Effect of Thickness for Sound Absorption of High Density Biopolymer Foams

Abstract

Waste cooking oils are problematic disposal especially in the developed countries. In this paper, waste cooking oil is used as raw material to produce foam. The purpose of the study is to develop the high density solid biopolymer (HDB) by using hot compression moulding technique based on flexible and rigid crosslinking agents. Physical properties such as Scanning Electron Microscope (SEM) and density of HDB were examined. The acoustic study of HDB for flexible and rigid has been measured using impedance tube test according ASTM E1050 standard with multiple layers of thicknesses. It was revealed that higher thicknesses of HDB exhibit less sound absorption coefficients. This situation is occurred for both flexible and rigid HDB. The frequency also shifted to the left when the layers of HDB were increased for both materials. The highest increment was 63.46%, observed from two layers from flexible and rigid HDB. For the conclusion, rigid HDB showed that they could absorb more sound, thus having higher noise reduction coefficient (NRC) than flexible HDB at low frequency.

On the Role of Acoustical Improvement and Surface Morphology of Seashell Composite Panel for Interior Applications in Buildings

“…Many studies found that the density factor will affect the acoustic performance on both sound absorption and transmission loss. Research by Wang and Torng [23] and Latief, et al found the increment of density could increase the sound absorption coefficient in low frequencies [24]. Different results were released in research by Nandanwar, et al where low density fiber boards possess a higher sound absorption coefficient than high density fiber boards [25].…”

“…Many studies found that the density factor will affect the acoustic performance on both sound absorption and sound transmission loss. Acoustical response of wool board was reported by Hua and Enhui (2017) [22], while glass fiber and rockwool materials and high desinty bio-polymer foam (HDBP) were reported by Wang and Trong (2001) [23] and Latief et al (2014) [24] respectively. Another research by Nandanwar et al (2017) [25] showed that lower density fiber board posed a better sound absorption performance compared to similar board with a higher density.…”

Thermal Degradation and Damping Characteristic of UV Irradiated Biopolymer

“…The porosity of BF is higher as compared to CB due to the high porosity in the samples: 0.014 and 0.0043, respectively. This is due to the fact that the materials produced from particle structure gave higher density than the materials produced from cellular structure [18].…”

“…One hundred and sixty grams of biopolymer foam was weighed and filled in the mould cavity with internal core size of 180 × 180 × 15 mm in order to decrease the thickness and pore size by using hot compression moulding. The parameter of the hot compression machine was set at 90 ∘ C of temperature, under 26 tonnes of pressure within 1 hour [18][19][20][21][22]. The compress biopolymer (CB) samples and compress biopolymer composite (CBC) were further prepared into 50 mm × 50 mm × 10 mm block.…”