Search Results (154)

This study discusses the frictional wear performance of three 3D-printed materials, acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and high-impact polystyrene (HIPS), while evaluating different layer thickness levels. The materials were subjected to wear volume and rate tests by ball-on-disc wear tests at various thickness levels (0.1, 0.2, and 0.3 mm) and sliding distances. Lastly, SEM analysis was carried out to study the wear tracks and debris developed during the testing. Quantitatively, ABS maintained a mean wear volume below 0.15 mm³ across all test conditions (e.g., 0.05 ± 0.01 mm³ at 0.1 mm layer thickness and 150 m sliding distance), whereas PLA and HIPS recorded much higher averages of 1.5 mm³ and 3.0 mm³, respectively. With the increase in layer thickness, which caused an upward trend in the obtained results, the wear volume of the investigated materials also increased. ABS exhibited the smallest material loss of all three polymers; for example, at 0.1 mm layer thickness and a 150 m sliding distance, the mean wear volume was only 0.05 mm³, and even under the harshest condition tested (0.3 mm layer thickness, 300 m), the value remained below 0.15 mm³. PLA and HIPS showed higher wear volumes, while HIPS had the lowest resistance among the three materials. The multifunctional wear behavior difference contributed by material type was 59.76%, as shown through ANOVA, and that by layer thickness was 21.32%. Among the parameters investigated, material type had the largest control in wear behavior due to inherent variation in the structural characteristics of the material such as interlayer adhesion, toughness, and brittleness. For instance, the amorphous nature of ABS and its good layer adhesion provided significantly superior wear resistance compared to the brittle PLA and the poorly adhered HIPS. It is highlighted in this research that selecting appropriate material and layer thickness combinations can improve the durability of 3D-printed components. Full article

The demands of the green economy necessitate modern polymer materials that are not only environmentally friendly but also durable and capable of long service life. Bio-based polylactide (PLA) polyesters have gained significant traction in various industrial markets; however, their application in specialized sectors is hindered by high brittleness. This study extensively examines the effects of 1–5% of synthetically obtained tetracyclosiloxane (CS) and octaspherosilicate (OSS) derivatives with methacrylate (MA) and trimethoxysilyl (TMOS) groups as functional modifiers for PLA. The research provides a detailed characterization of PLA/CS and PLA/OSS materials, including a comparative analysis of mechanical properties such as tensile, flexural, and dynamic resistance. Notably, incorporating 5% CS-2MA-2TMOS into PLA resulted in a remarkable 104% increase in impact resistance. The study further evaluates the influence of these modifications on thermal properties (DSC, TGA), heat deflection temperature (HDT), and surface character (WCA). The miscibility between the organosilicon additives and PLA was assessed using oscillatory rheometry and SEM-EDS analysis. The melt-rheology analysis explained the mechanisms behind the interaction between the CS and OSS additives with the PLA matrix, highlighting their lubricating effects on the melt flow behavior. The study was complemented by XRD structural analysis and verification of the structure of PLA-based materials by optical microscopy and SEM analysis, demonstrating a plasticizing effect and uniform distribution of the modifiers. The findings strongly suggest that, even at low concentrations, organosilicon additives serve as effective impact modifiers for PLA. Full article

In this study, the mechanical behavior and interfacial bonding characteristics of multi-material composites produced using the Hybrid Fused Deposition Modeling (HFDM) technique were systematically investigated. Polylactic Acid (PLA), Polyethylene Terephthalate Glycol (PETG), and Acrylonitrile Butadiene Styrene (ABS) filaments were utilized within a single structure to explore the effects of material combinations on mechanical performance. Specimens were fabricated using two distinct levels of infill density (50–100%) and raster angle (45–90°) to evaluate the influence of these parameters on tensile strength, flexural resistance, and impact toughness. Experimental tests were conducted following ASTM standards, and microstructural examinations were performed using Scanning Electron Microscopy (SEM) to assess interfacial adhesion between different polymers. The results revealed that PETG demonstrated the highest tensile strength among single-material samples, while the PLA-PETG-ABS configuration exhibited notable mechanical stability among hybrid structures. Increasing infill density and raster angle significantly enhanced mechanical performance across all configurations. SEM analyses confirmed that interfacial bonding quality critically affected structural integrity, with better adhesion observed in PLA–PETG interfaces compared to PLA–ABS transitions. The potential of HFDM in developing tailored multi-material components with optimized mechanical properties offers valuable insights for the advancement of functional additive manufacturing applications in engineering fields. Full article

