Synergistic effect of acetonedicarboxylic acid diethyl ester and calcium/zinc stearates on poly(vinyl chloride) thermal stability

Abstract

Acetonedicarboxylic acid diethyl ester (AADE) is obtained by the interaction of ethanol with acetonedicarboxylic acid that is prepared from anhydrous citric acid. The thermal stabilizing effect of calcium and zinc stearates (CaSt2/ZnSt2) combined with AADE on poly (vinyl chloride) (PVC) is evaluated by the Congo red test, conductivity test, thermal aging test, and thermogravimetric analysis. The results of thermal stability tests show that the addition of AADE can improve not only the thermal stability but also the color stability of PVC. The improvement in stabilizing effectiveness is ascribed to the synergistic effect between CaSt2/ZnSt2 and AADE. The thermal stability mechanism of AADE is also under discussion with the help of quantum chemical calculations. The results of quantum chemical calculations indicate that, besides having the ability to form complexes with zinc ion, AADE has an evident tendency to replace the allyl chloride of the PVC. The results of the thermal aging test and quantum chemical calculations show that the thermal stabilizing effectiveness of AADE is higher than that of stearoyl benzoyl methane (β‐Diketones). J. VINYL ADDIT. TECHNOL., 21:228–234, 2015. © 2014 Society of Plastics Engineers

A “one‐pot” method for synthesizing zinc tryptophan and its derivatives as highly efficient PVC thermal stabilizer with excellent mechanical properties

“…However, its charge density was lower than the Zn atoms, which were preferentially attacked by chloropropyl. In summary, it can be seen from quantum chemical calculations that Trp‐Zn and SalTrp‐Zn can replace the unstable allyl chloride structure produced during the degradation of PVC 39 …”

“…In summary, it can be seen from quantum chemical calculations that Trp-Zn and SalTrp-Zn can replace the unstable allyl chloride structure produced during the degradation of PVC. 39 The experimental and calculation results showed that the thermal stability mechanism of Trp-Zn as PVC thermal stabilizer was mainly divided into absorption of HCl to inhibit its autocatalytic effect on PVC, substitution of active chlorine atoms on PVC molecular chain and complexation of ZnCl2, as shown in Scheme 2. First, the unstable Cl atoms in the PVC chain fell off and released HCl at high temperatures, and the N atoms in the amino group had lone pairs of electrons that can therefore absorb HCl and inhibit the autocatalytic effect, as shown in Scheme 2a.…”

Improvement of photostability and thermal stability of PVC by carbon quantum dots loaded on TiO2

“…2,3 PVC is used in a wide range of applications, such as window frames, medical catheters and blood bags, curtains, wiring, paint, and packaging. 4,5 However, PVC will undergo degradation such as dehydrochlorination under ultraviolet (UV) irradiation, causing PVC aging and shortening the service life. [6][7][8] Therefore, lightblocking agents, UV-light absorbers, quenching agents, and free radical trapping agents are commonly used as light stabilizers in PVC products to retard photodegradation.…”

“…From the 1940s to the 1960s, PVC was commercially produced in Japan, the United States, and Europe as a new type of material 2,3 . PVC is used in a wide range of applications, such as window frames, medical catheters and blood bags, curtains, wiring, paint, and packaging 4,5 . However, PVC will undergo degradation such as dehydrochlorination under ultraviolet (UV) irradiation, causing PVC aging and shortening the service life 6–8 .…”

Phosphate ester groups‐containing ricinoleic acid‐based Ca/Zn: Preparation and application as novel thermal stabilizer for PVC

“…For this reason, various methods have been tried to solve this problem. The most efficient and practical way is to add thermal stabilizers to further retard degradation …”