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In this study, two kinds of bioplastic materials, where the first consists of 10% PLA, corn starch of 80% and CaCO₃ 10%, and the second consists of 45% PLA content, corn starch of 45% and CaCO₃ 10%, were used. The composites were also reinforced by the carbon fibers, which were prepared with one and two layers of carbon fiber and then ply orientations of [0${}^{\circ }$] and [45${}^{\circ }$]. The maximum tensile strength was observed for PLA 45% with a [0${}^{\circ }$] ply orientation of two layers of carbon fiber. For composite with two layers of carbon fiber, the tensile strength showed higher for the [0${}^{\circ }$] ply orientation than for the [45${}^{\circ }$] ply orientation. The fatigue strength strongly depends on the orientation of carbon fiber, but in the long fatigue life range, the difference of fatigue strength between the fiber ply orientations reduces.

This study aims to determine the effectiveness of silver nanoparticles (Ag⁰-NPs) and silver oxide (Ag₂O) as antibacterial agents against E. coli bacteria in PLA/PBS-D matrix. In addition, 10% of diatomite (D) was added to be the absorbent for Ag⁰-NPs. Synthesis of composites PLA/PBS-10D-Ag⁰NPs-1% and PLA/PBS-10D-Ag₂O-1%-GPTS-3% was carried out where 3-glycidyloxypropyl-trimethoxysilane (GPTS) was used as the compatibilizer. The resulting composites were analyzed by IR, XRD, hardness, impact, tensile strength, and thermal properties. The antibacterial agent was obtained from Ag⁰-NPs, which impregnated into diatomite pores to form silver nanoparticle-diatomite (Ag⁰-NPsD). The XRD diffractograms showed peaks at 2$𝜃$ 16.64${}^{\circ }$, 33.01${}^{\circ }$, 38.1${}^{\circ }$, and 44.38${}^{\circ }$ for PLA-PBS, Ag₂O, and Ag⁰-NPs. Adding 10 phr of Ag⁰-NPsD, D and 3%-GPTS to the PLA-PBS system increased the hardness to 84.67 and 86.33, respectively. The impact strength of the composites increased significantly after the addition of 3% GPTS. The addition of Ag⁰-NPsD and 3%GPTS increased thermal properties of the composites. The antibacterial test results showed that the composite PLA/PBS-10D-Ag₂O-1%-GPTS-3% was not effective as an antibacterial agent. In contrast, PLA/PBS-10D-Ag⁰ NPs-1% showed the ability to inhibit the E. Coli bacterial growth up to 99%. In the PLA/PBS-D system, Ag⁰-NPs are more effective for inhibiting the E. Coli bacterial growth than Ag₂O.

One of the most widely used 3D printing techniques is fused deposition modeling (FDM) which builds things layer by layer by dispensing molten materials through a heated nozzle. To showcase the flexibility of 3D printing, test samples were made using polylactic acid (PLA). Trial runs with Taguchi’s (L27) orthogonal array were performed. Layer thickness, printing speed, and carbon deposition (C-deposition) were the three input parameters that were improved. This was accomplished by combining principal component analysis (PCA) with multi-objective optimization based on ratio analysis (MOORA) in an integrated approach to multi-criteria optimization. The main goal of this study is to maximize the input parameters for the Industry 4.0 technological production process of embossing components. The MOORA-PCA technique finds the best combinations of process variables; for example, printing at a speed of 75mm/s, layer thickness of 0.1mm, and carbon content of 15mg yield the required results. The results of this study will help production managers and researchers choose the best FDM 3D printing methods for improving mechanical qualities and surface roughness. The economic feasibility of the 3D printing businesses may be strengthened by these research findings, which will benefit customers looking for ecologically friendly items.

Single and coaxial electrospraying techniques are superior nanofabrication methods for nanomaterial production. These nanomaterials have the unique capability to manipulate various surfaces and bring diverse additional functionalities. The objectives of the present study are to produce poly(lactic acid) (PLA)/chitosan nanoparticles and investigate the synergy of nanosize effect with different morphology structures in terms of achieved functionality. The impact of ambient humidity on coating morphology was examined via a scanning electron microscope, field emission scanning electron microscope and dynamic light scattering for size measurements and dimensional characterization of nanoparticles. The obtained results indicate that electrosprayed PLA polymer shows a tendency to have a more distinct pore structure than electrosprayed chitosan polymer. Humidity has an increasing effect on particle size. Another finding is the relationship between hygroscopic characteristics of polymer with nanoparticle size, polydispersity, surface morphology and pore structure. Overall, these methods introduced high antibacterial activity obtainment on electrosprayed surfaces. Up to 99.99% antibacterial activity was accomplished against Escherichia coli ($E.coli$) and Staphylococcus aureus (S. aureus) bacteria in regard to this study. The created surface layers also have the extensive potential of practicability for diversified kinds of surfaces and numerous combinations of polymers for multifunctional applications.

3D-printed polylactic acid (PLA+) is one of the newest biodegradable materials seeking entrance into the industrial field. The effect of 3D printing process parameters (infill pattern (IP), infill density (ID), layer height (LH), line width (LW), shell thickness (ST), printing temperature (PT), printing speed (PS), and raster angle) on mechanical properties has been studied. In addition, this paper aims to investigate the effect of changing both the IP and raster angle on the mechanical properties of 3D-printed PLA+. The results revealed that the highest value of tensile strength can be obtained at an ID of 100%, concentric IP, LH of 0.1mm, LW of 0.8mm, ST of 0.8mm, PT of 215^∘C, and PS of 60mm/s.