Characterization of aerosolized particles in effluents from carbon fibre composites incorporating nanomaterials during simultaneous fire and impact.

This work investigates the aerosols emitted from carbon fibre-reinforced epoxy composites (CFC) incorporating nanomaterials (nanoclays and nanotubes), subjected to simultaneous fire and impact, representing an aeroplane or automotive crash. Simultaneous fire and impact tests were performed using a previously described bespoke testing methodology with the capability to collect particles released from the front/back faces of the impacted composites plus the effluents. In this work the methodology has been further developed by connecting the Dekati Low Pressure Impactor (DLPI) and Mini Particle Sampler (MPS) sampling system in the extraction chimney. The aerosols emitted have been characterized using various devices devoted to the analysis of aerosols. The influence of the nanoadditives in the matrix on the number concentration and the size distribution of airborne particles produced, was studied with a cascade impactor in the 5 nm-10 µm range. The morphology of the separated soot fractions was examined by SEM. The measurement of aerodynamic size of particles that can deposit in human respiratory tract indicate that 75% of the soot and particles released from CFC could deposit in the lungs reaching the bronchi region at a minimum. There was however, a minimal difference between the number particle concentrations or particle-size mass distribution of particles from CFC and CFC containing nanoadditives. Moreover, no fibres were found in the effluents.

Biopolymer blends from hardwood lignin and bio-polyamides: Compatibility and miscibility.

The compatibility of hardwood lignin (TcA)/bio-polyamide (PA) blends, prepared by melt compounding TcA with three different biobased polyamides, PA 1012, PA 1010 and PA 11 in a twin screw extruder has been studied. FTIR studies indicated the existence of physicochemical interactions between the TcA and polyamide. The melting temperatures of the blends were significantly reduced compared to the respective neat polyamides, which was attributed to the enhanced compatibility between the two components. The compatibility was also attributed to the increased glass transition (Tg) of the polyamide. Thermogravimetric studies, while not indicating any interaction during the processing stage, suggested that there was some during the thermal degradation stage, which assisted formation of carbonaceous residue. The addition of each polyamide to TcA considerably reduced its viscosity and enhanced its processability even at high lignin contents. Morphological analysis showed that heterogeneity for all the blends was quite uniform, although TcA domain sizes were considerably smaller (~0.5 µm) in the PA11 matrix compared to those in PA1010 and PA1012, suggesting better compatibility in the TcA/PA11 blends. This observation was consistent with the thermodynamic Gibbs' free energy values of the respective blends. Overall, the order of blend compatibility was TcA/PA11 > TcA/PA1010 > TcA/PA1012.