Acoustic and Thermal Properties of Polymer Composites Reinforced with Lignocellulosic Fibers

2014 ◽  
Vol 624 ◽  
pp. 25-29 ◽  
Author(s):  
Elammaran Jayamani ◽  
Sinin Hamdan ◽  
Pushparaj Ezhumalai ◽  
Soon Kok Heng
Keyword(s):  
Rice Straw ◽  
Sound Absorption ◽  
Polymer Matrix Composites ◽  
Practical Interest ◽  
Acoustic Energy ◽  
Absorption Coefficients ◽  
Compression Moulding ◽  
Lignocellulosic Fibers ◽  
Polypropylene Matrix ◽  
Kenaf Fibers

In this research the Thermogravimetric analysis (TGA) under nitrogen was used to investigate the thermal decomposition processes and sound absorption coefficients was measured using Impedance tube according to ASTM standard E1050 - 10 two microphone method for 2 types of polymer matrix composites. Sample 1 was made of rice straw (RS) reinforced with polypropylene matrix and Sample 2 was made of kenaf fiber reinforced with polypropylene matrix, both composites were fabricated using hot compression moulding technique. The thermal behaviour is of practical interest for conditions associated with temperatures above the atmospheric, as in fire damage, curing or process involving heating procedures. The sound absorption coefficient for a material is the fraction or percentage of incident sound energy that is absorbed by the material. The function of absorptive materials is to transform impinging acoustic energy into heat. The thermal stability of the composites was found to be higher than that of rice straw, kenaf fibers and the polypropylene matrix. The sound absorption coefficients of composites increased as the frequency increased. However, they decreased at the frequency of 1000 Hz and increased again. This decrease and increase was due to the specific characteristic of Lignocellulosic fibers reflecting sound at 1300 Hz but absorbing sound in the middle and high frequency ranges.

Fabrication of Chemically Treated Natural Fibre Reinforced Polymer Matrix Composites and Measurement of its Sound Absorption Coefficients to Regulate Industrial Noise

2013 ◽  
Vol 465-466 ◽  
pp. 896-900
Author(s):  
Elammaran Jayamani ◽  
Pushparaj Ezhumalai ◽  
Sinin Hamdan ◽  
M. Rezaur Rahman
Keyword(s):  
Rice Straw ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Polymer Matrix Composites ◽  
Fiber Reinforced ◽  
Absorption Coefficients ◽  
Compression Moulding ◽  
Industrial Noise ◽  
Polypropylene Composites ◽  
Chemically Treated

The effects of chemically treated natural fibres (rice straw and kenaf) embedded as filler into polypropylene matrix were investigated for its sound absorption properties to regulate the industrial noise. In this respect, untreated natural fiber as well as treated natural fiber reinforced with polypropylene composites were fabricated and compared. The composites were prepared by compression moulding technique. Its sound absorbing characteristic was investigated with the Impedance tube, according to a transfer function method. A two microphone setup was fabricated according to American society for testing materials ASTM E1050-10 and it is used to measure sound absorption coefficients of composites in the frequency range of 300 Hz to 2000 Hz. The sound absorption coefficients of the composites increased with the frequency. However, at 1000 Hz, the sound absorption coefficient decreased for all treated samples and then increased again which is due to specific character of natural fibers. This point of inflexion was due to the specific characteristic of natural fiber reflecting sound at around 1000 Hz, but absorbing sound in the middle and high frequencies. The results indicates that the process of chemical treatment enhanced the sound absorption coefficients by 12.5% for rice straw reinforced Polypropylene and 15.78% for kenaf fiber reinforced Polypropylene composites respectively.

