Synthesis of hollow tin dioxide and its improvement of flame retardancy and toughness on poly(vinyl chloride)

Hollow tin dioxide (S-SnO2) and solid SnO2 (B-SnO2) were prepared by a hydrothermal-calcination method with and without carbon spheres as templates, respectively. The flame retardancy, mechanical and thermal degradation properties, and char residues of the poly(vinyl chloride) samples treated with S-SnO2 and B-SnO2 were contrastively investigated by a limiting oxygen index instrument, cone calorimeter (Cone), tensile properties tests, and thermogravimetric analyzer. When the loading level of SnO2 was 2？phr, the limiting oxygen index of the poly(vinyl chloride) sample treated with S-SnO2 (poly(vinyl chloride)/S-SnO2) increased by 5.3% and 2%, and its elongation is 27.3% and 29.9% higher than that of the blank poly(vinyl chloride) and the poly(vinyl chloride) sample treated with B-SnO2 (poly(vinyl chloride)/B-SnO2), respectively. Compared with the blank poly(vinyl chloride) and the poly(vinyl chloride)/B-SnO2, the total heat release of poly(vinyl chloride)/S-SnO2 decreased by 24.5% and 9.4%, and the peak of smoke production rate decreased by 56.7% and 11.7%, respectively