performance, printability, and functionality in printed objects.

The Use of 3D Model Printing for Acute Planning in Oral and Maxillofacial Traumatology

Introduction Due to the complex anatomy of craniomaxillofacial structures, facial reconstruction following high-impact traumas is extremely challenging. Therefore, this study aimed to evaluate the use of biomodels in the surgical planning of complex fractures and the sequelae in the oromaxillofacial region. Materials and Methods This is a cross-sectional, exploratory, descriptive, and quantitative documentary study. It was conducted at the “Dom Luiz Gonzaga Fernandes” Emergency and Trauma Hospital, in the hinterland of the state of Paraíba, in Brazil, based on cases recorded between November 2021 and November 2022. The research instrument utilized was a self-developed questionnaire. Results No statistically significant correlation was observed between the biomodel acquisition time and the length of hospitalization, with a Spearman's correlation coefficient of r = -0.079. Although the need for adjustment of osteosynthesis material was 50% in cases where acrylonitrile butadiene styrene (ABS) models were used, with p (1) = 0.464, in order to be significantly more faithful, it would require a study with a higher sample size. The average length of surgery, in minutes, was 91.25 ± 28.00. The average cost of the materials used to manufacture the biomodels, in Brazilian reais (R$), was R$122.00 ± R$89.09. Conclusion The use of biomodels in the surgical planning of complex fractures and oromaxillofacial sequelae did not increase the length of hospitalization. The material used for the prototype manufacture suggests a potential influence on its faithfulness. The length of surgery was shorter in interventions that utilized biomodels in the planning phase. It was also noted that the average cost of manufacture varies according to the type of material chosen and the quantity required.

Thirty two port super wideband diversity antenna for indoor communications

This paper introduces a novel design featuring a thirty-two port diversity antenna with an elliptical shape, fed by an asymmetric coplanar waveguide (CPW). The antenna incorporates uneven meander lines, tailored for super-wideband (SWB) applications. The structure of the unit cell is of an elliptical patch with an elliptical slot, and it is connected to a rectangular stub and asymmetric meander line. The size of the single element is 22 mm × 20 mm, and it operates from 3 to 40 GHz. The bandwidth dimension ratio of the unit cell is 3911, bandwidth ratio is 13.33:1, and fractional bandwidth is 172.09%. The single element is developed into a 3-D thirty-two port diverse antenna, composed of a horizontal plane and four planes perpendicular to it. The diverse antenna has a peak gain of 12.5 dBi and an efficiency of 94%. The computed envelope correlation coefficient (ECC), as determined using S-parameters and far-field measurements, is less than 0.1. The attained diversity gains (DGs) of the developed MIMO antenna are above 9.9 dB in terms of both S-parameter and far-field computations. The obtained thirty-two port diverse antenna channel capacity loss (CCL) is below 0.25 bits/s/Hz. The mean effective gain (MEG) of the constructed thirty-two port antenna is below 2. To validate the appropriateness of the developed thirty-two port antenna for wireless indoor environment, an enclosure made of acrylonitrile butadiene styrene (ABS) is crafted and fabricated, and the characteristics of the proposed diverse antenna are investigated.

Investigation of Effect of Part-Build Directions and Build Orientations on Tension-Tension Mode Fatigue Behavior of Acrylonitrile Butadiene Styrene Material Printed Using Fused Filament Fabrication Technology.

This article explores the fatigue characteristics of acrylonitrile butadiene styrene (ABS) components fabricated using fused filament fabrication (FFF) additive manufacturing technology. ABS is frequently used as a polymeric thermoplastic material in open-source FFF machines for a variety of engineering applications. However, a comprehensive understanding of the mechanical properties and execution of FFF-processed ABS components is necessary. Currently, there is limited knowledge regarding the fatigue behavior of ABS components manufactured using FFF AM technology. The primary target of this study is to evaluate the results of part-build directions and build orientation angles on the tensile fatigue behavior exhibited by ABS material. To obtain this target, an empirical investigation was carried out to assess the influence of building angles and orientation on the fatigue characteristics of ABS components produced using FFF. The test samples were printed in three distinct directions, including Upright, On Edge, and Flat, and with varying orientation angles ([0°, 90°], [15°, 75°], [30°, 60°], [45°]), using a 50% filling density. The empirical data suggest that, at each printing angle, the On-Edge building orientation sample exhibited the most prolonged vibrational duration before fracturing. In this investigation, we found that the On-Edge printing direction significantly outperformed the other orientations in fatigue life under cyclic loading with 1592 loading cycles when printed with an orientation angle of 15°-75°. The number of loading cycles was 290 and 39 when printed with the same orientation angle for the Flat and Upright printing directions, respectively. This result underscores the importance of orientation in the mechanical performance of FFF-manufactured ABS materials. These findings enhance our comprehension of the influence exerted by building orientation and building angles on the fatigue properties of FFF-produced test samples. Moreover, the research outcomes supply informative perspectives on the selection of building direction and building orientation angles for the design of 3D-printed thermoplastic components intended for fatigue cyclic-loading applications.

