Intumescent flame retardant based on sepiolite filled rigid polyurethane foam

Abstract

This research aims to investigate the role of a new carbonizing agent (that is sepiolite) in the RPUF polymeric system's intumescent flame retardants (IFR) system, as well as the impact of sepiolite nanoclay on the morphology and flame resistance of the rigid PU foam polymeric system. This paper presents work on IFR formulation of ammonium polyphosphate (APP), sepiolite (SEP) and melamine (MEL) embedded in rigid polyurethane (foam RPUF). Rigid This research aims to investigate the role of sepiolite as a carbonizing agent in the RPUF polymeric system's intumescent flame retardants (IFR) system, as well as the impact of sepiolite nanoclay on the morphology and flame retardancy of the RPUF polymeric system. PU foam was prepared in a closed mould, and the amount of IFR constituents was varied in each foam formulation. The obtained foam was tested for its morphology and flame retardance. Scanning electron microscopy (SEM) revealed a fine, closed-cellular structure at 16phr IFR loading; increasing IFR content induced larger cell sizes with blowholes. Incorporating 16 and 20 phr IFR into RPUF increased the nanocomposites LOI values to 22.80 and 20.0 % respectively relative to pristine RPUF (18.00 %). The highest improvement in the LOI values for the nanocomposites was achieved at 16 phr IFR/RPUF compared to previous studies with 25 phr. The nanocomposites passed the UL-94 testing with a V-0 grade in comparison with neat RPUF that failed the test. These results affirm that IFRs of APP/SEP/MEL have changed the morphology and improved the flame resistance of RPUF nanocomposites. Therefore, we identify robust possibility that the RPUF nanocomposite produced can be useful as an insulation material.