In a study in which sound-absorbing composites were used using sawdust and polyurethane foam, the value of the coefficient in the sound-absorbing tests at 500 Hz increased with a 10% increase in polyurethane concentration. Polyurethane foam is commonly used as a sound-absorbing material due to...
A large number of hydrophilic phenolic hydroxyl and hydroxymethyl groups of PF easily absorb atmospheric moisture, resulting in the damage of the glue line and hydrolysis of resin [8]. The modification of anti-aging property for PF is mainly achieved by three methods. One is to reduce the ...