Evaluation of Mechanical Properties of ABS-like Resin for Stereolithography Versus ABS for Fused Deposition Modeling in Three-Dimensional Printing Applications for Odontology.

This study investigates the differences in mechanical properties between acrylonitrile butadiene styrene (ABS) samples produced using fused deposition modeling (FDM) and stereolithography (SLA) using ABS filaments and ABS-like resin, respectively. The central question is to determine how these distinct printing techniques affect the properties of ABS and ABS-like resin and which method delivers superior performance for specific applications, particularly in dental treatments. The evaluation methods used in this study included Shore D hardness, accelerated aging, tensile testing, Izod impact testing, flexural resistance measured by a 3-point bending test, and compression testing. Poisson's ratio was also assessed, along with microstructure characterization, density measurement, confocal microscopy, dilatometry, wettability, Fourier-transform infrared spectroscopy (FTIR), and nanoindentation. It was concluded that ABS has the same hardness in both manufacturing methods; however, the FDM process results in significantly superior mechanical properties compared to SLA. Microscopy demonstrates a more accurate sample geometry when fabricated with SLA. It is also concluded that printable ABS is suitable for applications in dentistry to fabricate models and surgical guides using the SLA and FDM methods, as well as facial protectors for sports using the FDM method.

Drilling parameter optimisation for three-dimensional prints of acrylonitrile butadiene styrene

Abstract Over the past decade, additive manufacturing has transformed the industry, leading to a range of innovative products. In this study, the acrylonitrile butadiene styrene specimen was produced using the fused deposition modeling process. To assess the effectiveness of additive manufacturing parts in final product development, it’s crucial to establish the optimal drilling process parameters to minimize thrust force and torque. The investigation utilized two different drill geometries. Drilling with an end mill resulted in a 24.22% reduction in thrust force and a 12.37% decrease in torque compared to using a twist drill. Additionally, factors such as orientation, infill density, feed rate, and drill geometry have a significant impact on drilling forces.

Assessment of the carcinogenic potential of particulate matter generated from 3D printing devices in Balb/c 3T3-1-1 cells

