TG/DTA/MS of poly(methyl methacrylate), The Role of the Oxidative Environment

Degradation of relatively large particle size, 0.5 mm of Type-G PMMA (Rohm and Haas) were conducted with thermogravimetric analysis and evolved gas measurements using quadrupole mass spectrometer under conditions of mass transport limitation. In addition, differential thermal analysis was performed in order to furnish information with regards to exothermic or endothermic reactions associated with the degradation. The tests were conducted in an inert environment of pure N₂ and oxygenated environment. The results indicated one step degradation process in pure N₂ and the degradation process is endothermic. As the O₂ fraction increases the degradation process is transformed to exothermic. This revised version was published online in July 2006 with corrections to the Cover Date.     

TG/DTA/MS of Poly(Methyl Methacrylate), The Effect of Particle Size

Thermogravimetric analysis in conjunction with evolved gas analysis are discussed for powder PMMA, particle diameter of 0.1 mm. Furthermore, differential thermal analysis measurements were performed in both pure nitrogen and oxidative environment. These measurements are conducted to assess major differences associated with particle size. The results indicated for powder PMMA, in pure nitrogen the degradation can be described as three-step reactions, while in oxidative environment it is two-step reactions. Furthermore the reaction in both environments are mainly endothermic. This in contrast to results reported for industrial-grade PMMA with relatively larger particle size of 0.5 mm. This revised version was published online in July 2006 with corrections to the Cover Date.     

TG/MS of Poly (Methyl Methacrylate), The Effect of Heating Rate on the Rate of Production of Evolved Gases

Thermogravimetric analysis coupled with quadrupole mass spectrometry was performed to study the effects of heating rate on the rate of gasification of gases evolving from 0.5 mm particles size industrial-grade PMMA. The controlled mass loss measurements and the evolved gases were conducted in pure nitrogen and various oxidative environments under heating rates of 2 to 5°C min^-1. The results indicated major differences, in pure nitrogen, the rate of production of gases is steeper compared to those associated with oxidative environment. Furthermore as the heating rate is lowered, it appears that the gases emanating from the surface are more volatile in the sense that they burst more abruptly from the surface. This revised version was published online in August 2006 with corrections to the Cover Date.