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

Diethylene glycol and maleic anhydride are used as raw materials to prepare bismaleic acid dibasic acid without catalyst. This intermediate product reacts with pentaerythritol (PER) to obtain bismaleate pentaerythritol (MDPP) as an auxiliary heat stabilizer. The structure of the product was verified by Fourier infrared test and hydrogen nuclear magnetic spectrum analysis. The ether bond, ester group, carbon-carbon double bond, polyol, and other characteristic structures contained in the molecule can improve thermal stability. Therefore, it can be used as an auxiliary heat stabilizer for PVC and used in combination with the main heat stabilizer. In order to verify the thermal stability performance and further analyze the thermal stability mechanism, testing methods such as thermal aging, Congo red, thermal weight loss, and electrical conductivity were adopted. The results show that when MDPP is added together with calcium/zinc stearate, the thermal stability of PVC is the best. The initial whiteness can reach 40 min, and the static stabilization time is 65 min, which is 15 min higher than the PVC sample with PER and calcium/zinc stearate. It can be seen that MDPP has greatly improved performance compared with the commercial auxiliary heat stabilizer PER.