Acoustic Insulation Materials Research Articles

Upcycling of industrial footwear waste into nonwoven fibrous structures with thermal and acoustic insulation properties

The footwear industry significantly impacts the environment, from raw material extraction to waste disposal. Transforming waste into new products is a viable option to mitigate the environmental consequences, reducing the reliance on virgin raw materials. This work aims to develop thermal and acoustic insulation materials using polyester waste from footwear industry. Two nonwoven and two compressed nonwoven structures, comprising 80% polyester waste and 20% commercial recycled polyester (matrix), were produced. The materials were created through needle-punching and compression molding techniques. The study included the production of sandwich and monolayer nonwoven structures, which were evaluated considering area weight, thickness, air permeability, mechanical properties, morphology using field emission scanning electron microscopy, and thermal and acoustic properties. The nonwoven samples presented high tensile strength (893 kPa and 629 kPa) and the highest strain (79.7% and 73.3%) and compressed nonwoven structures showed higher tensile strength (2700 kPa and 1291 kPa) but reduced strain (25.8% and 40.8%). Nonwoven samples showed thermal conductivity of 0.041 W/K.m and 0.037 W/K.m. Compressed nonwoven samples had higher values at 0.060 W/K.m and 0.070 W/K.m. While the sample with the highest conductivity exceeds typical insulation levels, other samples are suitable for thermal insulation. Nonwoven structures exhibited good absorption coefficients (0.640–0.644), suitable for acoustic insulation. Compressed nonwoven structures had lower values (0.291–0.536), unsuitable for this purpose. In summary, this study underscores the potential of 100% recycled polyester structures derived from footwear and textile industry waste, showcasing remarkable acoustic and thermal insulation properties ideal for the construction sector.

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.

Advancing sustainable construction through comprehensive analysis of thermal, acoustic, and environmental properties in prefabricated panels with recycled PET materials

Acoustic and thermal insulation materials play a crucial role in the construction industry as they ensure high-performance applications. This study analyzes three recycled insulations (two derived from PET and one is EPS with graphite additives) for innovative prefabricated panels. A multiphysics, multiscale, and multiobjective approach was developed to analyze the performance of the individual materials and three prototype prefabricated panels incorporating them, combined with numerical analysis enabling the thermal transmittances assessment of a full-scale panel. Thermal investigations were conducted at both small and large scales to assess their performance. Additionally, acoustic sound insulation measurements at both scales and a LCA analysis were carried out. Thermal conductivity of the insulation layer ranges from 0.026 to 0.043 Wm−1K−1. Furthermore, the sound transmission loss exhibits a positive trend with increasing frequencies, reaching approximately 10 dB after 1600 Hz for the 15 cm thick PET insulation. EPS performs exceptionally well at low frequencies, with sound insulation peaks reaching almost 40 dB around 400 Hz. At the large scale, the weighted sound reduction index showed a 3.5 dB increase compared to the reference. The environmental assessment emphasized that 80 % of global warming potential comes from material extraction, stressing the importance of using recycled materials.

Mycelium Agrowaste‐Bound Biocomposites as Thermal and Acoustic Insulation Materials in Building Construction

Mycelium Agrowaste‐Bound Biocomposites as Thermal and Acoustic Insulation Materials in Building Construction

A Brief Analysis of The Production of Building Materials Utilizing Waste-Based Reinforcements and Recycled Textiles

The utilization of composite materials in construction has recently exerted a significant impact on society, particularly concerning ecological responsibility and environmental considerations. On a daily basis, proposals advocating the use of emerging materials crafted from discarded or repurposed items are put forth to transcend the limitations posed by conventional resources. One notable aspect of this movement revolves around textile components, encompassing fibres such as wool, cotton, cannabis, and flax. Over the past decade, there has been a heightened focus on worn clothing, as it represents an unprocessed product that holds both commercial viability and ecological benefits. Approximately 1.5 percent of the global waste generated daily comprises textile scraps, with blue jeans, crafted from cotton, standing out as the most prevalent type of apparel worldwide. Textile scraps find new life through recycling, serving various purposes such as the creation of electrical wires, the production of pulverized substances for temperature and acoustic insulation materials, and the incorporation as filler or reinforcement in concrete construction. This paper delves into multiple themes, covering (i) the adverse environmental impacts stemming from the extensive use of clothing; (ii) the recycling and reclamation of textile waste; and (iii) the utilization of waste and reclaimed materials from textiles as building components.

