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High density polyethylene (rHDPE) is extruded 1 to 8 times, with and without detergent, to simulate the effects of impurities on the material and on the artificial ageing process. The mechanical properties, thermal stability, rheology, Fourier transform infrared spectroscopy (FTIR), and volatile organic compound (VOC) emissions are measured. According to the results, ageing of rHDPE increases tensile strength, reduces elongation, and enhances side chain branching of the material and thus causes rheological changes. The addition of detergent reduces changes in mechanical properties and rheological behavior but accelerates thermal degradation. VOC and FTIR measurements of the samples with detergent addition show generation of harmful 1,4‐dioxane. The amount of total emission, as well as emissions of important perfumes limonene and 1R‐α‐pinene, decreases during multiple extrusion cycles. Heating of the plastics is found to be a major factor in the VOC emission reduction. Impurities have a notable effect on the artificial ageing results. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43766.

Mechanical recycling of multilayer plastic films from food packages was investigated. The multilayer films were manually separated from municipal solid waste, washed, grinded, and finally compounded at 0–100 wt% concentrations with virgin low‐density polyethylene (PE‐LD). Polyethylene grafted with maleic anhydride (PE‐g‐MA) compatibilizer was used in two of the compounds to replace 2 and 5 wt% of the PE‐LD to study its effect as well. PE‐g‐MA is expected to improve the mechanical properties of the compounds by promoting the adhesion between incompatible polymer phases. The composition of the compounds was characterized with Fourier‐transform infrared spectroscopy and differential scanning calorimetry and their properties were studied with tensile testing and rotational rheometer measurements. All tested compounds had relatively good mechanical properties and processability. This indicates that recycled multilayer films could replace at least part of the virgin PE‐LD in applications where high‐thermal stability or good visual appearance is not required. The PE‐g‐MA compatibilizer did not have a significant effect on the mechanical properties of the compounds.