部分水解聚丙烯酰胺在水溶液中的氧化降解Ⅰ.温度的影响

OXIDATIVE DEGRADATION OF PARTIALLY HYDROLYZED POLYACRYLAMIDE IN AQUEOUS SOLUTIONⅠ. INFLUENCE OF TEMPERATURE

研究了不同条件下 ,部分水解聚丙烯酰胺 (HPAM)在水溶液中的化学降解作用 ,在氧存在时 ,HPAM溶液的稳定性下降 ,溶液粘度的损失随温度升高而加剧 ,相反 ,在脱氧条件下 ,溶液粘度发生轻微的上升。实验结果表明 ,HPAM在水溶液中的化学降解作用 ,主要包括氧化作用和水解作用两种反应。在无多价金属离子存在条件下 ,溶液粘度的降低主要由于氧化降解作用 ,它引起聚合物链断裂使聚合物分子量降低的结果。 HPAM在水溶液中的氧化降解反应活化能测得为 3 8k J mol,并提出了 HPAM在水溶液中的氧化降解的自由基连锁氧化机制。

Chemical degradation of HPAM in aqueous solutio was studied in different condition. A remarkable decrease in the solution viscosity of HPAM polymer was observed in the presence of O 2, and becomes more extensively at elevated temperatures. In contrast the viscosity of HPAM solution slightly increases in the oxygen free condition. The chemical degradation of HPAM involves two main reactions: oxidation and hydrolysis. It was evidenced that in the absence of multi valent metal ions the significant reduction of solution viscosity is mainly attributable to the oxidative degradation which results in chain scission and decrease of molecule weigth. The active energy of oxiditive degradation for HPAM in aqueous solution was determined to be 38 kJ/mol and the radical chain oxidation reaction mechanism was also suggested.