Synergistic effects of metal stearate, calcium carbonate, and recycled polyethylene on thermo-mechanical behavior of polyvinylchloride

Thermo-mechanical recycling process is the cheapest way to recover plastic waste such as LDPE with low ecological impact. Thus, the goal of this work is to obtain high-performance microcomposites from polyvinyl chloride (PVC), recycled low-density polyethylene (r-LDPE), calcium carbonate (CaCO3), and calcium/zinc stearate (CaSt2/ZnSt2). The effect of the two ratios of thermal stabilizers with different concentrations on the mechanical properties and thermal stability of PVC and PVC/r-LDPE (1:1) blend was studied. The samples were characterized using infrared spectroscopy (FTIR), mechanical tests, thermal analysis, and scanning electron microscopy (SEM). The addition of 5 phr of CaSt2:ZnSt2 (9:1) to PVC (MC4) resulted in optimal tensile strength and elongationat-break values. In addition, MC4 showed high thermal stability. Moreover, the incorporation of r-LDPE into PVC made the PVC matrix stronger and more stable than pure PVC, which yields high mechanical and thermal performances. Furthermore, an outstanding synergistic effect is obtained when a heat stabilizer rich in calcium is combined with CaCO3 and r-LDPE. This PVC/r-LDPE blend as a composite can be used in several industrial fields.