This study explores the development of long fiber-reinforced thermoplastic (LFT) composites based on blends of poly(lactic acid) (PLA) and polyhydroxyalkanoate (PHA), reinforced with sisal fibers. A novel lab-scale LFT line was employed to fabricate the long fiber composites, effectively addressing the challenges associated with dispersing and processing high-aspect-ratio natural fibers. The rheological, mechanical, thermal, and morphological properties of the resulting bio-LFT composites were systematically characterized using FTIR, SEM, rotational rheology, mechanical testing, DSC, and TGA. The results demonstrated generally homogeneous fiber dispersion, although limited interfacial adhesion between the fibers and polymer matrix was observed. Mechanical tests revealed that sisal fiber incorporation significantly enhanced tensile strength and stiffness, while impact toughness decreased. Thermal analyses showed improved crystallinity and thermal stability with increasing PHA content and fiber reinforcement. Overall, this work highlights the potential of natural fibers to create high-performance, sustainable biocomposites and lays a solid foundation for future advancements in developing eco-friendly structural materials. Full article

This study investigates the optimization of polyphenylene oxide (PPO) electrospinning for interlaminar toughening in composites, using sulfonation modification and physical blending with polylactic acid (PLA) and polystyrene (PS). Both strategies showed excellent electrospinning performance, significantly reducing fiber diameter (PPO: 12.1 ± 5.8 μm; sulfonated PPO: 524 ± 42 nm; PPO-PLA: 4.73 ± 0.94 μm; PPO-PS: 3.43 ± 0.34 μm). In addition, the PPO-PS fibers were uniform, while PPO-PLA exhibited a mixture of fine and coarse fibers due to phase separation. Interlaminar fracture toughness testing showed that PPO-PS offered the greatest toughening, with G_ICⁱⁿⁱ and G_IC^pre increasing by 223% and 232%, respectively, compared to the values of the untoughened sample, and by 65% and 61.5% compared to those of the PPO sample. G_IIC of the PPO-PS sample was 196% greater than that of the untoughened sample and 30% higher than that of the PPO sample. Scanning electron microscope (SEM) analysis of fracture morphology revealed that the high-toughness system dissipated energy through fiber bridging, plastic deformation, and multi-scale crack deflection, while the low-toughness samples failed due to interface debonding or cohesive failure. This work demonstrates that PPO-PS veils enhance interlaminar toughness through interface reinforcement and multiple toughening mechanisms, providing an effective approach for high-performance composites. Full article

Polylactic acid (PLA) exhibits remarkable biocompatibility and biodegradability, rendering it a highly promising material for applications in packaging and disposable products. However, its inherent brittleness, low melt strength, and slow crystallization rate significantly restrict its practical uses. Our previous studies have shown that incorporating the ADR chain extender can yield chitosan–polylactic acid–ADR (CS/PLA-ADR) composites with outstanding antibacterial properties, enhanced biodegradability, and the capability to effectively block water vapor and oxygen. However, the low elongation at break (less than 10%) limits its application in scenarios that require high ductility. To enhance the toughness of the CS/PLA-ADR composites, the flexible biodegradable polybutylene succinate (PBS) is innovatively introduced. The mechanical properties of PBS can be compared with polyethylene and polypropylene, providing high strength and toughness. The mechanism of introducing PBS is to construct a good, toughened structure through the flexible structure of PBS in collaboration with ADR toughening agent, achieving a balance between strength and toughness in CS/PLA-ADR-PBS composites. The incorporation of PBS is anticipated to improve the ductility of CS/PLA-ADR composites. This study systematically investigates the effects of varying PBS content (0–30%) on the properties of CS/PLA-ADR-PBS composites, aiming to determine the optimal PBS content and elucidate the mechanism by which PBS enhances the overall performance of the composites. The results indicate that when the PBS content is 20%, the composites exhibit optimal overall properties. This research provides a theoretical foundation and technical support for the development of environmentally friendly and sustainable packaging materials, offering significant research value and broad application prospects. Full article

