Search Results (241)

Although PLA is an attractive biodegradable polymer, its degradation under natural conditions is often slow. This study investigates whether incorporating pounamu (New Zealand jade) particles into PLA can enhance its biodegradation rate under composting conditions at room temperature. PLA composites containing 0 to 15 wt% pounamu were fabricated using both compression molding and 3D printing. A simple, reproducible protocol based on residual mass measurement was developed to monitor the biodegradation process over a 12-month period. The results showed that increasing pounamu content consistently accelerated mass loss of the composite in the compost, indicating enhanced biodegradation. The 3D-printed samples degraded more rapidly than compression-molded ones. This was attributed to the layered structure, internal microcavities, and lower crystallinity of the 3D-printed samples, which provided greater surface area and accessibility for microbial activity. These findings highlight the dual role of pounamu as both a crystallization promoter and a facilitator of biodegradation and underscore the importance of the processing method when designing biodegradable polymer composites for real-world applications. Full article

Biodegradable polymer composites offer promising alternatives to petroleum-based plastics, supporting the principles of a zero waste and circular economy. This study investigates the reinforcing potential of alkali-treated wood flour derived from recycled pine (Pinus brutia Ten.) and poplar (Populus alba L.) waste wooden pallets in poly(lactic acid) (PLA) biocomposites. Wood flour was initially recovered through grinding and screening during recycling, followed by alkali treatment via a green chemistry approach to enhance interfacial bonding with the PLA matrix. The impact of alkali concentration and two fabrication methods—additive manufacturing (AM) and injection molding (IM)—on the properties of developed biocomposite materials was assessed through mechanical, physical, morphological, and thermal analyses. IM samples outperformed AM counterparts, with the IM PLA containing 30 wt% wood flour (alkali-treated with 10% solution) showing the highest mechanical gains: tensile (+71.35%), flexural (+64.74%), and hardness (+2.62%) compared to untreated samples. Moreover, the AM sample with 10 wt% wood flour and 10% alkali treatment showed a 49.37% decrease in water absorption compared to the untreated sample, indicating improved hydrophobicity. Scanning electron microscopy confirmed that alkali treatment reduced void content and enhanced morphological uniformity, while thermal properties remained consistent across fabrication methods. This work introduces a green composite using non-toxic materials and treatments, facilitating eco-friendly production aligned with zero waste and circular economy principles throughout the manufacturing lifecycle. Full article

Dental caries can cause premature loss of deciduous teeth, affecting children’s growth and development. Endodontic treatment using polymer posts is an effective solution. This study explores biodegradable root canal posts made from Polylactic Acid (PLA), Polycaprolactone (PCL), and amorphous calcium phosphate (ACP), aiming to enhance mechanical properties, minimize polymer degradation acidity, and prevent inflammation. A root canal post with a spherical head and serrated structure was designed and produced via micromolding and optimized using the Taguchi experimental method. The melt temperature, injection speed, and holding speed were analyzed for their influence on shrinkage, revealing an optimal rate of 2.575%, representing the sum of axial and radial shrinkage. The melt temperature had the highest impact (55.932%), followed by holding speed (33.575%), with there being minimal effect from injection speed. The composite exhibited a flexural strength of 21.936 MPa, a modulus of 2.083 GPa, and a hydrophilic contact angle of 73.73 degrees. Cell survival tests confirmed biocompatibility, with a survival rate exceeding 70% and no toxicity. These findings highlight the potential of PLA/PCL/ACP composites, combined with injection molding, for developing biodegradable root canal posts in primary teeth. Full article

