The effect of chitosan-modified zinc hydroxystannate on the flame retardancy and mechanical properties of PVC Phragmites australis powder composites.

Zinc Hydroxystannate (ZHS) has been shown to have excellent flame retardant properties in polyvinyl chloride (PVC) and has the potential to improve the flame retardancy of Poaceae-PVC (PPC) composites. However, inorganic ZHS has adverse effect on the mechanical properties of PPC composites. In this paper, an ion exchange strategy was used to replace the Zn2+ in ZHS with chitosan (CS) cations, then applied to PPC composite materials. The result shows that the organic-inorganic compound can significantly improve the interfacial compatibility of PPC composite, resulting in a significant improvement of its mechanical properties. Compared with PPC composites with 5 parts per hundred parts of resin (phr) of ZHS, the flexural strength, impact strength and tensile strength of PPC composites with 5phr modified ZHS (CS3Zn2) increased by 24.04 %, 32.93 % and 43.42 %, respectively. Additionally, compared to PPC, the total smoke production of PPC composites with 5phr CS3Zn2 was reduced by 52.70 %. The unique structure of CS3Zn2 provides PPC with its exceptional flame retardancy, smoke suppression and mechanical properties, offering a new strategy to balance flame retardancy and mechanical performance in PPC. This study provides valuable insights for the development of sustainable and high-performance PPC composites.