Polyolefins filled with waste rigid polyurethane foam and compatibilized by solid-state shear pulverization during extrusion

Low density polyethylene (PE-LD), high density polyethylene (PE-HD), PE-LD/PE-HD blend at a ratio of 1:1, and polypropylene (PP) were filled with finely-ground waste of rigid polyurethane-polyisocyanurate (PUR-PIR) foam in an amount up to 40 wt %. The components were homogenized with two-roll-mill and then, after granulation, subjected to additional homogenization using the method of solid-state shear pulverization (so-called S3P process) during extrusion. The specimens for comparative studies were obtained by injection molding. The changes in chemical structure (using FT-IR spectroscopy), mechanical properties (tensile and impact tests), rheological properties (MFR, rotational rheometry), and thermal properties (Vicat temperature) of the investigated compositions were determined. It was found that the pulverization has a favorable effect on the characteristics of the examined systems, although the improvement is not significant and clearly depends on the type of matrix polymer and foam content.