The present work deals with the mixing of two green polymers at several definite ratios that led to the receiving of biodegradable polylactic acid (PLA)/polycaprolactone (PCL) blends possessing well-expressed macromechanical and shape memory properties. Four non-compatibilized polymer compositions were prepared by using a twin-screw melt extrusion technique, allowing for a homogeneous dispersion of the PCL droplets in the PLA matrix and higher interfacial adhesion between the two phases. The mechanical behavior of the specimens was estimated by tensile experiments conducted at three particular crosshead velocities. It was established that the addition of PCL as a soft segment redounded to an increment of the toughness and elongation at ultimate strength of the polymer composite at the expense of the maximum tensile stress and Young’s modulus. These latter two parameters were found to be more sensitive, in terms of reaching high values, to the content of PLA as a hard segment in the polymer blend. Performing thermoresponsive shape memory tests disclosed an overwhelming reversibility between the temporary and permanent states of the composite materials, including significant shape fixation ($R_f$) and shape recovery ($R_r$) rates. SEM analysis of the PLA/PCL compositions revealed a distinct phase-separated microstructure, confirming the immiscibility of the two polymers in the blend. Full article

In recent years, thermoplastic polymers and composites have seen increasing application across various industrial sectors to develop lightweight structures. These materials have gained popularity in the market due to advancements in additive manufacturing. Thermal direct joining serves as an effective solution for integrating such thermoplastic materials into existing or de-novo metal structures. This method enables the creation of lightweight and virtually reversible joints, which foster end-of-life recyclability, thus aligning with the principles of a circular economy. However, these joints are still affected by a low strength, which is mostly related to the poor polymer–metal interaction. The use of surface treatments that promote mechanical interlocking of the polymer within surface asperities in the mating metallic adherend can be an effective strategy to enhance the strength, as well as to improve the toughness and damage tolerance of the joints. In this work, a laser treatment was used to modify the surface texture of an aluminum sheet prior to thermal bonding with 3D-printed polylactic acid (PLA). Different surface textures were analyzed by modifying the main process parameters. Roughness and wettability measurements were performed to identify the most effective processing condition. Finally, mechanical tests were performed to verify the improvement in joint resistance obtained by interface modification. Full article

Polylactic acid (PLA) is widely used in 3D printing for its biodegradability and ease of processing, but its brittleness and low impact strength often restrict its suitability for more demanding applications. The novelty of this work lies in its direct comparative approach: we systematically reinforce PLA with two distinct agricultural residues—rice husk and rice straw—under identical conditions to clarify how particle size (100 vs. 200 mesh) and NaOH surface treatment affect mechanical performance. Composite filaments containing 5–20 wt% of each fiber were produced and 3D-printed into standard tensile and flexural specimens. The results show that, although tensile strength declines at higher fiber loadings, tensile modulus, flexural strength, and impact resistance can improve significantly—particularly with 200-mesh and NaOH-treated fibers. Fourier transform infrared (FTIR) spectroscopy confirms partial lignin removal and enhanced cellulose exposure, improving fiber–matrix adhesion, which is corroborated by scanning electron microscopy (SEM) observations of reduced voids. This comparative study demonstrates that surface-treated, finely milled rice husk and rice straw significantly enhance PLA’s stiffness and toughness, offering a sustainable alternative to conventional polymeric additives. The insights gained here on fiber content, chemical treatment, and 3D printing parameters can guide the broader industrial adoption of these natural fiber-reinforced PLA composites, particularly in automotive and construction applications that require lightweight, durable materials. Full article