Low-frequency sound-absorbing metamaterial based on a series-parallel arrangement structure

Low-frequency noise has a long wavelength, decays very slowly, and is extremely penetrating. Traditional marine acoustic insulation materials have difficulty achieving effective control of this low-frequency noise. In this paper, a series-parallel arrangement structure of a low-frequency metamaterial is designed, which mainly comprises convoluted channels and Helmholtz cavities in series and a sandwich arrangement of multiple cells (as opposed to the traditional parallel arrangement). We use a numerical method to establish an acoustic-solid coupling model for the metamaterial, consider the influence of thermal and viscous losses on its sound absorption performance, and investigate the sound absorption characteristics and mechanisms of the single-cell and multicell structures. The metamaterial designed in this paper shows an average absorption coefficient of 0.97 in the range of 130–145 Hz. An experimental model was prepared by 3D printing, and the intended sound absorption effect was experimentally verified.

STUDY OF REGULARITY OF CHANGES IN VOLUMETRIC MASS OF FOAMED GEOPOLYMER MATERIALS ON BASIS OF LIMESTONE WAST

The creation of composite construction materials, which have a less harmful impact on the environment both at the stage of their production and in the process of their use, is of great interest in the global construction industry. Recent innovations have led to the creation of foamed geopolymer concrete or geopolymer foam, which includes the operational advantages of thermal and acoustic insulation materials, saves energy by reducing heat loss, and contributes to the reduction of CO2 emissions into the environment. For a better understanding of the properties and benefits related to the use of foamed geopolymer materials, this paper presents studies of the volumetric mass of these materials obtained from limestone waste and silicate activator. Samples with a ratio of components (limestone waste: activator) of 70:30, 75:25, and 80:20 were obtained. Studies of the volumetric mass depending on changes in the concentration of alkali in the solution of the gas generation activator showed that the minimum values of the volumetric mass are achieved at 1 mol/L concentration of alkali. In addition, it was found that the best foaming geopolymer material is achieved at a ratio of components of 80:20 and at a content of the gas generation activator solution in the mixture of 18% mass. Keywords: foamed geopolymer, volumetric mass, porosity, thermal insulation material.

Insulation Materials Based on Recycled Feather Waste: A Review

Recently, the world has been moving towards reusing wastes in many industrial applications, such as buildings and automotive, to eliminate the environmental pollution impact due to increasing waste worldwide. Besides, waste reuse also leads to cost savings and improves sustainability. Therefore, this short review aims to present and discuss the recently used methods of utilizing feather waste as sustainable and renewable insulation instead of traditional petroleum-derived materials. The father's low thermal conductivity ranges from 0.024 W/(m. K) to 0.034 W/(m. K), and it's chemical composition and microstructure effectively trap air and produce a good barrier. So, feather waste fibers can be used as an effective thermal and acoustic insulation material with the same or better performance than commercially available products. However, several significant barriers and limitations associated with the manufacturing process of feathers insulations were identified in this review. These limitations make the commercial development of insulation materials based on feather waste a challenge. They need to be appropriately addressed to realize the potential of feather waste as a reliable insulation material.

Development of Acoustic and Thermal Insulation Materials from Pantyhose Waste

Population growth, urbanization, industrialization, developing technology, increasing welfare level and changing consumption habits cause solid wastes to increase day by day. There are also sub-waste groups that have not yet been fully recognized among the solid waste groups in which textile wastes have a large share. One of them is pantyhose, which has been indispensable for modern life since the day it was presented to the consumer. These socks, which are made of polyamide and elastane fibers that are easily punctured, run and become unusable when worn once or several times, are generally thrown away after use. These pantyhose wastes, which are not biodegradable due to their raw materials, also pose an environmental risk. Within the scope of the study, thermal and sound insulation properties of carded and needle-punched pantyhose wastes are investigated. The results show that the thermal and acoustic properties of the developed material are at a sufficient level, and it has ensured that polyamide wastes, which have superior properties among thermoplastic polymers and have high economic value, are brought back into the economy.

