RETRACTED ARTICLE: Preparation of Multilayers Zinc Hydroxystannate Microcapsules and its Application in Flame-Retardant PVC Composites

Although research on halogen free flame retardant has achieved great progress, its practical application is restricted due to high additive amount and low efficency. To solve this problem, multilayers microcapsule [melamine–formaldehyde resin (MF)/silicon dioxide (SiO2)/zinc hydroxystannate (ZHS)] was prepared through a two-step method. Moreover, when 16.40 wt% SiO2/ZHS microcapsules was mixed with poly(vinyl chloride) (PVC) matrix, the obtained PVC composites exhibited a high limited oxygen index (LOI) of 32.5%, showing its excellent flame retardancy. Furthermore, for the compatibility between MF/SiO2/ZHS microcapsules and PVC to be improved, MF was coated to SiO2/ZHS microcapsules by in situ polymerization. When 16.40 wt% MF/SiO2/ZHS microcapsules were mixed with PVC matrix, the obtained PVC composites exhibited a high LOI of 35.5%, showing its high flame retardancy. Therefore, this easily prepared multilayers microcapsule with sufficient flame retardancy in this work, it could have a potential for engineering applications.