High‐performance acoustic‐damping flexible polyurethane foams (FPUFs) were fabricated using synthesized linear saturated aliphatic polyesters, methylene diphenyl diisocyanate, and other reagents by one‐shot bulk polymerization (isocyanate index = 110 and water content = 5%). In this study, the effect of the chemical structure of different LSAPs on microphase separation and acoustic dampening behavior of FPUFs was investigated using atomic force microscopy, Fourier transform infrared spectroscopy, compressive strength, optical microscopy, and an impedance tube device. The results revealed that by increasing the microphase separation, sound absorption efficiency increased up to 45%. Also, by increasing microphase separation, compressive strength, open‐cell contents, roughness, and cell size distribution of FPUFs increased, and the average cell size decreased. Sound wave energy dissipation of FPUFs can be explained by the synergistic actions of the microphase separation including the viscoelastic behavior of segments and increasing of drainage flow pathway. Finally, the results revealed that soundproofing FPUFs under optimum conditions for microphase separation and drainage flow can be promising candidates for use as sound‐insulating materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46744.

In this study, a new high-performance acoustic damping flexible polyurethane foam (FPUF) was successfully designed and fabricated using synthesized linear saturated aliphatic polyester resin as polyol, methylene diphenyl diisocyanate, and ethylene glycol, monoethanolamine, and ethylenediamine as chain extenders and other reagents by one-shot bulk polymerization (isocyanate index = 100 and water content = 2.5%). The effect of the chemical structure of different chain extenders on micro-phase separation and acoustic damping properties of FPUFs were investigated using comprehensive characterization techniques such as atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), compressive strength, optical microscope, and‏ ‏impedance tube. It was indicated that the micro-phase separation degree of the FPUF matrix increased with increasing amine content in the chain extender structure due to the more bidentate hydrogen bondings formation between urea-urea groups. Also, by increasing micro-phase separation, average cell sizes decreased and compressive strength, open-cell contents%, cell walls roughness, and cell size distribution of FPUFs increased. According to the sound absorption spectra, it was found that sound absorption efficiency of FPUF containing DEA was higher than FPUF manufactured by EG by 13.23% in the range of 1500–4000 Hz due to the increase of the amine content of chain extenders. These results indicate that the acoustic properties of FPUFs can be explained with the synergistic actions of micro-phase separation including the viscoelastic behavior of hard-soft segments and increasing of airflow pathway leading to dissipating of the kinetic energy of sound waves. Finally, the results revealed that soundproofing FPUFs with an optimum condition for micro-phase separation and drainage flow can be a promising candidate for using as sound insulating materials in transportation industries such as airplanes, trains, etc.

High-efficiency sound absorbing flexible polyurethane foams (FPUFs) are manufactured using nonpolar polyester resin, methylene diphenyl diisocyanate, and other reagents by one-shot bulk polymerization. In this study, the impact of the isocyanate index (90, 100, and 110) and water content (2.5 and 5%) on the microphase separation and soundproofing behavior of FPUFs are examined using atomic force microscopy, Fourier transform infrared spectroscopy, optical microscope, and an impedance tube device. The results reveal that the increase of the isocyanate index and water content leads to the increase of the cell size, cell size distribution, open-cell content, cell wall roughness, and microphase separation. Also, maximum sound absorption coefficient (α) reaches to 0.98 and the average of α in the frequency range of 1500-4000 Hz increases from 0.7 to 0.87 by increasing the water content from 2.5 to 5% and isocyanate index from 90 to 110; therefore, acoustic damping performance enhances up to 26.24% due to the synergic effects of microphase separation on the viscose media formation, open-cell content, cell wall roughness, cell size, and cell size distribution. In conclusion, FPUFs with an optimal amount of microphase separation and drainage flow can be a promising candidate for sound insulating materials.

Highly crosslinked gelatin-based hydrogels were prepared via a green technique including a microwave-assisted methacrylation using glycidyl methacrylate or methacrylic anhydride and an LED-curing with a time, energy, and reagent-saving approach.

No abstract