Acoustic Insulation Properties Research Articles

Recycling Functional Fillers from Waste Tires for Tailored Polystyrene Composites: Mechanical, Fire Retarding, Electromagnetic Field Shielding, and Acoustic Insulation Properties-A Short Review.

Polymer waste is currently a big and challenging issue throughout the world. Waste tires represent an important source of polymer waste. Therefore, it is highly desirable to recycle functional fillers from waste tires to develop composite materials for advanced applications. The primary theme of this review involves an overview of developing polystyrene (PS) composites using materials from recycled tires as fillers; waste tire recycling in terms of ground tire rubbers, carbon black, and textile fibers; surface treatments of the fillers to optimize various composite properties; and the mechanical, fire retarding, acoustic, and electromagnetic field (EMI) shielding performances of PS composite materials. The development of composite materials from polystyrene and recycled waste tires provides a novel avenue to achieve reductions in carbon emission goals and closed-loop plastic recycling, which is of significance in the development of circular economics and an environmentally friendly society.

Scleroglucan-Based Foam Incorporating Recycled Rigid Polyurethane Waste for Novel Insulation Material Production.

This study details the synthesis and performance evaluation of a novel lightweight thermal and acoustic insulation material, resulting from the combination of a scleroglucan-based hydrogel and recycled rigid polyurethane waste powder. Through a sublimation-driven water-removal process, a porous three-dimensional network structure is formed, showcasing notable thermal and acoustic insulation properties. Experimental data are presented to highlight the material's performance, including comparisons with commercially available mineral wool and polymeric foams. This material versatility is demonstrated through tunable mechanical, thermal and acoustic characteristics, achieved by strategically adjusting the concentration of the biopolymer and additives. This adaptability positions the material as a promising candidate for different insulation applications. Addressing environmental concerns related to rigid polyurethane waste disposal, the study contributes to the circular economy.

Utilizing decommissioned windmill blades as reinforcement or filler for biocomposites

Decommissioned or damaged windmill blades and other wastes have limited applications and are generally disposed into landfills or incinerated. Increasing generation of wind energy will also lead to increase in blades available for disposal. It is estimated that more than 800,000 tons of blades will be available annually for disposal from 2050. Blades contain glass, carbon, resins and other valuable materials and hence it is prudent to develop methods to reuse or recycle the blades. In this study, we have used windmill blade waste (WBW) as reinforcement for polypropylene (PP) and also as filler/additive for coir-WBW-PP hybrid composites. Various proportions of the components were made into composites and studied for the changes in mechanical, acoustic, thermal and noise insulation properties. Tensile strength did not show major increase in properties whereas 70/30 WBW/PP composites had highest flexural strength and modulus. Addition of WBW considerably increased both the tensile and flexural properties of the hybrid composites with up to 180% increase in flexural strength and 173% increase in modulus. Similarly, hybrid composites had better thermal conductivity and the composites containing 80% WBW and 20% PP had the highest thermal conductivity. Coir improved the acoustic sorption due to the presence of pores and voids in the composites whereas WBW acts as filler and decreased the sound sorption. WBW can be effectively used as reinforcement or filler for PP based composites.

Development of fungal biocomposites for construction applications

AbstractMycelium materials represent a new class of environmentally friendly materials for structural applications that can grow on low‐cost organic waste while achieving satisfactory thermal or acoustic insulation properties. The aim of this study is to grow a biocomposite of mycelium on flax tows and then use it as a reinforcement with a geopolymer matrix. To achieve this, three species of mycelium were selected, a culture process was carried out, and then samples of the composite were synthesized with a geopolymer matrix. To determine the utility in terms of structural applications, the density, compressive strength, and thermal conductivity of the samples were tested. Scanning electron microscope images were also taken to observe the microstructure. The results indicate that it is possible to produce a mycelium composite with a geopolymer matrix. A lower density was achieved for all samples than for the geopolymer without reinforcement. The coefficient of thermal conductivity was reduced only for the sample with one of the mycelia. The compressive strength for biocomposites was between 12.1 MPa–14.2 MPa, this value is enough for some engineering applications.

