Study on the effect of novel intumescent flame retardant composed of β-cyclodextrin modified ammonium polyphosphate and THEIC on the flame retardancy of LDPE composites

Enhancing polymer flame retardancy is crucial for lowering combustion-related exothermic heat and flue gas production. β-cyclodextrin microencapsulated ammonium polyphosphate (β-CD@APP) were synthesis through in-situ polymerization and combined with 1, 3, 5-tris (2-hydroxyethyl) isocyanurate (THEIC) as a novel intumescent flame retardant (IFR) to enhance the flame retardancy of low density polyethylene (LDPE). The results showed that APP's hydrophobic characteristic increased, which enhanced its polymer dispersibility. Compared with LDPE, the LOI value of β-CD@APP/THEIC/LDPE (LDPE5) was enhanced from 17.5% to 28.7% and the composites could meet the UL-94 V-0 standard. Smoke volume and thermal decomposition rate were reduced. Furthermore, a stable char layer was found, which can be seen from the SEM of the char slag and the Raman results. According to the above results, the thermal decomposition and possible mechanism of flame retardants in LDPE composites during combustion were studied.