Polypropylene based Novel Flame Retardant Nanocomposite Compositions

摘要

In this research we investigated chemical mode of flame retardant action of calcium carbonate nanoparticles (CC) along with ammonium polyphosphate (APP) on burning of polypropylene (PP). We prepared PP/CC/APP nanocomposites with five different percentage loadings of additives by melt mixing. In each nanocomposite, the weight ratio of APP to CC was kept 2:1 because of stoichiometry of the expected reaction between them. We studied the effect of the additives on flame spread rate of polypropylene films using standard horizontal flame spread test and observed reduction in burning rate without appreciable char formation up tp 30 percent loading additives. But at higher percentage loading of additives, there was char formation at the flame front, which further reduced the burning rate significantly. Thermogravimetric analysis (TGA) of the mixture of CaCO{sub}3 and APP showed that calcium carbonate nanoparticles react with APP prior to the degradation of the phosphate chains. TGA-FTIR studies were carried out on nanocomposite samples and powder mixture of the additives to confirm evolution of ammonia and carbon dioxide due to interaction between the additives. X-ray diffraction (XRD) analysis of chars, obtained after burning nanocomposite films, showed definite crystal pattern and diffraction peaks corresponding to that of calcium meta phosphate.