Sound Absorption Property of Agricultural Lignocellulsic Residue Fiber Reinforced Polymer Matrix Composites

2014 ◽  
Vol 663 ◽  
pp. 464-468 ◽  
Author(s):  
Elammaran Jayamani ◽  
Sinin Hamdan ◽  
Soon Kok Heng ◽  
Md. Rezaur Rahman
Keyword(s):  
Rice Straw ◽  
Polymer Matrix ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Urea Formaldehyde ◽  
Natural Fibers ◽  
Construction Materials ◽  
Fiber Reinforced ◽  
Absorption Coefficients ◽  
Low Frequencies

In this research, the sound absorption coefficients of polymer matrix reinforced lignocellulosic fiber composites were investigated. The sound absorbing characteristic of composites was investigated in the impedance tube, according to transfer function method. A two microphone setup was fabricated according to American society for testing materials ASTM E1050-10 and it is used to measure sound absorption coefficients of composites. In this investigation, the influences of two kinds of polymer matrix (Polypropylene and Urea-formaldehyde) and two kinds of natural fibers (rice straw and kenaf) were studied for sound absorption coefficients. Four samples of novel sound absorbers were made with different matrix and fibers composition, Sample 1 and 2 was made of rice straw reinforced with polypropylene and Urea-formaldehyde and Sample 3 and 4 was made with kenaf fiber reinforced with polypropylene and Urea-formaldehyde matrix. Sound absorption coefficients were measured at frequencies from 300 Hz to 2000 Hz. The results showed when the frequencies increased, sound absorption increased until it reached a frequency of 2000 Hz but at 1200 Hz sound absorption decreased for all the samples this is due to specific character of natural fibers. From the result, the kind of natural fiber did not have significant influences on sound absorption coefficients. As results it was found that the matrix influence more in sound absorption properties in low frequencies; and due to that fact the above composites are low sound absorbing materials; but still they are better than other construction materials available in sound absorbing properties.

The influence of alkaline treatment on acoustical, morphological, tensile and thermal properties of Kenaf natural fibers

2020 ◽  
pp. 152808372094424
Author(s):  
Seyed Ehsan Samaei ◽  
Hasan Asilian Mahabadi ◽  
Seyyed Mohammad Mousavi ◽  
Ali Khavanin ◽  
Mohammad Faridan ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Sound Absorption ◽  
Hybrid Composites ◽  
Natural Fibers ◽  
Alkaline Treatment ◽  
Strength Properties ◽  
Absorption Coefficients ◽  
Surface Appearance ◽  
Kenaf Fibers ◽  
The Impact

Among fibers with lignocellulosic origin, Kenaf fiber, because of its advantages and as a sustainable alternative to synthetic fibers has received increasing attention for manufacturing hybrid composites with reasonable acoustical and physical properties. The present study deals with the impact of chemical treatment of Kenaf fibers on the overall properties of hybrid composites fabricated from these fibers. Also, the results from predictive analytical model of sound absorption for these composites were employed for comparison with the experimental findings. Kenaf fibers were treated at room temperature with 6% concentration of sodium hydroxide (NaOH) and 4 h immersion time. Having manufactured the composites with the treated and untreated fibers, the normal sound absorption coefficients and tensile strength properties of these sample composites were determined according to ISO 10534-2 and ASTM C1557 − 14, respectively. The SEM analysis of the treated and untreated fibers revealed that in terms of fiber diameter and morphology the former was thinner and had better surface appearance. The experimental measurement of acoustic absorption coefficients of the composites made of treated fibers demonstrated superior sound absorption properties and tensile strength. The revised empirical models proposed by Delany & Bazley and Garai & Pompoli along with Nelder-Mead simplex method were employed and well predicted the sound absorption coefficients of the sample composites. There was also a fair consistency between the experimental and predicted results.

Investigation on Sound Absorption Coefficients of Betel Nut Fiber Reinforced Polymer Matrix Composites

2013 ◽  
Vol 465-466 ◽  
pp. 901-905
Author(s):  
Elammaran Jayamani ◽  
Pushparaj Ezhumalai ◽  
Sinin Hamdan ◽  
M. Rezaur Rahman
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Polymer Matrix ◽  
Sound Absorption ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Wave Method ◽  
Betel Nut ◽  
Absorption Coefficients ◽  
Standing Wave Method

