Studies on Thermal Polymerization of Acrylamide

Thermal polymerization of acrylamide has been followed by the DSC technique, and the activation energy (E) values at different stages of the fraction polymerized (a) have been determined from the exotherm of the thermograms obtained. The trend of variation of E with agr shows that E remains constant up to agr = 0.5 and decreases with a further increase in agr. A close look at the composite nature of the exotherms, agr-t, and agr-T curves shows that the polymerization of acrylamide involves two processes. The first process is the formation of linear polyacrylamide and the second is the simultaneous cross-linking of the linear chains together with the formation of linear polyacrylamide. Experiments such as NH3 detection by differential thermal analysis techniques and annealing studies have been made to shed further light on the polymerization process.

Kinetics of thermal decomposition of barium zirconyl oxalate

Kinetics of the thermal decomposition of anhydrous barium zirconyl oxalate and a carbonate intermediate have been studied. Decomposition of the anhydrous oxalate, though it could be explained based on a contracting-cube model, is quite complex. Kinetics of decomposition of the intermediate carbonate Ba2Zr2O5CO3 is greatly influenced by thermal effects during its formation. (agr-t) curves are sigmoidal and obey a power law equation followed by first order decay. Presence of carbon in the vacuum-prepared carbonate has a strong deactivating effect. Decomposition of the carbonate is accompanied by growth in particle size of the product barium zirconate.

Thermal decomposition of ethyl and isopropyl amine perchlorates

Thermal decomposition of ethyl and isopropyl amine perchlorates has been studied by methods such as DTA, TG, isothermal weight loss measurements and the decomposition products have been analyzed in a mass spectrometer. Activation energy values for thermal decomposition have been calculated fromagr-t plots. The proton transfer dissociation mechanism proposed for the thermal decomposition of ammonium perchlorate (AP) has been extended to explain the decomposition products of these twosubstituted amine perchlorates.