Influence of Processing Conditions on Productivity, Thermal and Rheological Properties of Reprocessed Low Density Polyethylene

Abstract

The market for recycled thermoplastic polymers is undergoing a sharp increase, although recyclate polymers are regarded as materials with inferior properties when compared to the virgin material. This study investigates the behavior of non-contaminated scraps of low density polyethylene (LDPE) from the plastic packaging industry after single processing stage, in terms of the productivity and the thermal and rheological properties. The LDPE used was reprocessed on a single-screw extruder (Miotto) of 90 mm screw diameter and L/D = 25. Three screw speeds (80, 90 and 100 min−1) were investigated at three processing temperatures (200, 250 and 300°C). The reprocessed materials were characterized by thermogravimetric analysis TGA, parallel plates rheometry and productivity. The results obtained by TGA showed a typical range of polyolefin degradation (350 to 450°C). The viscoelastic properties did not show significant changes in relation to the rheological behavior. Increasing the temperature and screw speed promoted a productivity gain of approximately 30%. This suggests that under the conditions studied it is possible to reprocess this material with good productivity ensuring its thermal, mechanical and rheological properties.

Evaluation of mechanical properties and physical interactions of a ternary blend of poly(ethylene‐co‐octene)/poly(ethylene‐co‐vinyl acetate)/poly(vinyl chloride) in the molten state

“…At low amplitudes of deformation, under linear viscoelastic regimen, the relaxation modulus can be obtained for all levels of deformation 13. However, in the study of viscoelasticity, several physical functions, such as relaxation H (τ), cannot be directly obtained from experiments 14. Nevertheless, in many cases, these can be obtained from an experimentally measurable quantity through the resolution of an inverse problem.…”

Influence of different organomodified clays on the viscoelastic response of ethylene vinyl acetate//poly(vinyl chloride)/organoclay nanocomposites

“…The relaxation spectra (H(t)) were estimated from theoretical concepts that can be obtained in the literature. 8,[12][13][14][15] A dynamic mechanical analyzer (DMA; model 2980, TA instruments, New Castle, Delaware, USA) was used to perform temperature sweeps in dual cantilever mode from À130 to 60 C at a heating rate of 3 C min À1 at 1 Hz and a strain amplitude of 10 mm to ensure a linear response.…”