Highly toughened bio-based polylactic acid (PLA)/Eucommia ulmoides gum (EUG) blends were prepared using organic montmorillonite (OMMT) as a compatibilizer through melt-blending. Both the theoretically predicted values and the experimental results confirm that the majority of the OMMT’s nanolayers are selectively localized at the PLA/EUG interface. This localization leads to improved interfacial properties and a more refined morphology of the dispersed EUG phase. By increasing the OMMT content from 0 phr to 2 phr, the notched Izod impact strength of the PLA/EUG/OMMT (85/15/2) blend increases to a maximum value of 44.6 kJ/m². This is significantly higher than the values observed for neat PLA at 3.8 kJ/m² and the PLA/EUG (85/15) blend at 4.7 kJ/m². Moreover, compared to neat PLA and the PLA/EUG (85/15) blend, which exhibit poor tensile ductility, as indicated by their low elongation at break, the PLA/EUG/OMMT blend demonstrates a substantial improvement in its tensile ductility when an appropriate amount of OMMT is added. It is believed that the enhanced toughness of the PLA/EUG/OMMT blends can primarily be attributed to the refinement and more uniform dispersion of the EUG domains, which is caused by the incorporation of OMMT. In addition, the crystalline properties, thermal degradation behavior, and extrudate swell behavior of the PLA/EUG blends with and without OMMT were also evaluated in detail. Finally, the experimental results prove that the PLA/EUG (85/15) blend containing 2 phr of OMMT exhibits the highest impact toughness and tensile ductility, accompanied by improved thermal stability and extrusion stability. Full article

This study investigates enhancing polylactic acid (PLA) by incorporating recycled polycarbonate (r-PC) to address PLA’s inherent brittleness and limited thermal stability. Blends with varying PLA/r-PC ratios (100:0 to 0:100) were prepared using an internal mixer, with r-PC sourced from discarded compact discs. The thermogravimetric analysis (-A) demonstrated significant improvements in the thermal stability. The degradation onset temperature (T₅ wt%) increased from approximately 315 °C for pure PLA to about 400 °C in the blends, with a maximum decomposition temperature (T_max) of 520 °C observed for pure r-PC. The char residue also increased markedly, from 1.35% in pure PLA to 24.42% in r-PC, indicating enhanced thermal resistance. Differential scanning calorimetry (DSC) revealed a considerable reduction in PLA crystallinity, declining from 68.17% in pure PLA to 10.32% in the 10PLA90r-PC blend, indicative of the disruption of PLA’s crystalline structure. The X-ray diffraction (XRD) analysis supported these findings, showing a transition to a predominantly amorphous structure at higher r-PC contents. Tensile testing highlighted the mechanical improvements achieved through blending. While pure PLA exhibited brittle failure, the 30PLA70r-PC blend displayed plastic deformation, signifying improved toughness. The stress–strain analysis revealed that the 30PLA70r-PC blend achieved a peak toughness of 8725 kJ/m³, nearly ten times higher than the 924 kJ/m³ recorded for pure PLA. However, excessive r-PC content introduced brittleness, diminishing toughness. The dynamic mechanical thermal analysis (DMTA) demonstrated a broadening of the glass transition range, with the T_g shifting from 61 °C for pure PLA to 141 °C in r-PC-dominant blends, reflecting improved phase interactions between the two polymers. Scanning electron microscopy (SEM) revealed significant morphological changes; at high r-PC contents, phase separation and voids were observed, leading to reduced mechanical performance. These results highlight the synergistic potential of blending PLA’s biodegradability with r-PC’s superior thermal and mechanical properties. Full article

