Effect of iron poly(acrylic acid-co-acrylamide) and melamine polyphosphate on the flammability properties of linear low-density polyethylene

Iron poly(acrylic acid-co-acrylamide) (FeAA) and melamine polyphosphate (MPP) were synthesized, characterized by FTIR and blended with linear low-density polyethylene (LLDPE). The thermogravimetric analysis results exhibited that MPP, FeAA and MPP/FeAA increased the char residue of LLDPE at 750 degrees C. Cone calorimeter data demonstrated that MPP, FeAA and MPP/FeAA decreased the peak of heat release rate (pHRR) and total heat release of LLDPE. Digital photographs, SEM images, EDXS and FTIR analyses of char formed after cone test indicated that the presence of FeAA did not support formation of coherent char during combustion process of LLDPE. In contrast, LLDPE/MPP composite formed high-quality char layer on polymer surface. Moreover, addition of MPP to LLDPE/FeAA composites assisted in formation of char containing iron polyphosphate and polyaromatic structure. The mechanical properties, namely tensile strength, Young's modulus, elongation at break and hardness of LLDPE composites, were measured.