Study on flame retardant polycarbonate

The authors utilized tris(l-oxo-2,6,7-trioxa-l-phosphobicyclo[2.2.2]octane methylene-4) phosphate (trimer) to prepare flame retardant polycarbonate (PC), and studied its effects on flame retardancy, mechanical properties, thermal decomposition behavior and post-burn residue of the PC resin. Adding 8% in mass fraction of the trimer could make the flame retardance level of the PC resin specimen with thickness of 3.2 mm reach UL 94 V-0 rating and its limited oxygen index attain 33%. It is noticeable that the introduction of the trimer can improve the PC resin's tensile strength, particularly the flexural strength and flexural modulus. The thermal analysis reveals that the trimer can facilitate and accelerate crosslinking and char forming of the PC resin, but can not raise its char yield. In addition, scanning electron microscopic observations indicate that the trimer can promote foaming and expansion of the char layer to a slight extent, and can improve quality of the char layer as well.