The present work aims to examine the influence of designing mini channel heat sinks using Stereolithography (SLA) 3D printing. Stereolithography (SLA) is a common additive manufacturing technique. The internal mini channels of the heat sink are made of aluminium materials and the outer cover is made of commercial polymer. Three models of the mini channel heat sinks are considered. A constant heat flow is applied to the bottom wall of the heat sink, and water is used as a coolant. The flow and heat transfer were studied for different cooling speeds. The physical properties of the fluid provided good thermal performance for the heat sink, especially at increased flow rates. The acrylonitrile butadiene styrene (ABS) copolymer resin has shown its good insulator for the heat sink and has improved the performance of the heat sink. This study demonstrates that the ABS copolymer resin enhances the cooling of electronic components.
The structure and thermophysical properties of polymer blends polyamide 6/high-density polyethylene with component ratios of 70:30, 45:55 and 30:70, which not only provide phase inversion of the blended polymers, but also the formation of an interpenetrating network, have been investigated by differential scanning calorimetry, scanning electron microscopy and light flash method. The data on the influence of blends composition on their mechanical properties, density, structure, temperature, as well as melting and crystallization heats of polymer components have been obtained. The regularities of changes in thermal diffusion, heat capacities and thermal conductivity coefficients of polyamide 6 and high-density polyethylene individually and as part of the blends in dependence on their composition and temperature have been established. A nonlinear increase of the thermal conductivity coefficient from temperature was revealed when melting a more easily melting component of the blend. It was found that the maximum increase in thermal conductivity occurs in the blend forming an interpenetrating network. A possible way of creating composites with adaptive thermal conductivity by melting one of the components of the blend is proposed.
In this work, Cobalt oxide nanoparticles (Co3O4·NPs) were synthesized via a simple sonochemical reaction by using polyethylene glycol (PEG) as a surfactant. Structural, morphological and spectroscopic analysis of obtained powder (Co3O4·NPs) was investigated by X-ray diffraction, FTIR spectroscopy and scanning electron microscope (SEM). The nanocrystalline nature of the sample was confirmed by XRD, which exhibits the cubic face-centered normal spinel structure of (Co3O4·NPs) and the space group of Fd-3m with the average crystallite size around 15 nm. FTIR spectrum shows two strong absorption bands of (Co+2–O) and (Co+3–O) which confirm the spinel structure of Co3O4·NPs. Moreover, SEM micrographs showed that the agglomeration of the nanoparticles was reduced by the addition of (PEG) surfactant and UV-Vis was used to study the synthesized material’s optical properties. The Co3O4 band gap ranged around 2.2 and 3.5 eV.
In response to the growing environmental threats and pollution linked to synthetic plastics, current scientific inquiry is prioritizing the advancement of biodegradable materials. In this context, this study investigates the possibility of developing fully biodegradable materials using plant fibers extracted from the Diss plant (Ampelodesmos mauritanicus) as reinforcement in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-based biocomposites. The biocomposites were prepared by melt blending in the following weight ratio: PHBV/Diss fibers 80/20. The chemical structure of Diss fibers was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray fluorescence spectrometry (XRF). The impact of Diss fibers on the mechanical properties of biocomposites has also been investigated in comparison to neat PHBV. FTIR and XRF analyses identified cellulose, hemicellulose, and lignin as the main components of Diss fibers. On the other hand, the results showed a significant enhancement of Young’s modulus (⁓21%) of PHBV/DF biocomposites in comparison to neat PHBV due to a better dispersion of the fibers in the matrix, as confirmed by atomic force microscopy (AFM) images.
Fire-Retardant Wastepaper Reinforced Waste Polyethylene Composite: A Review
The increase in fire
outbreaks recently and the need for eco-friendly and fire-resistant materials
have inspired a wave of studies, focusing on producing innovative composite
materials with effective fire-resistant properties. This review delves into the
world of fire-resistant wastepaper-reinforced waste polyethylene composites.
Using wastepaper as a strengthening factor in polyethylene matrices, combined
with fire-retardant additives like nanoparticles, introduces a hopeful path for
waste management and improved material properties. This work carefully
considers the combining approaches, physical and mechanical properties,
fire-resistant mechanisms, and environmental impacts of these composites. The
review underscores the possible and potential applications, difficulties, and
prospects of such environmentally friendly materials in various industries.
Understanding these composites’ blending, attributes, and conceivable
utilization is essential for advancing maintainable and fire-safe material innovation
in pursuing a greener future.
Phase change materials (PCMs) face challenges such as low thermal conductivity and leakage, often addressed through attempts at encapsulation or integration into polymer matrices or porous materials. This study uses expanded perlite to prepare a PCM composite. The perlite is treated with hydrochloric acid to remove impurities and improve its absorption, then impregnated with paraffin at 65 °C, with the addition of copper to enhance thermal conductivity. After drying, the material was coated with epoxy resin to prevent leakage and mixed with high-density polyethylene (HDPE) to improve its mechanical strength and facilitate integration with other materials. Characterization techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), evaluate the structure and properties of the composite. TGA results show that acid treatment increases paraffin absorption to 80% by weight, while weight loss tests confirm the effectiveness of the epoxy coating against leaks. A decrease in melting temperatures was observed in all HDPE blends, ranging from 4.72 °C to 9.58 °C, likely due to the integrated elements interfering with the reorganization of the molecular chains of HDPE. Although the preparation improved thermal conductivity, thermal tests revealed that increasing the (perlite/PCM) phase in HDPE is essential for further optimization, highlighting the potential of the composite as an effective energy storage solution for sustainable systems.
