Applied Science and Engineering Progress

Eco-friendly Biocomposites: A Step Towards Achieving Sustainable Development Goals

Sathish Kumar Palaniappan — 2024-10-17

Modern Applications of Polymer Composites in Structural Industries: A Review of Philosophies, Product Development, and Graphical Applications

Isiaka Oluwole Oladele — 2024-10-17

Polymer-based materials have been discovered as the most outstanding class of material that is fast displacing other materials in all areas of human needs. The dire need for durable, aesthetic, and lightweight materials has favored the increasing demand for polymer-based materials in structural industries. The application of polymeric-based materials in all aspects of human endeavor is based on their ease of formation, lightweight, and acceptable properties. The philosophy of composite development has also contributed immensely to the production of components from polymer-based materials suitable for several structural applications. More recently, interest in green materials also encourages the use of polymer-based materials in structural applications. The suitability of a material for any selected application is justified by structural and environmental compatibility. Thus, researchers have focused on these two major areas in their investigations for product development. Despite continuous efforts in these two directions, they are still issues of great concern to researchers in satisfying the desires of users presently. Hence, this review presents the philosophies of researchers, the product developed, and areas of application for polymer-based materials in structural industries such as biomedical, building and construction, energy, and sports. The paper advanced graphical presentation of the application of developed products and strongly supports the recommendation of polymer-based composite materials as a viable alternative to other materials due to their remarkable capabilities in many application domains.

A Study on the Influence of Functionalized Graphene on the Mechanical and Biocompatibility Performance of Electrospun Polyvinyl Alcohol Nanocomposites

Mogana Priya Chinnasamy — 2024-10-17

Polyvinyl alcohol (PVA), a synthetic polymer produced by polymerizing vinyl acetate and subjecting it to alkaline hydrolysis, exhibits properties such as film formation, emulsification, and adhesion. However, pure PVA’s biocompatibility and mechanical properties are limited. Its hydrophilicity also causes it to dissolve in water and blood, rendering it less suitable for drug delivery applications. To address these limitations, PVA was crosslinked with glutaraldehyde (GA) to enhance toughness and resistance to water and blood dissolution. Additionally, carboxyl (COOH) and hydroxyl (OH) functionalized graphene were incorporated into electrospun PVA nanocomposites to further improve their mechanical properties. The results show that adding COOH- and OH-functionalized graphene in four different concentrations (0.5, 1.0, 1.5, and 2.0 wt.%) significantly enhanced the mechanical characteristics of PVA nanocomposites. Tensile strength and Young's modulus increased substantially, with OH-functionalized graphene increasing tensile strength and Young's modulus by 224% and 338.3%, respectively, and COOH-functionalized graphene increasing these properties by 245.6% and 371.4%. Morphological characterization using FT-IR and FESEM confirmed the successful incorporation of graphene into the PVA matrix. Biocompatibility testing through APTT and PT assays showed both nanocomposites are biocompatible, suggesting their potential for biomedical applications. The optimal filler concentration for both graphene types was 1.5 wt.%. This research demonstrates the promising potential of innovative materials for healthcare and biomedical engineering applications.

Acoustic, Mechanical and Thermal Properties of Luffa/Jute Fiber-Reinforced Bio-Composites

Johnson Annie Suba — 2024-10-17

Due to the growing environmental awareness, more attention has been drawn to finding alternative fiber sources to curb deforestation and reduce the usage of synthetic fiber. In the current work, an attempt was made to hybrid bio-composites using the blended fibers of Luffa and Jute in different ratios. Eight different needle-punched nonwoven fabric samples were prepared with the variation of fiber blend ratios. Both the fibers were pre-treated with a 3% alkali concentration to enhance the bonding property with the resin. After this process, the polymer composites were produced using epoxy resin through the compression molding technique. The investigations, such as physical, mechanical, water absorption, dynamic mechanical (DMA), and acoustic properties of the composite material were analyzed systematically. The mechanical and DMA properties were appreciable for composites with higher jute content, whereas acoustic properties were higher for composites with higher Luffa content. Based on the findings, the hybrid composites showed effective functional performance in load-bearing and acoustic applications.

