Synthesis of a Solid Superacid and Its Application in Flame-Retardant Poly(vinyl chloride) Material

Abstract

TiO 2 /PO 4 3– solid superacid was synthesized by using the precipitation immersion method and characterized by means of X-ray diffraction (XRD) and an energy-dispersive spectrometer; it was added into flexible poly(vinyl chloride) (PVC) composites as a flame retardant. The smoke suppression and flame retardance of TiO 2 /PO 4 3– accompanied by Sb 2 O 3 were investigated through the limiting oxygen index (LOI), cone calorimetry test, and thermogravimetry analysis (TGA). The results indicated that the LOI value of PVC/Sb 2 O 3 /(TiO 2 /PO 4 3– ) reached to 32.3%, which is higher by 6% than that of neat PVC (26.3%). In addition, Sb 2 O 3 /(TiO 2 /PO 4 3– ) greatly reduced the peak heat release rate and total heat release simultaneously in comparison to using Sb 2 O 3 separately, suggesting a significant synergistic effect between TiO 2 /PO 4 3– and Sb 2 O 3 on improving the flame retardancy of the PVC. Further, results of TGA and differential thermal analysis showed that the thermal stability of the composites was greatly improved. For the Fourier transform infrared analysis, Sb 2 O 3 /(TiO 2 /PO 4 3– ) leads to a large amount of functional group surplus, which specifically indicates that its carbon residue increases. The surface of the char formed after combusting of the PVC compounds was observed through scanning electron microscopy. It is found that the solid superacid can promote decomposition, pyrolysis, and cross-linking of PVC into the compact and continuous char layer on the surface of the material, which improved the flame retardancy and smoke suppression of PVC.

Poly(vinyl chloride) Composites with Raspberry Pomace Filler

“…At this stage, the composite mass loss decreases with increasing concentration of filler in the matrix and ranges from 59.5% to 54.9%. It is smaller compared to the 61.4% mass loss observed for PVC that corresponds to the value specified in the literature for unmodified polymers [ 56 ]. The degradation rate at this stage decreased with increasing RRGED content in the polymer matrix ( Table 6 b).…”

Effects of TiO2@ZnAlSn/PETMP on the properties of plasticized polyvinyl chloride composites

“…Incorporation of TiO 2 @ZnAlSn and PETMP can inhibit the intramolecular cyclization of PVC chains after dehydrochlorination and improve the intermolecular cross‐linking and cyclization, which leads to the formation of less aromatic compounds and more char residues. [ 52,53 ] Therefore, PVC/TiO 2 @ZnAlSn/1.6PETMP† composite shows excellent flame retardancy and smoke suppression.…”

Composites of Poly(vinyl chloride) with Residual Hops after Supercritical Extraction in CO2

“…The degradation of PVC and the composites occurred in two stages [ 66 , 67 , 68 ]. During the first stage (200–400 °C), weight loss on the level of 54–65 wt % was associated with PVC dehydrochlorination and the degradation of organic additives in the PVC blend and filler components: mainly hemicellulose, cellulose and lignin [ 53 , 56 , 57 , 58 , 69 ]. Moreover, the weight loss decreased as the filler content in the matrix increased, which indicated the degradation of the matrix, especially the HCl release reaction, which dominated at this stage.…”