Size-Dependent HCl Generation of PVC/SiO2 Micro- and Nanocomposites

Abstract

In this study HCl generation of polyvinyl (chloride) (PVC)/SiO2 composites during its combustion was investigated. SiO2 with different particle sizes were used as HCl absorbers and their HCl uptake ability results were compared to that of CaCO3. It was found that the amount of released HCl gas during PVC combustion decreased in the presence of SiO2. The HCl uptake ability of SiO2 improved with decreasing of its particle size. Although thermogravimetric analysis (TGA) results showed that SiO2 particles decreased the first thermal degradation temperature (T-onset) of PVC by initiating dehydrochlorination of PVC at lower temperatures, SiO2 particles had more effective HCl uptaking ability than that of CaCO3. Scanning electron microscopy (SEM) micrographs showed that some aggregates whose size was less than 100 nm were formed when Si-25 nm was used as filler. When SiO2 with micron size was added to PVC as filler, more uniform and better distribution of the SiO2 on the surface was observed.