相转变温度范围窄的聚(N-异丙基丙烯酰胺)温敏性微凝胶

Poly(N-isopropylacrylamide) Temperature-Sensitive Microgels with Narrow Phase Transition Temperature Range

采用间歇式、半间歇式和连续式无皂乳液聚合(SFEP)法合成温敏性聚(N-异丙基丙烯酰胺)(PNIPAM)微凝胶。连续式或半间歇式SFEP法合成的PNIPAM微凝胶相转变温度范围明显地比间歇式SFEP法合成的窄,其中又以连续式SFEP法的效果最明显。相同交联剂用量的情况下,连续式SFEP法合成的PNIPAM微凝胶的粒径和溶胀比最大,而间歇式SFEP法合成的最小。通过研究微凝胶合成过程中溶胀比随反应时间的变化关系,证明了连续式或半间歇式SFEP法合成的PNIPAM微凝胶具有比较均匀的内部交联结构。

Temperature-sensitive poly（N-isopropylacrylamide） （PNIPAM） microgels are synthe- sized by batch, semi-batch or continuous surfactant-free emulsion polymerization （SFEP）. The continuous or semi-batch PNIPAM microgels have narrower phase transition temperature range than batch PNIPAM microgels, among which continuous PNIPAM microgels have the narrowest one. With the same amount crosslinkor, the continuous PNIPAM microgels have the greatest particle size and swelling ratio, while the batch PNIPAM microgels have the smallest ones. The PNIPAM microgels prepared by continuous or semi-batch SFEP have more homogeneous internal crosslinking structure than the ones prepared by batch process, which is confirmed by the measurement of their swelling ratios against reaction time.