Synergistic Effects of Nanoporous Nickel Phosphates VSB-1 on an Intumescent Flame-Retardant Low-Density Polyethylene (LDPE) System

Abstract

Nanoporous nickel phosphates VSB-1 was synthesized by hydrothermal method, and its structure was characterized by X-ray diffraction (XRD), thermogravimetric analyses (TGA) and high resolution transmission electron microscopy (HRTEM). The flame retardancy and thermal behaviour of intumescent flame retardants (IFR) with and without VSB-1 for low-density polyethylene (LDPE) were evaluated by LOI, UL-94 burning test, TGA and cone calorimeter test. With the addition of 2 wt% VSB-1 to LDPE/IFR systems, the LOI value increases from 28.7 to 31, and UL-94 rating raises from V-1 rating to V-0 rating. The results of cone calorimeter show that heat release rate (HRR) peak decrease substantially from 511 KW/m² to 407 KW/m² with 2 wt% VSB-1 in LDPE/IFR systems. The scanning electron microscopy (SEM) indicates the quality of char forming of LDPE/IFR/ VSB-1 is superior to that of LDPE/IFR.

Keywords:

• Intumescent flame-retardant (IFR)
• LDPE
• Nanoporous nickel phosphates
• Synergistic effect

ACKNOWLEDGMENTS

The work was financially supported by National key Technology R&D Program (2006BAK06B06, 2006BAK06B07, 2006BAK01B03), Specialized Research Fund for the Doctoral Program of Higher Education (20040358056), China Postdoctoral Science Foundation (20080430101), and Program for New Century Excellent Talents in University.