Recently, there have been reports of sarcoma occurring in a Korean science teachers who used a 3D printer with acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) filaments for educational purposes. However, limited toxicological research data on 3D printing make it challenging to confirm a causal relationship between 3D printing and cancer. Therefore, occupational accidents involving teachers who have developed sarcoma have not been officially recognized. To address this gap, we aimed to evaluate the carcinogenic potential of particulate matter produced from ABS and PLA filaments commonly used in 3D printing. We created a generator mimicking 3D printing to generate particulate matter, which was used as an experimental material. The collected particulate matter was exposed to an in vitro system to investigate genetic damage, effects on cell transformation, and changes in carcinogenesis-related genes. Various assays, such as the comet assay, cell transformation assays, microarray analysis, and glucose consumption measurement, were employed. Cytotoxicity tests performed to determine the exposure concentration for the comet assay showed that cell viability was 83.6, 62.6, 42.0, and 10.2% for ABS at exposure concentrations of 50, 100, 200, and 400 µg/mL, respectively. PLA showed 91.7, 80.3, 65.1, and 60.8% viability at exposure concentrations of 50, 100, 200, and 400 µg/mL, respectively. Therefore, 50 µg/mL was set as the highest concentration for both ABS and PLA, and 25 and 12.5 µg/mL were set as the medium and low concentrations, respectively. The comet assay showed no changes in genetic damage caused by the particulate matter. Cytotoxicity results performed to establish exposure concentrations in the transformation assay showed that ABS showed cell viability of 88.0, 77.4, 84.7, and 85.5% at concentrations of 1.25, 2.5, 5, and 10 µg/mL, respectively, but few cells survived at concentrations above 20 µg/mL. PLA showed minimal cytotoxicity up to a concentration of 20 µg/ml. Therefore, in the cell transformation assay, a concentration of 10 µg/mL for ABS and 20 µg/mL for PLA was set as the highest exposure concentration, followed by medium and low exposure concentrations with a common ratio of 2. In cell transformation assays, only one transformed focus each was observed for both ABS and PLA particulate matter-exposed cells. The microarray assay revealed changes in gene expression, with a 41.7% change at 10 µg/mL for ABS and an 18.6% change at 20 µg/mL for PLA compared to the positive control group. Analysis of carcinogenesis-related gene expression changes on days 1, 7, and 25 of the promotion phase revealed that in cells exposed to 5 µg/mL of ABS, RBM3 gene expression increased by 3.66, 3.26, and 3.74 times, respectively, while MPP6 gene expression decreased by 0.33, 0.28, and 0.38 times, respectively, compared to the negative control group. Additionally, the measurement of glucose consumption showed that it increased in cells exposed to ABS and PLA particulate matter. Our findings suggest that the carcinogenic potential of ABS- and PLA-derived particulate matter in 3D printing cannot be completely ruled out. Therefore, further research in other test systems and analysis of additional parameters related to carcinogenesis, are deemed necessary to evaluate the carcinogenic risk of 3D printers using these materials.

Preparation and Properties of Cyano-Functionalized Graphitic Nanoplatelets for High-Performance Acrylonitrile Butadiene Styrene Resin.

Cyano-functionalized graphitic nanoplatelets (CyGNs) are synthesized by means of a mechanochemical reaction between graphite and acrylonitrile. The resulting CyGNs exhibit excellent mechanical properties and are highly dispersible in various solvents (i.e., THF). Due to their chemical compatibility (specifically, cyano functional groups), the CyGNs serve effectively as a reinforcing filler for acrylonitrile butadiene styrene (ABS) resin. Consequently, compared to pure ABS, CyGN&ABS-X demonstrates improved mechanical properties and better thermal stability. Notably, the CyGN&ABS-1 specimen exhibits significant enhancements in the tensile strength (26 ± 1 MPa), Young's modulus (992 ± 71 MPa), and tensile toughness (22 ± 3 MPa), representing increases of approximately 130.6%, 19.2%, and 59.6%, respectively, over pure ABS. This underscores the ability of a mechanochemical reaction to directly modify the functional groups of graphitic nanoplatelets (GnPs) as fillers, facilitating their strong compatibility with a variety of polymers, including copolymers.

Degradation of thermoplastic polymers for fused filament fabrication under (S)TEM electron beam irradiation

The structural characterization of polymers and, in particular, of those used in Additive Manufacturing (AM) technologies, is essential to improve the understanding of their structure-property relationship for promising high-performance applications. For this, (scanning) transmission electron microscopy-electron energy loss spectroscopy, (S)TEM-EELS is an outstanding tool for exploring materials chemical and structural characteristics at high spatial resolution. However, the high beam-sensitivity of soft materials, such as polymers, hinders the possibility of probing in-depth analysis provided by (S)TEM-EELS. In this work, we analyse the electron beam irradiation damage of four polymers commonly used in Fused Filament Fabrication (FFF), namely polylactic acid (PLA), polycaprolactone (PCL), acrylonitrile butadiene styrene (ABS) and acrylonitrile styrene acrylate (ASA). For this, sequential low-loss and core-loss EEL spectra have been recorded, and the related signals have been monitored as a function of the accumulated dose. Our results show that the critical electron doses using the specimen thickness variations are larger for polymers containing aromatic groups (ABS and ASA) than for aliphatic polymers (PLA and PCL). Regarding the different elements, a larger sensitivity to the electron beam of oxygen regarding carbon and nitrogen is also evidenced. Our results have shown that polymer degradation occurs to a larger extent in the initial steps of electron irradiation, for very low accumulated electron doses, meaning that care should be taken in the selection of the microscopy settings to avoid artefacts produced by the electron beam. Degradation pathways for the four polymers studied are discussed.