Biodegradable plastics are a potential sustainable alternative to conventional petrochemical-based non-degradable plastics. Due to their lightweight, flexibility, durability, versatile applications, chemical inertness, electrical and heat insulation, and conductivity, plastics have become an essential material for many industries, with annual production currently exceeding 450 million tons. However, these materials are non-biodegradable, leading to detrimental consequences such as the formation of microplastics from improper disposal and the generation of toxic gases, including furans, dioxins, mercury, and polychlorinated biphenyls, from burning plastic waste. This results in environmental pollution, affecting land, water bodies, and the atmosphere. In response, studies where the focus has been on creating bio-degradable polymers such as polylactic acid, polyhydroxy alkanoates, Polycaprolactone, Poly(butylene adipate-co-terephthalate), and Polybutylene succinate, which were extracted from renewable resources or chemically modified as biodegradable polymers. Biodegradable polymers exhibit a wide range of properties and can now be modified to be used in various applications suitable for substituting some conventional plastic products. Thus, the article highlights the critical issue of environmental pollution caused by non-biodegradable plastics and provides a comprehensive overview of the synthesis processes, properties, novel applications, and challenges associated with the use of biodegradable plastics.
Multi-objective optimization (MOO) techniques are crucial in addressing complex engineering problems with conflicting objectives, particularly in pharmaceutical applications. This study focuses on optimizing a biodegradable micro-polymeric carrier system for drug delivery, specifically maximizing the encapsulation efficiency and drug release of Candesartan Cilexetil antihypertensive drug. Achieving a balance between these two goals is essential, as higher encapsulation efficiency ensures adequate drug loading. In contrast, optimal drug release rates are critical for maintaining bioavailability and achieving therapeutic efficacy. Using response surface models to formulate the problem definition, five prominent MOO algorithms were employed: NSGA-III, MOEAD, RVEA, C-TAEA, and AGE-MOEA. The optimization process aimed to generate Pareto fronts representing compromise solutions between encapsulation efficiency and drug release. The results revealed inherent conflicts between objectives: increasing encapsulation efficiency often came at the cost of reducing the drug release rate. Evaluation of MOO algorithms using performance metrics such as hypervolume, generational distance, inverted generational distance, spacing, maximum spread, and spread metric provided insights into their strengths and weaknesses. Among the evaluated algorithms, NSGA-III emerged as the top performer, achieving a Weighted Sum Method (WSM) score of 82.0776, followed closely by MOEAD with a WSM score of 80.8869. RVEA, C-TAEA, and AGE-MOEA also demonstrated competitive formulation quality, albeit with slightly lower WSM scores. In conclusion, the study underscores the importance of MOO techniques in optimizing pharmaceutical formulations, providing valuable insights for decision-makers in selecting optimal formulations.
The analysis of rheological properties of suspensions requires the use of models such as Einstein’s formulation for viscosity in dilute conditions, but its effectiveness diminishes in the context of concentrated suspensions. This study investigates the rheology of suspensions containing solid particles in aqueous media thickened with starch nanoparticles (SNP). The goal is to model the viscosity of these mixtures across a range of shear rates and varying amounts of SNP and SG hollow spheres (SGHP). Artificial neural networks (ANN) combined with swarm intelligence algorithms were used for viscosity modeling, utilizing 1104 data points. Key features include SNP proportion, SGHP content, log-transformed shear rate (LogSR), and log-transformed viscosity (LogViscosity) as an output. Three swarm algorithms—AntLion Optimizer (ALO), Particle Swarm Optimizer (PSO), and Dragonfly Algorithm (DA)—were evaluated for optimizing ANN hyperparameters. The ALO algorithm proved most effective, demonstrating strong convergence, exploration, and exploitation. Comparative analysis of ANN models revealed the superior performance of ANN-ALO, with an R2 of 0.9861, mean absolute error (MAE) of 0.1013, root mean absolute error (RMSE) of 0.1356, and mean absolute percentage error (MAPE) of 3.198%. While all models showed high predictive accuracy, the ANN-PSO model had more limitations. These findings enhance understanding of starch suspension rheology, offering potential applications in materials science.
The rapid development of 3D printing, also known as additive manufacturing, has opened up new opportunities for applying shape memory polymers (SMPs) in various fields. The use of abundant, inexpensive, and easily accessible biomass materials as printing raw materials not only facilitates the creation of more intricate SMPs but also aligns with the principles of low-carbon, green, and sustainable development. Here, we successfully printed a shape memory cross-linked network (NW-MO-TTMP) in a single step by direct-ink-writing printing and an in-situ thiol-ene click reaction with magnolol and trimethylolpropane tris(3-mercaptopropionate) as raw materials. The resulting NW-MO-TTMP network exhibited high mechanical properties and a tensile strength (σ) of up to 2.7 MPa when the thiol-ene ratio was 1.0:1, and the photo-initiator content was 1.5%. To improve printability, ethyl cellulose (EC) derived from biomass was incorporated to enhance the viscosity of the printing precursor fluid, resulting in a significant increase in the σ of the NW-MO-TTMP/EC network, reaching 20.6 MPa. Moreover, the successful printing of intricate models, such as the ‘whale’ and ‘octopus,’ demonstrated excellent shape memory effects. This approach highlights the potential of combining biomass-derived materials with advanced 3D printing techniques to develop sustainable and high-performance SMPs.
