THERMOGRAVIMETRIC STUDY OF POLYACRYLAMIDE WITH EVOLVED GAS-ANALYSIS

Dried samples of polyacrylamide in an He atmosphere have been subjected to thermogravimetric analysis in the 30-600-degrees-C range, and the evolved gases were monitored by FTIR. Water, ammonia, and small quantities of carbon dioxide are released in the first stages of decomposition (220-340-degrees-C), where the polymer chains remain intact and the reaction occurs on the pendant amide groups. In the second stage of decomposition (340-440-degrees-C), the majority of the weight loss occurs, and main chain breakdown occurs, releasing carbon dioxide, water, nitrile compounds, and imides. Trapping of the gases in this stage and analysis by GC-FTIR and GC-MS reveals the presence of more than 20 decomposition products, and confirms that a large proportion of these can be assigned to glutarimide and its substituted analogs. Imidization and dehydration reactions on the amide groups, as well as free radical breakdown of the main chains, with inter- and intramolecular hydrogen transfer, can account for many of the products of the decomposition.