Effect of high molecular weight isocyanate contents on manufacturing polyurethane foams for improved sound absorption coefficient

Noises generated in automobile compartments can be controlled by utilizing sound absorption and insulation materials such as polyurethane foams. Polyurethane foams are synthesized by varying polymeric methylene diphenyl diisocyanate (MDI) content for exploring the effect of high functional isocyanate on cellular and acoustic properties. The use of polymeric MDI affects polyurethane matrix modulus and drainage flow rate of the foams, and it also has strong effects on cell structure and air flow resistance (AFR). The highest sound absorption coefficient is achieved at the optimum amount of the polymeric MDI. Therefore, the optimum amount of polymeric MDI content is recommended to achieve not only high sound absorption coefficient but also high transmission loss from the polyurethane foams.