分散聚合法合成聚（N-异丙基丙烯酰胺）温敏性微凝胶

以PVP为稳定剂,在水或醇/水介质中通过分散聚合法合成出聚（N-异丙基丙烯酰胺）（PNIPAM）温敏性微凝胶。研究结果表明,可通过改变稳定剂用量和分散介质极性来控制PNIPAM微凝胶的大小,这两种因素对PNIPAM微凝胶的溶胀比有明显的影响,而对其相转变行为影响不大;交联剂用量对PNIPAM微凝胶的粒径、溶胀比和相转变行为都有比较明显的影响。PNIPAM微凝胶可能主要通过接枝共聚物聚结机理成核,通过初级粒子之间的聚并完成粒子增长过程。

Synthesis of poly(N-isopropylacrylamide)(PNIPAM)microgels by dispersion polymerization

Temperature-sensitive poly(N-isopropylacrylamide)(PNIPAM)microgels were synthesized by dispersion polymerization in the presense of poly(N-vinylpyrrolidone)as stabilizer and water or alcohol/water mixture as dispersion medium.The results indicated that the particle size and swelling ratio of the PNIPAM microgels can be controlled by changing the amount of the stabilizer and the polarity of the medium,but their phase transition behavior was not influ- enced by the two factors.The particle size,swelling ratio and phase transition behavior of the PNIPAM microgels were markedly influenced by the amount of crosslinker used.It was speculated that the PNIPAM mierogel nucleus may be formed by graft copolymer coalescence mechanism,and their growth were conducted by the aggregate between the primary PNIPAM particles.