【摘要】 采用沉淀聚合法合成了不同共聚组成的亚微米级N-异丙基丙烯酰胺-丙烯酰胺(NIPA-AM)共聚物水凝胶粒子,利用光子相关光谱(PCS)技术测定其在水中的温敏相变行为.结果表明,随着亲水性单体丙烯酰胺摩尔分数的增大,水凝胶粒子粒径增大.考虑交联剂交联效率和物理交联作用的影响,修正了Flory-Rehner弹性理论,并结合Choi混合自由能理论模型,提出了一种水凝胶体积相变热力学理论模型.模型计算结果与试验结果吻合很好,说明该模型能够准确预测共聚水凝胶的温敏溶胀行为.更多还原

【Abstract】 Submicron-sized N-isopropylacrylamide-acrylamide(NIPA-AM) copolymer hydrogel particles with various compositions were prepared by precipitation polymerization in water.Their swelling behavior at different temperature was determined by photon correlation spectroscopy(PCS).The results showed that the average diameter of the hydrogel particles increased with increasing molar ratio of AM in feed.In the model development,the Flory-Rehner theory was modified by considering the elastic contribution of physical crosslinking and the crosslinking efficiency,and the extended Choi theory was applied for the free energy of the mixing term.Comparison of the model calculation results with the experimental swelling data indicates that the model can predict fairly well the swelling behaviors of the thermosensitive gel particles.更多还原