Organic Compounds Controled Synthesis Of Zinc Hydroxystannate And Application In PVC As Flame Retardants

Zinc hydroxystannate [ZnSn(OH)6] is well-documented as nontoxic flame-retardant and smoke suppressant additives. But the poor compatibility between inorganic flame retardants and polymer matrix can not only deteriorate the mechanical properties of materials, but aslo reduce the flame retarded effect. The inorganic flame retardants with unique morphology and structure were synthesized via biomimetic synthesis and they are expected to achieve better compatibility between the flame retardants and matrix, as well as improve the flame retarded efficiency.In part I, firstly Zinc hydroxystannate was prepared by using zinc oxide and sodium hydroxystannate, then zinc hydroxystannate with different morphology was synthesized by using different organic templates including PEG400, PVA, cyclodextrins, L-alanine, L glutamate and SDBS. The formation of zinc hydroxystannate is related to the interaction between organic compound and particular faces on the crystals. The TGA test results showed that the sequence of thermal stability is as following:irregular polyhedron> cube octahedron.In the second section, firstly the optimum conditions were determined to synthesize zinc hydroxystannate:temperature:25℃, reaction time:4h, terminal PH:9.4, raw materials mole ratio,1:1. Then the organic templates including PEG400, cyclodextrins, etc were added in the reaction system. The results showed that the zinc hydroxystannate synthesized by glycol and glucose has the most specific area.The third part, several Zinc hydroxystannates were applied in PVC and the flame retarded properties were investigated. The results showed that the Zinc hydroxystannates modified with PEG400 and glycol gave the best flame retarded efficiency. They can not only reduce the flammability of PVC, but also improve the mechanical strength of the materials.