自由基聚合氧化还原引发体系的分解速率常数

探讨了过硫酸盐与亚硫酸盐组成的氧化还原引发体系在水溶性单体丙烯酰胺溶液聚合中的引发作用,观察到在相同聚合条件下不同摩尔比时,聚合反应速率有明显差异。实验结果表明:氧化还原引发体系中氧化剂与还原剂的摩尔比对分解速率常数值有明显影响,从而影响聚合速率,在30℃下当SO₃^2-与S₂O₈^2-摩尔比为6.7∶10时,分解速率常数和聚合速率达到最大。从引发速率及分解速率常数方面进行了理论分析,找出了其分解速率常数的变化规律,给出了分解速率常数值的范围,并认为氧化还原引发体系的分解速率常数随其摩尔比的变化而变化,是催化因素的影响。

DECOMPOSITION RATE CONSTANT OF OXIDATION REDUCTION INITIATION SYSTEMS IN FREE RADICAL POLYMERIZATION

The initiation reaction of sulfite (SO₃^2-) and persulfacte (S₂O₈^2-) system in acrylamide polymerization has been studied in this paper. Results has indicated that the mole ratio of reductant to oxidant in initiation system influences remarkably on the decomposition rate constant and the polymerization rate. When the mole ratio of SO₃^2- to S₂O₈^2- is 6.7/10 at 30℃, the decomposition rate constant of initiation system and the polymerization rate of acrylamide have reached their maximums respectively. The law that the decomposition rate constant changes with the mole ratio of reductant to oxidant in the initiation system has been discovered. The range of value of the decomposition rate constant has been presented. The catalysis was considered as a reason that the decomposition rate constant changes with the mole ratio of reductant to oxidant in initiation system.