Cellular structure control and sound absorption of polyolefin microlayer sheets

In this work, a novel microlayer foam/film sheet with alternating soft/soft layers was successfully made via the microlayer co-extrusion technology. A blend of linear low density polyethylene (LLDPE) with poly (ethylene-octene) elastomer (POE) and foamed POE were used as the film and foam layers, respectively. Cross-linked POE showed enhanced melt strength, enabling well-defined cellular structure in the foam layers of the microlayer structure. Meanwhile, this technique provides a new mean to obtain polyolefin foaming material with excellent sound absorption characteristics. In select wavelengths, the sound absorption coefficient of the microlayer foam/film structure improved 2–3 times compared with conventional single-layer materials. In addition, the mechanical properties of the foam/film sheets were also improved markedly through the multilayer assembly of foam/film layers at the micron scale.