Explore the vast range of titles available.

This work presents the synthesis, structural investigation, and some properties of a new PLA-Siloxane-PEO hybrid featuring covalent bonds between polymers and siloxane nodes. The synthesis simultaneously connecting PLA and PEO chains directly to the inorganic phase is first achieved through the use of sol–gel process. The structural features, thermal properties and chemical stability of this biocompatible system have been studied by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, 29 Si Nuclear Magnetic Resonance (NMR), scanning electron microscopy (MEV), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). SEM and SAXS measurements showed that the siloxane nodes act as crosslinks between the polymer chains promoting high miscibility between PLA and PEO. FTIR, Raman XRD, DSC, and TGA showed that the presence of the siloxane nodes diminishes the crystallinity of both polymers and increases their thermal resistance. In addition to the absence of brittleness due to the low crystalline character of PLA, this new material exhibits a fantastic resistance to PLA degradation in aqueous medium, attributed both to the presence of the siloxane particles acting as a barrier towards water diffusion and to the hydrophilic PEO segments which may attract water molecules, preventing PLA hydrolysis. All of these characteristics offer an amazing perspective for the use of this hybrid material in biological, medical, and pharmaceutical applications. Structural model of the new PLA-Siloxane-PEO composite in which PEO chains, PLA chains, and siloxane particles are interpenetrated at nanoscopic scale. Such structure induces simultaneously high thermal stability, high resistance to degradation, and absence of brittleness. Highlights Siloxane nodes bonded to polymer chains promotes PLA–PEO miscibility. Presence of siloxane nodes promote PLA–PEO miscibility enhances PLA thermal stability and inhibits PLA crystallization and degradation. Low PLA crystallinity induces absence of brittleness. Presence of siloxane nodes and PEO inhibits PLA degradation. Biocompatible material exhibiting high chemical stability in aqueous medium.

Over the past few decades, with the development of science and technology, the field of biomedicine has rapidly developed, especially with respect to biomedical materials. Low toxicity and good biocompatibility have always been key targets in the development and application of biomedical materials. As a degradable and environmentally friendly polymer, polylactic acid, also known as polylactide, is favored by researchers and has been used as a commercial material in various studies. Lactic acid, as a synthetic raw material of polylactic acid, can only be obtained by sugar fermentation. Good biocompatibility and biodegradability have led it to be approved by the U.S. Food and Drug Administration (FDA) as a biomedical material. Polylactic acid has good physical properties, and its modification can optimize its properties to a certain extent. Polylactic acid blocks and blends play significant roles in drug delivery, implants, and tissue engineering to great effect. This article describes the synthesis of polylactic acid (PLA) and its raw materials, physical properties, degradation, modification, and applications in the field of biomedicine. It aims to contribute to the important knowledge and development of PLA in biomedical applications.

A Scotch pine wood annual ring (AR) structure was modeled using AutoCAD and SolidWorks software. The same AR was separately modeled to create earlywood (EW), transition wood (TW), and latewood (LW). All 3D models were additively manufactured using Hyper PLA material and Creality 3D printer. Compression tests were performed to obtain load-deformation curves. The maximum force, compression strength (CS), and deformation at 500N load were determined. The EW presented the highest deformation while LW presented the highest CS. The TW and AR displayed intermediate behaviors. Finite Element Modeling and Analysis (FEM&A) was performed to compare with the experimental results. The numerical results presented considerable high deviations from the experiment. Around 78.7%, 41.7%, 89.3%, and 52% differences were observed for AR, EW, TW, and LW, respectively. Therefore, the capability of the model for prediction of mechanical behavior was not found to be successful. The essential reason for these discrepancies is the contrast between the orthotropic nature of wood and partially anisotropic nature of 3D printed models even if the filament is isotropic material. However, it should be taken into consideration that such high differences are not abnormal for the wood material even if the tested samples belong to the same log because of the variations in the material due to sampling details such as cutting location, orientation, etc. Furthermore, when considering the 3D printing parameters such as infill density, printing orientation, layer height, etc., the FEM&A results can be considered partially successful, although the differences were high.

Fused deposition modeling (FDM) is an additive manufacturing (AM) technology capable of producing functional parts with complex geometries. However, optimizing both dimensional and mechanical quality characteristics is challenging due to the influence of multiple process parameters. This study aims to determine how key FDM parameters affect the multivariate dimensional and mechanical quality characteristics and to establish an integrated framework for optimizing these responses simultaneously. An experimental design based on response surface methodology (RSM) was implemented to optimize four process parameters: layer thickness, extruder temperature, plate temperature, and printing speed. Cylindrical PLA samples adhering to compression standards were fabricated, and both dimensional characteristics (length and diameter) and mechanical characteristics (compressive strength and modulus) were evaluated. Multivariate process capability indices (MPCIs) were then estimated to assess overall process capability. The results revealed that layer thickness and extruder temperature are the most influential parameters affecting MPCIs. The optimal dimensional MPCI was achieved with a low layer thickness, high extruder temperature, low plate temperature, and low printing speed. Also, the proposed model explained 88% of the total variability in mechanical MPCI. This research introduces an integrated RSM–multivariate process capability analysis approach for the simultaneous optimization of multiple correlated quality characteristics in FDM, which improves both dimensional precision and mechanical performance in AM processes.

