IMPROVEMENT OF THERMAL AND FIRE RETARDANCY PROPERTIES OF A (AMMONIUM POLYPHOSPHATE/MELAMINE POLYPHOSPHATE/ METAL OXIDE NANOPARTICLES/) TERNARY SYSTEM IN PMMA BY EXPERIMENTAL DESIGN

摘要

A design of experiment (DoE) was performed on PMMA-(ammoniumpolyphosphate/melamine polyphosphate/titanium dioxide) ternary system for optimizing both fireretardancyproperties and thermal stability. The software JMP~? was used for this purpose. Inpoly(methyl methacrylate) (PMMA), progressive substitution of titanium dioxide (TiO_2) nanoparticlesby melamine polyphosphate (MPP) led to the reduction of the peak of Heat Release Rate (pHRR),whereas the substitution with ammonium polyphosphate (APP) first led to the reduction of pHRRfollowed by an increase from 9wt% APP onwards. The presence of titanium dioxide led to theincrease of the time to ignition (TTI) and thermal stability.Laser Flash Analysis (LFA) measurement showed the heat insulation effect (i.e. low thermaldiffusivity) of the residues that have developed during combustion.PMMA-7.5%APP/7.5%TiO_2 showed the major increase of the time of combustion alongside with thedecrease of pHRR due to the barrier effect. The high carbon monoxide amount released during thecone calorimeter experiment confirmed an incomplete combustion. That sample presented aceramized structure and the formation of titanium pyrophosphate (TiP_2O_7) was detected by XRDmeasurements. TiP_2O_7 resulted from the reaction between APP and TiO_2 upon combustion.