چكيده لاتين
Polyvinyl chloride (PVC) is one of the most widely used polymers in everyday applications due to its versatile properties. PVC is typically processed at temperatures between 160 and 220 °C. However, at temperatures above 120 °C, it starts to lose hydrogen chloride (HCl) gas, which, through an autocatalytic effect, leads to further HCl release and eventually, due to the formation of unsaturated structures and polymer backbone breakage, causes the degradation of this polymer. In this research, zinc arginine stearate with a strong ability to absorb and neutralize HCl gas and substitution with labile chlorine and magnesium-aluminum hydrotalcite (Mg-Al LDH) as a strong HCl gas adsorbent was synthesized to investigate the synergistic effect of a metal-organic stabilizer with two different anions and an inorganic thermal stabilizer as a multi-mechanism thermal stabilizer. The structures of the synthesized compounds were confirmed by FT-IR and XRD analyses. Then, by adding different thermal stabilizers to EPVC, their stability was investigated using various tests. The results showed that this multi-mechanism stabilizer (LDH + ZnArgSt), in addition to high HCl gas absorption in the Congo red test and increasing thermal stability from 5 minutes to 15 minutes and 36 seconds compared to pure PVC, and also better performance compared to ZnArgSt alone (13.11 minutes) and the stabilizer containing zinc stearate and hydrotalcite (LDH + ZnSt2) which had a stability of 8 minutes and 13 seconds, prevented the formation of unsaturated structures, as evidenced by the visual color change of the sample in the oven and UV-Vis spectroscopy in the polymer chain. Not only did it delay the visual color change of the sample during degradation, but according to the mechanical properties tests of tensile strength and hardness, the sample exhibited better mechanical properties such as tensile strength of 1.76 MPa, toughness of 16.03 J, and elastic modulus of 9.94 MPa compared to pure PVC (1.77 MPa, 15.17 J, and 8.33 MPa), as well as hardness of 80.33 which had less hardness reduction compared to pure PVC (81) after processing.
