沉淀聚合制备单分散聚脲微球及其表征

Preparation of Uniform Polyurea Microspheres through Precipitation Polymerization and Their Characterization

摘要: 以异佛尔酮二异氰酸酯(IPDI)为单体，在水与丙酮或水与乙腈的混合溶剂中通过沉淀聚合制备了单分散聚脲(PU)微球。探讨了单体用量和混合溶剂种类及其配比对微球产率及粒径等的影响，并对静置与振荡两种聚合条件下的聚合过程进行了比较，通过红外和热失重对微球进行了表征。结果表明，微球产率及粒径随单体用量逐渐增加。当水/丙酮质量比及IPDI用量相同时，静置和振荡两种聚合方式下所得微球的产率基本相同，但在保证所制备微球高度单分散的前提下，静置聚合条件下能够允许的单体加入量比振荡时高，而且所得微球的单分散性更好。在静置聚合条件下以水和丙酮为溶剂制备单分散微球时，单体用量最高为11.0%，微球产率为88.5%；而在水和乙腈混合溶剂中制备单分散微球时，IPDI用量最高可达21.0%，微球产率为93.1%，比在水丙酮中聚合时的微球产率明显提高。红外和热失重检测显示，所得微球富含胺基，且微球聚合物具有较高的热稳定性。

Abstract: Uniform polyurea (PU) microspheres were prepared through precipitation polymerization using isophorone diisocyanate (IPDI) as the only monomer in mixed solvent of water-acetone (H2O-AT) or water-acetonitrile (H2O-AN) under shaking or with a quiescent process. The effects of IPDI loading, H2O/AT and H2O/AN mass ratio on the formation of PU microspheres were studied, and the properties of the microspheres obtained were tested. The results showed that the yield and size of the microspheres increased with the amount of IPDI added. The yield of the microspheres obtained was basically the same under shaking or quiescent process, while higher IPDI loading with better uniformity of the microspheres was achieved under the quiescent process. To get uniform PU microspheres in H2O-AT mixture under the quiescent condition, the maximal IPDI loading was 11.0 wt% with the yield of the microspheres of 88.5%. With acetone replaced by acetonitrile, the maximal IPDI loading reached 21.0% combined with a yield of 93.1%, a significant increase in the productivity of the microspheres in comparison with the yield obtained by polymerization in H2O-AT mixture. Infrared and thermo gravimetric data showed that the PU microspheres were rich in amine groups, and of higher thermal stability.