Life cycle assessment of mycelium-based composite materials

Mycelium-based composites (MBCs) show promising acoustic and thermal insulation, fire safety, and mechanical strength properties and are suitable for multiple applications in the construction, packing or furniture industry. A life cycle assessment confirmed climate change and fossil energy demand benefits in a laboratory scale production modelled for Germany. MBC are associated with 0.3668 kg CO2e / kg MBC (EN 15804 + A2). The electricity required to run MBC production and hemp cultivation, if used as a substrate, contribute significantly to the environmental impact categories considered. Compared to conventional insulation materials, environmental advantages of MBC can be confirmed. Particularly, MBC has a better climate change impact than extruded polystyrene, quadcore sandwich panel, foam concrete and rockwool. However, since the end-of-life is not assessed, the wood-fiber and straw panels perform better regarding climate change. Moreover, MBC has lower fossil energy demand than all conventional insulation materials. Land-use and water demand are higher than for conventional materials.

Low shrinkage polyimide aerogel cross-linked with amino-functionalized hollow glass microbeads for thermal and acoustic insulation

As a nanoporous material, polyimide (PI) aerogels have excellent thermal and acoustic properties. However, their high air flow resistance is detrimental to the development of their acoustic properties. To enhance the thermal and acoustic insulation properties of PI aerogels, we have selected hollow glass microbeads (HGM) with a low thermal conductivity coefficient to be combined with the PI aerogel, leading to the fabrication of PI/HGM aerogel composite materials. In this study, there are two preprocessing methods for HGM: untreated and aminized (HGM-NH2). These were then individually combined with PI aerogel to fabricate two distinct PI/HGM composite aerogels: a physically blended variant (PIHGM) and a chemically bonded one (PHN). The thermal insulation and acoustic properties of these two composite aerogels were compared. The results show that HGM-NH2 not only functions as a cross-linking agent but also plays a key role in forming the three-dimensional network structure, which effectively reduces the shrinkage rate and density of the composite aerogel. Moreover, the thermal conductivity of PHN reached a low of 27.92 mW m⁻1 K⁻1, which is a reduction compared to PIHGM's thermal conductivity of 29.83 mW m⁻1 K⁻1. Moreover, the PHN composite aerogel with 10% HGM addition exhibited an average sound insulation level that was 120% higher than that of PIHGM. The method of incorporating pore structures with different scales also offers valuable insights for enhancing the sound insulation performance of other materials.

Foam-filled aramid honeycomb sandwich composites with high acoustic insulation properties prepared using a unique thermal expansion molding process

Contemporary advancements in technology and the rapid development of transportation systems have led to the rise of noise pollution as a major environmental issue globally. Foam sandwich composites, distinguished by their lightweight yet robust attributes such as high-strength functionality, effectively combine the superior noise insulation properties of foam structures with the strength inherent in their surface skins. However, traditional foam core materials exhibit limitations in terms of mechanical durability and suboptimal interfacial bonding with the surface skin. This study addressed these shortcomings by employing a novel approach involving a self-developed thermally expandable epoxy resin and an aramid honeycomb composite. These components were co-cured with a fiber prepreg, culminating in the formation of enhanced sandwich composites. The composites fabricated through this method demonstrate an impressive average sound insulation capacity of 70 dB, alongside a significant enhancement in the mechanical properties of the core material, surpassing the performance of standalone foam structures.

Preparing Eco-friendly Composite from End-life Tires and Epoxy Resin and Examining Its Mechanical, and Acoustic Insulation Properties

Preparing Eco-friendly Composite from End-life Tires and Epoxy Resin and Examining Its Mechanical, and Acoustic Insulation Properties

Enhancing Sustainability and Performance of Pineapple Leaf Fibres in Textile Applications: A Comprehensive Review