In this work, biocomposites of polylactic acid (PLA) and polypropylene (PP) with micronized cellulose (MC) were produced by mold injection and subjected to accelerated aging with ultraviolet (UV) radiation. The tests took place over 10 weeks, during which the produced specimens were exposed to a total of 1050 h of ultraviolet light. During the UV aging test, images were captured, and spectral reflectance and colorimetric measurements were carried out on the specimens exposed to UV and on specimens of the same materials kept in the dark (originals). As expected, only residual color differences were observed in the original specimens with values of ΔE*_ab always below 0.5. On the other hand, spectral reflectance and colorimetric changes were noticed over time in the specimens subjected to UV radiation. In particular, the values of ΔE*_ab increased over time and were found to be higher for PLA with MC compared to PP with MC. Values of ΔE*_ab = 4.7, 9.0, and 10.4 were obtained for weeks 1, 5, and 10, respectively, for the specimens of PLA with MC, whereas ΔE*_ab = 4.5, 6.8, and 7.3 were obtained for weeks 1, 5, and 10, respectively, for the specimens of PP with MC. Therefore, it was found that the specimens of PLA with MC showed greater color fading compared to the specimens of PP with MC when subjected to UV exposure. In addition, it was also found in this work that besides the color differences noted in the tested specimens, those made of PP with MC also showed signs of surface damage. Full article

As the global plastic pollution problem intensifies and the environmental hazards of traditional petroleum-based plastics become increasingly significant, the development of sustainable alternative materials has become an urgent need. This paper systematically reviews the research progress, application status and future trends of new generation bioplastics in the field of food packaging. Bioplastics are categorized into three main groups according to their sources and degradability: biobased biodegradable materials (e.g., polylactic acid PLA, polyhydroxy fatty acid ester PHA, chitosan, and cellulose-based materials); biobased non-biodegradable materials (e.g., Bio-PE, Bio-PET); and non-biobased biodegradable materials (e.g., PBAT, PCL, PBS). Different processing technologies, such as thermoforming, injection molding, extrusion molding and coating technologies, can optimize the mechanical properties, barrier properties and freshness retention of bioplastics and promote their application in scenarios such as food containers, films and smart packaging. Although bioplastics still face challenges in terms of cost, degradation conditions and industrial support, promising future directions are found in the development of the large-scale utilization of non-food raw materials (e.g., agricultural waste, algae), nano-composite technology to enhance the performance, and the development of intelligent packaging functions. Through technological innovation and industry chain integration, bioplastics are expected to transform from an environmentally friendly alternative to a mainstream packaging material, helping to realize the goal of global carbon neutrality. Full article

The agricultural sector faces growing pressure to enhance productivity and sustainability, prompting innovation in machinery design. Traditional materials such as steel still dominate but are a cause of increased weight, soil compaction, increased fuel consumption, and corrosion. Composite materials—and, more specifically, fiber-reinforced polymers (FRPs)—offer appealing alternatives due to their high specific strength and stiffness, corrosion resistance, and design flexibility. Meanwhile, increasing environmental awareness has triggered interest in biocomposites, which contain natural fibers (e.g., flax, hemp, straw) and/or bio-based resins (e.g., PLA, biopolyesters), aligned with circular economy principles. This review offers a comprehensive overview of synthetic composites and biocomposites for agricultural machinery and equipment (AME). It briefly presents their fundamental constituents—fibers, matrices, and fillers—and recapitulates relevant mechanical and environmental properties. Key manufacturing processes such as hand lay-up, compression molding, resin transfer molding (RTM), pultrusion, and injection molding are discussed in terms of their applicability, benefits, and limits for the manufacture of AME. Current applications in tractors, sprayers, harvesters, and planters are covered in the article, with advantages such as lightweighting, corrosion resistance, flexibility and sustainability. Challenges are also reviewed, including the cost, repairability of damage, and end-of-life (EoL) issues for composites and the moisture sensitivity, performance variation, and standardization for biocomposites. Finally, principal research needs are outlined, including material development, long-term performance testing, sustainable and scalable production, recycling, and the development of industry-specific standards. This synthesis is a practical guide for researchers, engineers, and manufacturers who want to introduce innovative material solutions for more efficient, longer lasting, and more sustainable agricultural machinery. Full article

