The synergistic effects of zinc oxide (ZnO) with layered double hydroxides (LDH) in ethylene vinyl acetate copolymer/LDH (EVA/LDH)
composites have been studied using thermal analysis (TG), limiting oxygen index (LOI), UL-94 tests, and cone calorimeter test
(CCT). The results from the UL-94 tests show that the ZnO can also act as flame retardant synergistic agents in the EVA/LDH
composites. The CCT data indicated that the addition of ZnO in EVA/LDH system can greatly reduce the heat release rate. The
TG data show that the ZnO can increase the thermal degradation temperature and the charred residues after burning.
Microencapsulated ammonium polyphosphate (MAPP) is prepared using hydroxyl silicone oil by in situ polymerization and characterized by XPS. Microencapsulation gives MAPP better water resistance and flame retardance compared with APP in thermoplastic polyurethane (TPU). Thermal stability and fire resistance behavior have been analyzed and compared. The LOI value of the TPU/MAPP composite is higher than that of the TPU/APP composite. The UL 94 rating of the TPU/MAPP composite is V-0 at the 20 wt% additive level, whereas TPU/APP gives V-2 rating at the same loading level. The water resistant properties of the TPU composites are studied. Results of the cone calorimeter and microscale combustion calorimeter experiment show that MAPP is an effective flame retardant in TPU compared with APP.