 The utilization of pineapple leaves (Ananas comosus) has gained significant momentum as a source of value-added products, owing to the myriad benefits offered by Pineapple Leaf Fibres (PALF). PALF presents a range of advantages, including its contribution to a greener environment and sustainability. PALF production plays a pivotal role in reducing environmental pollution and minimizing waste. Moreover, PALF stands out due to its availability, remarkable thermal and acoustic insulation properties, cost-effectiveness, and exceptional tensile strength. Further, the extraction of PALF can be accomplished manually or mechanically, and various methods have been explored to enhance its compatibility with textile applications. In this context, extensive research has been carried out to modify PALF for its application in the textile industry. Researchers have primarily focused on surface modifications. These modifications encompass chemical treatments, physicochemical treatments, physical treatments, and thermal treatments. All of these contribute to improved interfacial adhesion and enhanced physical, mechanical, and thermal properties of PALF. Additionally, investigations into bleaching and dyeing of PALF have led to achieving superior whiteness and the ability to impart various colours to the fibres. PALF fibres exhibit remarkable qualities, including excellent sweat absorption, breathability, durability, and notable air and water permeability. These attributes make PALF a sought-after material for creating blended fabrics in conjunction with other polymers, such as polyester and wool, enhancing the performance of resulting textiles. The versatility of PALF enable its integration into an extensive range of textile products, underscoring its significance in the industry. This review also explores innovative approaches, such as blending PALF with jute, resulting in the creation of home textiles and carpets, while simultaneously improving the quality of blended yarns. Furthermore, within the textile industry, PALF fibres find diverse applications in the production of an array of products. This involves the crafting of wedding dresses, casual attire, and formal garments. It also includes the manufacturing of table linens, mats, bags, shoes, belts, cords, transmission cloths, airbag tying cords, and carpets. This comprehensive review delves into the wealth of research conducted on PALF modifications, shedding light on the potential of PALF as a sustainable and high- performance material in the textile industry, contributing to further eco-friendly and innovative future.
 
 Keywords: Pineapple Leaf Fibres (PALF), Textile Industry, Sustainability, Greener environment

Advanced Drone Surveillance System for Traffic Management

The growing need for sustainable and efficient construction practices has spurred a surge in the development of advanced building materials. Lightweight wall panels have emerged as a promising solution to address the challenges of traditional construction methods. This abstract delves into the design, composition, and benefits of lightweight wall panels, highlighting their contributions to sustainability, energy efficiency, and ease of installation. The lightweight wall panel comprises a combination of materials such as foam cores, composite materials, and reinforcements, carefully engineered to optimize strength while significantly reducing overall weight. This innovative construction material offers various advantages over conventional walls, including enhanced thermal and acoustic insulation properties, increased structural integrity, and improved resistance to fire and moisture. Furthermore, the streamlined manufacturing process of lightweight wall panels minimizes waste generation and reduces the carbon footprint associated with transportation and installation. These panels also facilitate quicker construction timelines, enabling cost-effectiveness and increased flexibility in building design. This abstract discusses the diverse applications of lightweight wall panels across residential, commercial, and industrial sectors, emphasizing their adaptability and versatility in meeting diverse construction requirements. Additionally, it explores ongoing research and developments in the field, aiming to further enhance the performance and sustainability aspects of these panels.

Towards sustainable building solutions: Development of hemp shiv-based green insulation material

There is currently a growing need for sustainable and environmentally friendly materials. One promising candidate is hemp shiv, which is considered waste material. hemp shiv exhibits lightweight properties and high insulation capabilities. This study focuses on the development of a material based in hemp shiv, recycled cardboard fibers is used as binder material, with the addition of a vegetable coating (colophony and arabic gum) for moisture protection and citric acid to enhance cellulose crosslinking. Thermal insulation properties were assessed measuring the heat transfer through the material. Acoustic insulation properties were evaluated using a Kundt tube within a frequency range of 100–6500 Hz. Mechanical tests, including compression, shear, and bending, were performed to assess the material’s strength. Additionally, moisture and fire resistance properties, as well as microstructure analysis, were examined. The influence of citric acid in the cellulose crosslinking was verified using FTIR-ATR spectroscopy. Results demonstrated that a higher percentage of hemp shiv content led to improved insulation performance, achieving attenuation values greater than 0.85–0.95 dB/dB and a thermal conductivity of 0.02–0.03 W/m K. These findings indicate a great performance compared to commercial materials. The coating shields the material from external factors. It was observed that the citric acid does not react with hemp shiv.