Three-dimensional (3D) printing has become a promising alternative to conventional methods in plastic part production, particularly for customized or low-volume applications such as toys. This study compares toy components produced by Fused Deposition Modeling (FDM) using polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) filaments and those produced by traditional injection molding using ABS pellets. Unlike in many previous studies based on standardized test samples, a real toy part was evaluated in terms of compressive strength, dimensional accuracy, surface quality, and cost. Experimental results revealed that ABS parts produced by injection molding exhibited the highest compressive strength (3.93 kN), followed by PLA-FDM (2.97 kN) and ABS-FDM (0.95 kN). Similarly, injection-molded parts showed superior surface smoothness and dimensional accuracy. Cost analysis indicated that injection molding is economically viable only when production exceeds 735 pieces, while FDM becomes more attractive for smaller batches due to its low initial cost. A multi-criteria decision-making analysis using the TOPSIS method was conducted to integrate technical and economic factors. Results showed that injection molding is preferable for mass production, whereas PLA-FDM is more suitable for low-quantity, cost-sensitive scenarios. Full article

Soft lithography with microfabricated molds is a widely used manufacturing method. Recent advancements in 3D printing technologies have enabled microscale feature resolution, providing a promising alternative for mold fabrication. It is well established that the curing of PDMS is influenced by parameters such as temperature, time, and curing agent ratio. This study was conducted to address inconsistencies in PDMS curing observed when using different 3D-printed mold materials during the development of a Lab-on-a-Chip (LoC) system, which is typically employed for investigating the effect of hydrodynamic cavitation on blood clot disintegration. To evaluate the impact of mold material on PDMS curing behavior, PDMS was cast into molds made from polylactic acid (PLA), polyethylene terephthalate (PET), resin, and aluminum, and cured at controlled temperatures (55, 65, and 75 °C) for various durations (2, 6, and 12 h). Curing performance was assessed using Soxhlet extraction, Young’s modulus calculations derived from Atomic Force Microscopy (AFM), and complementary characterization methods. The results indicate that the mold material significantly affects PDMS curing kinetics due to differences in thermal conductivity and surface interactions. Notably, at 65 °C, PDMS cured in aluminum molds had a higher Young’s modulus (~1.84 MPa) compared to PLA (~1.23 MPa) and PET (~1.17 MPa), demonstrating that the mold material can be leveraged to tailor the mechanical properties. These effects were especially pronounced at lower curing temperatures, where PLA and PET molds offered better control over PDMS elasticity, making them suitable for applications requiring flexible LoC devices. Based on these findings, 3D-printed PLA molds show strong potential for PDMS-based microdevice fabrication. Full article

The use of natural fibers in hydro turbine rotors promotes sustainability by offering biodegradable, renewable materials with a lower carbon footprint. This study compares the hydrodynamic performance of two rotors in a gravitational vortex turbine: Rotor 1, 3D-printed with polylactic acid (PLA), and Rotor 2, made from fique fiber and epoxy resin using manual molding. To compare the rotors, experimental tests were conducted on a laboratory-scale setup, where the behavior of both rotors was evaluated under different flow regimes. Rotor 1 achieved 61.01% efficiency at an angular velocity ($\omega$) 160 RPM, while Rotor 2 reached only 19.03% at $\omega$ of 165 RPM. The lower performance of Rotor 2 was due to dynamic imbalances and mechanical vibrations, leading to energy losses. These challenges highlight the limitations of manual molding in achieving precise rotor geometry and balance. To improve natural fiber rotor viability, optimizing manufacturing techniques is crucial to enhance dynamic balance and minimize vibrations. Advancements in fabrication could bridge the performance gap between natural and synthetic materials, making bio-based rotors more competitive. This study emphasizes the potential of natural fibers in sustainable energy and the need to refine production methods to maximize efficiency and reliability. Addressing these challenges will help integrate eco-friendly rotors into hydro turbine technologies. Full article