This article is focused on a mechanical properties investigation of three types of sustainable poly lactic acid materials manufactured using the fused filament fabrication process. The purpose of this work was to study the impact of printing strategies on the mechanical properties and predict mechanical behavior under tensile loading using finite element analysis. The testing of mechanical properties was conducted according to the ISO 527 standard. The numerical simulations were conducted in Simufact Forming 2022 software. Analysis of the experimental data showed a dependance of mechanical properties on the used printing strategy. The Clear PLA samples printed in the XY plane exhibited a 43% reduction in tensile strength and a 49% reduction in elongation compared to samples printed from the same material in YZ plane. The experimental results show the influence of the printing orientation on the mechanical properties of 3D-printed samples.

The use of three-dimensional (3D) printing technologies is an ever-growing solution. The product realized in many cases is applicable not only for visual aid, or model, but for tool, or operating element, or as an implant for medical use. For correct calculation, a proper model that is based on the theory of elasticity is necessary. The basis of this kind of model is the knowledge of the exact material properties. The PLA filament has been used to perform this study for matrix material. Our presumption is that the different layers do not fuse completely, and they do not fill up the space available. The failures between the layers and the deposited filaments and the layer arrangement could be the reason for the direction-dependent material properties of the 3D printed objects. Based on our investigation, we can conclude that the increase of the layer thickness and printing speed adversely affect the mechanical properties of the product.

In recent times, the growing popularity of joint-free mechanical systems and structures is attributed to advancements in 3D printing technology. Unlike traditional mechanically joined systems, 3D-printed products require fewer fasteners. However, the widespread adoption of additive manufacturing in the mechanical industries is hindered by limitations in handling various engineering materials. Currently, only a restricted range of ductile and plastic materials is utilized in additive manufacturing processes. This study aims to replace adhesive bonding and bolt joints with an innovative approach involving equivalent geometrical layers. The strength of these joints is intended to be achieved through careful consideration of layer thickness and geometry. The research investigates the strength of conventional lap joints, such as adhesive-bonded or bolted joints, across different materials. Finite element models of these ASTM specimens will be developed in ANSYS for static analysis and comparison. The ultimate goal is to establish an equivalent design procedure that replaces traditional joints with layers of materials through the additive manufacturing process. To validate this approach, a quadcopter structure was designed using 3D printing technology, fabricated with ABS and PLA materials, assembled, and flight-tested to achieve a thrust-to-weight ratio of nearly two. The successful validation of the design demonstrates that 3D-printed additive manufacturing is a valuable technology for constructing lightweight and high-performance UAV structures. Notably, the quadcopter frame was produced as a single component, streamlining the assembly process compared to traditional assemblies consisting of eight to ten parts.

Poly(lactic acid) (PLA) is characterized by unique features, e.g., it is environmentally friendly, biocompatible, has good thermomechanical properties, and is readily available and biodegradable. Due to the increasing pollution of the environment, PLA is a promising alternative that can potentially replace petroleum-derived polymers. Different biodegradable polymers have numerous biomedical applications and are used as packaging materials. Because the pure form of PLA is delicate, brittle, and is characterized by a slow degradation rate and a low thermal resistance and crystallization rate, these disadvantages limit the range of applications of this polymer. However, the properties of PLA can be improved by chemical or physical modification, e.g., with biomolecules. The subject of this review is the modification of PLA properties with three classes of biomolecules: polysaccharides, proteins, and nucleic acids. A quite extensive description of the most promising strategies leading to improvement of the bioactivity of PLA, through modification with these biomolecules, is presented in this review. Thus, this article deals mainly with a presentation of the major developments and research results concerning PLA-based materials modified with different biomolecules (described in the world literature during the last decades), with a focus on such methods as blending, copolymerization, or composites fabrication. The biomedical and unique biological applications of PLA-based materials, especially modified with polysaccharides and proteins, are reviewed, taking into account the growing interest and great practical potential of these new biodegradable biomaterials.

In recent years, additive production technology has spread to almost all manufacturing areas. In most cases, a fiber is used as an input material in the 3D printing process, the required properties of which are mainly its strength and durability. With the ongoing development of the 3D printing techniques, the need to develop fibers that do not pose a burden to the environment comes to the fore. This paper points out the possibilities of producing fibers intended for additive production. The paper describes the fiber production on FilaFab PRO EX350 device used for producing fibers for the 3D printing technology. The aim of the paper is to describe the production of fibers and to compare commonly available fibers with the experimentally made ones. To run the tests, a clear fiber and a composite fiber with carbon powder filler were produced. The mechanical properties achieved by these experimentally produced fibers were compared in tensile tests with commonly available fibers purchased from sellers of 3D printing materials.

Oily wastewater is an urgent issue that threatens the ecosystem and human health. Superhydrophobic porous materials are widely concerned as promising candidates for effective oil/water separation and oil adsorption. However, superhydrophobic porous materials are still confronted with frustrations such as complex preparation processes and secondary pollution to the environment. Superhydrophobic porous materials with biodegradability and a relatively simple preparation process are more attractive to practical application and environmental protection. In this work, biodegradable and industrially applied polylactic acid (PLA) nonwoven materials were used as porous membranes, then PLA nanoparticles were loaded on the membrane surface to construct the hierarchical rough structure. The modified PLA nonwoven membrane (nano-PLA) shows superhydrophobicity and efficient oil/water separation performance. Moreover, strong mechanical strength and acceptable toughness are obtained. This work offers an easily controlled and industrially used pathway for the design of robust, highly selective, and biodegradable oil/water separation materials.