Steam explosion of windmill palm fiber as the filler to improve the acoustic property of rigid polyurethane foams

Rigid polyurethane foam is a common sound absorption material in the construction owing to its structure that can effectively absorb sound waves by air friction and structural vibration. Windmill palm fibers pretreated with acid, alkali, or steam explosion were employed with polyurethane foam to improve foam acoustic performance in this study. The open porosity of the composite foam is closely related to the different treatments of windmill palm fiber and the content of windmill palm fiber in the composite. Steam explosion treatment removes silicon and wax layers on the surface of the windmill palm fiber, and the increased surface area after steam explosion provides a number of possible coupling reaction sites between the fiber and matrix. The model calculation shows that high airflow resistivity leads to high acoustic property, which is approach with the experimental results. The peak value of acoustic property indicated that the optimal content of windmill palm fiber in the rigid polyurethane foams is 1 wt%.