Investigation of flammability properties of poly (methyl methacrylate) reinforced with phosphorus based compound

In this study, flame retardent polymethyl methacrylate (PMMA) production was made by using three different phosphorpus based flame retardent materials DOPO (9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-oxide), phenoxy phosphazene (PPZ), and three phenyl phosphate (TPP). The flame retardent properties of the produced materials were charactarized by limit oxygen index test (LOI), vertical flame test (UL-94V), horizantal flame test (UL-94HB), mass loss calorimeter test (MLC), thermogravimetric analysis test (TGA). By using flame retardent materials, burning behavior to the handler (BC) of PMMA rised to V2 in UL-94V test because phosphorpus based flame retardent materials make PMMA increase the dripping behaviour. LOI value also increased with the amount of added phosphorpus based flame retardent materials. The highest LOI value of 23 was achieved by DOPO at 20 % by weight. It was understood that the main effect mechanism of all flame retardent materials were dilution and reactive effects in gaseous phase. A synergic interaction with nano particles (nanoclay, POSS (Polyhedral Oligomeric Silsesquioxane)) was also studied in order to increase the solid phase effect mechanism after determining the most effective flame retardent material (DOPO). The nanoparticles ensured having lower pHRR due to the clay stratum structure that cause for continous clay layer structure in particularly 10% of concentration by weight in solid phase. The highest LOI value of 23 was achieved in the sample that has 10% of clay. Becuase the clay decreased the dripping behaviour, the sample containing 10% of clay burned till the handler. LOI values of the samples having POSS decreased from 23 to 19. Although the ash formation in the solid phase increased, the formation of a continously protective clay layer was not observed. The antagonistic effect inherent to POSS usage is considered to have arisen from the reaction between highly reactive P-H group in the structure of DOPO and methacrylate group. Because of this reaction, the activity of the gaseous phase of DOPO decreased. Keywords: PMMA, Flame Retardant, Phosphorous Containing Flame Retardant, Nonoclay, Polyhedral Oligomeric Silsesquioxane.