Chemical treatment of wood fibers to enhance the sound absorption coefficient of flexible polyurethane composite foams

2018 ◽  
Vol 156 ◽  
pp. 19-27 ◽  
Author(s):  
Hyeon Choe ◽  
Giwook Sung ◽  
Jung Hyeun Kim
Keyword(s):  
Absorption Coefficient ◽  
Chemical Treatment ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Wood Fibers ◽  
Polyurethane Composite ◽  
Composite Foams ◽  
Flexible Polyurethane

scholarly journals Extrusion Foaming of Lightweight Polystyrene Composite Foams with Controllable Cellular Structure for Sound Absorption Application

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 106 ◽  
Author(s):  
Yanpei Fei ◽  
Wei Fang ◽  
Mingqiang Zhong ◽  
Jiangming Jin ◽  
Ping Fan ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Cellular Structure ◽  
Sound Absorption ◽  
Lignin Content ◽  
Normal Incidence ◽  
Sound Absorption Coefficient ◽  
Multiwall Carbon Nanotube ◽  
Nucleation Effect ◽  
Composite Foams ◽  
Extrusion Foaming

Polymer foams are promising for sound absorption applications. In order to process an industrial product, a series of polystyrene (PS) composite foams were prepared by continuous extrusion foaming assisted by supercritical CO2. Because the cell size and cell density were the key to determine the sound absorption coefficient at normal incidence, the bio-resource lignin was employed for the first time to control the cellular structure on basis of hetero-nucleation effect. The sound absorption range of the PS/lignin composite foams was corresponding to the cellular structure and lignin content. As a result, the maximum sound absorption coefficient at normal incidence was higher than 0.90. For a comparison, multiwall carbon nanotube (MWCNT) and micro graphite (mGr) particles were also used as the nucleation agent during the foaming process, respectively, which were more effective on the hetero-nucleation effect. The mechanical property and thermal stability of various foams were measured as well. Lignin showed a fire retardant effect in PS composite foam.

scholarly journals Marble Powder Blended Utilization Polyurethane as Soundproof Materials

2021 ◽  
Vol 6 (1) ◽  
pp. 30-36
Author(s):  
Yusrizal MT ◽  
Muhammad Ali ◽  
Nuzuli Fitriadi ◽  
Irwansyah Syam ◽  
Balkhaya ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Test Specimen ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Mass Composition ◽  
Test Results ◽  
Polyurethane Composite ◽  
Alternative Material ◽  
Marble Powder ◽  
The Relationship

As technology advances, the development of equipment used by humans is increasing and most of the equipment produces unwanted sounds that cause noise. To overcome this, an alternative material for soundproofing is needed which is relatively cheap and easily available in the community by using marble powder as a polyurethane mixture in soundproof panels. The purpose of this study was to determine the effect of the sound absorption coefficient value and to determine the relationship between the frequency of the sound source and the sound absorption coefficient of acoustic materials using marble powder mixed with polyurethane in different compositions. The sound absorption test in this study was carried out using a two-microphone impedance tube and has a frequency limit of 125 Hz - 4000 Hz, variations in the mass composition of marble and polyurethane powder 1: 1, 1: 2 and 1: 3 with a thickness of 5 cm, 3cm and 1 cm. Then the test results of the 1: 1 test specimen, the lowest sound absorption coefficient value was obtained 0.10 0.73 cm-1 at a thickness of 1 cm with a frequency of 4000 Hz and the highest was 0.73 cm-1 at a thickness of 5 cm with a frequency of 125 Hz, the test results 1: 2 test specimen, the lowest sound absorption coefficient value is 0.29 cm-1 at a thickness of 5 cm at a frequency of 4000 Hz and the highest is 0.67 cm-1 at a thickness of 5 cm at 250 Hz, then the test results of the test specimen are 1: 3 values The lowest sound absorption coefficient was 0.24 at a thickness of 1 cm at a frequency of 4000 Hz and the highest was 0.71 at a thickness of 5 cm at a frequency of 250 Hz. For the comparison of the sound absorption coefficient values ​​based on the composition and thickness, the lowest and highest sound absorption coefficient values ​​are found in 1: 1 specimens with a thickness of 1 cm and 5 cm with the best sound absorption coefficient values ​​on average at a frequency of 500 Hz, but in material 1:2 and 1:3 obtained the sound absorption coefficient values ​​are in between on the grounds that the thicker the material, the higher the sound absorption coefficient value. Thus it can be concluded that the polyurethane composite material mixed with marble powder can be used as a sound absorbing panel material, especially in a 1: 1 composition

