Organic tin, calcium-zinc and titanium composites as reinforcing agents and its effects on the thermal stability of polyvinyl chloride

In view of the polyvinyl chloride (PVC) in the processing and molding easy degradation, the stability effect of different components is not good when used alone, and PVC in thermal degradation with the release of hydrogen chloride will lead to the formation of toxic gas dioxins to the environment and human problems. For this purpose, the nanosized titanium dioxide (NT), calcium-zinc (Ca-Zn)*, dipentaerythritol (Dip) and organotin (OT) were modified with butyl titanate (BT), coupling agent to synthesize the composite material and used as the strengthening agent for PVC. The composites and PVC were characterized, and their properties were determined using Raman, XRD, TG, TG-IR, Congo red and DMA. The results showed that the BT/NT/Dip/OT/(Ca-Zn)* complex not only kept the basic configuration of NT particles, but also had strong interaction between components due to BT coupling, which had synergistic effect on PVC. Similarly, BT was involved in the coupling between PVC and Dip/OT, resulting in prolonged initial discoloration time. When 3.8mass%BT/NT, 0.32mass%OT, 0.32mass%(Ca-Zn)* and 0.63mass% Dip were added to the PVC film, compared with blank sample and only 1phr of OT stabilizer, the new composite material was formed. The longest initial discoloration time was observed by Congo red, and the temperature was improved when TG was used to analyze the maximum mass loss rate, and the maximum mass loss rate was reduced by 115%. As the conversion rate reached 1%, the decomposition temperatures of PVC composite film and blank sample were 234.7 degrees C and 175.2 degrees C, respectively, indicating that the formed PVC film had excellent thermal stability. TG-FTIR analysis showed that after adding OT at 0.5 phr, (Ca-Zn)* at 0.5 phr and Dip at 1.0 phr, the composite film was around 331.1 degrees C and 476.6 degrees C, and the peak strength of CH4 gas released by thermal degradation was 114.0 and 262.0% higher than that of blank sample, respectively. It can be seen that pentaerythritol has a promoting effect on CH4 release of PVC, and the peak strength of CO2 is shifted to the high temperature zone, contrary to the blank sample, there is no formation of hydroxyl or water, which means that the thermal degradation pathway of PVC has changed, and it is possible to inhibit the generation of aromatic hydrocarbons and dioxins. By introducing 3.8 mass% BT/NT composite reinforcement, compared with the blank sample, the observed storage modulus increased by 22.4%, and the mechanical properties of PVC composite material were improved.