Effect of Porous and Nonporous Carbonaceous Substrates on Polystyrene Thermal Degradation during Fast CO₂ Laser Heating

Abstract

To investigate the effect of porosity on elution of volatiles from a devolatilizing coal particle under pulverized coal combustion (PCC) type heating rate conditions, polystyrene was doped into porous model char (Spherocarb) particles and also coated on the surface of nonporous model char (Glassy Carbon) particles. Particles of approximately 80 µm (( 10 µm) diameter were then individually handpicked. These 80 µm diameter particles were heated to a temperature in the range of 1200-2000 K in 32 ms by means of two converging CO 2 laser beams. The eluted products were analyzed by combined gas chromatography/mass spectrometry (GC/MS). The evolved product information was used to construct yield curves. These yield curves were compared to a simple first-order rate law prediction. It was observed that while the styrene yield profile was predicted satisfactorily in the case of nonporous Glassy Carbon, styrene evolution rates were approximately four times slower than predicted in the case of porous Spherocarb. Also, the ratio of secondary pyrolysis products of polystyrene (benzene, toluene, etc.) to a primary pyrolysis product (styrene) was approximately four times higher in the case of Spherocarb than in the Glassy Carbon case. Both findings strongly suggest the presence of transport limitations in porous Spherocarb under PCC-type heating rate conditions.

Kinetics of the Thermal and Thermo-Oxidative Degradation of Polystyrene, Polyethylene and Poly(propylene)

“…Factor-jump TGA [28] PS Vacuum 187 Isothermal TGA [26] PS Vacuum 205 Isothermal TGA [27] PS Vacuum 198 e) Nonisothermal TGA [31] PS He 322 Nonisothermal TGA [29] PS He 203 Nonisothermal TGA [35] PS He 180 Isothermal TGA [30] PS He 235 Nonisothermal Pyrolyzer [17] PS Air 129 Nonisothermal TGA [31] PS O 2 90 Factor-jump TGA [28] a) Three-step mechanism is assumed. b) Increases with extent of degradation.…”

Kinetic studies of polystyrene using non - isothermal degradation by TGA

“…Also, this observation explained how the problem of selecting and utilizing different analytical technique for thermal degradation of polystyrene will be affected the kinetic results. Authors E, KJ/mol Guoxi,X.,et al (11) 250 Marcilla,A.,et al (12) 203-218 Marcilla,A.,et al (12) 220-277 Dickenes,A.,et al (13) 188 Tripathi,C.L.,et al (14) 322 Lin,R., et al (15) 203 Kuljanin Jakovljevic,J, et al (16) 90-100 don't vary highly than the other methods. These values suggest that the degradation of polystyrene as a single reaction.…”