In recent years, rapid growth in industries and urbanization due to economic development has led to the emergence of multiple environmental problems such as noise pollution and global warming. According to a recent report by the World Health Organization, noise pollution is the second most threatening environmental factor to human health after air pollution. On the other hand, global warming has emerged as one of the most serious environmental problems in the past two decades, with potential consequences such as climate change and the release of greenhouse gases. This has resulted in increased public awareness and the implementation of stringent laws to control noise and reduce energy consumption. One of the most common methods for reducing noise pollution and managing energy consumption is the use of fibrous porous materials as sound absorbers and thermal insulators in buildings. On the other hand, municipal and industrial waste has become a serious environmental problem for countries. Cigarette filters, mostly made of cellulose acetate fibers, are one of the most important types of waste. The aim of this research is to design and construct fibrous panels made of cigarette filters for use as sound absorbers and thermal insulators in buildings. To this end, cigarette filters were opened using an opener. The opened fibers were then mixed with a binder, according to the experimental design based on the Response Surface Method (RSM) with a Central Composite Design (CCD) approach, and molded into panels of four different thicknesses (10, 15, 20, and 25 mm) and four different densities (120, 160, 200, and 240 kg/m³). The acoustic properties of the panels were eva‎luated using the two-microphone impedance tube based on the transfer function method according to ASTM E1050, and their thermal properties were eva‎luated using the guarded hot plate method according to ASTM C177-85. Additionally, the morphological properties of the panels were examined using FE-SEM. The results showed that the average sound absorption average (SAA) and effective thermal conductivity (Keff) of the fabricated panels are within the range of 0.29-0.62 and 0.038-0.052 W/mK, respectively. It was found that increasing the density in low and medium thicknesses (10 to 15 mm) improves the acoustic properties of the samples while increasing the density in thicknesses greater than 15 mm has a negative effect on SAA. Furthermore, it was identified that increasing the density leads to an increase in Keff and consequently a decrease in the effectiveness of the thermal insulation properties. The results revealed that increasing the thickness in low and medium densities (120-180 kg/m3) results in an increase in SAA, whereas in higher densities, it has the opposite effect. Additionally, the thickness did not show a significant effect on Keff. Statistical analyses demonstrated that based on the p-value, lack of fit p-value, and reasonable agreement between the adjusted R² and the residual sum of squares, the cubic model is able to accurately predict the values of SAA and Keff of the panels. Based on the proposed models, optimal conditions for achieving the highest SAA and the lowest Keff were determined at a thickness of 25 mm and a density of 120 kg/m3. Under these conditions, the predicted values of SAA and Keff for the panel are 0.540 and 0.370, respectively. Ultimately, three fibrous panels were produced under optimal conditions and their acoustic and thermal properties were eva‎luated. The results showed that there is a very good agreement between the model results and the experimental results with a confidence interval of 95%. It was concluded that fibrous panels made from cigarette butts as innovative and sustainable building materials provide a highly competitive performance compared to their commercial counterparts.

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ابراهيم تابان

حسين حسني , فاطمه حقيقت