This research investigates the sound absorption coefficients of betel nut fibers (Areca Fibers) reinforced with thermoplastic (Polypropylene) and thermoset (Unsaturated polyester) matrix composites with different fiber loadings and frequencies. In this research we used 5%, 10%, 15%, and 20% of betel nut fibers in the polymer matrix and the test frequencies are from 400 Hz to 1800 Hz. There are two standardized methods used for measuring the normal incidence sound absorption coefficient of composites namely, standing wave method (ISO 10534-1) and two fixed microphone method (ISO 10534-2). From this research, betel nut fibers reinforced with polymer matrix composites have good sound absorption coefficients at high frequency although the overall sound absorption coefficient is quiet low. The Increase in fiber loading increases the sound absorption coefficients of composites. The types of polymer did not have significant influences on sound absorption coefficients. Both methods of measurement show the same results where the two fixed microphone method is much quicker than standing wave method.

scholarly journals Study of Sound Absorption Coefficients and Characterization of Rice Straw Stem Fibers Reinforced Polypropylene Composites

BioResources ◽  
2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Elammaran Jayamani ◽  
Sinin Hamdan ◽  
Md Rezaur Rahman ◽  
Muhammad Khusairy Bin Bakri
Keyword(s):  
Rice Straw ◽  
Sound Absorption ◽  
Absorption Coefficients ◽  
Polypropylene Composites

scholarly journals Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1091 ◽  
Author(s):  
Dengke Li ◽  
Daoqing Chang ◽  
Bilong Liu
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Porous Materials ◽  
Sound Absorption ◽  
Azimuthal Angle ◽  
Octave Band ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Perforated Plates ◽  
Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

scholarly journals Preparation and Characterization of Gradient Compressed Porous Metal for High-Efficiency and Thin-Thickness Acoustic Absorber

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1413 ◽  
Author(s):  
Xiaocui Yang ◽  
Xinmin Shen ◽  
Panfeng Bai ◽  
Xiaohui He ◽  
Xiaonan Zhang ◽  
...  
Keyword(s):  
Sound Absorption ◽  
High Efficiency ◽  
Structural Parameters ◽  
Porous Metal ◽  
Theoretical Models ◽  
Absorption Efficiency ◽  
Total Thickness ◽  
Porous Metals ◽  
Absorption Coefficients ◽  
Optimal Average

Increasing absorption efficiency and decreasing total thickness of the acoustic absorber is favorable to promote its practical application. Four compressed porous metals with compression ratios of 0%, 30%, 60%, and 90% were prepared to assemble the four-layer gradient compressed porous metals, which aimed to develop the acoustic absorber with high-efficiency and thin thickness. Through deriving structural parameters of thickness, porosity, and static flow resistivity for the compressed porous metals, theoretical models of sound absorption coefficients of the gradient compressed porous metals were constructed through transfer matrix method according to the Johnson–Champoux–Allard model. Sound absorption coefficients of four-layer gradient compressed porous metals with the different permutations were theoretically analyzed and experimentally measured, and the optimal average sound absorption coefficient of 60.33% in 100–6000 Hz was obtained with the total thickness of 11 mm. Sound absorption coefficients of the optimal gradient compressed porous metal were further compared with those of the simple superposed compressed porous metal, which proved that the former could obtain higher absorption efficiency with thinner thickness and fewer materials. These phenomena were explored by morphology characterizations. The developed high-efficiency and thin-thickness acoustic absorber of gradient compressed porous metal can be applied in acoustic environmental detection and industrial noise reduction.

scholarly journals COMPARATIVE ANALYSIS OF SOUND SUPRESSING LIGHTWEIGHT STRUCTURED PANELS AND MODERN NOISE PROTECTION MEANS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 30-35
Author(s):  
Valery Murzinov ◽  
Pavel Murzinov ◽  
Irina Ivanovna
Keyword(s):  
Comparative Analysis ◽  
Sound Absorption ◽  
Absorption Coefficients ◽  
Acoustic Insulation ◽  
Materials Used ◽  
And Control

This article provides an overview of modern soundproof materials and structures used for acoustic insulation. Presently, we can find plenty of such noise insulation and sound absorption materials. One of the popular means to reduce noise and control sound today is the acoustic panels able to suppress and absorb different sounds. The article also analyses the effectiveness of acoustic and sound protection materials used in the industrial sphere. The comparative analysis of the sound protection and absorption effectiveness is carried out using sound absorption coefficients. It also presents the construction of a sound suppressing lightweight structured panel designed by the authors. The authors noted that these panels have better characteristics in comparison with other modern sound protection materials.

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