激光光散射研究丙烯酰胺丙烯酸共聚物的溶液行为

用激光光散射技术研究了丙烯酰胺 丙烯酸共聚物 (简称P(AM AA) )的溶液行为 .结果表明 ,纯水中P(AM AA)分子的流体力学半径Rh的分布存在 10 0～ 5 0 0nm的范围 ,与溶液中的网状结构对应 .当加入NaCl后 ,Rh 分布变窄 ,集中在 10 0nm以下的范围内 ,10 0～ 5 0 0nm这一范围消失 ,说明P(AM AA)在纯水溶液中主要以网状结构存在 ,小分子盐如NaCl的加入会破坏这种网状结构 .网状结构的破坏导致溶液稳定性下降 ,在0 1mol LNaCl溶液中 ,当c c 时 ,放置一段时间后 ,溶液中出现白色絮状沉淀 .

LASER LIGHT SCATTERING STUDY ON SOLUTION BEHAVIOR OF POLY(ACRYLAMIDE-co-ACRYLIC ACID)

Poly(acrylamide co acrylic acid) [P(AM AA)] has attracted many researchers for its special properties and potential applications in enhanced oil recovery (EOR).The network structure of P(AM AA) in aqueous solutions and the behavior in 0^1 mol/L NaCl aqueous solutions were investigated by a combination of static and dynamic laser light scattering techniques.In the hydrodynamic radius ( R h) distribution of P(AM AA) molecules in aqueous solutions,a size range of 100～500 nm,which is coincident with the network structure,is dominant.With the addition of NaCl,the width of hydrodynamic radius distribution decreases,and the radii concentrate in a range below 100 nm.These results provide strong evidence of the existence of network structure in aqueous solutions of P(AM AA). The network structure will be destroyed with the addition of a small amount of salts,such as NaCl,and then the stability of the solution decreases due to the destruction of the network structure.In 0^1 mol/L NaCl aqueous solutions,there exists a critical concentration c *(≈1 34×10 -3 g/mL):when cc *, white flocculent precipitates appear after a period of time.