Innovative Thermal and Acoustic Insulation Foams from Recycled Fiberglass Waste

AbstractThis study examines a lightweight thermal and acoustic insulation material, produced starting from a hydrogel‐based mixture composed by renewable biopolymer and fiberglass waste powders. The gel 3D porous network is preserved after water removal by sublimation, resulting in a lightweight thermal and acoustic insulation material with good overall performance. Mechanical, thermal, and acoustic properties can be tuned as a function of biopolymer and additives concentration. This material addresses environmental concerns both in terms of secondary raw sources use and fiberglass waste disposal. Moreover, contrary to mineral wools currently on the market, it can overcome the problem of fiber release, with significant human health benefits. Thanks to its good properties and its fabrication process based on a circular economy approach, it can be appealing for thermal and acoustic insulating applications in building and industrial sectors and also in terms of environmental footprint.

Low-Cost Alpha Cabin Like Test Box Proposal for the Development of New Acoustic Sound Insulation Materials

Experimental criteria for sound insulation material recommendation and design have an important share in indoor acoustic control. Among these criteria, laboratories with devices such as impedance tubes, alpha cabins and reverberation rooms used to measure and analyze parameters such as sound transmission loss and sound absorption coefficient have been investigated. In literature, it has been observed that there are studies on acoustic materials and the tests applied to these materials, but the application is more limited. According to research data, an Alpha Cabin model system design that can be used to develop new types of acoustic sound materials has been proposed. In addition to the fact that a large number of experimental measurements can be performed at lower costs using the designed Alpha Cabin model system, many tests can be performed easily for different material designs in a very short time. To perform these tests, the Alpha Cabin system has been designed based on noise and sound insulation. For example, floating flooring, ribbed connection, and so on. Afterward, different insulation materials were used for insulation purposes and standards were achieved. The Alpha Cabin test system, which was designed and developed, overlaps the experimental and theoretical data for 500, 2000, and 4000 Hz when compared with the values of 29.1 dB for 500 Hz, 38.6 dB for 2000 Hz, and 49 dB for 4000 Hz measured in the Acoustic Facade Panel Test Room, and it has been observed that it can be used in the development of new sound insulation materials.

Thermal and acoustic performance evaluation of 3D-Printable PLA materials

In this study, additive manufacturing or three dimensional (3D) printing technology was utilized to develop thermal and acoustic insulation materials. A 3D model was carefully designed to obtain thermal and acoustic insulation properties using Autodesk software and print the materials using QIDI X-PLUS 3D printer with precise and controlled shape and structure. Biodegradable PLA filament was used as printing ink. A comprehensive evaluation was conducted to check whether this new branch of technology is suitable for producing insulation materials. Testing results revealed that insulation materials produced from 3D printing technology have excellent thermal and acoustic insulation properties. The lowest obtained thermal conductivity value was 0.037 W/mK, and the maximum obtained sound transmission loss was 48.27 dB at 1600 Hz frequency. In case of physical properties, density of insulation panels ranges from 366.46 to 721.26 kg/m3, and porosity ranges from 43 to 71%. Life cycle cost (LCC) analysis was carried out to obtain the optimum insulation thickness, energy savings, and payback period of developed insulation materials for different locations in the USA. It was found that the optimum insulation thickness varies between 4 and 10 mm, energy savings varies between 45.0% and 67.2%, and payback period varies between 8.5 and 14.8 years. The effect of structural parameters (thickness, density, air permeability, and porosity) on insulation properties was also checked in order to obtain a relationship between structural parameters and insulation properties. It was found that both density and porosity have significant influence on insulation properties. Testing results also revealed that thermal and acoustic insulation properties follow opposite trends with the increase of density and porosity. The increase in density and decrease in porosity causes increase in acoustic insulation property, but decrease in thermal insulation property. A comparison was also made with commercially available acoustic and thermal insulation panels, and it was observed that produced 3D printed samples have better insulation properties. This indicates that developed materials have very good potential to be commercially used as building insulation materials. As produced insulation material has colored and glossy surfaces, it can be used in the interior or exterior of building walls and may also replace plasterboard or tiles of building walls.

