We designed four distinct polyurethane foam (PUF) cellular morphologies by employing low-molecularweight polyols and two types of gelling catalysts. The cellular morphologies contained cavity sizes ranging from 458 μm to 287 μm and open porosities between 0.97 and 0.63. The highest values of the sound absorption coefficient from the four individual specimens were observed at specific frequencies (1,550, 2,000, 2,650, 3,800Hz) owing to their distinct morphological characteristics. Specimen combinations showed enhanced sound absorption compared to their individual specimens due to the synergistic effect between its highly open porosity, which dissipates high-frequency waves, and its small cavity, which diffracts low-frequency waves. The acoustic activity reached to the highest (0.82) value from the double-layered sample with the front small and back large cavities. The small front cavities resulted in a high noise reduction coefficient because of the destructive interference effect of the low-frequency waves through the relatively large cavity of the back layer. However, its reversely arranged specimen showed increased noise reduction coefficient (0.53) due to the air gap effect. Therefore, suitable layer combinations of the different cellular structures can assist in achieving high sound absorption in PUF systems and be utilized in various practical engineering applications.

Polyurethane Sound Absorption Layered Foam Morphology Noise Reduction Coefficient

Choe H, Choi Y, Kim JH, J. Ind. Eng. Chem., 73, 344 (2019)
Sung G, Kim JW, Kim JH, J. Ind. Eng. Chem., 44, 99 (2016)
Kausar A, Polym. Plast. Technol. Eng., 57, 346 (2018)
Zhang C, Li J, Hu Z, Zhu F, Huang Y, Mater. Des., 41, 319 (2012)
Gwon JG, Kim SK, Kim JH, Mater. Des., 387, 448 (2015)
Yang WJ, Lee GY, Park SH, Int. J. Precis. Eng. Manuf., 20, 2041 (2019)
Choi HJ, Kim JH, Polym. Korea, 45, 143 (2021)
Hyuk J, Hyun S, Rae H, Bin C, Yeol S, Sung C, June Y, Ryoun J, J. Sound Vib., 397, 17 (2017)
Cao L, Fu Q, Si Y, Ding B, Yu J, Compos. Commun., 10, 25 (2018)
Sung CH, Lee KS, Lee KS, Oh SM, Kim JH, Kim MS, Jeong HM, Macromol. Res., 15, 181 (2008)
Sung G, Kim JH, Compos. Sci. Technol., 146, 147 (2017)
Choe H, Sung G, Kim JH, Compos. Sci. Technol., 156, 19 (2018)
Baek SH, Kim JH, Compos. Sci. Technol., 198, 108325 (2020)
Oh JH, Kim JS, Nguyen VH, Oh IK, Compos. Part B Eng., 186, 107817 (2020)
Nine MJ, Ayub M, Zander AC, Tran DNH, Cazzolato BS, Losic D, Adv. Funct. Mater., 27, 1 (2017)
Baek SH, Choi HJ, Kim JH, Polym. Korea, 44, 91 (2020)
Kim SK, Sung G, Gwon JG, Kim JH, Int. J. Precis. Eng. Manuf.- Green Technol., 3, 367 (2016)
Choe H, Kim JH, J. Ind. Eng. Chem., 69, 153 (2019)
Wang Y, Zhang C, Ren L, Ichchou M, Galland MA, Bareille O, Polym. Compos., 34, 1847 (2013)
Chen S, Jiang Y, Polym. Compos., 39, 1370 (2018)
Oh JH, Kim J, Lee H, Kang Y, Oh IK, ACS Appl. Mater. Interfaces, 10, 22650 (2018)
Sung G, Choe H, Choi Y, Kim JH, Korean J. Chem. Eng., 35, 1045 (2018)
Jingfeng N, GuiPing Z, JVC/Journal Vib. Control, 22, 2861 (2016)
Bai P, Yang X, Shen X, Zhang X, Li Z, Yin Q, Jiang G, Yang F, Mater. Des., 167, 107637 (2019)
Shen X, Bai P, Yang X, Zhang X, To S, Appl. Sci., 9, 1507 (2019)
Gwon JG, Sung G, Kim JH, Int. J. Precis. Eng. Manuf., 16, 2299 (2015)
Choi HJ, Kim JH, J. Ind. Eng. Chem., 90, 260 (2020)
Choi HJ, Choe H, Seo WJ, Kim JH, Polym. Korea, 43, 532 (2019)
Verdejo R, Stämpfli R, Alvarez-Lainez M, Mourad S, Rodriguez-Perez MA, Brühwiler PA, Shaffer M, Compos. Sci. Technol., 69, 1564 (2009)
Sung G, Kim JS, Kim JH, Polym. Adv. Technol., 29, 852 (2018)
Mvubu MB, Anandjiwala R, Patnaik A, J. Eng. Fiber. Fabr., 14, 874 (2019)