P – N inorganic clay flame retardant for polyethylene
A novel flame retardant compound combining phosphorus, nitrogen (melamine) and inorganic clay (montmorillonite, a nautral clay) was experimentally produced in a three-stage reaction by progressively reacting the readily available PIN components phosphoruic acid – pentaerythritol (a widely used “blowing agent” for intumescent systems) – montmorillonite and melamine.
The resulting MPPM was tested as a flame retardant in linear low density polyethylene (LLDPE), a widely used, low cost polymer which poses issues of high flammability and burn dripping. Loadings of 25 – 35% MPPM in the polyethylene reduced peak heat release rate (PHRR) by 50 – 75%, and 35% MPPM enabled to achieve UL94-V0 with no burning dripping.
“A Novel Intumescent Flame Retardant: Synthesis and Its Application for Linear Low-Density Polyethylene”, G. Makhlouf, Arab J Sci Eng 2017 http://dx.doi.org/10.1007/s13369-017-2443-0