Insights into the use of zinc–mannitol alkoxide as a novel thermal stabilizer for rigid poly(vinyl chloride)

Abstract

Zinc–mannitol alkoxide (Zn–Man) was synthesized through alcohol exchange reaction, and investigated by means of Fourier transform infrared spectroscopy and elemental analysis. The thermal stability of Zn–Man for rigid poly(vinyl chloride) (PVC) was evaluated by Congo red testing, conductivity measurements, thermal aging testing, thermogravimetric analysis (TGA), and ultraviolet–visible (UV–vis) spectroscopy test. The experimental results demonstrate that the addition of Zn–Man not only apparently prolonged the static thermal stability time to approximately 96.5 min but also evidently improved the initial color of PVC. More importantly, the color of the PVC sheets stabilized with Zn–Man did not change to black within 180 min; this showed that no zinc‐burning phenomenon occurred. In addition, the results of TGA reveal that Zn–Man raised the initial degradation temperature of PVC to about 273.4°C. UV–vis testing indicated that the presence of Zn–Man decreased the content and shortened the length of the conjugated double bonds of PVC. The possible thermal stability mechanism is discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42038.

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

“…Recently, we have synthesized a series of polyols-based metal alkoxides as PVC thermal stabilizers, and showed that they were efficient in inhibiting the degradation of PVC [24,25] . There is still a challenge for these polyols-based metal alkoxides to be used as PVC thermal stabilizers, because their melting point (about 220 o C) [1,2] are significantly higher than the processing temperature of PVC, affecting their consistency with PVC [26] . In order to reduce the melting point of the polyol-based metal alkoxides, Shentu et al employed mannitol with a low melting point of 166 o C to synthesize mannitol-zinc metal alkoxides, which was then used to improve PVC thermal stability [2] .…”

“…There is still a challenge for these polyols-based metal alkoxides to be used as PVC thermal stabilizers, because their melting point (about 220 o C) [1,2] are significantly higher than the processing temperature of PVC, affecting their consistency with PVC [26] . In order to reduce the melting point of the polyol-based metal alkoxides, Shentu et al employed mannitol with a low melting point of 166 o C to synthesize mannitol-zinc metal alkoxides, which was then used to improve PVC thermal stability [2] . New strategy has been applied by our group to overcome this shortcoming by esterification.…”

“…[1] In the applications the poor thermal stability is the biggest weakness of PVC. When the temperature reaches 130 o C or higher, PVC starts to break down and release hydrogen chloride (HCl), which can further aggravate this degradation process [2] . The color of PVC will change significantly from white to brown, and finally black, meanwhile mechanical properties also decline rapidly [3] .…”

Development and Investigation of Lanthanum Sulfadiazine with Calcium Stearate and Epoxidised Soyabean Oil as Complex Thermal Stabilizers for Stabilizing Poly(vinyl chloride)

“…The oven discoloration method was also used to evaluate the influence of different thermal stabilizers on stabilizing PVC, and the results are shown in Figure 4 [31]. As can be seen from Figure 4, the PVC sample with ZnSt 2 has a good initial color, but it turned completely black after 10 min.…”

“…However, ZnCl 2 will be produced in this process and catalyzes PVC degradation. PVC samples suddenly turn black with the increase in the concentration of ZnCl 2 , which is called the “zinc burning” phenomenon [31]. For PVC samples with Ca/Zn(1:1), the complete discoloration time is prolonged to 60 min, which is caused by the reaction of ZnCl 2 and CaSt 2 to produce CaCl 2 [32].…”