Effect of Blend Composition on Barrier Properties of Insulating Mats Produced from Local Wool and Waste Bast Fibres

This paper concerns the management of natural waste fibres. The aim of this research was the production of multifunctional acoustic and thermal insulation materials from natural protein and lignocellulosic fibre wastes, according to a circular bioeconomy. For the manufacture of the materials, local mountain sheep wool and a mixture of bast fibre waste generated by string production were used. Insulating materials in the form of mats produced by the needle-punching technique with different fibre contents were obtained. The basic parameters of the mats, i.e., the thickness, surface weight and air permeability were determined. To assess barrier properties, sound absorption and noise reduction coefficients, as well as thermal resistance and thermal conductivity, were measured. It was shown that the mats exhibit barrier properties in terms of thermal and acoustic insulation related to the composition of the mat. It was found that mats with a higher content of the bast fibres possess a greater ability to absorb sounds, while mats with higher wool contents exhibit better thermal insulation properties. The produced mats can serve as a good alternative to commonly used acoustic and thermal insulating materials. The production of the described materials allows for a reduction in the amount of natural fibre waste and achieves the goal of "zero waste" according to the European Green Deal strategy.

Expanded obsidian as composite material for light concretes

Creation of composite building materials is a way of improvement of certain properties compared with such properties of source components as mechanical, physical, heat-insulating, acoustic, and in addition chemical stability, life span etc., or materials prime cost reduction, including at the expense of various waste utilization. In this connection, there is a lively interest in heat-insulating and acoustic insulation materials. In creating such materials the problem lies in an optimal solution concerning the choice of a light aggregate, binder and the simplest manufacturing technique for products of quite various shape and size. The advantage of a porous composite material is in unique combination of heat-insulating and structural properties and puts it on the same level with durable building materials designed for the same application. Many man-made formations, in particular solid waste, are valuable technological raw materials and can be involved in technological redistribution in order to obtain new composite building materials. In the production of crushed stone, sands from lithoid pumice and perlite, it is advisable to make the separation and separate obsidian. In this case, the separated obsidian turns into a production waste. Expansion of obsidian will make it possible to obtain a superlight large porous material and thereby solve environmental issues - to utilize production wastes. Concretes, produced using expanded obsidian, are of strength class B 12,5 and average density 1150-1200kg/m3 can be called structural and superlight concretes based on expanded obsidians. Heat conductivity factor of such concretes of 400-1200 kg/m3 average density varies from 0.125 to 0.35W/m0K.

Sound Insulation Properties of Malaysian Biomass Waste Fibre UF Composites

Natural fibrehas a good capacity as acoustic insulation materials because of its characteristics, and therefore it is widely used in many applications. This research aims to explore biomass waste from the palm oil mill and coconut production as insulation materials. Fibre wastes used for this study included the empty fruit bunch (EFB), mesocarp fibre (MF) and coconut coir fibre (CF), which were treated using sodium hydroxide (NaOH) to eliminate excess oil and fibre surface impurities. The effect of the treatment was also considered to observe the effect towards the sound transmission loss (STL) performance of natural fibre. Three varying concentrations of NaOH (1%, 2% and 3%) were used to treat the fibre. The STL of EFB, MF and CF were measured using the impedance tube method with four microphones at frequencies from 160 Hz to 5,000 Hz. Pretreatment on EFB, MF and CF showed a decrement on the fibre diameter and changes on the fibre surface morphologies after examining using the scanning electron microscopy (SEM) analysis. The results showed that EFB, MF and CF treated fibre had higher STL performances than untreated fibre. The STL performances were increased by increasing the tested frequency from 160 Hz to 5,000 Hz. Changes in fibre morphology following the fibre pretreatment affected the STL performances of EFB, MF and CF. Additionally, treated MF using 2% of NaOH concentrations obtained the highest STL amongst all the test samples.

