聚(丙烯酸-丙烯酰胺)的溶胀动力学

采用实验方法研究了不同交联剂用量的高吸水剂聚(丙烯酸-丙烯酰胺)(P(AA-AM))在去离子水、质量分数为0.9%和3 0%的 NaCl 水溶液中的溶胀动力学。实验结果表明,P(AA-AM)的溶胀动力学符合二次速率方程,并得到脱水动力学模型常数。随交联剂用量的增加,P(AA-AM)的平衡溶胀度(Q_e)降低,而溶胀速率(k_s)提高;随介质中 NaCl 含量的增加,Q_e 显著降低,而 k_s增大。NaCl 水溶液中的溶质和溶剂一起被 P(AA-AM)吸收,P(AA-AM)在 NaCl 水溶液中与在去离子水中的吸收机理相同。P(AA-AM)溶胀凝胶的脱水动力学常数很小,保水能力良好,而且随交联剂用量的增加和环境温度的降低,保水能力增强。

Swelling Kinetics of Poly (Acrylic Acid-Acrylamide)

The swelling kinetics of superabsorbent resin poly(acrylic acid-acrylamide)(P(AA- AM))in deionized water and in NaCl aqueous solutions(NaCl 0.9%,3.0% mass fraction)were studied.Swelling kinetics conforms to second-order rate equation.Constants of dewatering kinetics were also obtained.The equilibrium swelling ratio(Q_e)of P(AA-AM)decreases with increase of used crosslinking agent concentration.The swelling rate constant(k_s)changes contrarily,Q_e drops markedly with raising of concentration of NaCl aqueous solution,however,k_s increases.It was proved that the swelling mechanisms are identical both in deioniszed water and NaCl aqueous solution. Dewatering rate constant of P(AA-AM)is very small,which indicates P(AA-AM)is good in water- preserving.The water-preserving improves with the increase of the used crosslinking agent concentration and the lowering of environment temperature.The phenomena can be easily understood on base of dewatering kinetic mechanism.