- Author
- Kashiwagi, T. | Omori, A.
- Title
- Effects of Thermal Stability and Melt Viscosity of Thermoplastics on Piloted Ignition.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Book or Conf
- Combustion Institute, Symposium (International) on Combustion, 22nd. August 14-19, 1988, Seattle, WA, 1329-1338 p., 1988
- Keywords
- thermoplastics | thermal stability | viscosity | melting | pilot ignition
- Abstract
- The effects of material characteristics on piloted ignition were studied by using two different polystyrene, PS, samples and two different poly(methyl methacrylate), PMMA, samples. The difference between the two PS samples was melt viscosity due to two different initial molecular weights and that between the two PMMA samples was thermal stability and melt viscosity also due to two different initial molecular weights. Ignition delay times and time histories of surface temperature and sample weight changes were measured in the external radiant flux range of 0.9-3.0 W/mc(2). A comparison of results between the two PS samples and between the two PMMA samples was made. The comparison indicates that the transport process of indepth degradation products through the molten polymer layer to the sample surface has negliible effects on piloted ignition. However, the thermal stability of the material has significatnt effects on the piloted ignition delay time and the surface temperature at ignition. The surface temperature at ignition is 260-270 deg C for the thermally unstable PMMA sample and 320-340 deg C for the thermally stable PMMA sample. The surface temperatures at ignition of the two PS samples are 350-370 deg C. The mass flux at ignition for PMMA is 0.06-0.09 x 10(-3) g/cm(2) s and larger than 0.03-0.05 x 10 (-3) g/cm(2) s for PS.