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

scholarly journals Air permeability and sound absorption coefficient changes from ultrasonic treatment in a cross section of Malas (Homalium foetidum)

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Chun-Won Kang ◽  
Eun-Suk Jang ◽  
Nam-Ho Lee ◽  
Sang-Sik Jang ◽  
Min Lee
Keyword(s):  
Absorption Coefficient ◽  
Ultrasonic Treatment ◽  
Sound Absorption ◽  
Gas Permeability ◽  
Treated Wood ◽  
Untreated Wood ◽  
Sound Absorption Coefficient ◽  
Permeability Constant ◽  
Average Value ◽  
Permeability Increase

AbstractWe investigated the effect of ultrasonic treatment on Malas (Homalium foetidum) gas permeability and sound absorption coefficient using the transfer function method. Results showed a longitudinal average Darcy permeability constant of 2.02 (standard deviation SD 0.72) for untreated wood and 6.15 (SD 3.07) for ultrasound-treated wood, a permeability increase of 3.04 times. We also determined the average sound absorption coefficients in the range of 50 to 6.4 kHz and NRC (noise reduction coefficient: average value of sound absorption coefficient value at 250, 500, 1000, and 2000 Hz) of untreated Malas. Those values were 0.23 (SD 0.02) and 0.13 (SD 0.01), respectively, while those of ultrasonic-treated Malas were 0.28 (SD 0.02) and 0.14 (SD 0.02), a 19.74% increase in average sound absorption coefficient.

Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of ​​Noise Reduction

2014 ◽  
Vol 1001 ◽  
pp. 171-176 ◽  
Author(s):  
Pavol Liptai ◽  
Marek Moravec ◽  
Miroslav Badida
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Absorption Coefficient ◽  
Physical Parameters ◽  
Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

scholarly journals Study on the sound absorption behavior of multi-component polyester nonwovens: experimental and numerical methods

2018 ◽  
Vol 89 (16) ◽  
pp. 3342-3361 ◽  
Author(s):  
Tao Yang ◽  
Ferina Saati ◽  
Kirill V Horoshenkov ◽  
Xiaoman Xiong ◽  
Kai Yang ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Absorption Coefficient ◽  
Empirical Model ◽  
Surface Impedance ◽  
Sound Absorption ◽  
Low Frequency ◽  
Accurate Method ◽  
Small Error ◽  
Sound Absorption Coefficient ◽  
Acoustical Properties

This study presents an investigation of the acoustical properties of multi-component polyester nonwovens with experimental and numerical methods. Fifteen types of nonwoven samples made with staple, hollow and bi-component polyester fibers were chosen to carry out this study. The AFD300 AcoustiFlow device was employed to measure airflow resistivity. Several models were grouped in theoretical and empirical model categories and used to predict the airflow resistivity. A simple empirical model based on fiber diameter and fabric bulk density was obtained through the power-fitting method. The difference between measured and predicted airflow resistivity was analyzed. The surface impedance and sound absorption coefficient were determined by using a 45 mm Materiacustica impedance tube. Some widely used impedance models were used to predict the acoustical properties. A comparison between measured and predicted values was carried out to determine the most accurate model for multi-component polyester nonwovens. The results show that one of the Tarnow model provides the closest prediction to the measured value, with an error of 12%. The proposed power-fitted empirical model exhibits a very small error of 6.8%. It is shown that the Delany–Bazley and Miki models can accurately predict surface impedance of multi-component polyester nonwovens, but the Komatsu model is less accurate, especially at the low-frequency range. The results indicate that the Miki model is the most accurate method to predict the sound absorption coefficient, with a mean error of 8.39%.

Towards more reliable measurements of sound absorption coefficient in reverberation rooms: An Inter-Laboratory Test

2020 ◽  
Vol 165 ◽  
pp. 107298 ◽  
Author(s):  
Chiara Scrosati ◽  
Francesco Martellotta ◽  
Francesco Pompoli ◽  
Alessandro Schiavi ◽  
Andrea Prato ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Laboratory Test ◽  
Sound Absorption ◽  
Sound Absorption Coefficient
Sign in / Sign up

Export Citation Format

Share Document