Solid phase synthesis of alkoxyl tin and the role of alkyl for Multi-stage thermal decomposition of polyvinyl chloride

To prepare an innovative thermal stabilizer for polyvinyl chloride (PVC), the micro-nano powders of alkoxyl tin (RxOSn) were synthesized via a solid phase reaction at room temperature, using the surfactant sodium benzene sulfonate (SBS) as a catalyst. Theoretical calculation of deprotonation reaction energy of monobasic alcohol and tin chloride was performed with the framework of DFT, and their structures were characterized by XRD, SEM, FT-IR, XPS, and its surface wetting performance was carried out by contact angle (CA). Meanwhile, the multi-stage thermal stability of PVC with 10% RxOSn sample, and the role of alkyl groups (Rx, x = 2 ∼ 5) in the RxOSn/PVC were investigated. The results show that the RxOSn samples exhibit a microstructure akin to the rutile of SnO2. Multi-stage kinetic studies of exothermic reactions has confirmed that the alkoxyl wetting performance of stabilizers becomes a determining factor, while the variation in activation energy (Ea) values seems to be mainly influenced by the Rx alkyl groups in the RxOSn samples. Besides, the differences in the lattice parameter a of RxOSn were validated to have a certain impact on the stabilizing effect of PVC, and the Ea of PVC degradation is closely related to the relative value of exposed crystal surfaces (D(110)/D(101)). This series of materials is easily synthesized and can effectively enhance the thermal stability of PVC, offering a wide range of potential applications