Analysis and Optimization of Delamination Factor for Microwaved Cured Pineapple Leaf Fiber Polymer Composite through ANOVA Analysis

Manabendra Saha — 2024-10-17

Natural fiber-reinforced composites are quickly replacing other materials as the material of choice for various engineering applications because of their high specific strength, low weight, and affordability. Additionally, natural composites come in various forms and are environmentally benign. In particular, the composite needs to be drilled to put the pieces together. The entry and exit levels of the holes are prone to damage during the drilling process. In the present work, Low-density polyethylene (LDPE) was combined with pineapple leaf fiber (PALF) mat after first undergoing a chemical treatment in this investigation. Microwave curing was applied for fabricating the natural fiber composite with the three specified process parameters i.e., microwave power, % of NaOH solution, and weight percentage of treated fiber. After fabrication, the composite delamination factor and modified delamination factor were determined for evaluating the crack propagation after the drilling operation. At constant speed, the feed and diameter of the drill were used for making the drill in different samples. A CNC drilling machine was used to drill the constructed structure at various input parameters. Using the Taguchi approach, the entire work was analyzed. A tensile test was conducted to estimate the strength of the samples with specific parameters. The tensile strength increases up to 24.34 MPa. ANOVA analysis was used to find the best combination and affecting factors. It was observed that the weight percentage of the treated fiber mat has a maximum contribution percentage of 61 % for the processing of natural fiber polymer composite.

Development and Characterization of Hybrid Particulate-fiber Reinforced Epoxy Composites

Akeem Damilola Akinwekomi — 2024-10-17

Although considered wastes, animal fibers and gastropod shell particles are biodegradable, have low density, high stiffness, considerably high impact absorption capacity and relatively low cost. Therefore, they are finding increasing use as reinforcement materials in polymer composites. This research work studied the tensile, hardness, and wear resistance properties of hybrid snail shell (SSP) and chicken feather barb fibers (CFB) reinforced epoxy composites. The stir cast molding technique was utilized to synthesize the composite samples with 3, 6, 9, 12, 15, and 18 wt.% of the hybrid SSPs/CFB. Compared with the control samples, SSP/CFB hybrid reinforcements enhanced the mechanical properties of the composites. Composites with intermediate weight fraction of 9 wt.% SSP/CFB exhibited overall optimum properties when benchmarked against the control sample with approximately 37, 37, 133, 19, and 59% improvement in wear, hardness, impact, and ultimate tensile strength properties respectively. These enhancements suggested a synergistic effect of the two reinforcement phases. The results presented in this study demonstrated the potential of utilizing bio-derived waste materials for synthesizing eco-friendly composites.

Dewaxing and Post-Pretreatment Washing: Impact on Sugar and Ethanol Yields from Tobacco Residue

Muhammad Ayub Khan Muhammad Ayub Khan — 2024-10-17

Waste generated from tobacco cultivation has negatively impacted the environment due to its inappropriate disposal methods. This negative impact can be mitigated by valorizing tobacco residue. In this study, tobacco residue was pretreated and the effect of dewaxing and washing on sugar and ethanol yields was studied. Tobacco residue was pretreated with alkali (2.17 M NaOH, 94 °C, 4.5 h) or acid (2.95 wt% H2SO4, 133 °C, 0.92 h). The effect of dewaxing was studied by incorporating the dewaxing step prior to pretreatment. Similarly, the effect of washing was analyzed by omitting post-pretreatment washing. Compositional analysis revealed that dewaxing prior to alkaline pretreatment improved cellulose content by 80% compared to the standard pretreated sample. Enzymatic hydrolysis of the samples showed that pretreatment had improved sugar yield by up to 6.1 times. Moreover, the sugar yield further improved when dewaxing and post-pretreatment washing steps were incorporated into the process. The unwashed biomass showed a 3-fold decrease in sugar compared to untreated biomass. Furthermore, fermentation studies showed that the dewaxed alkaline pretreated tobacco residue enhanced ethanol yield by 34% compared to standard pretreated biomass. Thus, this study reveals the potential of tobacco residue valorization and emphasizes the importance of dewaxing and post-pretreatment washing in a biorefinery.

