https://doi.org/10.36719/2707-1146/54/16-21
Roman Hasanov
Azerbaijan State Oil and Industry University
PhD student
https://orcid.org/0009-0002-3587-8393
roman.manar6299@gmail.com
Rasmiyya Mammadova
Azerbaijan State Oil and Industry University
PhD in Chemical Sciences
https://orcid.org/0009-0007-8698-8302
rasmiyyamamedova@rambler.ru
Sabir Amirov
Azerbaijan State Oil and Industry University
https://orcid.org/0009-0000-0692-9396
sabir.54@mail.ru
Zumrud Aliyeva
Scientific Research Institute and Project-Design
Construction Materials named after S.A.Dadashov of
The Ministry of Emergency Situations
https://orcid.org/0009-0003-1020-7339
zuma.aliyeva.96@mail.ru
The Role of Calcium carboxylate in PVC Heat Stabilization:
Mechanisms and Applications
Abstract
To replace heat stabilizers containing heavy metals in polyvinyl chloride (PVC), the effectiveness of calcium carboxylate synthesized from soybean wax—produced via the hydrogenation of soybean oil—as an environmentally friendly heat stabilizer was investigated. The thermal stability of PVC in the presence of this stabilizer was evaluated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). TGA curves obtained from polymer samples indicated that decomposition occurred in two distinct stages, with the initial stage dominated by dehydrochlorination, resulting in a mass loss of more than 50%. The thermal degradation behavior was further analyzed by examining the temperatures at which the polymer mass decreased by 5%, 10%, and 20%. In the absence of a stabilizer, these temperatures were recorded as 256.56°C, 270.71°C, and 279.25°C, respectively. However, after incorporating 5 phr (parts per hundred resin) of the synthesized calcium carboxylate, the corresponding degradation temperatures increased to 270.13°C, 279.68°C, and 295.21°C, respectively. Furthermore, the activation energy of the decomposition process was determined using the Coats-Redfern integral method. The analysis revealed that the activation energy in both decomposition stages increased following the addition of the stabilizer, indicating an improvement in thermal stability. These results demonstrate that the bio-based stabilizer effectively captures hydrogen chloride (HCl) released during the thermal degradation of PVC, exhibiting a strong suppressive effect on dehydrochlorination. The findings suggest that to combine this stabilizer with other compounds may further enhance its stabilizing performance.
Keywords: heat stabilizer, polyvinyl chloride, poly(vinyl chloride), thermal stabilizer, calcium soap, calcium carboxylate, thermal degradation