Structural, mechanical, electronic and thermodynamic analysis of calcium aluminum silicate crystalline phases in stone wool insulation materials: A first-principles study

Stone wool materials have gained considerable attention due to their effectiveness as thermal and acoustic insulation solutions. The comprehension of crystal structure properties is pivotal in determining the overall performance of these materials, as it enables us to optimize their composition for enhanced insulating capabilities. Crucial factors such as structural, mechanical, and thermodynamic characteristics of crystalline phases within stone wool are vital for evaluating its thermal and acoustic insulation properties. This study investigates the properties of calcium aluminum silicate crystal phases commonly present in stone wool, including anorthite, svyatoslavite, scolecite, and dehydrated scolecite using density functional theory (DFT) calculations. In comparison to previous works, this study provides a more comprehensive analysis using advanced DFT calculations. Our analysis reveals the complex interplay between the crystal structures and mechanical behavior of these phases. The calculated bulk modulus of the phases varies significantly, ranging from 38 to 83 GPa. We have compared the calculated elastic properties with available experimental data and found excellent agreement, confirming the accuracy of the computational approach. Moreover, we find that polymorphism has a significant impact on the mechanical strength, with anorthite exhibiting higher strength compared to svyatoslavite. Furthermore, dehydration is found to cause a reduction in unit volume and mechanical strength. The thermodynamic properties of dehydrated scolecite, including entropy and heat capacity, are significantly lower due to the absence of water molecules. These findings highlight the importance of understanding the structural and mechanical characteristics of calcium aluminum silicate phases in stone wool materials. Additionally, our findings have broader implications in various industries requiring effective insulation solutions such as to develop new materials or to enhance the energy efficiency of existing insulating products.

Recycling of glass waste and spent alkaline batteries cathodes into insulation materials

Expanded glass with thermal and acoustic insulation properties are obtained from a foaming blend composed of 97% glass waste and 3% expanding agent. This latter is a blend of carbon and manganese oxides, recovered from exhausted alkaline batteries. The samples are produced after heating the mixture in a ventilated furnace at temperatures between 850 and 950 °C, for times between 15 and 60 min. Mechanical, thermal and acoustic properties are characterized as a function of process parameters. The glass foam samples have densities in the range of 290–350 kg/m3, porosity of 86–90%, thermal conductivity values of 107–120 mW m−1 K−1, noise reducing factors of 0.2–0.3 and compressive strengths up to 4.6 MPa. Although the resulting insulating performances are not as outstanding as those of polymer foams or mineral wool, these materials can emerge as competitive candidates for applications requiring low weight and moderate thermal and acoustic insulation properties, in combination with non-flammability and high temperature load bearing-capacity. Moreover, the use of 100% recycled raw materials limits the energy and the resource required for their production, if compared to those needed for the extraction, transportation, and processing of primary raw materials, making these foams attractive also in terms of environmental impact.

Research on manufacturing of precast concrete hollow wall panels using thermoelectric ASH and slag as replacements for natural aggregates

Precast concrete hollow wall panels have emerged as a compelling choice in the construction industry because of their lightweight characteristics, which effectively mitigate structural burdens, coupled with their commendable acoustic and thermal insulation properties. Additionally, their expedited construction process provides a significant advantage over labor-intensive brick wall alternatives. It is noteworthy that the production of these precast concrete panels heavily relies on the utilization of natural aggregates, a practice that has raised concerns, particularly in light of the progressively dwindling reserves of sand resources within our country. Concurrently, there is an escalating volume of ash slag emissions from coal-burning thermal power plants in Vietnam. Therefore, research endeavors aimed at exploring alternative materials, specifically the incorporation of thermal power ash and slag wastes into concrete production for the manufacturing of precast hollow wall panels, assume a dual significance—both from a scientific and practical perspective. These initiatives not only alleviate the strain on our natural aggregate resources but also offer a sustainable solution for managing thermal power wastes, thereby carrying substantial environmental and societal implications. This article presents empirical findings derived from a comprehensive investigation into the integration of thermoelectric ash and slag as substitutes for natural aggregates, encompassing replacement ratios ranging from 70% to 100%, within the production processes of precast concrete hollow wall panels, employing extrusion technology. The results unequivocally demonstrate that with a replacement rate of up to 100% of aggregates with thermoelectric ash and slag, the quality of wall panels using thermoelectric ash slag completely meets the technical requirements according to TCVN 11524:2016 "Wall panels hollow precast concrete using extrusion technology" for use in construction projects.

