This paper investigates the possibility of integrating the combination of nanofillers, titanium dioxide (TiO₂) and carbon nanotubes (CNT) into the thermoplastic polymer matrix. This combination of fillers can possibly modify the physico-chemical properties of composites compared to the pure polymer matrix. The composites were blended using the extrusion method. The composite filament produced was used to manufacture static mixers on a 3D printer using the additive manufacturing technology fused filament fabrication (FFF). The aim of this work was to inspect the influence of the filler addition on the thermal and mechanical properties of glycol-modified polyethylene terephthalate (PET-G) polymer composites. The fillers were added to the PET-G polymer matrix in several ratios. Tensile test results showed an increase in the overall strength and decrease in the elongation at break of the material. Melt flow rate (MFR) showed a decrease in the viscosity with the initial filler addition and reaching a plateau after 2 wt% filler was added. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed minor changes in the thermal properties. Scanning electron microscope (SEM) results showed homogenous distribution of the filler in the matrix and strong filler–matrix adhesion. The results indicate suitable properties of new functional composites for the 3D printing of static mixers for application in tubular reactors.

The article discusses the importance of optimizing process parameters in 3D printing to achieve better mechanical properties of printed parts. It emphasizes the material extrusion 3D printing technology and some of the most commonly used materials, acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate glycol (PETG). Optimizable process parameters such as, print angle, outer layer number, extruder flow ratio, extrusion (nozzle) temperature, and layer thickness are examined. The article also highlights the importance of postprocessing techniques, specifically thermal postprocessing (annealing) and chemical postprocessing in the acetone (AC) chamber, to enhance mechanical properties of printed parts. The results show that the wall structures played a crucial role in defining mechanical properties, acting as main load-bearing elements. Adjusted flow ratios influenced mechanical properties. Samples with a 25% extruder flow rate increase demonstrated a 44% rise in elongation at break, while a 50% increase led to slight strength reduction. The ABS material AC-treated sample exhibited 58.2% lower tensile strength and 1.9% lower elongation due to stress concentration, while thermally treated showed similar results to the default, printed at manufacturer-recommended settings. The PETG material AC-treated sample exhibited 53.2% lower tensile strength, but 17.5% higher elongation, while thermally treated showed similar results to the default. Samples printed at 0° orientation exhibited plastic deformation with the highest tensile strength and elongation, while samples at 45° and 90° orientations experienced delamination, leading to brittle fracture, proving that the orientation and interlayer adhesion have a great influence on mechanical properties. While the print settings and orientation had similar effects on mechanical properties of each material, postprocessing effects are greatly influenced by the polymer matrix.

The addition of static mixers within reactors leads to higher productivity of a process and an additional increase in mass and energy transfer. In this study, we developed millireactors with static mixers using stereolithography, an additive manufacturing technology. Computational fluid dynamics (CFD) simulations were conducted to study the flow, identify potential dead volumes, and optimize the design of the millireactors. We produced five millireactors with various static mixers and one tubular reactor without static mixers, which served as a reference. The Fenton reaction was performed as a model reaction to evaluate the performance of the millireactors. We observed that some of the reactors with static mixers had air plugs that created a significant dead volume but still exhibited higher conversions compared to the reference reactor. Our results demonstrate the potential of stereolithography for producing intricate millireactors with static mixers, which can enhance the productivity of chemical processes.

The aim of this research was to prepare pH sensor films based on litmus using the sol–gel method with tetraethoxysilane (TEOS) and phenyltrimethoxysilane (PTMS) as precursors. The pH sensor film was then applied to millireactors to evaluate its performance on the intricate geometries of static mixers commonly found in millireactor designs. Millireactors were made from Formlabs High Temp resin using stereolithography (SLA) and from Anycubic Basic resin using digital light processing (DLP) technology. The performance of the pH sensor films was evaluated by tracking color changes in the pH sensor films and analyzing RGB (red, green, blue) and hue values through a smartphone application. The experiment involved mixing solutions with different pH values at varying flow rates within the millireactor channels. Furthermore, along with analyzing the hue values, characterization techniques involved measuring contact angles with water and diiodomethane. A film combining a litmus indicator with titanium dioxide (TiO₂) displayed a color change within one minute and maintained this color throughout the study, confirming its reusability. Sensor films exhibited excellent reversibility (RSD = 2.4–3.3%) and stability. The findings demonstrate that the pH-sensitive films perform robustly across varying geometries, paving the way for their integration into advanced millireactor systems with static mixers and continuous chemical monitoring within Industry 4.0.

This study investigates the fabrication of 3D-printed microfluidic devices for solid/liquid separation, focusing on additive manufacturing technologies. Stereolithography (SLA) and fused filament fabrication (FFF) were used to create microseparators with intricate designs optimized for separation efficiency. Model suspensions containing quartz sand, nano-calcium carbonate, and talc-based baby powder in water were prepared using an electric magnetic stirrer and conveyed into the microseparator via a peristaltic pump. Different flow rates were tested to evaluate their influence on the separation efficiency. The highest separation efficiency for the model systems was observed at a flow rate of 200 mL min⁻¹. This was due to the increased turbulence at higher flow rates, which hindered the secondary flow perpendicular to the primary flow direction. The particle size distribution before and after separation was analyzed using sieve and laser diffraction, and particle morphology was inspected by scanning electron microscopy. The laser diffraction analysis revealed post-separation particle size distributions, indicating that Outlet 1 (external stream) consistently captured larger particles more effectively than Outlet 2 (internal stream). This work highlights the potential of additive manufacturing to produce customized microfluidic devices, enabling rapid prototyping and fine-tuning of complex geometries, thus enhancing separation efficiency across various industrial applications.