Abstract
In this study, blends of poly(lactic acid) (PLA)/linear medium density polyethylene (LMDPE) at different weight ratios were prepared by rotational molding. Two mixing strategies were used to evaluate the effect of phase dispersion on the physical and mechanical properties: (i) Dry-blending (DB) using a high shear mixer, and (ii) melt-blending (MB) using a twin-screw extruder. Thermal, morphological, and mechanical analyses were performed on the neat polymers and their blends. The thermal analysis was completed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and the blends prepared by MB had lower thermal stability than the ones prepared via DB due to some thermo-oxidative degradation through the double thermal process (extrusion and rotomolding). The morphology of the rotomolded parts showed that DB generated larger particle sizes (around 500 µm) compared to MB (around 5 µm) due to the shear and elongational stresses applied during extrusion. The tensile and flexural properties of the rotomolded parts combined the PLA stiffness with the LMDPE toughness independent of the blending technique. Neat PLA presented increments in tensile strength (54%) and flexural strength (111%) for DB compared with MB. A synergistic effect in impact strength was observed in blends with 12 and 25 wt. % of PLA prepared by DB.
Highlights
IntroductionRotational molding is a process to manufacture hollow plastic parts over a wide range of sizes, shapes, and thicknesses [1]
The potential of rotational molding as a manufacturing process for plastic products is limited by some aspects such as difficulties in process control, materials in powder form, long cycle times, and a narrow range of polymers
An extrusion the rotomolding process, the blends were prepared by a simple dry-blending (DB) or an extrusion based melt-blending (MB) process to determine the effect of the mixing strategy on the final thermal and mechanical properties of the rotomolded samples
Summary
Rotational molding is a process to manufacture hollow plastic parts over a wide range of sizes, shapes, and thicknesses [1]. This method presents important advantages over other technologies such as parts without weld lines having low residual stresses combined with lower capital investment costs and greater flexibility for colors and materials changes from part to part [2]. The potential of rotational molding as a manufacturing process for plastic products is limited by some aspects such as difficulties in process control, materials in powder form, long cycle times, and a narrow range of polymers. Some other materials available for rotational molding include polyvinyl chloride, polypropylene, acetate butyrate, polycarbonate, and polyesters, among others [5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