Drop-weight Impact Responses of Kenaf Fibre-Reinforced Composite-Metal Laminates: Effect of Chemical Treatment and Fibre Composition

Lin Feng Ng — 2024-10-17

Recently, fiber-metal laminates have gained high attention from material scientists and engineers, particularly when it comes to impact-critical applications. When compared to metallic alloys and composite materials, fiber-metal laminates offer several distinguishing advantages. This work intends to evaluate the low-velocity response of kenaf fiber-reinforced polypropylene metal-composite laminates with various fiber compositions, in line with the current trend of using natural fiber as possible reinforcement in composite materials. In addition, a comparison was made between the low-velocity impact response of non-treated and chemical-treated kenaf fiber-reinforced composite-metal laminates. A hot molding compression technique was employed to fabricate the laminates. Low-velocity impact tests were performed based on ASTM D7136 to determine the peak force, maximum displacement, and energy absorption of the materials. The results confirmed that NaOH treatment and increased fiber content resulted in a higher peak force of NaOH-treated kenaf-based metal laminates. For NaOH-treated laminates, the peak force of laminates with 70 wt% was found to be 11.20% higher than laminates with 50 wt% at the impact energy of 60 J. At fiber content of 70 wt%, the peak force of NaOH-treated laminates is 2.14% greater than that of untreated laminates when subjected to low-velocity impact with an energy level of 60 J. However, laminates with low fiber content and without NaOH treatment manifested higher maximum displacement and energy absorption due to the ductile behavior of such materials.

Investigation of Mechanical Properties of 3D Printed Biodegradable Polylactic Acid Reinforced with Paper Microcrystalline Cellulose

Tom Anto — 2024-10-17

Fused Deposition Modeling (FDM) is an additive manufacturing technique that constructs objects layer by layer by depositing thermoplastic material through a nozzle. This method allows for the creation of intricate, custom designs that are often difficult to achieve with traditional manufacturing processes. To enhance the mechanical properties of composite materials, cellulose is used as a filler, which has shown significant potential in improving the physical and mechanical characteristics of polymer composites. In this study, waste paper is used to extract cellulose, resulting in microcrystalline cellulose (MCC), which is then used to reinforce the PLA matrix. Composite filaments containing different proportions of MCC (1%, 2%, and 3% by weight) are produced using a twin-screw extruder for subsequent 3D printing. The study examines the impact of MCC content on the structural, morphological, and thermal properties of the filaments and 3D-printed objects. Characterization methods include scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and tensile tests. The results show that the addition of MCC does not cause chemical changes. For the 3D-printed samples, the tensile strength of neat PLA is significantly improved with the addition of 1% MCC and continues to increase with higher MCC concentrations.

Effects of Modified Silicon Carbide on The Physical Properties of Bioplastic Blends

Natkrita Prasoetsopha — 2024-10-17

The study’s goal is to improve the physical properties of biodegradable plastics by mixing poly(lactic acid) (PLA), polybutylene succinate (PBS), and silicon carbide (SiC) to make composites that could be used as filaments for 3D printing. Polymer blends and composites were fabricated using an internal mixer. The fraction of SiC was varied from 10 to 40 phr and filled in PLA/PBS blends with a retained ratio of 80/20 wt.%. Then, the mechanical properties, thermal properties, melt flow rate and morphology of PLA/PBS/SiC composites were investigated. Field emission scanning electron microscope images present a uniform dispersion of silane-treated SiC particles throughout the PLA/PBS matrix. The morphology showed better adhesion between PLA/PBS and treated SiC particles. Therefore, this was also the reason for the improvement of Young’s modulus and impact strength when the SiC fraction was increased, which were improved by 33% and 104%, respectively, compared to neat PLA. Furthermore, the melt flow rate increased with an increasing SiC fraction. This might be because adding SiC reduces the viscosity of the composites, which affects the molecular chain movement of the PLA/PBS and the crystallinity of PLA, therefore decreasing the ΔH_m of PLA and X_c,PLA. However, T_g and T_m of PLA and PBS remained relatively stable with an increasing fraction of SiC particles.

