Effect of isocyanate molecular structures in fabricating flexible polyurethane foams on sound absorption behavior

Fabrication and characterization of functional graded polyurethane foam (FGPUF)

“…Indeed, polyurethane foam (PUF) is suitable to fabricate multilayer FGMs. Polyurethane foams consist basically of 2 components, an isocyanate and a polyol component . The isocyanate and polyol are available with variation and different number equivalent weights.…”

Sound Absorption Properties of Polyurethane Foams Derived From Waste Cooking Oil Incorporated With Waste Wood Fiber Filler

“…Therefore, the reduction in pore size is in consistent with further increments of the filler percentage loading. The fibres fillers turn as defects in the matrix as well as it might attribute to the agglomeration of fillers in the matrix at high percentage loading of filler [19]. Smaller pore size directly affects the air flow resistivity and collisions of sound waves with struts through vibration and dissipation energy transfers.…”

Sound absorption behavior of flexible polyurethane foams including high molecular‐weight copolymer polyol

“…Environmental and noise pollution are 2 critical quality‐of‐life issues that have impacted human beings since the expansion of the automobile industry. Noise pollution, in particular, eg, structural and airborne noise, is a major issue that has to be resolved because of the fact that it poses latent health hazards to the hearing of drivers and passengers . Therefore, automotive manufacturers have been adopting porous mediums as sound absorbents to achieve both noise pollution reduction and enhancing the comfort of car travel .…”

“…Therefore, automotive manufacturers have been adopting porous mediums as sound absorbents to achieve both noise pollution reduction and enhancing the comfort of car travel . Absorption of a sound wave in porous materials can be mainly achieved by 2 representative mechanisms: frictions with air and dissipation by collision with cell walls . Polyurethane foam, one of the typical materials used in sound absorption applications, has been used as a good candidate to dissipate the sound energy, and also its sound absorption characteristic can be controlled by varying raw materials such as polyol, isocyanate, cross‐linking agent, blowing agent, surfactant, catalysts, and any other additives .…”

“…Chen et al studied applications of various foaming and cross‐linking agents to improve sound absorption property by examining porosity, airflow resistivity, and foam density. In addition, types of isocyanate molecular structure were also studied for increasing sound absorption performance by controlling phase separation by Sung et al…”