Effect of Elastomer on Flame Retardancy, Thermal Degradation, and Mechanical Properties of Intumescent Flame-Retardant Polyethylene

Abstract

Ethylene—acrylic ester—maleic anhydride (EAEM), as a compatibilizer, has been used to modify a new halogen-free flame retardant linear low-density polyethylene (LLDPE) in this article. Intumescent flame retardants (IFRs) consist of a charring—foaming agent (CFA), ammonium polyphosphate (APP), organic montmorillonite (OMMT) and an antidripping agent. Based on limiting oxygen index values and UL-94 ratings, the IFRs show the effective flame retardancy in the blend of LLDPE and EAEM. Comparative study on the thermal degradation of the composites demonstrates that the IFRs can reduce initial temperature ( Tinitial) of thermal degradation of the composites, and make the main thermal degradation peak move to the high temperature. CONE results reveal that the IFRs can form a char layer on the surface of the composites and clearly change the decomposition behavior of the IFR-LLDPE/ EAEM composites. Whether OMMT is contained or not in the IFRs, the IFRs show a little effect on reducing tensile strength of the composites. This result is proved by well dispersion of IFRs in the blend observed from scanning electron microscopic images. EAEM is also beneficial for improving the flame retardancy and mechanical properties of the composites.