Efficient Separation of Organic Dyes using Polyvinylidene Fluoride/Polyethylene Glycol-Tin Oxide (PVDF/PEG-SnO2) Nanoparticles Ultrafiltration Membrane

Abdullah Ghanim Saleem — 2024-10-17

This work studies developing ultrafiltration (UF) membranes using organic and inorganic additives to remove organic dyes at UF conditions with high effectiveness. Flat sheet (18 wt%) polyvinylidene fluoride (PVDF) membranes were prepared via phase inversion and then developed by adding 6 wt% polyethylene glycol (PEG) as a pore former. Furthermore, the PVDF/PEG membranes were developed by embedding tin oxide nanoparticles (SnO₂ NPs) with different contents of 0.3, 0.6, and 0.9 wt%. The prepared membranes were examined for their performance in the dye removal before being characterized using the field emission scanning electron microscope, atomic force microscopy, contact angle, Fourier-transform infrared spectroscopy, surface charge, porosity, mean pore size, tensile strength, and elongation at break. The performance was tested regarding pure water flux (PWF), permeate flux, and dye removal (R%). The effect of dye concentration and pH of the feed solution on the permeate flux and R% was also investigated. In addition, the antifouling features in terms of flux recovery ratio, reversible fouling, irreversible fouling, total fouling, and the R% were studied using the PVDF/PEG membrane and the membrane containing 0.3 wt% of SnO₂ NPs. The contact angle decreased from 78.85° to 51.88°, and the PWF rose from 7.16 to 135.71 L/m².h for PVDF and PVDF/PEG-SnO₂ (0.3 wt%) membranes, respectively. The R% of rhodamine B (RhB) slightly decreased from 93.08 to 91.26, and 87.71% for PVDF, PVDF/PEG, and PVDF/PEG-SnO₂ (0.3 wt%) membranes, respectively. Then, it increased with increasing NPs concentration up to 90.17 and 92.23% for PVDF/PEG-SnO₂ (0.6 wt%) and PVDF/PEG-SnO₂ (0.9 wt%) membranes, respectively. Also, the molecular weight cutoff was calculated using RhB as a cationic dye, acid orange 10, and congo red as an anionic dye and it was 520 Da.

Effects of Geographical Conditions on the Physiochemical Properties of Natural Fiber Extracted from the Root of Prosopis juliflora

Kumarappan Palaniappan — 2024-10-17

Biomass-derived Natural Fiber Composites (BDNFCs) are becoming popular in versatile applications in aerospace, biomedical, energy storage automotive, etc. due to their biodegradability, environmental friendliness, and cost-effectiveness. In the current work, root fibers extracted from Prosopis juliflora were selected as the natural fiber. Characterization results for physical and chemical properties on the effects of soil types and moistures in 2 different states of India, i.e. Telangana, and Tamil Nadu on fiber compositions and properties. The results reveals that hemicellulose content of tamilnadu fiber (81 wt%) is less than that of the Telangana fiber (85.7 wt%). Based on analysis results of Fourier Transform Infrared Spectroscopy (FTIR) andThermo Gravimetric Analysis (TGA), Tamil Nadu fiber has the themal stability at 239 °C and maximum degradation temperature at 359.1 °C. Whereas Telangana fiber has thermal stability at 253 °C, and maximum degradation temprature at 387.5 °C. The crystallinity indexes of Tamil Nadu and Telangana fibers were calculated, based on analysis of X-Ray Diffraction (XRD), to be 69.6% and 67.4%, respectively. The crystal sizes of Tamil Nadu and Telangana fibers were 14.38 and 13.21 nm, respectively.