Polymer 3D printing is popular due to its accessibility and low material waste. While commonly used in prototyping and medical applications, its potential for molds in complex concrete geometries, such as heritage reproductions or artificial reefs, remains underexplored. These applications require resistance to degradation from UV exposure, rain, and highly alkaline concrete (pH~13). This study evaluates the accelerated degradation of 3D-printed PLA specimens. Four PLA types were tested: virgin PLA extruded in the lab, commercial PLA, PLA with 50% metal powder, and PLA with encapsulated metal powder. Rectangular specimens were printed and tested under flexural loads following ISO-167 standards. Initially, their performance was assessed without exposure. Then, half of the specimens underwent UV and rain simulation, while the rest were immersed in an alkaline solution (pH 13, 50 °C). Dimensional changes and flexural strength were measured at five intervals. Exposure to an alkaline medium at 50 °C is more aggressive than UV radiation, limiting the lifespan of PLA formwork. Adding metal powder weakens PLA by 65% after 7 days, making it unsuitable. Printing defects accelerate degradation. Unmodified PLA is the best choice for concrete formwork, with commercial PLA and PLA from pellets showing nearly identical behavior. Full article

Nanoscale amorphous calcium phosphate (ACP) exhibits superior bioactivity, degradability, and osteoblast adhesion compared to hydroxyapatite (HAp), making it a promising bioactive ceramic material for bone regeneration applications. This study explores the integration of ACP as a bioactive additive in polylactic acid/polycaprolactone (PLA/PCL) composites. Nanoscale ACP powder was synthesized through low-temperature wet chemical methods without additional reagents. The composite, consisting of 10 wt.% ACP, 80 wt.% PLA, and 20 wt.% PCL, achieved optimal tensile strength (>12 MPa) and elongation (>0.1%). Utilizing the Taguchi experimental design, the microinjection molding parameters were optimized, and they are a material temperature of 190 °C, an injection speed of 50 mm/s, and a holding pressure speed of 30 mm/s. Variance analysis identified the injection speed to be the most significant factor, contributing 50.73% to the overall effect. Immersing ACP in simulated body fluid (SBF) for six hours reduced its calcium ion concentration by 28%, with this concentration stabilizing thereafter. Biocompatibility was confirmed through an MTT assay with NIH-3T3 cells, demonstrating the PLA/PCL/ACP composite’s compatibility. Bone differentiation and mineralization tests showed the enhanced performance of both ACP and the composite material. Degradation tests indicated an initial 0.29% weight increase in the first week, followed by a 2% reduction by the fifth week. These results underscore the PLA/PCL/ACP composite’s excellent mechanical properties, biocompatibility, and suitability for injection molding, positioning it as a strong candidate for biodegradable bone screw applications. Full article

This study presents a novel approach to manufacture a rigid printed circuit board (PCB) using sustainable polymers. Current PCBs use a fossil-fuel-based substrate, like FR4. This presents recycling challenges due to its composite nature. Replacing the substrate with an environmentally friendly alternative leads to a reduction in negative impacts. Polylactic acid (PLA) and Polyhydroxybutyrate (PHB) biopolymers are used in this study. These two biopolymers have low melting points (130–180 °C, and 170–180 °C, respectively) and cannot withstand the high temperature soldering process (up to 260 °C for standard SAC (SnAgCu, tin/silver/copper) lead free solder processes). Our approach for replacing the PCB substrate is applying the PLA/PHB carrier substrate at the end of the PCB manufacturing process using injection molding technology. This approach involves all the standard PCB processes, including wet etching of the Cu conductors, and component assembly with SAC solder on a thin flexible polyimide (PI) foil with patterned Cu conductors and then overmolding the biopolymer onto the foil to create a rigid base. This study demonstrates the functionality of two test circuits fabricated using this method. In addition, we evaluated the adhesion between the biopolymer and PI to achieve a durable PCB. Moreover, we performed two different end-of-life approaches (debonding and composting) as a part of the end-of-life consideration. By incorporating biodegradable materials into PCB standard manufacturing, the CO₂ emissions and energy consumption are significantly reduced, and installation costs are lowered. Full article

