ABSTRACT

Covalent crosslinking can improve the water resistance of waterborne polyurethanes (WPUs), but the preparation time of WPUs will be greatly extended by the crosslinking process, and the long-term storage stability of WPU emulsions will decrease because the crosslinked molecular chains cannot disperse in any organic solvents or water. In this paper, a crosslinked WPU was prepared through a post metal-organic crosslinking toward a conventional linear WPU. This post crosslinking is quite fast since it is based on the ionic bond interaction between metal cations and organic anions. The crosslinked WPU emulsion has narrow particle size distribution and small average size, giving rise to excellent long-term storage stability. Additionally, the water absorptions of the crosslinked WPU at 25°C and 60°C are 6.3% and 8.6% respectively, which decrease by 47.9% and 39.4% compared with those of the linear counterpart, indicating that the post metal-organic crosslinking highly improves the water resistance of the WPU. The mechanical strength of the crosslinked WPU also improves compared with the linear WPU.

摘要

共价交联可以提高水性聚氨酯（WPUs）的耐水性，但交联过程会大大延长WPUs的制备时间，并且由于交联的分子链不能分散在任何地方，WPU乳液的长期储存稳定性会降低。有机溶剂或水。在本文中，通过对传统线性 WPU 进行后金属有机交联来制备交联的 WPU。这种后交联非常快，因为它基于金属阳离子和有机阴离子之间的离子键相互作用。交联的 WPU 乳液粒径分布窄，平均粒径小，具有优异的长期储存稳定性。此外，交联的 WPU 在 25°C 和 60°C 的吸水率分别为 6.3% 和 8.6%，降低了 47。与线性对应物相比分别提高了9%和39.4%，表明后金属有机交联极大地提高了WPU的耐水性。与线性 WPU 相比，交联 WPU 的机械强度也有所提高。