Control of the Structure and Morphology for Production of Novel LDPE Acoustical Foams

This paper discusses the control of the foaming process for production of variable microcellular structures and morphologies for novel acoustical foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Crosslinked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 – 95%), high microcellular cell densities (9×10 ⁸ – 1.6×10 ⁹ cells/cm ³ ) and desired expansion ratios (3 – 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced.