Synthesis of pentaerythritol stearate ester‐based zinc alkoxide and its synergistic effect with calcium stearate and zinc stearate on PVC thermal stability

Abstract

A novel pentaerythritol stearate ester‐based zinc alkoxide (PSE‐Zn) was synthesized through a two‐step method. Zinc ethoxide was first prepared from zinc acetate and ethanol, and then with ethanol as the solvent, the obtained zinc ethoxide ester was heated together with pentaerythritol stearate to produce PSE‐Zn. PSE‐Zn could be used as a promising poly(vinyl chloride) (PVC) thermal stabilizer. Conductivity tests, thermal aging tests, and UV‐visible spectroscopy were used to study the thermal stabilization performance of the thermal stabilizers of PSE‐Zn on PVC. The results showed that, with a lower melting point and a good compatibility with PVC, PSE‐Zn presented a significant improvement in maintaining the initial color of PVC. However, the color of PVC stabilized with pure PSE‐Zn began to degrade when the sample was heated at 180°C for 60 min indicating the unsatisfactory long‐term thermal stability presented by PSE‐Zn on PVC. So, some commercial thermal stabilizers, for example, calcium stearate (CaSt2), zinc stearate (ZnSt2), or CaSt2/ZnSt2 were employed along with PSE‐Zn to further improve the stabilizing performance. The results showed that there was a synergistic effect that was between 2 phr PSE‐Zn and 2 phr CaSt2 and made the stabilized PVC possess the best thermal stability. Because of the presence of free hydroxyl in PSE‐Zn, which could chelate ZnCl2, PSE‐Zn can then restrain “zinc‐burning” phenomenon when PSE‐Zn and ZnSt2 were used together. It was also found that PVC stabilized with 3 phr PSE‐Zn and 1 phr CaSt2/ZnSt2 had the best color stability. The mechanism of thermal stability of PSE‐Zn was also discussed. As a metal alkoxide, PSE‐Zn is readily to neutralize HCl. In addition, PSE‐Zn is able to replace the allyl chloride to terminate the dehydrochlorination of PVC. Moreover, because of the stearate radicals, PSE‐Zn had a very low melting point, a better compatibility with PVC, and a lubrication action. With these excellent properties, PSE‐Zn would be able to make PVC achieve an excellent initial color and a long‐term stability. J. VINYL ADDIT. TECHNOL., 24:314–323, 2018. © 2017 Society of Plastics Engineers

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

“…Thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) of the samples were performed using a Q500 analyzer (TA instruments, Selb, Germany) at a 10 °C min −1 heating rate from 25 to 700 °C in a nitrogen atmosphere. The results were used to investigate the decomposition of the materials [26].…”

“…Recently, we synthesized a series of polyol-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 polyol-based metal alkoxides to be used as PVC thermal stabilizers, because their melting point (about 220 °C) [1,2] is significantly higher than the processing temperature of PVC, affecting their consistency with PVC [26]. In order to reduce the melting point of polyol-based metal alkoxides, Shentu et al employed mannitol with a low melting point of 166 °C to synthesize mannitol-zinc metal alkoxides, which was then used to improve PVC thermal stability [2].…”

“…A new strategy was applied by our group to overcome this shortcoming by esterification. For example, we synthesized pentaerythritol stearate ester-based zinc alkoxides (PSE-Zn) [26] and cis-1,2-cyclohexanedicarboxylic acid di-mannitol ester-based zinc metal alkoxides [27]. We observed that the new ester-based alkoxides have a lower melting point and a good thermal stabilization performance on PVC.…”

Rheological properties and dynamic thermal stability ofPVC/La L2/Ca‐Zncomposite stabilizer

“…The lubrication could reduce the friction between PVC chains and the friction between PVC melt and rotor, thus reducing the shear force on the melt and effectively improving the rheological properties of PVC melt. [ 11,15,26,27 ] Figure 1 showed the rheological curves of PVC with La L 2 /CaSt 2 composite stabilizer. Compared with La L 2 , La L 2 /CaSt 2 composite stabilizer remarkably reduced the plasticizing torque and equilibrium torque of PVC melt.…”

Synthesis of bismaleate pentaerythritol ester and its application as PVC auxiliary heat stabilizer

“…This article uses maleic anhydride and diol as raw materials to synthesize maleic acid‐based dibasic acid, and then further reacts with pentaerythritol. The molecular structure of the final product contains ether bond, ester group, carbon–carbon double bond, polyol structure, and can be used as PVC The auxiliary heat stabilizer is used in combination with the main heat stabilizer 11–13 . The prepared bismaleic anhydride‐based pentaerythritol ester heat stabilizer is compounded with calcium zinc stearate in an appropriate ratio and added to PVC, which can effectively alleviate the thermal degradation of PVC and improve the thermal stability of PVC 14 …”