Unidirectional infiltrated PI/SiO2 composite aerogels with a confined reinforcing strategy for integrated thermal and acoustic insulation

It is of great significance to develop integrated thermal insulation and noise reduction materials for energy saving and pollution control. As a nanoporous material, aerogels have excellent thermal and acoustic properties, however, the thermal stability of organic aerogels is insufficient, and the mechanical properties of inorganic aerogels limit their practical application. Herein, we designed a confined reinforcing strategy for organic-inorganic composite aerogels with high strength and excellent acoustic insulation properties. A directional freezing technology was utilized to control the pore structure of a polyimide (PI) aerogel, and then a continuous SiO2 aerogel was filled in the unidirectional pore channels, forming a double-network structure consisting of both PI and SiO2 aerogels. The results showed that the compressive strength of the composites was 1.83 MPa at 10% strain, the initial thermal decomposition temperature was about 530 °C, and the lowest thermal conductivity was 22.37 mW m−1·k−1 at radial direction. Moreover, the average sound transmission loss (STL) of the composites with an 18 mm thickness was 30–33 dB in the range of 500–6300 Hz. This confined reinforcing strategy can safeguard fragile aerogels while maximize their inherent characteristics, which offers a novel approach to the creation of multi-functional aerogel composites.

Feasibility Review of Aerated Materials Application in 3D Concrete Printing.

Recent years have witnessed a growing global interest in 3D concrete printing technology due to its economic and scientific advantages. The application of foamed concrete, renowned for its exceptional thermal and acoustic insulation properties, not only holds economic attractiveness but also aligns seamlessly with the principles of sustainable development. This study explores various solutions related to 3D printing technology in construction, discussing the design, production, and properties of foamed concrete mixtures. The integration of 3D printing and the potential for automating the entire process offers opportunities to boost productivity and reduce construction costs. Furthermore, the utilization of foamed concrete with its commendable insulation properties will enable a reduction in the usage of materials other than concrete (e.g., mineral wool, facade mesh, and polystyrene), significantly facilitating the recycling process during building demolition. This, in turn, will lead to the preservation of nonrenewable natural resources and a decrease in CO2 emissions. Despite the promising results, there have been limited studies focusing on 3D printing with foamed materials, whereas a survey of the existing body of literature indicates a notable absence of endeavors pertaining to the utilization of aerated concrete within the realm of 3D printing, especially geopolymer composites (GP) and hybrid geopolymer composites (HGP). The outcomes delineated in the ensuing discourse are demonstrative for conventionally used materials rather than the additive manufacturing variant. Hence, this work aims to systematically review existing practices and techniques related to producing foamed concrete with 3D printing technology. This analysis also contributes to the establishment of a foundational framework and furnishes a preliminary basis upon which future endeavors aimed at the 3D printing of aerated concrete can be embarked. The findings from the literature analysis justify the desirability of continuing research on this topic, particularly when considering the potential for large-scale industrial implementation. This article provides a comprehensive state of the knowledge on the development of 3D printing techniques for foamed concrete mixtures. By consolidating and analyzing findings from different studies, this article offers insights into the advancements, challenges, and potential applications of foamed concrete in additive manufacturing processes. This, in turn, contributes to the overall understanding and advancement of 3D printing technologies using foamed concrete as a versatile and sustainable construction material. The encouraging results obtained from the analysis further underscore the need for the continued exploration of 3D printing, especially with an eye towards its industrial-scale implementation.