In this study, the microinjection molding technology was adopted to prepare polylactic acid (PLA)/polycaprolactone (PCL)/bioactive glass (BG) composites with varying BG contents for biomedical applications. The various measurement techniques, including scanning electronic microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, the water contact angle (WCA) test, the mechanical test, and in vitro biological evaluations, were applied to characterize the above interesting biocomposites. The experimental results show that the extremely strong shear force field generated during the microinjection molding process could induce the in situ formation of micron PCL dispersed phase fibril structures and strongly promote the homogeneous dispersion of micron BG filler particles in the PLA/PCL polymer matrix, which therefore leads to a significant improvement in the specific mechanical property of the PLA/PCL/BG composite. For example, with BG fillers content increasing to 10 wt%, the Young’s modulus of the above obtained PLA/PCL/BG composite could reach 2122.9 MPa, which is 1.47 times higher than that of the unfilled PLA/PCL blend material. In addition, it is also found that under the simulated body fluid (SBF) environment, the incorporated BG fillers in the PLA/PCL polymer matrix could be effectively transformed into hydroxyapatite (HA) components on the treated sample surface, thus being greatly advantageous to enhancing the material’s in vitro bioactivity. Obviously, the microinjection molded PLA/PCL/BG biocomposites could exhibit excellent comprehensive performance, revealing that the microinjection molding processing method could hold great potential in industrialization applications of the resulting biodegradable biomedical materials. Full article

In this study, poly(lactic acid) biocomposites were prepared from sugarcane bagasse (SB) via extrusion and injection molding. The effects of the content and inorganic salt modification of SB on the properties of the biocomposites were investigated. The results showed that the incorporation of SB reduced the biocomposites’ mechanical strength and modulus as well as thermal stability but increased their crystallinity, hydrophobicity, and water absorption compared with neat PLA. Among all the biocomposites, the sample containing 30 wt % SB(SB-30/PLA) had the best comprehensive performances, with tensile strength, tensile modulus, flexural strength, and crystallinity values of 31.78 MPa, 219.49 MPa, 53.25 MPa, and 16.8%, respectively. After SB modification with Na₂SO₄ and MgSO₄, the increased interfacial adhesion led to a considerable improvement in reinforcement and increases in the flexural strength, flexural modulus, impact strength, and crystallinity of SB-30/PLA; furthermore, the biocomposite became more thermally stable and hydrophobic and contained much less water. In conclusion, SB-30/PLA, especially after MgSO₄ modification, is an ideal degradable biocomposite for applications in packaging, decoration, and other areas. Full article

The push for sustainability in all facets of manufacturing has led to an increased interest in biomass as an alternative to non-renewable materials. Hemp bast fiber mats were produced from a bacterial retting process, named BFM, as the fiber reinforcement. The objective of this study was to evaluate the feasibility of laminating BFM with polylactic acid (PLA) for a composite panel product. Since both BFM and PLA are biodegradable, the resulting BFM-PLA composites will be 100% biodegradable. PLA pallets were processed into thin polymer sheets which served as the matrix. The BFM and PLA plates were laminated in five layers and compression-molded into composite panels. Experiments were conducted on the three BFM-to-PLA ratios (35/65, 45/55, and 50/50). Mechanical properties (tensile and bending properties) and physical properties (thickness swell and water absorption) were tested and compared to the currently commercial sheet molding compound (SMC) from fiber glass. The thermal behavior of the BFM/PLA composites was characterized using dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). The developed BFM/PLA composite product is a sustainable alternative to existing synthetical fiber-reinforced polymer (FRP) that is biodegradable in landfill at the end of life. Full article