Synthesis And Properties Of Cu～(2+)-OMMTs Flame Retardant And Smoke Suppressant Of PVC

Polyvinyl chloride (PVC) is a sort of commodity thermoplastic resin. It is widely used in various respects of people's life and production because it has fine processing behavior, electrical property and chemical conosion-resistance and so on. Though PVC has a great deal of advantages, it still has poor thermal stability, heavy smoke produced during burning which restrict its development. So it is the key of sustained development of PVC that high-performance flame retardants and smoke suppressants will be developed.In this paper, under the pH< 4(regulated by acetic acid)condition, four kinds of copper-organic montmorillonites(Cu²⁺-OMMTs) were synthesized using sodium montmorillonite as raw material, silane couple agents(KH550,KH560,KH570,KH792) and copper sulfate as(CuSO₄) intercalating agent and distilled water as solute. The contents of silane couple agents and cupric ion were determined by thermogravimetry analysis, mass loss and atom absorption spectrophotometry. The structures of modified montmorillonites were characterized by means of X-ray diffraction. The test results showed that silane couple agents intercalated into the layers of montmorillonite and increased the space of layers. The data of X-ray diffraction show that the spaces between layers of Cu²⁺-OMMTs were narrower than those of organic montmorillonites (OMMTs) which proved that cupric ion intercalated into the layers of montmorillonite.MMTs/PVC composites were prepared using PVC, the processing agent and montmorillonites as raw material with different ratio by means of twin screw extruder and two-roll mixing machine milling. In addition, mechanical properties, structures, thermal degradation, flame retardancy, smoke suppression and rheological properties of the composites were measured and characterized.The data of mechanical properties showed that Cu²⁺-OMMTs enhanced tensile strength, flexural strength and Notched Izod impact of PVC composites. The mechanical properties of composites varied with the content and type of modified montmorillonites. Compared with Na-MMT/PVC, the tensile strength and flexural strength of Cu²⁺-OMMTs/PVC were superior to Na-MMT/PVC, but the Notched Izod impacts were inferior to Na-MMT/PVC. The SEM demonstrated that montmorillonites changed fracture surface of PVC composites and made its close and smooth.TGA results indicated that MMTs made the temperature of initial decomposition appear earlier and reduce the mass loss rate of PVC in first stage and increased the char residues of PVC composites, especially Cu⁽²⁺-OMMTs.The data of cone calorimeter indicated that montmorillonites made PVC release hydrogen...