Thermal characterization and flammability of polypropylene containing sepiolite-APP combinations

• Published in: e-Polymers 2017-06, Vol.17 (4), p.341-348
• Main Authors: Kaynak, Elif, Ureyen, Mustafa Erdem, Koparal, Ali Savaş
• Format: Article
• Language: English
• Subjects: Additives; Bundles; Bundling; Combustion; cone calorimetry; flame retardant; Flame retardants; Flammability; Heat measurement; Heat release rate; Materials science; Oxygen; Polymers; Polypropylene; Sepiolite; simultaneous thermal analysis; Thermodynamic properties; Zeta potential
• ISSN: 2197-4586; 1618-7229
• DOI: 10.1515/epoly-2016-0275

The effects of sepiolite on fire behavior of ammonium polyphosphate-based intumescent flame retardant (IFR)/polypropylene (PP) were investigated. The disaggregation of sepiolite bundles has been provided by wet-milling as the zeta potential value decreased from −9.6 to −31.3 mV. PP and additives were compounded by a twin-screw extruder and molded by injection. A total additive content of 20 wt% in PP and various proportions of sepiolite (1.0–10.0 wt%) in flame retardant (FR) formulation were studied. The flammability of the samples was measured by limit oxygen index (LOI) test and cone calorimetry. The LOI of neat PP (19%) was increased to 32.2% when sepiolite and IFR were used. The peak heat release rate of neat PP (1566.4 kW/m ) was also significantly reduced (94.7 kW/m ) when sepiolite was added with IFR. Thermal analyses results showed that, at higher temperature (700°C), IFR and sepiolite increased the char residue (9 wt%) compared to neat PP (0 wt%).