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To effectively reduce the fire hazard of flexible polyvinyl chloride (PVC), this study explored the synthesis of perovskite‐type copper hydroxystannate (CuSn(OH)6) microspheres by co‐precipitation method. Then an organic–inorganic hybrid microsphere (CuSn(OH)6@PZS) with core‐shell structure was fabricated by in situ coating with poly(cyclotriphosphazene‐co‐4,4′‐sulfonyldiphenol) (PZS). The results showed that CuSn(OH)6@PZS performs most significantly in reducing the total heat release, while the CuSn(OH)6 alone achieves the best smoke suppression effect. The limiting oxygen index (LOI) value of the PVC composites is improved from 29.0% to a maximum of 35.3%. During combustion, the peak heat release rate (PHRR) and total smoke production (TSP) decrease by a maximum of 50.8% and 44.9%, respectively. Significantly, the presence of the PZS coating also improves the interfacial compatibility with PVC. The mechanical properties were significantly improved and the elongation at break improving by 40.9%.

With the widespread application of CO 2 -Enhanced Oilfield Recovery (CO 2 -EOR) technology, CO 2 in large quantities enters oil and gas gathering pipelines and causes severe corrosion. As a result, this paper investigates the corrosion behaviour of 20# steel in produced water and 40% water content emulsion with different CO 2 contents by combining Wire Beam Electrode (WBE) technology and the corrosion weight loss method, and establishes a corrosion mechanism model for analysis and explanation. The results demonstrate that variations in CO 2 concentration have a greater impact on the corrosion process in the produced water simulated fluid, and there is considerable corrosion non-uniformity in the CO 2 saturated state, as well as polarity reversal throughout the whole corrosion process. On the contrary, corrosion in the emulsion is more stable and uniform because the crude oil in the emulsion obstructs the mass transfer process of the depolariser agent and forms a 'surface wetting' effect on the metal surface, which seriously hinders the corrosion process.