Investigation on Synergistic Effects and Char Morphology during Co-pyrolysis of Poly(vinyl chloride) Blended with Different Rank Coals from Northern China

Abstract

Co-pyrolytic technology of plastic wastes and coal has been widely studied as a promising method to dispose of plastic wastes. Evaluation on pyrolytic behavior and product properties is important for optimizing this technology. In this work, pyrolytic behavior of poly(vinyl chloride) (PVC) blended with two typical coals from northern China (Pingzhuang lignite and Shenmu bituminous) was investigated by applying a nonisothermal thermogravimetric analyzer. Furthermore, scanning electron microscopy technique (SEM) was applied to explore the surface morphology of residual chars. Thermal analysis curves of PVC/ coal blends showed nonadditivity performance meaning the existence of synergistic effects between PVC and coal during copyrolysis. Negative synergistic effects were observed in the temperature below about 370°C, whereas positive synergistic effects happened at high temperature. In the final pyrolytic temperature, the formation of volatiles was promoted due to synergistic effects. In addition, isoconversional method was applied to calculate activation energy, and nonadditivity performance on the mean activation energies of PVC/coal blends was also found. The SEM results showed the fractal dimensions of the residual chars from pyrolysis of PVC/coal blends were larger than those from isolated samples, and increased with the increment of coal blending ratio. This variation trend showed that the inhomogeneous degree of the residual char from PVC increased by copyrolysis with coals, which can improve its reactivity of gasification or combustion.

Thermogravimetric analysis on the co-combustion of biomass pellets with lignite and bituminous coal

“…TG analysis can summarize combustion characteristics and kinetic model shows the variation of the activation energy. However, the reaction mechanisms between coal and biomass are not fully understood, and there are some different or even contrary conclusions [19]. In addition, there is nearly no research report regarding the utilization of catkins added into biomass pellets.…”

Facile Synthesis of Di-Mannitol Adipate Ester-Based Zinc Metal Alkoxide As Bi-Functional Additives for PVC

“…Although lead salts have the best thermal stability for PVC, the toxicity restricts their application. Metal soap, such as calcium stearate (CaSt2), and zinc stearate (ZnSt2), has no toxicity, but the thermal stabilizing effect on PVC is not ideal, especially the "zinc-burning" will lead to rapid degradation of PVC [5][6][7][8][9][10] . Organotin has an excellent thermal stability on PVC, but the cost of is too high [11] .…”

Facile Synthesis of Di-Mannitol Adipate Ester-Based Zinc Metal Alkoxide as a Bi-Functional Additive for Poly(Vinyl Chloride)

“…Although lead salts provide the best thermal stability of PVC, their toxicity restricts their application. Metal soap, such as calcium stearate (CaSt 2 ) and zinc stearate (ZnSt 2 ), has no toxicity, but its thermal stabilizing effect on PVC is not ideal, especially as “zinc-burning” leads to the rapid degradation of PVC [5,6,7,8,9,10]. Organotin provides an excellent thermal stability of PVC, but its cost is too high [11].…”