Enhancing Mechanical Properties of PLA Filaments through Orange Peel Powder Reinforcement: Optimization of 3D Printing Parameters

Muthu Natarajan Shunmugam — 2024-10-17

This study investigates the augmentation of the mechanical properties of Polylactic Acid (PLA) filaments by incorporating Orange Peel Powder (OPP) as an eco-friendly filler for 3D printing applications. The study delves into optimizing the printing parameters to achieve enhanced mechanical characteristics while maintaining printability. Various 3D printing process parameters were analyzed systematically to assess their impact on tensile strength, flexural strength, and impact resistance. A thorough investigation was conducted to determine the impact of layer height, infill density, and printing speed on the overall mechanical properties of the printed specimens. The findings demonstrate that adding 25% OPP significantly enhances the mechanical strength of the PLA composite without compromising printability, with optimal concentration and printing parameters identified. Thermo gravimetric study reveals that the PLA/OPP composite filament has a higher maximum thermal degradation temperature of 329 °C, compared to the PLA’s temperature of 316 °C. This research contributes to advancing the development of sustainable and mechanically robust materials for additive manufacturing, offering insights into the fabrication of PLA-based biodegradable composites tailored for specific applications in various industries.

Fused Deposition Modelling Approach in Recycled Polypropylene/Aluminum Powder Composites for Sustainable Development

Manveer Rana — 2024-10-17

Polypropylene (PP) is a versatile and widely used thermoplastic polymer that has found its way into various aspects from packaging materials and consumer products to automotive components and industrial applications. However, this widespread use of polypropylene also presents a significant challenge in the disposal of polypropylene waste and its durability aspects. So, the fused deposition modeling (FDM) technique arises as compiling outcomes for recycling discarded PP waste to create functional products. The properties of FDM components produced from recycled polypropylene (r-PP) are notably inferior to those of virgin PP FDM counterparts. Hence, it becomes imperative to comprehend the substantial alterations that r-PP undergoes during successive extrusion processes, including chain scission, alterations in viscosity, and reductions in breaking strength. The incorporation of additives has emerged as a promising solution to enhance the performance of r-PP. In this context, the present study explores the development of a novel composite material by blending r-PP with aluminum powder. The combination of these materials leverages the sustainability benefits of r-PP and the excellent thermal and mechanical properties of aluminum, making it a promising candidate for a wide range of applications. The tensile results show a significant increase in Young’s modulus for pre-heat treated composite specimen at 214 ℃ extrusion temperature. The SEM fractrographic analysis confirms the homogenized distribution after pre-heat treatments. XRD results analyzed the degree of crystallinity in the composite specimens.

Effect of Borax-Boric Acid Treatment on Fire Resistance, Thermal Stability, Acoustic, and Mechanical Properties of Mycelium Bio Composites

Tom Anto — 2024-10-17

Mycelium biocomposite materials have been established as a sustainable alternative to polystyrene in single use applications like packaging. However only little investigations are done on improving their resistance to fire and heat, which can find use in newer applications. This paper focuses on the development and characterization of a mycelium-based sawdust-coir pith biocomposite material treated with a combination of fire-retardant compounds (borax and boric acid). The outcomes of fire resistance tests, such as flammability, flame penetration and rate of burning demonstrated a significant improvement in values with respect to untreated samples. However, samples having 30% boron compounds by weight in it exhibited the best fire resistance properties. The thermal analysis of treated samples indicated that the presence of fire-retardant chemicals has not significantly affected their thermal stability. The glass transition temperature (T_g) of treated mycelium composite material was found to be 212.75 °C against a value of 207.78 °C for untreated samples. The fire retardant treated mycelium composite samples having 30% boron by weight in it, exhibited an average sound absorption coefficient of 0.38 compared with a sound absorption coefficient of 0.29 for polyurethane foam. The prepared mycelium biocomposite has a self-extinguishing nature and exceptional fire resistance capabilities with an LOI value of 50%. The mechanical testing revealed that the presence of fire-retardant chemicals has significantly improved the flexural properties. However, only a marginal increase was visible in the compression strength of mycelium biocomposites.

