Meta -aramidic electrospun nanofibers as innovative wood surface flame retardants

An innovative approach to wood flame retardant modification has been proposed, using electrospun nanofibrous membrane to cover the wood surface and delay the fire ignition. Poly(meta-phenylene isophtalamide) (PMIA) has been used for nanofibrous membrane production and it has been applied onto wood panels via either vinyl glue or using a thin layer of polyurethane painting. Cone-calorimetric tests proved the ability of PMIA electrospun nanofibers to almost double the time to ignition of the wood panel. Tests carried out on the membranes still containing the LiCl salt required for the electrospinning process did not reach the same satisfying results of the washed PMIA membrane, where the inorganic component was completely removed. The fire testing measurements also pointed out the importance of a good adhesion between the coating membrane and the wood surface, demonstrating a better ability of the polyurethane paining as coupling agent. It is worth to point out the negligible impact of the applied polymeric nanofibrous shielding coating on both the overall weight of the sample (24-27 g/m2) and thickness (50 μm overall thickness increase after application and rolling).