Effect carbon black microencapsulated ammonium polyphosphate on the flame retardancy and mechanical properties of polyurethane composites

Carbon black microencapsulated ammonium polyphosphate (APP@CB) was synthesized to enhance the interfacial compatibility, mechanical property and flame retardancy of polyurethane (TPU). The chemical structure of APP@CB hybrids were characterized by Raman spectra and scanning electron microscope. Compared with APP flame retardant TPU composite, the tensile strength of TPU composite containing APP@2CB increased by 23%, and the smoke density approximately decreased by 46%. This is owing to the strong interaction between the CB and TPU in TPU4 (flame retardant by APP@2CB) composite. Furthermore, the TPU4 composite restrained the smoke and toxic volatiles evolved, indicating suppressed toxicity of the TPU composites.