Natural fibre materials are one of the major ways to improve environmental pollution and new materials need to be considered to find the best solutions. This study presents an experimental investigation on pure micro porous materials from two types of fibres: Date Palm Fibre (DPF) and Coconut Coir Fibre (CCF). This study was conducted to examine the potential for using these two types of fibres as sound absorbers. To account for the effects of the characteristics of these materials, such as thickness and density, on the acoustic absorption coefficient of a sound absorber, the measurements were conducted in an impedance tube on normal incidence acoustic absorption. The experimental data indicate that two peak values of Acoustic Absorption Coefficient (AAC) are 0.98 at 1381.25 Hz-1506.25 Hz for the 40 mm thick sample and the AAC at high frequency for the same thickness is 0.99 at 4521.88-4906.25 Hz; for 20 mm thickness, the peak value is 0.84 at 2606.25-3025 Hz. The AAC of the CCF sample is 0.77 at 2434.38-2543.75 Hz for a 40 mm thickness, but for 20 mm thickness, the value is 0.71 at 4184.38-4575 Hz. The Acoustic Absorption Coefficients (AAC) of the two types of materials were increased at all frequencies when the thickness of the sample was increased. The results show that date palm fibre and coconut coir fibre have good acoustic properties at low and high frequencies and can be used as an alternative replacement to conventional products. The comparisons between the two panels show a good potential because they are cheaper and lighter in comparison to asbestos and rock wool industrial materials

This study investigated and compared the acoustic characteristics of two natural organic fibres: date palm fibre and oil palm fibre, these materials eligible for acoustical absorption. During the processing stage, both fibre sheets are treated with latex. The two fibres are compressed after latex treatment Circular samples (100 mm in diameter and 28 mm, based on the measurement tube requirements) are cut out of the sheets. The density of the date palm fibre sheet is 150 kg/m 3 for a 50 mm thickness and 130 kg/m 3 for a 30 mm thickness. In contrast, the density of oil palm fibre is 75 kg/m 3 for a 50 mm thickness and 65 kg/m 3 for a 30 mm thickness. An impedance tube was used to test the thicknesses of both samples based on international standards. The results show that the date palm fibre exhibits two Acoustic Absorption Coefficient (AAC) peaks: 0.93 at 1356 Hz and 0.99 at 4200-4353 Hz for the 50mm-thick sample. In contrast, the 30-mm-thick sample has a single AAC peak of 0.83 at 2381.38-2809.38 Hz. However, the 50-mm-thick oil palm fibre has an AAC peak of 0.75 at 1946.88-2178.13 Hz and the 30-mm-thick oil palm fibre has an acoustic absorption coefficient peak 0.59 at 3225-3712.5 Hz. Thus, the date palm fibre has a higher acoustic absorption coefficient for high and low frequencies than does oil palm fibre. Both fibres are promising for use as sound absorber materials to protect against environmental noise pollution.

Problem statement: An organic material is one of the major requirements to improve living environment and the invention of materials need to consider for the best solution. This study presents an experimental investigation on pure porous from Date Palm Fibre (DPF). The effectiveness of sound absorbers depends on structural architecture of this material. This study was conducted to examine the potential of using date palm fibre as sound absorber. The effects of porous layer thicknesses, densities and compression on Acoustic Absorption Coefficient (AAC) of sound absorber using date palm fibre were studied. Approach: Rigid frame Johnson-Allard Model for various sample thicknesses was used in this study. The measurements were conducted in impedance tube on normal incidence acoustic absorption. The date palm fibre was mixed with latex which used for physical treatment on this material. Acoustic absorption behaviour of a porous material with different thicknesses was studied as well as samples with same thickness but different densities. In addition, samples with same properties but different period of compression time were inspected. The tests were in accordance to ISO 10534-2 and ASTM E1050-98 international standards for Acoustic Absorption Coefficient (AAC). Results: The experimental data indicates that two peak values of AAC is 0.93 at 1356Hz for sample with 50 mm thickness, also the AAC at high frequency for same thickness is 0.99 at 4200-4353 Hz that means able to improve acoustic absorption coefficient at low and high frequencies with significant increasing. Meanwhile, another experimental results were acquired for AAC of date palm fibre, with samples thicknesses of 35 mm at different densities .The results show that denser sample (11 Kg m −3 ) has higher AAC value of 0.83 at 1934-2250 Hz as compared to less dense sample (9.92 Kg m −3 ) with AAC value 0.84 at 2443-2587 Hz . Conclusion: Acoustic absorption coefficient AAC of date palm fibre was increased at all frequencies when the thickness of sample was increased, particularly at low frequencies less than 1200 Hz. The introduction of latex on the samples adds stiffness, so that sound can be dissipated significantly as it travels through material. Results from the experimental tests show that date palm fibre has good acoustic properties at low and high frequencies and can be used as an alternative replacement to conventional product. Increasing density of the samples, increase the AAC as well. The innovative acoustic absorption panel has a good potential because they are cheaper and lighter in comparison to asbestos and rock wool industrial materials.