Investigation of the Motion of a Spherical Object Located at Soft Elastic and Viscoelastic Material Interface for Identification of Material Properties

Hasan Koruk — 2024-10-17

Measuring the properties of soft viscoelastic materials is challenging. Here, the motion of a spherical object located at the soft elastic and viscoelastic material interface for the identification of material properties is thoroughly investigated. Formulations for different loading cases were derived. First, the theoretical models for a spherical object located at an elastic medium interface were derived, ignoring the medium viscosity. After summarizing the model for the force reducing to zero following the initial loading, we developed mathematical models for the force reducing to a lower non-zero value or increasing to a higher non-zero value, following the initial loading. Second, a similar derivation process was followed to evaluate the response of a spherical object located at a viscoelastic medium interface. Third, by performing systematic analyses, the theoretical models obtained via different approaches were compared and evaluated. Fourth, the measured and predicted responses of a spherical object located at a gelatin phantom interface were compared and the viscoelastic material properties were identified. It was seen that the frequency of oscillations of a spherical object located at the sample interface during loading was 10–15% different from that during unloading in the experimental studies here. The results showed that different loading cases have immense practical value and the formulations for different loading cases can provide an accurate determination of material properties in a multitude of biomedical and industrial applications.

Investigation of the Thermal and Mechanical Properties of Glass Fiber Reinforced ABS/Epoxy Blended Polymer Composite

Ramakrishna Pramod — 2024-10-17

This research investigates the formation of polymer blends by blending Epoxy LY556 with Acrylonitrile-Butadiene-Styrene (ABS) at weight percentages ranging from 2 to 10% wt. The thermal properties, morphological characteristics, tensile strength, flexural strength, and interlaminar shear strength (ILSS) characteristics of these composites were examined. The X-ray Diffractometer (XRD) and Fourier Transform Infrared Spectrometer (FTIR) studies confirmed the presence of binary blends. The miscibility of epoxy/ABS blends is shown by the presence of a single melting peak in the Differential Scanning Calorimetry (DSC) analysis. The Thermogravimetric Analysis (TGA) findings indicate that epoxy and ABS blends exhibit greater thermal stability than pure epoxy. The tensile strength increased from 183.6 to 380.6 MPa, flexural strength increased from 165.3 MPa to 335.6 MPa, ILSS increased from 32.4 MPa to 72 MPa for 8% wt. of ABS blending, and the laminates witnessed a decrease in density and hardness values. The Scanning Electron Microscopy (SEM) images demonstrate the commendable blending characteristics and the synergistic impact of the ABS/Epoxy composite, yielding superior outcomes to the pure epoxy material.

Mechanical Properties of Bacterial Cement Mortar Integrating Natural Banana Fibres

Sunantha Balachandran — 2024-10-17

This investigation analyzes the usage of bacterial content and different lengths of banana fiber reinforced with variable percentages in cement mortar. Portland pozzolana cement (PPC) was combined with bacterial solutions (Bacillus cereus) at a concentration of 1.15×10⁴cells/ml to produce a mortar composite. By adding natural fibers like banana fiber to the composite components, the mechanical behavior of the bacterial mortar was enhanced. Mortar mixtures using banana fibers with different fiber concentrations (0.25, 0.5, 0.75, and 1%) and lengths (0.5, 1, 1.5, and 2 cm) were evaluated. Compressive and flexural strength was found to be greatly affected by the addition of banana fibers to concrete, but only at lower fiber levels of up to 0.25% for all fiber lengths. At lower fiber levels of up to 0.25%, the length of the fiber had no discernible effect on compressive strength; however, at larger dosages exceeding 0.25%, shorter fibers were shown to outperform longer ones. However, the mixing of bacterial content in the mortar is not only significant to the mechanical properties but also potentially lowers the carbon emissions, making it a more sustainable option for composite preparation. The stability of bacterial-based mortar and its compatibility with natural fibers further underscores the potential for eco-friendly construction materials. By exploring the chemical and physical properties of banana fibers treated with alkali chemicals and their compatibility with bacterial cultures, this study adds depth to our understanding of these composite materials. Overall, the proposed methodology for preparing these composites holds promise for future applications in the construction industry, offering a sustainable and efficient alternative to traditional materials.

