The Effects Of Triphenylphosphate and Recorcinolbis(Diphenylphosphate) on the Thermal Degradation Of Polycarbonate in Air

The thermal degradation of polycarbonate/triphenylphosphate (PC/TPP) and PC/resocinolbis(diphenylphosphate) (PC/RDP) in air has been studied using TGA/FTIR and GC/MS. In PC/phosphate blends, the phosphate stabilizes the carbonate group of polycarbonate from alcoholysis between the alcohol products of polycarbonate degradation and the carbonate linkage. Thus, the evolution of bisphenol A, which is mainly produced via hydrolysis/alcoholysis of the carbonate linkage, is significantly reduced, while, the evolution of various alkylphenols and diarylcarbonates increases. The bonds that are broken first in the thermal degradation of both the carbonate and isopropylidene linkages of polycarbonate are the weakest bonds in each, when a phosphate is present. Triphenylphosphate and resocinolbis(diphenyl-phosphate), even though they exhibit a significant difference in their volatilization temperature, appear to play a similar role in the degradation pathway of polycarbonate

Is UV laser ablation a suitable tool for geochemical analysis of organic rich source materials?

Abstract not available

Analysis of Tagish Lake macromolecular organic material

Macromolecular material is, by far, the major organic component of meteorites. Flash pyrolysis GCMS has been used to investigate this organic component in Tagish Lake. It is more condensed, less susbtituted than Murchson

Absolute Electron Scattering Cross Sections for the CF2 Radical

Using a crossed electron-molecular beam experiment, featuring a skimmed nozzle beam with pyrolytic radical production, absolute elastic cross sections for electron scattering from the CF2 molecule have been measured. A new technique for placing measured cross sections on an absolute scale is used for molecular beams produced as skimmed supersonic jets. Absolute differential cross sections for CF2 are reported for incident electron energies of 30–50 eV and over an angular range of 20–135 deg. Integral cross sections are subsequently derived from those data. The present data are compared to new theoretical predictions for the differential and integral scattering cross sections, as calculated with the Schwinger multichannel variational method using the static-exchange and static-exchange plus polarization approximations

Functional Relationships between Kinetic, Flow, and Geometrical Parameters in a High-Temperature Chemical Microreactor.

Computational fluid dynamics (CFD) simulations and isothermal approximation were applied for the interpretation of experimental measurements of the C10H7Br pyrolysis efficiency in the high-temperature microreactor and of the pressure drop in the flow tube of the reactor. Applying isothermal approximation allows the derivation of analytical relationships between the kinetic, gas flow, and geometrical parameters of the microreactor, which, along with CFD simulations, accurately predict the experimental observations. On the basis of the obtained analytical relationships, a clear strategy for measuring rate coefficients of (pseudo) first-order bimolecular and unimolecular reactions using the microreactor was proposed. The pressure- and temperature-dependent rate coefficients for the C10H7Br pyrolysis calculated using variable reaction coordinate transition state theory were invoked to interpret the experimental data on the pyrolysis efficiency

Pyrolytic formation of polyaromatic hydrocarbons from steroid hormones

Four steroid hormones, namely androsterone, cholesterol, estrone and estradiol, have been pyrolysed at 300, 400 and 500 °C and the pyrolysates from these have been analysed by GC-MS. The results indicate that these formed different products under the pyrolysis and most of them evolved into polycyclic aromatic hydrocarbons during their residence in the pyrolysis chamber at high temperatures. The products from the pyrolysates, at all temperatures, were analysed for similarities and differences using multivariate data analysis. The products possessed some similarities on pyrolysis at 300 °C but were entirely different when pyrolysed at 500 °C. Androsterone and cholesterol formed a higher percentage of substituted PAH than did estrone and estradiol. These compounds included carcinogens, such as phenanthrene, methylphenanthrene, fluorene and its derivatives. The side chain of cholesterol had no effect on the products formed, while the presence of the aromatic ring in estrone and estradiol led to a higher percentage of phenol and its derivatives in the pyrolysates. Furthermore, estrone was subjected to flash pyrolysis and the products formed were compared with those which resulted from the long time pyrolysis: flash pyrolysis produced small amounts of PAH

Laboratory test methods for evaluating the fire response of aerospace materials

The test methods which were developed or evaluated were intended to serve as means of comparing materials on the basis of specific responses under specific sets of test conditions, using apparatus, facilities, and personnel that would be within the capabilities of perhaps the majority of laboratories. Priority was given to test methods which showed promise of addressing the pre-ignition state of a potential fire. These test methods were intended to indicate which materials may present more hazard than others under specific test conditions. These test methods are discussed and arranged according to the stage of a fire to which they are most relevant. Some observations of material performance which resulted from this work are also discussed

Two-stage gasification: fine characterisation of wood chips pyrolysis step in a continuous fixed bed reactor

Two-stage gasification is a proven technology for combined heat and power generation, particularly as it enables the production of a high quality, virtually tar-free gas. In this work, we focused on the pyrolysis step of the process and carried out a parametric study on the effect of temperature and bed height on the yields and quality of the char/gases/tars produced. We used the Continuous Fixed Bed reactor (CFiB) at CIRAD that replicates the pyrolysis zone separately from the rest of the process. At the reactor outlet, char, gases and oils were sampled and analyzed; this enabled mass balance calculations over the whole process and provided relevant information on evolution and composition of pyrolysis products. When the temperature varied from 350 to 600°C, char yield decreased from 40 to 25% wt. while gases yield increased from 9 to 38% wt. Regarding condensates, pyrolytic water remained constant while secondary tars (phenol) increased when increasing pyrolysis temperature. Moreover, a larger bed height seems to favor secondary reactions on pyrolysis condensates, leading to the formation of additional char and gases. (Résumé d'auteur

Pyrolysis of brominated feedstock plastic in a fluidised bed reactor

Fire retarded high impact polystyrene has been pyrolysed using a fluidised bed reactor with a sand bed. The yield and composition of the products have been investigated in relation to fluidised bed temperature. The bromine distribution between the products and a detailed analysis of the oils using GC-FID/ECD, GC-MS, FT-ir, and size exclusion chromatography has been carried out. It was found that the majority of the bromine transfers to the pyrolysis oil and the antimony was detected in both the oil and the char. Oil made up over 89.9% of the pyrolysis products. Over 30% of the oil consisted of benzene, toluene, ethylbenzene, styrene and cumene. The pyrolysis gases were mainly hydrocarbons in the C1-C4 range but some HBr and Br2 was detected