Thermal stability and flammability of ethylene vinyl acetate copolymers in presence of nanoclay and a halogen‐free flame retardant

Abstract

In this study, thermal stability behavior and flammability of ethylene-vinyl-acetate (EVA) copolymers containing organo-modified nanoclay particles (Cloisite 15A) and ammonium polyphosphate (APP) along with pentaerythritol (PER), as halogen-free flame retardants, were investigated. Transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) were employed for evaluation of the level of dispersion of nanosheets within the EVA matrix. Moreover, thermal stability behavior and flammability of the samples were studied using thermogravimetric analysis (TGA), cone calorimetry thermometer (CCT) and limiting oxygen index (LOI). The obtained results from TEM and SAXS showed that nanosheets exhibited a rather proper level of dispersion within the EVA matrix. According to TGA and CCT results, despite improving the thermal stability and flame retardancy of EVA due to incorporation of the individual additives, a considerable synergistic effect was observed upon simultaneous use of clay nanosheets and the flame retardants. Such synergistic effect was explained by the physical mechanism of the solid phase due to the increased residual ash resulted from combustion of the samples containing flame retardants and clay nanosheets. While clay nanosheets had no significant effect on the LOI of EVA, the halogen-free flame retardants substantially increased the LOI of EVA. J. VINYL ADDIT. TECHNOL., 23:E92-E98, 2017.

Novel nanocomposites based on poly(ethylene- co -vinyl acetate) for coating applications: The complementary actions of hydroxyapatite, MWCNTs and ammonium polyphosphate on flame retardancy

“…The connectivity, thickness and porosity of the char remained from combustion as well as its dimensional expansion as an integrated layer could be attributed to the improvement of flame retardancy [23][24][25]. Therefore, the use of phosphorous flame retardants like ammonium polyphosphate (APP) in combination with mineral nanoparticles of different nature such as montmorillonite [26,27], zeolite [28], MgO [29], expandable graphite [30], expanded graphite [31], layered double hydroxides (LDH) [32], CaCO 3 [31] in EVA has been reported by several authors.…”

PET/CLOISITE 15A composite fibers - studies on the structure and the flame inhibition mechanism

“…C15A nanoclay dispersion was prepared using an ultrasonic bath for 15 min. After the modification treatment investigated samples were washed in a solution of detergent Pretepon G (PCC Group, Poland) in the amount of 5 g/dm 3 . The washing time was 30 min and the temperature 60°C The effectiveness of the modifier was tested in a wide range of flame retardant concentrations from 0 to 7.5% in relation to the fiber weight.…”

“…In recent years, the importance of nanoclay used to modify polymers increased, thus resulting in an improvement in polymer performance characteristics (including fire resistance). Nanoclays used as an additive to the polymer melt significantly improve the flame retardant properties of the material, especially if they are used in synergistic systems with other non-halogen flame retardants [1][2][3][4][5][6].…”

Combination Effect of Organically Modified Montmorillonite and Nano‐Silica on Reducing the Fire Hazards of Intumescent Flame‐Retarded Epoxy Resins

“…[7,8] Among these nano‐fillers, the layered silicates show desirable performance in reducing heat release rate of polymers in the cone calorimeter test, but they do hardly improve the flame retardancy in regulatory fire safety tests such as the limiting oxygen index (LOI) and UL94 vertical burning tests. [9,10] The combination of IFR and layered silicates exhibits superior synergistic flame‐retardant effect in both the cone calorimeter test and regulatory fire safety tests. [11,12] Shen et al found that the introduction of organically modified layered silicates (OMMT and OLDH) into ethylene‐propylene‐diene terpolymer (EPDM)/IFR composites exerts well synergism in the condensed phase via the formation of a more compact and continuous char against fire.…”