Nanostructured Composites: Modelling for Tailored Industrial Application

Gh Owais Shah — 2024-10-17

This comprehensive study explores the application of metallic, polymeric, and hybrid nanocomposites, particularly integrating carbon nanotubes (CNTs) to enhance mechanical properties. Various mathematical models predict critical properties like elastic modulus, with analyses assessing mechanical behavior across different CNT volume fractions. Findings emphasize the influence of fiber distribution and porosity on mechanical properties, with clusters acting as stress concentrators. Matrix materials include Aluminum 356 and HDPE, with CNTs and Coir fibers as reinforcements, and hybrid composites combining HDPE, Coir, and CNTs are studied. Elastic modulus calculations employ micromechanical models, with results varying based on volume fractions and composite compositions. Experimental validation enhances technical robustness, ensuring applicability in real-world scenarios. Aerospace applications favor models like Combined Voigt–Reuss, Halpin–Tsai Equations, and Hashin–Strikman for their accuracy and computational efficiency, while automotive applications prefer Halpin–Tsai Equations and Combined Equations for practical use. These models balance accuracy and computational efficiency, providing valuable insights for industrial applications. The calculated effective modulus ranged from 81.67 GPa to 118.78 GPa for Al-CNT composites, from 11.09 GPa to 51.05 GPa for HDPE-CNT composites, and from 1.15 GPa to 1.34 GPa for HDPE-Coir composites, showcasing the wide range of mechanical properties achievable through different composite compositions and volume fractions.

The Effects of Microwave Curing on Dielectric Properties of Banana Fiber Reinforced High-Density Polyethylene Composite

Tasha Lai Sie Ming — 2024-10-17

This study investigates the dielectric properties of banana fiber reinforced high-density polyethylene composites, both with and without magnesium oxide (MgO) as conductive filler, utilizing microwave curing. Dielectric properties play a crucial role in the design and performance of materials in various fields, including electronics and energy storage systems. The introduction of MgO as a conductive filler significantly enhances the dielectric constant of the composites, resulting in improved electrical energy storage capacity. Microwave curing emerges as a key factor in enhancing dielectric properties. Compared to conventional oven and room temperature curing techniques, microwave cured composites consistently exhibit higher dielectric constants. The dielectric constant of 0.24 at 2 MHz for microwave cured NaOH treated fibers. In addition, the comparison of dielectric permittivity made from oven-cured and microwave-cured composites at relaxation frequencies of 10 kHz exhibited an 11 percent increase through microwave curing. The rapid and volumetric heating properties of microwave curing enable more effective dispersion and distribution of MgO particles within the composites, ultimately enhancing interfacial polarization and dielectric performance.

Tuning Rigid Polyurethane Foam with Eco-friendly Cellulose Nanocrystals from Oil Palm Empty Fruit Bunches as Energy-Efficient Material Composites for Buildings

Dilla Dayanti — 2024-10-17

The development of novel materials based on renewable materials with beneficial properties that assist with energy efficiency and conservation has been encouraged by increasing consciousness of environmental issues. This research intends to use sustainable cellulose nanocrystals (CNC) obtained from oil palm empty fruit bunches (OPEFB) as reinforcement to enhance the properties of rigid polyurethane foam (RPUF). RPUF reinforcement with varied CNC concentrations (0.25–1 wt%) was examined by foaming behavior, surface morphology, mechanical properties, thermal insulation properties, dimensional stability, efficiency energy study, and CO₂ reduction through their thermal conductivity values. The results achieved an optimal improvement of mechanical properties of the RPUF composite by around 23.53% compared to RPUF control, at the addition of 0.5 wt% of CNC concentration while maintaining the density of 37–39 kg/m³. Further, incorporating CNC improved thermal insulating performance by 9.95%, as reflected by decreased thermal conductivity from 0.0292 W/mK to 0.0269 W/mK and decreased cell size by 28.12%. Finally, based on the energy and cost efficiency studies, RPUF-CNC composites offer up to 0.78 kWh/m² and 0.031 kWh/m² compared to conventional wall materials made of concrete and wood, respectively. Furthermore, it contributed to reduced greenhouse gas (GHG) emissions by 110 and 7.2 kg CO₂/year compared to concrete and wood, respectively. This work demonstrates the promising use of eco-friendly building insulation materials to mitigate the energy and environmental crisis.