Application of the time-of-flight mass spectrometer to monitor time-dependent behaviour following pulsed laser heating of solids

摘要: Because of its very fast scanning capability, the time-of-flight mass spectrometer (TOFMS) would appear to be an ideal instrument for real-time monitoring fast, transient chemical processes. Realisation this objective has been handicapped by so-called “statistics” problem and difficulty recording data. Instrumental developments overcome these difficulties are described with reference work concerned TOFMS pulsed laser heating solids. Early experiments at NASA showed that power density incident irradiation on a sample significant influence composition vapour generated pyrolysis. In general, higher lower molecular weights species detected greater number produced ions. Thus it is important simulate conditions interest when determining vaporisation characteristics particular material. The Salford pyrolysis-TOFMS technique used monitor benzene evolution from flame-retarded PVC samples containing different plasticisers. The information obtained interpreted in relation smoke-generating behaviour samples. This indicates plasticisers which favour rather than aromatics probably produce less smoke conflagration. Preliminary studies cotton fabrics also reported. Although initially cellulose pyrolysis, main direction candidate thermal protection materials space vehicles. Laser pyrolysis various forms carbon graphite multiple ions up C+19 C+10 C+11 being most intense. neutral vapours were dominated C, C2 particularly C3. Silicon carbide fibres yielded negligible but mostly SiC2, Si2C Si 10–60 kW cm−2. WO3 was only case dissociation clustering observed.