A Basic Study of Applicability of Regrind Polyethylene in Rotational Molding

Abstract

An experimental study on the use of regrind in rotomolded polyethylene parts is described. We investigated the introduction of 15, 30, and 100% reground polyethylene into the rotational molding operations. The number of regrind cycles varied from one to four. Rotational molding was done in air and nitrogen inner gas, respectively. The mechanical properties of the parts were investigated, including low temperature dart impact test, tensile test, and Izod impact test. Generally it was found that nitrogen atmospheres substantially improved the impact properties of rotomolded parts made with virgin polyethylene. With parts containing 15% and 30% regrind, the impact properties of boxes made in nitrogen are substantially higher than those molded in air. Also, adjustment of oven time to slight undercure for 15% regrind containing parts rotomolded in air gave good impact properties.