This study examines the effects of mastication time and the addition of a plasticizer (acetyl tributyl citrate (ATBC)) on the properties of non-vulcanized polylactic acid/natural rubber (PLA/NR) blends using a factorial design, along with the impact of changing the weight ratio of the blends. The results reveal the formation of plasticized PLA (P-PLA)-based thermoplastics with enhanced ductility. ATBC functions as both a PLA plasticizer and a compatibilizer in the binary PLA/NR system. However, improving compatibility requires the exclusive use of masticated NR with an appropriate mastication time (60 min) before blending. Optimal properties are achieved at a P-PLA/NR weight ratio of 90/10, maximizing the impact strength (~35.40 J/m) and toughness (~7.21 × 10⁶ MJ/m³). However, higher NR contents lead to reduced mechanical performance due to poor interfacial bonding. Thermal analysis reveals superior miscibility and dispersion in blends with a lower NR content (10 wt%), while the addition of plasticizers and NR leads to a decrease in the glass transition temperature (T_g) of the blends. The results suggest potential applications for developing biodegradable products with enhanced flexibility and improved low-temperature performance. The incorporation of ATBC can enhance material properties without relying on conventional synthetic compatibilizers. Full article

The prevalence of kidney stones, a significant urological health concern, necessitates advancements in the management and treatment methods, particularly in the domain of ureteral stents. This study explores the feasibility and potential benefits of utilizing three biodegradable polymers—Polylactic Acid (PLA), Tough Polylactic Acid (Tough PLA), and Polylactic Acid/Poly-hydroxybutyrate (PLA/PHB)—for the fabrication of 3D-printed ureteral stents tailored to patient-specific needs. Through the integration of CAD and Fused Deposition Modeling (FDM) 3D printing technology, ureteral stents were successfully produced, demonstrating key advantages in terms of biodegradability and mechanical properties. The study involved a rigorous evaluation of the biodegradability, tensile strength, and hardness of the stents. Biodegradability tests performed in a simulated physiological environment revealed that PLA/PHB and Tough PLA stents exhibited higher degradation rates compared to PLA, aligning with the requirements for temporary urinary tract support. Tensile strength testing indicated that while PLA showed the highest strength, PLA/PHB and Tough PLA stents provided beneficial ductility, reducing the risk of blockage due to material breakage. Hardness assessments classified PLA/PHB stents as medium soft, optimizing patient comfort during the stenting period. These findings demonstrate the potential of using biodegradable polymers to produce ureteral stents that could eliminate the need for removal procedures, thereby enhancing patient recovery and comfort. Full article

In cases of severe injuries or burns, skin grafts (scaffolds) are often required as skin substitutes. In order not to harm the patient or the donor, biodegradable and biocompatible materials are used, which validates the search for heterografts such as poly (L-lactic acid)—PLA. However, natural polymers applied to the skin suffer great degradation in environments with large amounts of carbon and water or via binders with considerable resistivity, which implies little durability due to their low ductility. For the proposal, this work investigates PLA-based scaffolds modified with a mixture of pseudoboehmite (PB) and graphene oxide (GO), produced via the sol–gel route. The nanomaterials are incorporated into the polymer at different loadings, seeking to improve mechanical and thermal properties. Analyses via SEM, EDS, and XRD confirm the presence and distribution of these fillers. Tensile and flexural tests indicate that adding the filler can increase stress resistance, prevent deformations before failure, and increase toughness when compared to pure PLA. Full article

Additive manufacturing is an attractive technology due to its versatility in producing parts with diverse properties from a single material. However, the process often generates plastic waste, particularly from failed prints, making sustainability a growing concern. Recycling this waste material presents a potential solution for reducing environmental impact while creating new, functional parts. In this study, the feasibility of creating printable filaments from recycled polylactic acid (PLA) waste and virgin PLA pellets was explored. Filaments were manufactured in the lab using a single-screw desktop extruder with four temperature zones, with compositions ranging from 100% virgin PLA to 100% recycled PLA in 10% composition increments. Test samples were 3D printed using a Material Extrusion 3D printer and subjected to tensile testing in conjunction with digital image correlation to evaluate their ultimate tensile strength, yield strength, Young’s modulus, ductility, toughness, and strain distribution. The results indicated that the optimal mechanical properties were observed in specimens made from 100% virgin PLA, 100% recycled PLA, and a 50% virgin/50% recycled PLA blend. Additionally, comparisons with a commercially produced PLA filament revealed that 100% virgin and 100% recycled blends have a 50.33% and 48% higher tensile strength than commercial filament, respectively. However, commercial filaments exhibited higher ductility and toughness than the lab-made extruded filament. Full article