Optimizing the environmentally friendly silica-cellulose aerogel composite for acoustic insulation material derived from newspaper and geothermal solid waste using a central composite design

Optimizing the environmentally friendly silica-cellulose aerogel composite for acoustic insulation material derived from newspaper and geothermal solid waste using a central composite design

Glass Waste Based Geopolymers and Their Characteristics

Inorganic polymer materials (Geopolymers) are synthesized using alumino-silicate sources as solid components with an alkaline solution. This material is used as an alternative for building materials and provides thermal protection as foaming materials. This paper presents the preparation of these materials by the reaction between glass waste (from brown color bottles BP) with sodium hydroxide NaOH and sodium aluminum (AN5) solutions as alkali activators. For the preparation of mortars (BP-N5 and BP-AN5), sand was used as aggregate. The compressive strengths were assessed (24 and 6 MPa) respectively before heat treatment, the hydrolytic stability (PH and conductivity) tests were performed. Furthermore, hardened mortars have been heated at very high temperatures in the range of 200℃ to 800℃ within two hours. Based on the nature of the foaming behavior of such materials, various variables have changed; (80-140) % volume increase and porosity rise through the process of heat treatment, particularly at 600℃ and 800℃. On the other hand, (3.5-7) % mass reduction occurred. It can be said that the more significant porosity with different geometrical configurations (sizes and shapes) of such materials can be considered as acoustic insulation and thermal materials.

Sustainable acoustic insulation for prefabricated concrete homes in Andean zones

The construction sector is undoubtedly one of the main promoters for economic and social development. The modern concept of the prefabrication of elements originated from the industrial revolution to reduce costs and increase production through the mechanization of work, increasing the quality and ease of control in the plant. Prefabricated concrete homes are aimed at the popular sectors, however, when talking about acoustic habitability comfort we refer to constructive solutions used in a building to minimize the transmission of sounds (noise pollution) from outside or from an adjoining enclosure. This is achieved with the use of acoustic insulation materials. In the present research, through a bibliographic review, the updated state-of-the-art search methodology is developed, supported by the Delphi and AHP (hierarchical analytical process) methods and with the opinion of experts to compare the properties of acoustic insulating materials; in order to publicize the best acoustic insulators to be installed inside prefabricated concrete homes. Within the bibliographic review, new technologies with sustainable materials found as feasible prototypes were investigated in Ecuador, where thanks to its diversity of ecosystems and the necessary existing technology, the natural fibers used in the prototypes for insulation/absorption are easily found acoustics in homes.

Effect of Meerschaum Stone Powder on Thermal and Acoustic Insulation Properties of Polyester Nonwoven

Abstract The aim of this study is to develop thermal and acoustic insulation materials using textiles. To achieve this aim, each polyester nonwoven fabric was coated with meerschaum stone powder at different rates (10, 20, 30, and 40 %) using a polyurethane-based material. After the coating process, the thermal conductivity and sound absorption coefficients of the samples were measured and then compared with regard to the amount of meerschaum stone powder. According to the results, meerschaum stone powder improved thermal conductivity and sound absorption coefficients of the samples. Furthermore, the results show that the properties of samples concerning acoustic and thermal insulation increase with the increasing concentration of meerschaum stone powder. As the materials obtained in this study are quite lightweight, thin, and cheap, they can be used as insulation materials in buildings.

Microstructure and performance characteristics of acoustic insulation materials from post-consumer recycled denim fabrics

One of the key issues of the 21st century is to reduce the rate of continuously increasing environmental pollution from waste generated by human beings. Use of recycled materials and environmentally friendly approaches to manufacturing can be a good way to deal with these challenges. Similarly, sound pollution has been increasing at an alarming rate due to industrialization and modernization. Use of acoustic insulation materials produced from recycled textile waste can play a vital role in reduction of sound pollution while simultaneously helping reduce municipal solid waste. The goal of this study was to evaluate the recycling of used apparels to produce commercially feasible sustainable products using nonwoven fabrication techniques with a biodegradable thermoplastic binder fiber for possible use as acoustic insulation panels. Recycled denim fibers were used with Sorona® or a PLA binder fiber to successfully produce sound insulation with good performance properties. Maximum transmission loss of about 24 dB and transmission coefficient close to zero at around 1000 Hz were observed. The data indicated that there is a direct correlation between loss of sound transmission with increase in thickness, areal density and decrease in air permeability. When compared with commercially available acoustic insulation material (gypsum board), these products had better insulation properties, indicating that recycled textile products can be used to produce such value-added materials, giving them another useful life before safely disposing in composting environments.