Effects of ammonium persulfate on coconut wood (Cocos nucifera L.) cellulose, hemicellulose, and lignin polymers: Improved sound absorption capacity

Abstract

The rational design of sound absorption boards made of wood materials is an attractive field of research. This article describes a simple and low‐cost ammonium persulfate treatment on coconut wood cell walls (Cocos nucifera L.). Reaction parameters such as concentration of reactant and reaction time were optimized. The results of different instrumental characterization such as X‐ray photoelectron spectroscopy, X‐ray diffraction, attenuated total reflectance–Fourier transforms infrared spectroscopy, and scanning electron microscope supports the chemical alterations of the wood cell wall. The quantitative analysis of hemicellulose, cellulose, and lignin was performed. The significant changes in cell‐walls enhanced average sound absorption coefficient at each frequency range: 60.4% at 500–1000 Hz (t = −10.593 and p < 0.001), 80.8% at 1000–2000 Hz (t = −4.798 and p < 0.001), 96.2% at 2000–4000 Hz (t = −58.527 and p < 0.001) and 83.0% at 500–64000 Hz (t = −51.261 and p < 0.001). It is due to the increment of gas permeability (288.3%, p = <0.001). These results could be beneficial for new research on wood‐based sound absorption materials to regulate the acoustic environment in houses.

Innovative sound absorption technique: Step‐shaped ceramic fiberboards with veneer attachment for walls

“…The permeability measured by the porometer is correlated to sound absorption, while the measurement of ceramic fibers' pore diameter is related to gas permeability 44,45 . For testing with the capillary flow porometer, the “dry up/wet up” method was employed, involving creating a “dry curve” and then a “wet curve” using Galwick solution 46 . Gas flow rates for both curves were compared at the same pressures, and pore size was determined based on the pressure and pore size relationship.…”

“…Gas flow rates for both curves were compared at the same pressures, and pore size was determined based on the pressure and pore size relationship. The pressure is gradually increased on the wetted specimen, causing gas to be extruded consecutively from large to small pores according to capillary pressure 46 . The pressure at the start of this process is referred to as the “bubble point,” and the maximum pore size was calculated using Equation ().…”

“…44,45 For testing with the capillary flow porometer, the "dry up/wet up" method was employed, involving creating a "dry curve" and then a "wet curve" using Galwick solution. 46 Gas flow rates for both curves were compared at the same pressures, and pore size was determined based on the pressure and pore size relationship. The pressure is gradually increased on the wetted specimen, causing gas to be extruded consecutively from large to small pores according to capillary pressure.…”

“…The pressure is gradually increased on the wetted specimen, causing gas to be extruded consecutively from large to small pores according to capillary pressure. 46 The pressure at the start of this process is referred to as the "bubble point," and the maximum pore size was calculated using Equation ( 5). The limiting diameter (D), surface tension (τ), and pressure (p) are expressed in the following equation:…”

Cellulose Fibers-Based Porous Lightweight Foams for Noise Insulation

“…However, they do have some negative aspects when compared to other commonly used polymeric materials. Here are some of the drawbacks of using cellulose fibers in NISp applications [ 36 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. (i) Moisture sensitivity, (ii) poor fire resistance, (iii) pest attraction, (iv) settling and decomposition, (v) dust and allergen release and (vi) limited applications mean that CFs may not be ideal for situations where moisture or fire resistance is a critical concern.…”