Revisited investigation of fire behavior of ethylene vinyl acetate/ aluminum trihydroxide using a combination of mass loss cone, Fourier transform infrared spectroscopy and electrical low pressure impactor

摘要

A bench scale test combining mass loss cone, Fourier transform Infrared Spectroscopy and Electrical Low Pressure Impactor (MLC/FTIR/ELPI) was developed to assess simultaneously heat release rate (HRR), evolved gases (qualitatively and quantitatively) and particles (size distribution and concentration) in the smoke from fire. It was evidenced (external heat flux of 35 kW/m~2) with ethylene vinyl acetate copol-ymer as reference material a good repeatability on qualitative and quantitative analysis of evolved gases and particles out of the flame. The tests on neat ethylene vinyl acetate (EVA) and filled EVA with aluminum trihydroxide (EVA/ATH) show as main results, high concentration of evolved acetic acid before the ignition of EVA, high concentration of water before the ignition of EVA/ATH, and the evolution of acetone during the combustion of EVA/ATH assigned to the catalytic effect of alumina transforming acetic acid into acetone. In the two cases (EVA and EVA/ATH) the size distribution of particles in the smoke lies in similar range mainly made of ultrafine (＜0,1 μm) and submicron particles (＜1 μm). It is noteworthy that peaks of particles of 16 nm (almost 3. × 10~7 particles per cm~3) and 93 nm (2. × 10~7 particles per cm~3) are observed in the smoke of EVA. In the case of EVA/ATH, particles of 6 nm (around 5. × 10~6 particles per cm~3) are detected and of 54 nm (3.× 107 particles per cm~3) while they are not measured in the case of neat EVA. The evolved mass of particles out of the flame have shown a maximum of 50 g/m~3 (close to the flame out) from fire of EVA and a maximum of 6 g/m~3 (before the piloted ignition) from fire of EVA/ATH. These results show the interest and the efficiency as well as the reliability of coupling MLC/FTIR/ELPI as alternative bench test to expand simultaneous analysis of fire behavior of materials.