Effect of microencapsulation and 4A zeolite on the properties of intumescent flame-retardant natural rubber composites

A novel microencapsulated intumescent flame retardant (MIFR) agent containing 4A zeolite has been prepared. The morphology of MIFR agent is characterized by transmission electron microscopy (TEM). Properties such as cure and tensile characteristics, thermogravimetric analysis (TGA), and flame-retardant (FR) properties are researched and compared. The addition of this MIFR agent into natural rubber (NR) leads to an improvement in its physico-mechanical and FR properties. Results demonstrate that the NR composite filled with 50 phr of MIFR-4A zeolite and 50 phr of IFR-4A zeolite show better FR and tensile properties than that of pure and 50 phr of IFR-filled NR systems.