What are the differences in sound absorption between polyethylene and polypropylene?

Polyethylene and polypropylene are two widely used polymers with distinct acoustic properties. Polyethylene, particularly in foam form, exhibits moderate sound absorption due to its porous structure, which dissipates sound energy effectively. It performs well in mid-to-high frequency ranges. Polypropylene, on the other hand, has lower inherent sound absorption but can be engineered into fibrous forms that trap sound waves efficiently. The material's stiffness and density play crucial roles in its acoustic performance. Polypropylene fibers are often used in composite materials for noise reduction applications. While polyethylene foam is better for impact noise, polypropylene-based materials may outperform in airborne sound absorption when properly designed. The choice between them depends on specific frequency requirements, environmental conditions, and application needs.