Construction and evaluation of an aerosol generating apparatus for combustion products from polyurethane foam

A system has been constructed and evaluated for generating aerosols from co mbustion or pyrolysis of various cross-linked polymers. The system consists of an aerosol generator and an aerosol chamber with a sampling compartment designed for various samplers and sampling probes. A geared electric motor assembly is used to lower a polymer strip into the controlled atmosphere o f a quartz-lined furnace. The polymer used in this investigation was a poly urethane foam (PUF) based on toluene diisocyanate (TDI). Combustion of the PUF was conducted in filtered air at a temperature of 300 degrees C. The pa rticle number concentration of the generated aerosol was measured by light scattering in the particle size range from 0.1 mu m to greater than 5 mu m. Air samples were collected periodically in impinger flasks using dibutylam ine (DBA) in toluene as derivatization reagent. The TDI-DBA derivatives fro m the impinger samples were analyzed with high performance liquid chromatog raphy. The aerosol generating system was found to generate a stable, reprod ucible, and predictable concentration of particles and TDI monomer. Three p artial least squares models were created to evaluate the generator. The inv estigated responses were the TDI concentration, the particle number concent ration, and the stability of the particle number concentration during the g enerating process. The factor with most impact on the concentrations of the generated aerosol was found to be the interaction between linear feeding r ate of the polymer strip and the flow rate of combustion gas. For stability the linear feeding rate was the most important.