Properties of Lightweight Insulating Boards Produced from Triticale Straw Particles.

Insulating materials made from straw are becoming increasingly popular in the construction industry. Straw can be used in the construction of buildings as uncompressed straw chips or in the form of compressed panels. This study aimed to determine the possibility of manufacturing boards from straw particles with densities in the range of 150-400 kg/m3, allowing favorable mechanical properties while simultaneously providing high thermal and acoustic insulation properties. The study also analyzed the influence of the degree of carpentry density on the quality of the manufactured boards. The study shows that insulation boards can be produced from straw particles with satisfactory properties already at densities in the range of 200-150 kg/m3. Boards with this density have a compressive strength of 150 kPa, thermal resistance of 0.033-0.046 W/(m·K), and a sound absorption coefficient above 0.31.

Comparative Study to Assess the Thermal Behaviour of Sandwich Roof Panels with Coconut Fibre as an Alternative Core Material to Polyurethane

Sandwich panels (modular panels) promote optimal solutions to some major issues prevailing in the construction industry such as increased energy consumption by building elements, excessive disposal of constructional waste and unproductive time spent during construction. Hence, the inclination towards sandwich elements has been increased vastly deviating from conventional building construction materials and methods. However, the potentiality of using locally available natural materials for the development of sandwich panels is a salient sustainable approach that needs to be addressed. This study evaluates the current and potential materials used in modular panels and key properties of sandwich panels including mechanical, thermal insulation, and sound insulation properties. Moreover, various test methods followed, and standards specified to investigate the mechanical, thermal and acoustic insulation properties are also discussed. The possibility of using coconut fibre as a locally available natural alternative core material to polyurethane core of sandwich panels has been evaluated using simulations based on the material properties obtained from literature. The study identifies coconut fibre as a potential alternative core material for sandwich roof panels as it reflects nearly similar thermal behaviour to polyurethane.

Chemical composition, particle geometry, and micro-mechanical strength of barley husks, oat husks, and wheat bran as alternative raw materials for particleboards

Particleboards are used worldwide in various industry segments, like construction and furniture production. Nevertheless, increase in wood prices and logistical challenges urge the particleboard industry to find alternative raw materials. By-products and residues from the agricultural and food industries could offer possibilities for material sourcing at a local level. This study aimed to investigate the chemical composition, particle geometry, anatomical structure, and microtensile characteristics of such material, specifically barley husks (BH), oat husks (OH), and wheat bran (WB). BH and OH were found to have comparable hemicelluloses and lignin contents to industrial wood chips but contained more ash. WB was rich in extractives and showed high buffering capacity. Light microscopy and microcomputed tomography revealed details of leaf structure for BH and OH as well as the multi-layer structure of WB. The ultimate microtensile strength of BH, various OH samples, and WB were respectively 2.77 GPa, 0.84–2.42 GPa, and 1.45 GPa. The results indicated that the studied materials could have potential uses as furnish materials in non-load bearing particleboards, where thermal or acoustic insulation properties are desirable.

Heat treatment’s effect on properties of polystyrene from building demolitions

Polystyrene (PS) is a synthetic polymer widely used as a packaging material and in thermal insulation of buildings. At end-of-life, there are not many recycling management options of PS because of the reduced incentive and high cost. PS is non-biodegradable, and consequently, the disposal of this product causes serious health and environmental concerns. This study discusses the application of thermal treatment to modify the properties of PS waste foams. Both expanded and extended polystyrene were collected from building demolitions and subjected to different temperature treatments and duration. The effect of the treatment was investigated on the density, structure, glass transition temperature, mechanical properties (hardness, compression strength), thermal conductivity, and sound absorption of treated PS. The results showed that density increased with treatment temperature, which had a corresponding effect on the evaluated properties. The study concluded that thermal treatment is a beneficial way to improve the mechanical properties of PS waste from buildings. However, a trade-off between application and relevance still needs to be ascertained, as the thermal and acoustic insulation properties of PS decreased with the treatment.