Jinyang Chen

Combustion Characteristics and Synergistic Effect of Halogen-Free Flame-Retarded EVA/Hydrotalcite Blends with Expandable Graphite and Fumed Silica

The synergistic effect of hydrotalcite with EG and fumed silica in halogen-free, flame-retardant EVA blends have been studied by limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), and TGA. The EG is a very effective synergist in raising LOI and reducing the heat release rate (HRR) and SEA of the blends. The UL 94 tests show that samples with 2–15 wt% EG can exceed the V-0 rate. The CCT data show that 15 wt% higher expansible ratio EG shows maximum decreases for the pk-HRR and av-SEA values of the EVA/hydrotalcite blends. The fumed silica have no obvious synergistic effects with hydrotalcite.

Synthesis and Properties of a Novel Intumescent Flame Retardant (IFR) and Its Application in Halogen-Free Flame Retardant Ethylene Propylene Diene Terpolymer (EPDM)

The PDP, a novel intumescent flame retardant (IFR) with high charred residue of 40.8% in N2 at 700°C by TGA was synthesized successfully for preparing halogen-free flame-retardant EPDM composites. The UL-94 V-0 rating was achieved for EPDM composites with 20 phrs carbon black at the same time by using only 60 phrs PDP. In situ FTIR spectroscopy reveals that P–N rich charred residues are formed through the interaction between hydrogen atom in weak base of P–NH–C and phosphate. SEM characterizes the formation of intumescent chars during burning. The mechanical properties of composites are also discussed.